STRUCTURAL AND OPTICAL PROPERTIES OF LOW …€¦ · The 3D halide perovskites structure is a class...

UNIVERSIDADE FEDERAL DO CEARAacute

CENTRO DE CIEcircNCIAS

DEPARTAMENTO DE FIacuteSICA

PROGRAMA DE POacuteS-GRADUACcedilAtildeO EM FIacuteSICA

MAYRA ALEXANDRA PADROacuteN GOacuteMEZ

STRUCTURAL AND OPTICAL PROPERTIES OF LOW

DIMENSIONAL LEAD HALIDE PEROVSKITES

FORTALEZA-CE

2018

2


STRUCTURAL AND OPTICAL PROPERTIES OF LOW DIMENSIONAL

LEAD HALIDE PEROVSKITES

Msc thesis presented to the Post-Graduation

Course in Physics of the Federal University of

Cearaacute as part of the requisites for obtaining the

Degree of Master in Physics

Advisor Prof Dr Alejandro Pedro Ayala

FORTALEZA

2018

3

4




Dissertaccedilatildeo de mestrado apresentada ao Programa

de Poacutes-Graduaccedilatildeo em Fiacutesica da Universidade

Federal do Cearaacute como requisito parcial para

obtenccedilatildeo do Tiacutetulo de Mestre em Fiacutesica Aacuterea de

concentraccedilatildeo Fiacutesica da Mateacuteria Condensada

Aprovada em 20082018

BANCA EXAMINADORA

___________________________________________________________

Prof Dr Alejandro Pedro Ayala (Orientador)

Universidade Federal do Cearaacute (UFC)

___________________________________________________________

Prof Dr Carlos William de Arauacutejo Paschoal


___________________________________________________________

Prof Dr Maacuterio Ernesto Giroldo Valerio

Universidade Federal de Sergipe (UFS)

5

Acknowledgements

I am very grateful to my advisor Prof Dr Alejandro Pedro Ayala for having accepted me as your

student and having proposed me this project Thank you for your patience dedication and advices

Also for the opportunity to work in your group and learn from you

I like to thank the members of the Jury Prof Dr Carlos William Paschoal and Prof Dr Maacuterio

Ernesto Giroldo Valerio for comments and corrections that made possible this final work My

appreciation also goes to the Prof Dr Alexandre Paschoal and Prof Dr Paulo de Tarso because

with their experience they helped me during the analysis of the techniques involved in this

investigation

Many thanks to Cristiano and Enzo for the help in the measurements of Raman and SNOM

A special acknowledgment to Bruno Wellington e Fabio for the arduous hours we work making

measurements and analysis of Raman and Photoluminescence thank you for your company

I would like to express my appreciation to the members of LabCrEs for their company friendship

and support every day thanks for made the work environment more enjoyable

I very gratitude with the Central Analiacutetica of the UFC for the collaboration in the measurements of

microscopy and EDX

I would like to thank my family for all the support To my parents my brothers my uncles my

cousins my parents in law and friends Despite the distance they have always supported me

Thanks Juan for always be there and be my partner friend boyfriend colleague and believe in me

in the days that I did not Thank you for being the person who makes happy my days and

accompany me in this goal that we proposed to reach together I love you

Thanks to the UFC and Pos-Graduation for give me the opportunity of study Finally I would like

to thanks CAPES for the financial support

6

Abstract

The study of perovskites in last few years has grown exponentially and made then one of the

trending topic in materials science The lead-based family of perovskites are important for their

multiple applications as strong photoluminescence narrow emission line width and high exciton

binding energy Hybrid organic-inorganic perovskites are being widely explored for their

optoelectronic properties few of these materials exhibit broadband emission under ultraviolet

excitation In this work we were synthesized using the slow evaporation method five single

crystals of lead halide perovskites three of them are low dimensional hybrid lead perovskites

(DMA)11Pb4Br19 (DMA)14RbPb4Br23 and (DMA)9S4Pb5Br27 all compounds exhibit a novel crystal

structure Additionally we discuss the behavior of CsPb2Br43I07 and Cs4PbBr6 also low

dimensional compounds under high pressure investigated using Raman and photoluminescence

techniques Several structural phase transitions were identified on this compounds

Keywords Halide perovskites crystallography Raman spectroscopy hydrostatic pressure

7

Resumo

O estudo das perovskitas nos uacuteltimos anos cresceu exponencialmente e tornou-se um dos temas

dominantes na ciecircncia dos materiais A famiacutelia de perovskitas baseadas em chumbo eacute importante

pelas suas muacuteltiplas aplicaccedilotildees como forte fotoluminescecircncia estreita largura de linha de emissatildeo

e alta energia de ligaccedilatildeo de excitons Perovskitas hiacutebridas orgacircnicas e inorgacircnicas estatildeo sendo

amplamente exploradas por suas propriedades optoeletrocircnicas alguns destes materiais exibem uma

banda de emissatildeo larga quando excita no ultravioleta Neste trabalho foram sintetizados utilizando

o meacutetodo de evaporaccedilatildeo lenta cinco monocristais de perovskitas de haleto de chumbo sendo trecircs

perovskitas hiacutebridas de baixa dimensionalidade (DMA)11Pb4Br19 (DMA)14RbPb4Br23 e

(DMA)9S4Pb5Br27 todos os compostos exibem novas estruturas cristalinas Adicionalmente

discutimos o comportamento de CsPb2Br43I07 e Cs4PbBr6 tambeacutem compostos de baixa

dimensionalidade investigados a alta pressatildeo usando as teacutecnicas de Raman e fotoluminescecircncia

Vaacuterias transiccedilotildees de fase estruturais foram identificadas nestes compostos

Palavras-chave Perovskitas de haleto cristalografia Espectroscopia Raman pressatildeo

hidrostaacutetica

8

List of Figures

Figure 1 Typical structures of 3D 2D 1D and 0D perovskites (red spheres metal centers green spheres

halide atoms blue spheres nitrogen atoms gray spheres carbon atoms orange spheres oxygen atoms

purple polyhedrons metal halide octahedra hydrogen atoms are hidden for clarity) as well as their

corresponding conventional materials with different dimensionalities 2D 1D and 0D perovskites can

therefore be considered as bulk assemblies of 2D quantum wells 1D quantum wires and 0D

moleculesclusters12 13

Figure 2 Single crystal diffractometer Bruker D8 VENTURE 23

Figure 3 LabRam HR 800 HORIBA 25

Figure 4 Scanning Electron Microscopy (SEM) QUANTA FEG 450 26

Figure 5 View of (a) crystal unit structure of (DMA)11Pb4Br19 at room temperature along the a b and c

axis and (b) 1x2x2 bounding octahedrons 28



Figure 7 View of (a) crystal unit structure of (DMA)9S4Pb5Br27 at room temperature along the a b and c


Figure 8 Line 1 (DMA)11Pb4Br19 morphology Line 2 sum of composition element map and each

element map and Line 3 Spectrum map sum for all constituent element in (DMA)11Pb4Br19 perovskite

34

Figure 9 CsPb2(Br085I015)5 unit cell 36

Figure 10 CsPb2Br426I074 single crystal EDX Images 37

Figure 11 Representative unpolarized Raman spectrum of CsPb2(Br085I015)5 at room pressure 38

Figure 12 a) Pressure dependent Raman spectrum of CsPb2(Br085I015)5 b) Pressure dependent phonon

positions 39

Figure 13 Pressure dependent a) PL spectra b) PL intensity and c) PL emission center 41

Figure 14 Raman spectrum of Cs4PbBr6 0D-Perovskite single crystal observed at room temperature and

pressure The red continuous line represents the result of the decomposition of the spectrum with a set of

Lorentzian line profiles (blue lines) which are also shown in the figure 44

Figure 15 (a) Raman spectra measurements of Cs4PbBr6 0D-PRS single crystal under high pressure

conditions up to 1085 GPa Several pressure-induced phase transitions are observed (b)Wavenumber vs

pressure plots of the Raman modes observed in the Cs4PbBr6 crystal for compression experiments The

vertical lines indicate the pressures at which Cs4PbBr6 undergoes phase transitions 46

Figure 16 (a) Photoluminescence spectra of Cs4PbBr6 as a function of pressure (b) PL emission center

and intensity 47

9

List of tables

Table 1 Relationship between the crystal structure and Goldschmidt tolerance factors (t) 15

Table 2Effective Radii of Molecular Cations and Anions 17 16

Table 3 Reported crystal parameters for each novel hybrid perovskites 32

Table 4 Distribution of vibrational modes based on group theory analysis for tetragonal CsPb2(Br085I015)5

38

Table 5 Wyckoffs site positions of the atoms in the Cs4PbBr6 single crystal 42

Table 6 Correlation table for Cs4PbBr6 The degrees of vibrational freedom for a given site species γ is

given by the symbol 119891120574 The translational and rotational degrees of freedom of the (PbBr6)4minus octahedra

become translational and vibrational lattice modes in the crystal 43

10

List of abbreviations

XRD X-ray diffraction

SEM Scanning electron microscopy

PL Photoluminescence

EDX Energy-dispersive X-ray spectroscopy

PCE Power conversion efficiency

DMA Dimethylammonium

11

Contents

Introduction 12

Cesium-Lead-Halide Perovskites 17

Chapter 1 20

Experimental Section 20

Materials 20

Synthesis procedures 20

Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21

Single-crystal X-ray diffraction 22

Raman spectroscopy 24

Scanning Electron Microscopy (SEM) 25

Chapter 2 27

New Family of Lead Hybrid Perovskites 27

Chapter 3 35

CsPb2Br5I under High-pressure 35

Chapter 4 42

Pressure-Induced enhanced photoluminescence and Raman scattering study of the zero

dimensional Cs4PbBr6 lead halide perovskite 42

Conclusions 49

References 52

12

Introduction

In recent years perovskites emerged as a highly promising solution as materials for last

generation applications(YIN et al 2017a) There has been a large interest from technological point

of view because perovskites exhibit distinctive electric magnetic and optical properties(TILLEY

2016) These compounds have emerged as promising materials in diverse fields such as

optoelectronic devices photovoltaic devices and photodetectors According to data extracted from

Web of Science the number of publications in the last few years has grown exponentially which

made then one of the hot topics in materials science(LE et al 2018)

The perovskite structure has the chemical formula ABX3 where A-site have cube-octahedral

symmetry B-site ions are coordinated (surrounded) by an octahedron of X type ions The relative

ion size requirements for stability of the perovskite structure are quite stringent and distortion can

produce several low-symmetry distorted structures in which the coordination numbers of A

cations B cations or both are reduced (LI et al 2018)

One of the areas of approach of the perovskitas is solar cells(GRAumlTZEL 2014) This application

is a clean alternative to the current methods of generating energy so it is immensely important for

the preservation of the global environment(GRAumlTZEL 2001 ZHANG YIN 2018) Devices using

these materials have recently increased the efficiency up to 227 in solar cells with single-

junction architectures placing these compounds on the list of promising emerging

materials(AKIHIRO KOJIMA et al 2009)

The 3D halide perovskites structure is a class of bulk materials that consist of a framework of

corner-sharing metal halide octahedra that extends in all three dimensions with small cations fitting

into the unoccupied spaces between the octahedra the chemical formula for 3D perovskites is

ABX3 (LIN et al 2018) Perovskite materials exhibit many interesting and intriguing properties

from both the theoretical and the application points of view so many different properties are

commonly observed features in this family These compounds are used as sensors catalyst

electrodes and photovoltaic cells(HAO et al 2014) The perovskites used in solar cell applications

are denominated ldquoHalide perovskitesrdquo because in these compounds X is a halide element (F Cl

Br or I) This type of compounds attracts notable attention due to its high efficiency(LI et al

2017b) They have excellent optoelectronic properties fault tolerance sharp band edge and tunable

13

band range across the visible and near-infrared range(SALIBA et al 2018) Usually in solar cell

applications halide perovskites are commonly used as thin films but it is important to know how

their physical characteristics are defined by their crystalline structure A simple way for

understanding the properties of the organometallic halide perovskite family is classifying them by

the spatial arrangement of the halide octahedral units (MX6) as structures three-dimensional (3D)

two-dimensional (2D) one-dimensional (1D) and zero-dimensional (0D)(HUANG et al 2017

LIN et al 2018) The relationship between this spatial arrangement is shown in Figure 1

Figure 1 Typical structures of 3D 2D 1D and 0D perovskites (red spheres metal centers green

spheres halide atoms blue spheres nitrogen atoms gray spheres carbon atoms orange spheres

oxygen atoms purple polyhedrons metal halide octahedra hydrogen atoms are hidden for

clarity) as well as their corresponding conventional materials with different dimensionalities 2D

1D and 0D perovskites can therefore be considered as bulk assemblies of 2D quantum wells 1D

quantum wires and 0D moleculesclusters(LIN et al 2018)

The 2D and quasi-2D perovskites structures considered as sheets or layers ripped in a specific

crystallographic direction from the 3D perovskites In particular corrugated 2D perovskites consist

of twisted sheets ripped along a crystallographic direction Metal halide layers are connected by a

perovskites ligand The general chemical formula of 2D perovskites is An-1A2BnX3n-1 and are

14

known as RuddlesdenminusPopper-type perovskites(HUANG et al 2017 SOE et al 2017) In 1D

perovskites the metal halide octahedra are corner-sharing edge-sharing or face-sharing to form a

1D nanowire surrounded by cations Their configurations could be either linear or zigzag and their

chemical formulas are variable depending on the connecting methods and the chosen

cations(ZHANG et al 2018a) For 0D hybrid perovskites the octahedra is isolated in the structure

These molecular perovskite units are periodically distributed in crystal lattice together with cations

to form bulk materials The general chemical formula is A4BX6 (HUANG et al 2017 LIN et al

2018 SOE et al 2017 ZHANG et al 2018a) Finally due to the strictly periodical spatial

arrangement of these metal halide structures and the packing of the species around them 2D 1D

and 0D perovskites can therefore be considered as bulk assemblies of 2D quantum wells 1D

quantum wires and 0D moleculesclusters which are structurally different from morphological 2D

nanosheetsnanoplatelets 1D nanowiresnanorods and 0D nanoparticles based on 3D

ABX3(HUANG et al 2017 LIN et al 2018 SOE et al 2017 TSAI et al 2018 ZHANG et al

2018a)

As it has been shown the diversity of structures and properties of the perovskite-related

compounds is consequence of the different anions and cations can occupy the characteristic atomic

position of this family For example a wide spectrum of potential applications was proposed by

substituting the A cation for an organic molecule the new family of organic-inorganic perovskites

is called ldquoHybrid perovskitesrdquo They have recently received extraordinary attention from the

research community because provides new applications in photoluminescence and electric

conductivity(BAYRAMMURAD SAPAROV AND DAVID B MITZI 2016) One of the most

interesting properties of hybrid perovskites is the improvement of the fast power conversion

efficiency that this material has achieved in the solar cell field

Among the methylammonium hybrid halides studied so far the most common is the

methylammonium lead triiodide (CH3NH3PbI3) It has a high charge carrier mobility and charge

carrier lifetime that allow light-generated electrons and holes to move far enough to be extracted

as current instead of losing their energy as heat within the cell Also has effective diffusion lengths

for both electrons and holes The compound CH3NH3PbI3 using an organic sensitizer increments

the efficient of photovoltaic devices from 4 to 23 in last year which is the current cell

efficiency record at this moment(ALBERO ASIRI GARCIacuteA 2016)

15

The crystal structure is another big different part in halide perovskites for that reason is

important to pay attention to the close packing of these compounds Thus it is useful to consider

the Goldschmidt tolerance factor concept(BAYRAMMURAD SAPAROV AND DAVID B

MITZI 2016) namely ldquotrdquo as t=(RA+RX)(radic2(RB+RX)) where RA RB and RX are the ionic radii of

cation (A) the anion (B) and halogen (X) this expression is significant because it shows the

stability and distortion in perovskites Alternatively the tolerance factor can be used to calculate

the compatibility of an ion with a crystal structure The relationship between the perovskite crystal

structure and tolerance factors (t) is shown in Table 1 while Table 2 lists the effective radius for

organic cations used to synthesize hybrid perovskites

Table 1 Relationship between the crystal structure and Goldschmidt tolerance factors (t)

Goldschmidt tolerance

factors

Structure Explanation

gt 1 Hexagonal or tetragonal A ion too big or B ion too

small

09-1 Cubic A and B ions have ideal

size

071-09 OrthorhombicRhombohedral A ions too small to fit into

B ion interstices

lt 071 Different structures A ions and B have similar

ionic radii

16

Table 2Effective Radii of Molecular Cations and Anions (BAYRAMMURAD SAPAROV AND

DAVID B MITZI 2016)

Even though the big impact that actually has the lead hybrid perovskites area it is important to

study all inorganic metal halide materials because they have attracted a great deal of attention over

the recent years to their ideal band gap high photoluminescence and narrow emission linewidth

Therefore we focus on the structure and properties of the Cesium-Lead-Halide perovskites family

17

Cesium-Lead-Halide Perovskites

Perovskites with different cesiumndashleadndashbromide stoichiometry (CsndashPbndashBr) and diverse

crystalline structures are promising candidates for new generation low-cost visible LEDs due to

their efficient emission easy production and tunability As an all-heavy-element-composed system

the CsndashPbndashBr family has similar formation energies for its variable coordination structural

phases(ZHANG et al 2018d) The advantages of this class of compounds include the versatility

of their chemical and crystallographic structures and consequently their physical properties As

stated due to the growing interest in the use of inorganic halide perovskites different synthesis

methods have been in development for years giving rise to several new compositions based on Cs-

Pb-Br This group of elements forms a 3D arrangement with chemical formula CsPbBr3 The

characteristics of this compound are the outstanding photoluminescence and optoelectronic

properties(DIROLL et al 2017 KOVALENKO PROTESESCU BODNARCHUK 2017) This

material crystallizes in the orthorhombic (Pnma) space group adopting a distorted perovskite

structure as determined by single-crystal diffraction at room temperature In this structure

PbBr64minus octahedra are tilted with respect to the conformation of the ideal perovskite

structure(STOUMPOS et al 2013a)

However under operating conditions these 3D perovskites suffers phase transformation and

instability including surface hydration and ion migration thus their reduced-dimensionality

counterparts are being increasingly investigated especially for optoelectronic applications These

new phases are related to CsPbBr3 perovskite because they have the same element constitution but

with low dimensions Different synthesis conditions made bulk single crystals members with 0D

and 2D halide structures with compositions Cs4PbBr6 and CsPb2Br5 respectively(FRANCISCO

PALAZON SEDAT DOGAN SERGIO MARRAS FEDERICO LOCARDI ILARIA NELLI

PRACHI RASTOGI MAURIZIO FERRETTI MIRKO PRATO 2017)

The first member of the CsndashPbndashBr family is the 0D structure with the Cs4PbBr6 composition In

this case the octahedra PbBr64minus are completely isolated from each other and surrounded by

cations this leads to strong quantum confinement and strong excitonminusphonon interactions This

octahedron has the same coordination that the one in CsPbBr3 perovskite Cs4PbBr6 compound

crystallizes in a trigonal system with lattice parameters a =137130(4) Aring c=173404(7) Aring with the

18

space group of R3c also has a band gap of Eg=3953 eV (LIU et al 2017) Early works on 0D

perovskites focused mainly on their fundamental optical absorption and photoluminescence

properties and attempted to distinguish their emission properties from those of 3D-like compounds

These studies have demonstrated that like 3D (CsPbBr3) perovskites the optical characteristics of

Cs4PbBr6 are determined by transitions between electronic states of the Pb2+ ions and their

photoluminescence results from the radioactive decay of Frenkel-type excitons at Pb2+ sites (YIN

et al 2017b) Also the zero-dimensional composite have been speculated as efficient solid-state

emitter with strong green photoluminescence by achieving quantum confinement the origin of this

study luminescence comes from PbBr64minus itself (WANG et al 2017 ZHANG et al 2017)

The other compound CsPb2Br5 this family is a ternary halogen-plumbate with close

characteristics to well-reported halide perovskites Due to its unconventional two-dimensional

structure is often obtained as secondary product during the synthesis of CsPbBr3

perovskites(TSAI et al 2016) It is important to point out that unlike CsPbBr3 that requires high

temperature for the synthesis CsPb2Br5 can be prepared easily at room temperature which is very

attractive for future applications (LI et al 2017a)

The compound CsPb2Br5 crystallizes in (I4mcm) space group and is composed of two-

dimensional layers of Pb2Br5- spaced by an isolated Cs+ cations as a consequence it is

classified as a 2D material The crystal packing of this kind of materials is characterized by layered

or corrugated sheets separated by long cations While previous reports agree on its structure and

composition they greatly diverge on the interpretation of its intrinsic optical properties which

nowadays is a subject of controversy For example there is a debate about the exact value of the

indirect band gap which was reported to be between 25 and 31 eV(DURSUN et al 2017 TANG

et al 2018) Also CsPb2Br5 exhibits a high photoluminescence being an efficient green light-

emitter with a peak located around 520 nm the emission mechanism is also a subject of

discussion(LV FANG SHEN 2018) However this compound has been investigated for potential

applications in optoelectronics

Even though several properties of the described 2D and 0D perovskites have not been yet

investigated for example the behavior of these compounds under critical conditions as pressure

and temperature Considering the growing demand to develop miniaturized and integrated

incoherent light sources it is imperative to advance in the understanding of this kind of compounds

19

This dissertation is organized as follows the first chapter reports the methodology employed

for preparation of the samples and describes the characterization methods In the second chapter a

new family of hybrid perovskites is presented In chapter three and four the high-pressure Raman

and photoluminescence studies of respectively CsPb2Br5 and Cs4PbBr6 perovskites are described

Finally the conclusion and perspectives are presented

20

Chapter 1

Experimental Section

In this chapter we described the experimental section separated in the following parts first the

synthesis of halide perovskites and secondly the characterization techniques employed for the

analysis of these compounds

Materials

The reagents used in the synthesis for perovskites were all from commercial sources The raw

materials were cesium iodate (CsI 999 ) cesium sulphate (Cs2SO4 999 ) lead bromide

(PbBr2 999 ) HBr solution (47 wt in H2O) toluene (99) and N N-dimethylformamide

(DMF) all purchased from Sigma Aldrich and Alfa Aesar

Synthesis procedures

Single crystals of halide perovskites were grown by the slow evaporation method In this

technique the compounds formed a solution of selected reagents in a solvent lefting to evaporate

under controlled conditions (CHU et al 2017 HUANG et al 2015) Using this procedure the

following single crystals were obtained

Cs4PbBr6

The precursors Cs2SO4PbBr2 were added in a small beaker in a 11 stoichiometric ratio Then

2ml of DMF and 1ml hydrogen bromide (HBr) were mixture at 80 ordmC into the beaker under constant

stirring at 480 rpm until getting a clear solution The same temperature was maintained for 1h The

resulting solution was placed to evaporate at 24 ordmC covered with parafilm containing small holes

The final crystals were washed with toluene several times

21

CsPb2Br5I

The precursors CsIPbBr2 were added in a small beaker in a 12 stoichiometric ratio Then 2ml

of (DMF) was mixed at 80 ordmC into the beaker under constant stirring at 480 rpm until getting a

clear solution The same temperature was maintained for 1h The resulting solution was placed to

evaporate at 24 ordmC covered with parafilm containing tiny holes The final crystals were washed

with toluene several times

(DMA)11Pb4Br19

The precursor PbBr2 was added in a small beaker with 2ml of DMF and 1ml of HBr the mixture

kept at 75 ordmC in constant stirring at 450 rpm until getting a clear solution The same temperature

was maintained for 130 h The resulting solution was placed to evaporate at 24 ordmC and the final

crystals were washed with toluene several times

(DMA)14RbPb4Br23

The precursors PbBr2Rb2SO4 were added in a small beaker with 2ml of DMF and 1ml of HBr

the mixture at 80 ordmC in constant stirring at 450 rpm until getting a clear solution The same

temperature was maintained for 1 hour The resulting solution was placed to evaporate at 24 ordmC

and the final crystals were washed with toluene several times

(DMA)9S4Pb5Br27

The precursors PbBr2Cs2SO4 were added in a small beaker (molar ratio 12) with 2ml of DMF

and 1ml of HBr the mixture at 80 ordmC in constant stirring at 450 rpm until getting a clear solution

The same temperature was maintained for 150 h The resulting solution was placed to evaporate

at 24 ordmC and the final crystals were washed with toluene several times

22

Single-crystal X-ray diffraction

Single crystal X-ray diffraction is a crystallographic method for determination of crystalline

structures (YANG et al 2017) The diffraction phenomenon is observed when a propagating

wave hits an obstacle whose dimensions are comparable to its wavelength That is the case of an

X-ray beam being diffracted when it impinges a set of planes of a crystal defined by the Miller

indices (hkl) if the geometry fulfils a quite specific condition defined by the Braggsrsquos law

119899120582 = 2119889ℎ119896119897 sin 120579 (1)

where n is an integer and is the order of the diffracted beam λ is the wavelength of the radiation

dhkl is the interplanar spacing (the perpendicular separation) of the (hkl) planes and θ is the

diffraction angle This is the principle by which diffraction data is collected from the whole crystal

The arrangement of the diffracted beams is the diffraction pattern of the crystal The Bragg

equation applied to diffraction data results in a list of dhkl values of a compound It is necessary to

allocate the appropriate hkl value to each spot in order to obtain crystallographic information This

set of data allows us to determine the unit cell of the crystal (TOBERGTE CURTIS 2013) The

X-ray diffraction pattern of a substance can be likened to a fingerprint In effect the pattern of a

single phase is unique This method is the principal technique for the determination of molecular

and crystal structure of compounds(BAIKIE et al 2013) In Figure 2 we show the equipment

used to measure the samples

Single crystal data set were collected in the Bruker D8 Venture diffractometer which was

equipped with a Photon II detector and using Mo K120572 radiation (λ=071073 Aring) A suitable crystal

for each compound was chosen and mounted on a kapton fiber using a MiTeGen MicroMount In

figure 2 we show the equipment used for each measured It is also important describe how the data

was analyzed it was indexed and integrated using SAINT V837A included in the APEX3

software Finally the structure was solved by direct methods using the SHELXT 2015 and

refinement by SHELXL 2008 included in the OLEX2

23

Figure 2 Single crystal diffractometer Bruker D8 VENTURE

24

Raman spectroscopy

The Raman effect occurs when the radiation incident is spread at different frequencies after the

light interacts with a material (LEDINSKYacute et al 2015) The process of interacting electromagnetic

radiation with a molecule is due to the annihilation and creation of phonons caused by changes in

the vibrational levels of the molecule

In a dispersion spectrum three sets of bands can be observed a central one at the same frequency

of laser called Rayleigh radiation the most intense due to the elastic dispersion and two bands

with lower intensities called Stokes and Anti-Stokes with lower and higher frequencies

respectively than the excitation one In the Rayleigh radiation the interaction with the molecule

occurs only in the electrons around the nucleus without affecting it directly so there is an elastic

scattering in which neither the photon nor the molecule suffers variations in their energy (XIE et

al 2016) The frequencies of the Raman Stokes and anti-Stokes dispersions depend on the

difference between the frequency of the incident light and the allowed vibrational frequencies

Each material will have a set of different frequencies that are characteristics of its molecular

composition(LONG 2005)

25

Figure 3 LabRam HR 800 HORIBA

Raman and PL spectra were recorded in a Labram HR 800 Horiba spectrometer equipped with

a charge-coupled device (CCD) cooled with liquid nitrogen For exciting the sample a He-Ne

(633nm) and an Ar (488 nm) lasers were used This equipment was also employed to perform

Raman experiments under high-pressure conditions using a membrane high-pressure diamond

anvil cell This device consists of a metallic gasket where the sample the ruby and the compressor

medium (mineral oil) occupy the central hole The pressure was applied through two diamonds and

controlled by an Argon (Ar) flow

Scanning Electron Microscopy (SEM)

An electron microscope uses a beam of accelerated electrons as source of illumination The

electron wavelength is 100000 times shooter than visible light photons for that reason this

equipment have a higher resolution power and can reveal the morphologic of small objects In a

scanning electron microscope (SEM) images are produced by probing the specimen with a focused

electron beam that scanned across a rectangular area of the specimen This instrument allows the

observation and superficial characterization of materials like morphologic information of the

studied compound 40

26

Figure 4 Scanning Electron Microscopy (SEM) QUANTA FEG 450

The crystalline morphology and the stoichiometry of the synthetized materials were investigated

by scanning electron microscopy EDX analyses were performed using a Scanning Electron

Microscope QUANTA FEG 450 available at the Central Analiacutetica of the Universidade Federal do

Cearaacute (UFC) which allows the chemical characterization of the sample(PHILIPPE et al 2015)

27

Chapter 2

New Family of Lead Hybrid Perovskites

The hybrid lead halides perovskites have been widely used in the research of solar cells due to

their excellent properties in photovoltaic and optoelectronic devices (LONG YAN GONG 2018)

(CHEN et al 2018a) The power conversion efficiency (PCE) has increased rapidly to more than

20 in the past years (WANG et al 2018a) The choice of organic cations and the stoichiometry

of the reaction are the most influential parameters on the orientation and deformation of the

resultant inorganic frameworks because they both have a templating influence allowing certain

structures and properties (GARCIacuteA-FERNAacuteNDEZ et al 2018) The results of the new halide

hybrid perovskites family with the organic cation dimethylammonium [(CH3)2NH2]+ (DMA)

resulting from the decomposition of DMF and located in the anionic cavities and distorted [PbX6]-

4 octahedral [(DMA)PbX3 with (X= Br I or Cl)] suggest that different stoichiometry can offer new

possibilities to achieve novel hybrid lead halide perovskites

In this context we show the structural characterization by single-crystal X-ray diffraction and

scanning electron microscopy of three new hybrid lead halide perovskites designed as stated by

combining [PbBr6]-4 octahedra and DMA We obtained compounds which are new and original in

structure and formula these compositions are (DMA)11Pb4Br19 (DMA)14RbPb4Br23 and

(DMA)9S4Pb5Br27

Remarkably we have observed that all new hybrid lead halide perovskites are stable at room

temperature Another important aspect to highlight is the fact these compounds crystallize in

different space groups they display crystal structures even though they have significant differences

in cell parameters All structures consist on single-layered lead halide frameworks with DMA

cations Br- anions and Rb1+ and S+2 isolated atoms This material has halide octahedra formed by

Pb+2 cations with octahedral coordination through six halide ligands making the [PbBr6]4-

composition

28

Figure 5 View of (a) crystal unit structure of (DMA)11Pb4Br19 at room temperature along the a

b and c axis and (b) 1x2x2 bounding octahedrons

The crystal arrangement of the compound (DMA)11Pb4Br19 has bounded halide octahedra

[PbBr6]4- the compound crystallizes in a monoclinic symmetry with cell parameters a =108017(3)

Aring b =278009(8) Aring c =248172(7) Aring β =914880(10) deg and V =74500(4) Aring3 Z = 4 and

space group P21n As we can see in the Figure 5b the octahedral framework displays a peculiar

arrangement this one is composed by two different types of octahedral 1D chains The chain

29

formed by six octahedra bounded through corner and faces is denominated -chain whereas the

-chain has just two octahedra sharing a corner



30

The structure of the (DMA)14RbPb4Br23 exhibits an orthorhombic crystalline system with cell

parameters a = 438990(3) Aring b =156404(10) Aring c =145021(9) Aring V =99571(11) Aring3 Z =4 and

space group Pbcn This compound contains four independent Pb2+ cations twenty-three Br- anions

one Rb+ atom and twenty-three DMA cations both isolated this structure is shown in Figure 6(a)

This hybrid perovskite has a framework with chains of [PbBr6]4- octahedra it is shown in figure

6(b) Two octahedral motifs can be identified a -chain 1D structure formed by two corner sharing

octahedrons and isolated octahedrons with 0D dimensionality

Figure 7 View of (a) crystal unit structure of (DMA)9S4Pb5Br27 at room temperature along the

a b and c axis and (b) 1x2x2 bounding octahedrons

31

Finally the (DMA)9S4Pb5Br27 structure show in Figure 7(a) crystallizes in the monoclinic

crystal system with a =109761(4) Aring b =329494(12) Aring c =151073(6) Aring β =972490(10)deg Z = 4

and space group P21n This structure contains independent five Pb2+ cations twenty-seven Br-

anions four S+2 atom and nine DMA cations isolated The framework of this structure is formed

by 1D chains of four corner sharing collinear octahedrons denominated by -chain and 0D isolated

octahedrons

One important part of each structure is they have disordered octahedra and DMA molecules

The best indicator for disorder in a crystal structure is when the compound has big anisotropic

displacement or residual electron density Most of disorder problems can be diagnosed by looking

at the size andor shape of the displacement parameters or by finding higher noise in Q-peaks which

make unreasonable interactions SHELX as a program warn about the atoms appear to be split

which is good sing for looking disorder problems Typical disorder occurs around freely rotating

bonds or in solvent channels that are larger than the solvent molecules accommodating them

together in the same site very near or with an absence (SARJEANT 2018)

To solved this problem first we investigated the geometry of the site and chemistry involved

(stoichiometry) with the list of atoms to identify the disordered motifs After located the disordered

atoms subsequently we used the command EXYZ in SHELX to constrain the displacement

parameters and made them equal with this we have a separated list where the coordinates and

displacement parameters are identical then create a second atom directly overlaid on the first set

After we edit the value (distortion atom) either to set it manually to a known value (real place) or

to a free variable to be refined Later we refine the structure as usual (to mixture both list) paying

close attention to size of the displacement parameters

As we can see each crystalline framework displays a peculiar arrangement where their

respectively octahedra form 0D andor 1D chains (bounding through corner andor faces)

(KRISHNAMURTHY et al 2018) A combination of chains of different dimensionality is a novel

characteristic in this type of compounds this is a relevant packing because the optical properties

of perovskite-related compounds depend on the confined excitons in the octahedral motifs

32

Table 3 presents a comparison of the results obtained in this work for lead halide perovskites

(DMA)11Pb4Br19 (DMA)14RbPb4Br23 and (DMA)9S4Pb5Br27 with the structure reported by Garcia

et al (GARCIacuteA-FERNAacuteNDEZ et al 2018) In the current table we can find the cell parameters

space group refinement informations and dimensions of the crystals

Table 3 Reported crystal parameters for each novel hybrid perovskites

Empirical

formula

((DMA)7Pb4Br15)(GARCIacuteA

-FERNAacuteNDEZ et al

2018)

(DMA)11Pb4Br19 (DMA)14RbPb4Br2

3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K

Wavelength 071073 Ǻ

Crystal

system

Monoclinic Monoclinic Orthorhombic Monoclinic

Space group P21c P21n Pbcn P21n

Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2

Density 2942 Mgm3 2466 Mgm3 2039 Mgm3 2058 Mgm3

Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875

Crystal size 024x006x002 mm3 022x0136x011

6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method

Full-matrix least-squares on F2

R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain

2D chain α β β γ

33

It has been demonstrated that single crystal of hybrid lead halide perovskites can be obtained by

slow evaporation method To define the effective stoichiometry and morphology of each compound

we have used scanning electron microscopy on each of the novel hybrid perovskites As an

example Figure 8 shows the results obtained for the single crystal (DMA)11Pb4Br19 which was

divided in 3 parts The Line 1 shows a uniform surface morphology in the crystal O elemental

mapping images of Pb Br C and N can be observed in the Line 2 indicating the particles

distribution in the following spectrum where correspond to the perovskite phase In the Line 3 we

have a qualitative map for all most constituent elements

In conclusion we have obtained three new perovskite related compounds and the corresponding

crystalline structures have been reported These perovskites have differences in the [PbBr6]4-

octahedron framework exhibiting several 0D 1D and 2D dimensionalities which is potential

feature for the development of novel applications and the raising of new properties

34

Figure 8 Line 1 (DMA)11Pb4Br19 morphology Line 2 sum of composition element map and

each element map and Line 3 Spectrum map sum for all constituent element in (DMA)11Pb4Br19

perovskite

35

Chapter 3

CsPb2Br5I under High-pressure

The single-crystal X-ray analysis revealed that the obtained CsPb2(Br085I015)5 samples presents

a tetragonal structure belonging to 1198684119898119888119898 (ITA number 140) space group with lattice parameters

119886 = 85291(8) Aring and 119888 = 153428 (19) Å and four molecular units per unit cell The

CsPb2(Br085I015)5 structure is very similar to those reported for CsPb2Br5 (NAZARENKO et al

2017 WANG et al 2016a) and CsPb2Cl5 (CHEN et al 2018b KIM JO OK 2009) However

the insertion of I- ion induces an increasing into the bond lengths and as consequence the cell

parameters of CsPb2(Br085I015)5 are bigger in comparison to those 119886 = 84833(10) Aring and 119888 =

151830 (18) Å reported for CsPb2Br5 Besides the alterations on the bond lengths the single

crystal X-ray analysis also revealed that the I- presence induces a degree of disorder on

CsPb2(Br085I015)5 where the I- cations replaces the Br- atoms on 16l site On the other hand the

second Br site (4c) is ordered with Br- ions aligned with Cs atoms along c axis (Figure 9 (c)) In

this way the CsPb2(Br085I015)5 structure can be described as a sandwich configuration in which

[Pb2(BrI)5]- layers intercalated by Cs+ ions (Figure 9 (a)) Thus the [Pb2(BrI)5]

- layers are

constituted by one Pb2+ coordinates with four Br- or BrI- forming elongated decagon (see Figure

9) The disordered BrI 16l site is the one locate at the upper and lower edges of [Pb2(BrI)5]- layer

while the ordered 4c site occupied by Br- ions are located at the middle of those layers This atomic

configuration also induces an increased in the [Pb2(BrI)5]- layer width of 3994 Aring in comparison

to the one of 3921 Aring presented by CsPb2Br5

36

Figure 9 CsPb2(Br085I015)5 unit cell

EDX analyzes were carried out to determine the distribution of I- cations on crystal surface

Figure 10 shows a EDX image of a CsPb2(Br085I015)5 single crystal The EDX images showed that

the I- cations are uniformly distributed on all crystal surface (Figure 10 (a) and (b)) implying that

the synthetized crystals have good homogeneity and the border analysis shows no concentrations

of any structural ion or sub-phases as observed for CsPb2Br5 (WANG et al 2018b) (Figure 10 (c))

37

Figure 10 CsPb2Br426I074 single crystal EDX Images

Raman spectroscopy is known as a sensitive technique for detecting phase transitions or subtle

structural rearrangements Thus in order to investigate any structural modification due to pressure

increase Raman measurements were performed to investigate single-crystals of CsPb2(Br085I015)5

up to 708 GPa Figure 11 presents the representative unpolarized Raman spectrum recorded for a

single-crystal of CsPb2Br426I074 sample at ambient conditions Considering the group theory

analysis based on the site occupation in this tetragonal structure 13 Raman-active modes are

predicted whose the distribution in terms of irreducible representations for the D4h group factor at

the Γ point of Brillouin zone (ROUSSEAU BAUMAN PORTO 1981) is

31198601119892⨁21198611119892⨁31198612119892⨁5119864119892 (see table 4) As Figure 11 shows we observed 6 from those 13

expected Raman-active modes By means of theoretical calculations and confirmed by

experimental measurements Hadjiev et al(HADJIEV et al 2018) assigned the symmetry for the

observed phonons for CsPbBr5 which belongs to the same D4h group factor In this way the modes

observed at 65 103 and 143 cm-1 have the B2g symmetry those located at 81 and 132 present A1g

symmetry and the one located at 76 cm-1 have B1g symmetry Some modes present a lower

38

frequency in comparison to those observed by Hadjiev et al this fact is due to BrI disorder at 16l

site which increases the reduced mass and consequently decreases the vibrational frequency

Table 4 Distribution of vibrational modes based on group theory analysis for tetragonal

CsPb2(Br085I015)5

Ion Site Symmetry Contribution

Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906

Figure 11 Representative unpolarized Raman spectrum of CsPb2(Br085I015)5 at room pressure

39

Figure 11(a) shows selected stacked Raman spectra of CsPb2(Br085I015)5 under hydrostatic

compression All six assigned Raman-active vibrational modes in the range between 60 and 180

cm-1 at ambient conditions were analyzed under increasing pressure All vibrational modes

presented a continuous shift toward higher wavenumbers due to lattice contraction while the

overall signature of Raman spectra is maintained as the original state up to 176 GPa A new

vibrational mode appears around 85 cm-1 at 193 GPa (Figure 11(b)) The appearance of this mode

is associated to the occurrence of a structural phase transition Around 52 GPa we note the

disappearance of Eg B2g and B2g modes initially located at 103 and 143 cm-1 besides the

emergence of a new mode around 84 cm-1 The observed variation on the number of vibrational

modes evidences that CsPb2Br426I074 undergoes another phase transition between 51 and 55 GPa

Above 55 GPa the Raman spectra is maintained until 708 GPa without any evidence of amorphous

state or additional phase transitions Upon pressure releasing the Raman spectrum at 069 GPa

returned to the initial state matching well with the initial positions and the relative intensities

between the vibrational modes were recovered indicating that the two structural phase transitions

are reversible

Figure 12 a) Pressure dependent Raman spectrum of CsPb2(Br085I015)5 b) Pressure dependent

phonon positions

40

The CsPb2(Br085I015)5 single crystals emission spectra were studied under 488 nm laser

excitation The results showed a bright green PL band centered at 519 nm with full width at half

maximum (FWHM) of 20 nm under ambient conditions these results are consistent with those PL

emission peaks reported for other halide-perovskites as CsPbX3(X=Cl Br)(STOUMPOS et al

2013b VOLOSHINOVSKII MYAGKOTA LEVITSKII 2005) Cs4PbBr6 (DE BASTIANI et al

2017b) and FAPbBr3 (HANUSCH et al 2014)

Despite the similarities on crystal structure the CsPb2(Br085I015)5 single crystals presented a

strong PL emission peak whereas the CsPb2Br5 did not present any signal of PL emission Wang

et al (WANG et al 2018b) affirms that millimeters size crystals of CsPb2Br5 should be transparent

and non-emissive while very small crystals which size is in order of microns present edge emission

related to contamination of CsPbBr3 nanocrystals(LI et al 2017c QIN et al 2017 RUAN et al

2017) In case of CsPb2(Br085I015)5 the EDX results showed that the synthetized crystals present a

good homogeneity indicating that the observed PL emission in CsPb2(Br085I015)5 are not related to

presence of sub-phases and probably being related exclusively to presence of I cation on BrI

disordered site

The Figure 12 (a) shows the stacked PL spectra obtained for CsPb2(Br085I015)5 under pressure

increase The two very intense peaks located around 522 nm in all PL spectra are related to Raman

active modes of the diamonds of the high pressure cell The PL intensity showed a gradual increase

upon pressure until reaches a maximum value at 133GPa from this point the intensity decrease

until the pressure of 271 GPa where the PL emission vanish (Figure 12 (b)) This changing on

intensity around 133 GPa can be related to changes on structure or a starting point of phase

transitions Besides the changes on PL emission intensity the maximum position also showed a

gradual and linear red shift up to 176 GPa (Figure 12 (c)) At this point the PL undergoes a jump

from 526 to 528 nm at 193 GPa from which a sudden blue shift follows up to the pressure reaches

271 GPa where the PL peak disappear The abrupt change in the PL peak pressure behavior has

been understood as the crystalline structure undergoing a phase transition as observed in several

halide perovskite pressure dependent studies(JAFFE et al 2016 SZAFRAŃSKI KATRUSIAK

2016 ZHANG et al 2018c ZHANG ZENG WANG 2017b) Thus these results are indicative

that the CsPb2(Br085I015)5 undergoes a phase transition at 176 GPa reinforcing first phase transition

observed on pressure dependent Raman analysis showed above

41

Figure 13 Pressure dependent a) PL spectra b) PL intensity and c) PL emission center

Upon decompression at 069 GPa the PL peaks returns to the original state (Figure 13 (a)) with a

bright green PL peak centered at 521 nm and 23 nm of width Which is an indicative that the loss

of PL emission at high pressures also is a reversible phenomenon

In conclusion the structure CsPb2(Br085I015)5 presents tetragonal symmetry with space group

1198684119898119888119898 Shows occupational disorder in the 16l site and presents two-phase transitions around

18 and 53 GPa

42

Chapter 4

Pressure-Induced enhanced photoluminescence and Raman

scattering study of the zero dimensional Cs4PbBr6 lead

halide perovskite

As discussed previously Cs4PbBr6 is classified as a 0D-Perovskite structure which is composed

of isolated (PbBr6)4minus octahedra interspersed with Cs+ cations Having that in mind the (PbBr6)

4minus

octahedra can be treated as an isolated molecular group in the crystal Therefore the vibrational

modes of this crystal can be classified according the translational librational and intramolecular

vibrations of the (PbBr6)4minus octahedral group In order to identify the symmetry and predict the

Raman and infrared activity of each vibrational mode of Cs4PbBr6 the correlation method was

applied (FATELEY et al 1972 ROUSSEAU BAUMAN PORTO 1981)

The correlation method requires the knowledge of the number of formula units in the Bravais

cell (ZB) which is equal to Z (the number of the formula units per crystallographic unit cell) divided

by the number of lattice points (LP) determined by the designation of the space group Single

crystals of Cs4PbBr6 crystallizes in the trigonal structure with space group 1198773119888 Its Bravais cell

contains two formula units (ZB = 2) with N = 22 atoms

The Wyckoffrsquos site positons and the symmetry of the constituent ions are given in the Table 5

Since the site symmetry of the molecular group is the symmetry of the central atom the (PbBr6)4minus

octahedral ion occupies a S6 site symmetry

Table 5 Wyckoffs site positions of the atoms in the Cs4PbBr6 single crystal

Ion Wyckoff Site Site Symmetry

119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43

The isolated (PbBr6)4minus octahedral ion has Oh symmetry and its vibrational motions may be

designated by the standard Herzberg notation(HERZBERG 1945) 1198601119892 (1205841) 119864119892(1205842) 1198651119906 (1205843)

1198651119892 (rotation) 31198651119906 (translation 1205843 1205844 ) 1198652119892 (1205845) 1198652119906 (1205846) The representations of Oh specify the

motions of the (PbBr6)4minus octahedral ion and the designations in parenthesis after each

representation are the standard Herzberg notation (1205841 1205842 and 1205843 are the stretching modes of the

bonds Pb ndash Br and 1205844 1205845 and 1205846 are the deformation modes of the Br ndash Pb ndash Br angles)

Table 6 Correlation table for Cs4PbBr6 The degrees of vibrational freedom for a given site

species γ is given by the symbol 119891120574 The translational and rotational degrees of freedom of the

(PbBr6)4minus octahedra become translational and librational lattice modes in the crystal

Table 6 lists each of the Oh representations of the (PbBr6)4minus octahedral ion The effect of the

lowering of the symmetry is determined by the correlation between the Oh and the S6

representations (site symmetry) and finally with the 1198633119889 one (crystalline symmetry)

The correlation method yields the irreducible representations at the Γ-point phonon modes In

the Table 6 the degrees of vibrational freedom for a site species γ is given by the symbol 119891γ The

crystal has 3N = 66 vibrational freedom degrees including 3 acoustics (120548119860119888119900119906119904119905119894119888 = 1198602119906 oplus 119864119906)

44

and 63 optical modes (120548119900119901119905119894119888 = 41198601119892 oplus 51198601119906 oplus 61198602119892 oplus 61198602119906 oplus 10119864119892 oplus 11119864119906) Among

optical modes only 1198601119892 and 119864119892 are Raman actives and 1198602119906 and 119864119906 are IR actives The vibration

modes related to the octahedra are (120548119871119894119887119903119886119905119894119900119899 = 1198601119892 oplus 1198602119892 oplus 2119864119892) Besides these modes there

are 10 silent modes 120548119878119894119897119890119899119905 = 51198601119906 oplus 51198602119892 which are neither Raman nor IR active modes

The pressure effect on lead halide 3D-perovskite have been drawn extensive attention and

demonstrating an unavoidable impact on the optical properties of these structures (BEIMBORN et

al 2018 WANG et al 2016b 2015 WANG WANG ZOU 2016 ZHANG et al 2018b

ZHANG ZENG WANG 2017a) However on the other hand at the best of our knowledge the

pressure effect on 0-D perovskites structures have not been reported Another important

observation worth noting is that the dimensionality of (PbBr6)4minus octahedron strongly influences its

optical properties(ZEWEN XIAO et al 2017)(ZHANG ZENG WANG 2017a) Thus

considering this we carried out high-pressure optical photoluminescence and Raman experiments

on Cs4PbBr6 0D-perovskite to investigate the pressure-induced optical evolution

40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179

Figure 14 Raman spectrum of Cs4PbBr6 0D-Perovskite single crystal observed at room

temperature and pressure The red continuous line represents the result of the decomposition of

the spectrum with a set of Lorentzian line profiles (blue lines)

45

According to the group theory we expect up to 14 Raman (120548119877119886119898119886119899 = 41198601119892 oplus 10119864119892) and 17

infrared (120548119868119877 = 61198602119906 oplus 11119864119906) active modes at room temperature and pressure in the trigonal

phase As showed in Figure 14 12 Raman active modes described by the group theory were

observed experimentally which is a good number of modes considering we have broad and subtle

bands that induce mode overlaps Some of the observed modes can be assigned according to

previously reported works on Cs4PbBr6 and compounds with similar compositions and molecular

groups Therefore the modes at 84 cm-1 and 124 cm-1 are attributed to the PbminusBr rocking modes

in the [PbBr6]4minus octahedron (YIN et al 2017b) which is agree to group theory showed in Table 6

where was predicted two 1205845 modes associated to octahedron deformation with 119864119892 symmetry The

mode located around to 136 cm-1 is assigned to the PbminusBr stretching modes(YIN et al 2017b

ZHANG et al 2018b) According to the group theory this mode might be 1205841 with 1198601119892 symmetry

or 1205842 with 119864119892 symmetry

The pressure-dependence Raman spectra of the Cs4PbBr6 from ambient condition up to 1085

GPa are shown in Figure 15(a) As pressure increases all Raman peaks move continuously along

the high-frequency direction However with respect to the lower pressure values from to 071 GPa

a remarkable red shift in the profile of the spectra is observed When the pressure reaches 036

GPa the Raman spectra exhibit some significant changes the vibrational modes at 61 and 153 cm-

1 disappear and the modes around to 75 and 84 cm-1 become in a single broadened mode A similar

high pressure behavior with structural phase transitions at lower pressure values eg at 04 and

056 GPa were obeserved for lead-based halide inorganic 3D perovskites MAPbBr3 and FAPbBr3

respectively (WANG WANG ZOU 2016 WANG et al 2015) which is very close to one on the

0D Cs4PbBr6 crystal However for lead-based halide organic 3D perovskites such as CsPbBr3

(ZHANG ZENG WANG 2017a) and CsPbCl3 (CSPBCL et al 2018) the structural phase

transitions are observed starting approximately around to 13 GPa Thus the inorganic Cs4PbBr6

crystal requires lower pressures for phase transitions which indicated that it is much more

compressible under external pressures than those another lead-based halide inorganic cited above

As shown in Figure 15 an interesting behavior on the Raman modes at 22 GPa is observed the

splitting of the mode around to 55 cm-1 in two modes at 54 and 57 cm-1 which may indicate a

structural phase transition In general a similar pressure-induced structural phase transition

46

behavior is observed around to 20 GPa on all like structures reported so far (WANG et al 2016b

2015 WANG WANG ZOU 2016 ZHANG et al 2018b) Another phase transition can be

inferred near to 657 GPa This phase transition is subtle looking directly at the Raman spectra in

Figure 15 but can be clearly observed from the evolution of the modes with the pressure in Figure

15(b) However a more precise characterization can be obtained by means of a pressure X-ray

diffraction experiment

Upon further increase of pressure up to 353 GPa a clear change in the phonon spectrum of the

crystal is observed As showed in Figure 15(a) the modes associated to the lattice become broader

some of them disappear eg the modes around 92 and 106 cm-1 and a new mode arises at 117 cm-

1 due to the widening of the mode at 110 cm-1 (see Figure 15(b)) The most characteristic feature

is however the significant lowering and broadening intense as well as the red shift of the 1205845 mode

at 84 cm-1 assigned to octahedron Thus these results indicate a dramatic change in the crystal

structure for this pressure value which is highly relevant because the PbBr6 octahedra play a key

role in the optical properties of these structures

Figure 15 (a) Raman spectra measurements of Cs4PbBr6 0D-PRS single crystal under high

pressure conditions up to 1085 GPa Several pressure-induced phase transitions are observed

(b)Wavenumber vs pressure plots of the Raman modes observed in the Cs4PbBr6 crystal for

compression experiments The vertical lines indicate the pressures at which Cs4PbBr6 undergoes

phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa

290 GPa 275 GPa 248 GPa 220 GPa 190 GPa

150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47

Is worth note that some of the modes that were once lost during compression from 353 to 428

GPa reappeared at 473 GPa and we can also notice a subtle blue shift of the octahedral mode near

84 cm-1 As the applied pressure exceeds 921 GPa the broad modes significantly decrease in

intensity accompanied by broadening and disappearance of some initial modes implying the onset

of deteriorated crystal crystallinity due significant to disorder of the PbminusBr network structure under

high pressure

Figure 16 (a) Photoluminescence spectra of Cs4PbBr6 as a function of pressure (b) PL emission

center and intensity

In order to better understanding the pressure induced PL behavior we plot in the figure 16(a)

the selected photoluminescence spectrarsquos as a function of pressure The Cs4PbBr6 exhibits a single

PL centered at 506 nm in good agreement with recent reports which exhibits a peak around to 515

nm(CHA et al 2017 DE BASTIANI et al 2017a SAIDAMINOV et al 2018 SETH

SAMANTA 2017 YIN et al [sd]) While in the organic-inorganic lead halide 3D-perovskite

early reported(WANG et al 2016b 2015 WANG WANG ZOU 2016 ZHANG et al 2018b

ZHANG ZENG WANG 2017a) the PL is suppressed by the hydrostatic pressure in the Cs4PbBr6

0D-perovskite single crystal present an anomalous behavior under high pressure conditions The

PL peak showed a gradual red shift of up to 10 Gpa when the pressure was increased Above this

48

pressure the peak exhibits a blue shift which is accompanied by the decreasing of the PL intensity

The peak completely disappears above 43 GPa but a closer inspection of the pressure dependence

of emission peak shows that above this pressure the peak should be located below the wavelength

of the excitation laser From our results it is not possible to conclude if the decreasing of the

intensity of the PL emission is related to the pressure or to the reduction of the excitationemission

energy difference Regarding to the effect of the structural phase transitions the changes in both

the intensity and wavelength does not seems to be directly associated with the structural phase

transitions but to the local distortion of the PbBr4- octrahedra rather than the crystal symmetry

This could be consequence of the exciton confinement characteristics of the 0D perovskites and

could be a valuable mechanism to tune the PL emission by using hydrostatic pressure

49

Conclusions

The lead halide perovskites exhibit promising properties in different fields like solar cells

which is an alternative to generate energy preserving the global environment Halide perovskites

presents high efficiency and excellent optoelectronic properties due their crystalline structure and

spatial arrangement of octahedral units The configurations of dimensionality in perovskites

structures are classified in 2D quantum wellsnanoplatelets 1D quantum wiresnanorods and 0D

clustersnanoparticles

The new hybrid perovskites are compounds with characteristics that different organic-inorganic

cation can occupy the same atomic positions this property increase the efficient of photovoltaic

devices The principal focus of this work was study of critical effect as pressure under low

dimensional halide perovskites to achieve this goal our investigation was based in synthesis of

these compounds by the slow evaporation technique and his characterization by single crystal X-

ray diffraction Raman and PL analyses

We have successfully produced five different compounds with different crystalline structures

three of them are novel hybrid lead halide perovskites as (DMA)11Pb4Br19 (DMA)14RbPb4Br23 and

(DMA)9S4Pb5Br27 compositions these compounds are low dimensional perovskites based on

frameworks of the same [PbBr6]-4 octahedra Even though they have the same [PbBr6]

-4 group

they display peculiar and different arrangements where the structures had a combination of two

low dimensional motifs 1D chains of corner andor faces shared octahedral and isolated 0D

octahedral This distinguishing behavior is a new characteristic reported here for the first time

which could be relevant for future applications because perovskites properties depend on the

dimensional structure

The CsPb2(Br085I015)5 crystals showed a tetragonal structure belonging to 1198684119898119888119898 space group

with four molecular units per unit cell Single crystal X-ray analysis showed that the 16l site can

be occupied by Br- or I- ions creating a disorder in this site while the 4c site is ordered with Br-

ions aligned with Cs atoms along c axis The atomic configuration can be described as a sandwich

configuration in which [Pb2(BrI)5]- layers are intercalated by Cs+ ions in good agreement with

those reported for CsPb2X5 (X = Cl Br) EDX analysis revealed that CsPb2(Br085I015)5 crystals

50

have good homogeneity without any concentration of secondary phases along crystal surface The

PL emission of CsPb2(Br085I015)5 single crystals was studied under 488 nm laser excitation

showing a bright green PL emission exhibiting standard a Gaussian shape centered at 519 nm with

full width at half maximum (FWHM) of 20 nm at ambient conditions consistent with those PL

emission spectra reported for other halide-perovskites Based on EDX images the PL emission of

CsPb2(Br085I015)5 are related to I- cation and not due to secondary phases as observed as reported

for CsPb2Br5

The unpolarized Raman spectrum of CsPb2(Br085I015)5 at ambient conditions presented 6 of

those 13 predicted modes based on group theory analysis The pressure dependent Raman spectra

were carried out to monitor the changes in the crystalline structure under high-pressure revealing

two phase transitions around 18 and 53 GPa being the number of transitions in good agreement

with the pressure dependent behavior of halide-perovskites the structural evolution must be better

defined by performing high-pressure XRD analysis The pressure dependent PL emission also

showed a gradual increase of intensity upon pressure increase this behavior is held until 133 GPa

where the PL peak reaches a maximum value From this point the intensity decrease until the

pressure of 271 GPa where the PL emission vanishes Besides the intensity changes the PL

position also showed a gradual and linear red shift up to 176 GPa where a split from 526 to 528

nm was observed at 193 GPa From this point a sudden blue shift follows up to the pressure reaches

271 GPa The increase abrupt change pressure depend behavior around 176 GPa confirms the first

phase transition observed on Raman measurements

Also we investigated the effects of pressure on the crystalline structure and optical PL of the

single crystal Cs4PbBr6 The results suggest that the single crystal under study undergoes a

pressure-induced structural phase transition at low-pressure values very close those were observed

for lead-based halide inorganic 3D perovskites Other subtle changes in the Raman modes were

observed at 22 GPa and 657 GPa which can be associated to structural phase transitions From

353 GPa to 43 GPa a significant change in crystal structure were observed The modes associated

to octahedra undergo clear changes which is very interesting once the octahedra play a key role in

the optical properties However significant changes were not observed in the PL for this value

pressure but the peak completely disappears above 43 GPa The PL peak showed a gradual red

shift of up to 10 Gpa then a blue shift accompanied by the decreasing of the intensity when the

51

pressure was increased The results show that the pressure-induced PL behavior is associated to the

local distortion of the PbBr4- octahedra and is not related to structural phase transitions Therefore

our high-pressure studies of the structural stability and PL of Cs4PbBr6 0D-perovskite shed light

on a valuable mechanism to tune the PL emission by using hydrostatic pressure

52

References

AKIHIRO KOJIMA et al Organometal Halide Perovskites as Visible- Light Sensitizers for

Photovoltaic Cells J Am Chem Soc v 131 n October p 6050ndash6051 2009

ALBERO J ASIRI A M GARCIacuteA H Influence of the composition of hybrid perovskites on

their performance in solar cells Journal of Materials Chemistry A v 4 n 12 p 4353ndash4364

2016

BAIKIE T et al Synthesis and crystal chemistry of the hybrid perovskite (CH3NH3)PbI3 for

solid-state sensitised solar cell applications Journal of Materials Chemistry A v 1 n 18 p

5628 2013

BAYRAMMURAD SAPAROV AND DAVID B MITZI OrganicminusInorganic Perovskites

Structural Versatility for Functional Chemical Reviews v 116 p 4558ndash4596 2016

BEIMBORN J C et al Pressure Response of Photoluminescence in Cesium Lead Iodide

Perovskite Nanocrystals 2018

CHA J-H et al Photoresponse of CsPbBr 3 and Cs 4 PbBr 6 Perovskite Single Crystals The

Journal of Physical Chemistry Letters v 8 n 3 p 565ndash570 2017

CHEN F et al Structure Evolution of CH3NH3PbBr3 Single Crystal Grown in N N-

dimethylformamide Solution Crystal Growth amp Design p acscgd8b00256 2018a

CHEN Y et al Synthesis Crystal Structure and Optical Gap of Two-Dimensional Halide Solid

Solutions CsPb 2 (Cl 1ndash x Br x ) 5 Inorganic Chemistry v 2 p acsinorgchem8b01572 jul

2018b

CHU K et al An ABX3organicndashinorganic perovskite-type material with the formula

(C5N2H9)CdCl3 Application for detection of volatile organic solvent molecules Polyhedron v

131 p 22ndash26 2017 CSPBCL M P et al Pressure-Induced Structural Evolution and Optical

Properties of The Journal of Physical Chemistry C v 122 p 15220ndash15225 2018

DE BASTIANI M et al Inside Perovskites Quantum Luminescence from Bulk Cs4PbBr6 Single

Crystals Chemistry of Materials v 29 n 17 p 7108ndash7113 2017a

DIROLL B T et al High-Temperature Photoluminescence of CsPbX 3 (X = Cl Br I)

Nanocrystals Advanced Functional Materials v 27 n 21 p 1606750 2017

DURSUN I et al CsPb2Br5 Single Crystals Synthesis and Characterization ChemSusChem v

10 n 19 p 3746ndash3749 2017

FATELEY W G et al Infrared and Raman selection rules for molecular and lattice

vibrations 1972

53

FRANCISCO PALAZON SEDAT DOGAN SERGIO MARRAS FEDERICO LOCARDI

ILARIA NELLI PRACHI RASTOGI MAURIZIO FERRETTI MIRKO PRATO R K AND L

M From CsPbBr3 Nano-Inks to Sintered CsPbBr3minusCsPb2Br5pdf The Journal of Physical

Chemistry C v 121 p 11956ndash111961 2017

GARCIacuteA-FERNAacuteNDEZ A et al 7Pb4X15(X = Cl-and Br-) 2D-Perovskite Related Hybrids with

Dielectric Transitions and Broadband Photoluminiscent Emission Inorganic Chemistry v 57 n

6 p 3215ndash3222 2018

GRAumlTZEL M Photoelectrochemical cells Nature v 414 n 6861 p 338ndash344 15 nov 2001

GRAumlTZEL M The light and shade of perovskite solar cells Nature Materials v 13 n 9 p 838ndash

842 2014

HADJIEV V G et al Phonon Fingerprints of CsPb2Br5 Single Crystals n Md p 1ndash5 maio

2018

HANUSCH F C et al Efficient Planar Heterojunction Perovskite Solar Cells Based on

Formamidinium Lead Bromide The Journal of Physical Chemistry Letters v 5 n 16 p 2791ndash

2795 ago 2014

HAO F et al Lead-free solid-state organic-inorganic halide perovskite solar cells Nature

Photonics v 8 n 6 p 489ndash494 2014

HERZBERG G Molecular Spectra and Molecular Structure II Infra-Red and Raman

Spectra of Polyatomic Molecules New Jersey - Princeton D Van Nostrand Company-Inc 1945

HUANG J et al Understanding the physical properties of hybrid perovskites for photovoltaic

applications Nature Reviews Materials v 2 2017

HUANG L et al Solar Energy Materials amp Solar Cells Multi-step slow annealing perovskite fi

lms for high performance planar perovskite solar cells Solar Energy Materials and Solar Cells

v 141 p 377ndash382 2015

JAFFE A et al High-Pressure Single-Crystal Structures of 3D Lead-Halide Hybrid Perovskites

and Pressure Effects on their Electronic and Optical Properties ACS Central Science v 2 n 4

p 201ndash209 abr 2016

KIM M K JO V OK K M New Variant of Highly Symmetric Layered Perovskite with

Coordinated NO 3 minus Ligand Hydrothermal Synthesis Structure and Characterization of Cs 2 PbCl

2 (NO 3 ) 2 Inorganic Chemistry v 48 n 15 p 7368ndash7372 ago 2009

KOVALENKO M V PROTESESCU L BODNARCHUK M I Properties and potential

optoelectronic applications of lead halide perovskite nanocrystals Science v 358 p 745ndash750

2017

KRISHNAMURTHY S et al Molecular and Self-Trapped Excitonic Contributions to the

54

Broadband Luminescence in Diamine-Based Low-Dimensional Hybrid Perovskite Systems

Advanced Optical Materials v 1800751 p 1800751 26 jul 2018

LE Q VAN et al Low Temperature Solution-Processable Cesium Lead Bromide Microcrystals

for Light Conversion Crystal Growth amp Design p acscgd8b00264 2018

LEDINSKYacute M et al Raman Spectroscopy of OrganicndashInorganic Halide Perovskites The

Journal of Physical Chemistry Letters v 6 n 3 p 401ndash406 5 fev 2015

LI J et al Synthesis of all-inorganic CsPb2Br5perovskite and determination of its luminescence

mechanism RSC Advances v 7 n 85 p 54002ndash54007 2017a

LI M et al Colloidal CsPbX3(X = Br I Cl) NCs Morphology controlling composition evolution

and photoluminescence shift Journal of Luminescence v 190 n December 2016 p 397ndash402

2017b

LI P et al Novel synthesis and optical characterization of CsPb 2 Br 5 quantum dots in borosilicate

glasses Materials Letters v 209 p 483ndash485 dez 2017c

LI S et al Metal Halide Perovskite Single Crystals From Growth Process to Application

Crystals v 8 n 5 p 220 17 maio 2018

LIN H et al Low-Dimensional Organometal Halide Perovskites ACS Energy Letters v 3 n 1

p 54ndash62 2018

LIU Z et al Ligand Mediated Transformation of Cesium Lead Bromide Perovskite Nanocrystals

to Lead Depleted Cs4PbBr6Nanocrystals Journal of the American Chemical Society v 139 n

15 p 5309ndash5312 2017

LONG D A Introductory Raman Spectroscopy John R Ferraro Kazuo Nakamoto and Chris W

Brown Academic Press Amsterdam Second Edition 2003 xiii + 434 Journal of Raman

Spectroscopy v 36 n 10 p 1012ndash1012 out 2005

LONG J-Y YAN Z-S GONG Y Synthesis Structure and Band Gap of a Novel Inorganicndash

Organic Hybrid Material Based on Antimony Halide and Organoamine Crystallography

Reports v 63 n 3 p 433ndash437 2 maio 2018

LV J FANG L SHEN J Synthesis of highly luminescent CsPb2Br5nanoplatelets and their

application for light-emitting diodes Materials Letters v 211 p 199ndash202 2018

NAZARENKO O et al Luminescent and Photoconductive Layered Lead Halide Perovskite

Compounds Comprising Mixtures of Cesium and Guanidinium Cations Inorganic Chemistry v

56 n 19 p 11552ndash11564 2017

PHILIPPE B et al Chemical and Electronic Structure Characterization of Lead Halide Perovskites

and Stability Behavior under Different ExposuresmdashA Photoelectron Spectroscopy Investigation

55

Chemistry of Materials v 27 n 5 p 1720ndash1731 10 mar 2015

QIN C et al Centrifugal-Coated Quasi-Two-Dimensional Perovskite CsPb2Br5 Films for

Efficient and Stable Light-Emitting Diodes The Journal of Physical Chemistry Letters p

acsjpclett7b02371 2017

ROUSSEAU D L BAUMAN R P PORTO S P S Normal mode determination in crystals

Journal of Raman Spectroscopy v 10 n 1 p 253ndash290 jan 1981

RUAN L et al Alkyl-Thiol Ligand-Induced Shape- and Crystalline Phase-Controlled Synthesis

of Stable Perovskite-Related CsPb 2 Br 5 Nanocrystals at Room Temperature The Journal of

Physical Chemistry Letters v 8 n 16 p 3853ndash3860 ago 2017

SAIDAMINOV M I et al Pure Cs 4 PbBr 6  Highly Luminescent Zero-Dimensional Perovskite

Solids v 16 p 4 2018

SALIBA M et al Measuring Aging Stability of Perovskite Solar Cells Joule v 80 p 1ndash6 maio

2018

SARJEANT A A Structure Solution and Refinement with Olex2  A guide for Chem 435

Students [sl sn]

SETH S SAMANTA A Fluorescent Phase-Pure Zero-Dimensional Perovskite-Related

Cs4PbBr6Microdisks Synthesis and Single-Particle Imaging Study Journal of Physical

Chemistry Letters v 8 n 18 p 4461ndash4467 2017

SOE C M M et al New Type of 2D Perovskites with Alternating Cations in the Interlayer Space

(C(NH2)3)(CH3NH3)nPbnI3n+1 Structure Properties and Photovoltaic Performance Journal

of the American Chemical Society v 139 n 45 p 16297ndash16309 2017

STOUMPOS C C et al Crystal Growth of the Perovskite Semiconductor CsPbBr 3  A New

Material for High-Energy Radiation Detection Crystal Growth amp Design v 13 n 7 p 2722ndash

2727 2013a

SZAFRAŃSKI M KATRUSIAK A Mechanism of Pressure-Induced Phase Transitions

Amorphization and Absorption-Edge Shift in Photovoltaic Methylammonium Lead Iodide The

Journal of Physical Chemistry Letters v 7 n 17 p 3458ndash3466 set 2016

TANG X et al All-Inorganic Perovskite CsPb2Br5 Microsheets for Photodetector Application

Frontiers in Physics v 5 n January p 1ndash7 2018

TILLEY J D R Perovskites First Edit ed United Kingdom Wiley 2016

TOBERGTE D R CURTIS S Crystals and crystal structures [sl sn] v 53

TSAI H et al High-efficiency two-dimensional ruddlesden-popper perovskite solar cells Nature

56

v 536 n 7616 p 312ndash317 2016

TSAI H et al Design principles for electronic charge transport in solution-processed vertically

stacked 2D perovskite quantum wells Nature Communications p 1ndash9 2018

VOLOSHINOVSKII A MYAGKOTA S LEVITSKII R Luminescence of Ferroelastic

CsPbCl 3 Nanocrystals Ferroelectrics v 317 n 1 p 119ndash123 2005

WANG K-H et al Large-Scale Synthesis of Highly Luminescent Perovskite-Related CsPb 2 Br

5 Nanoplatelets and Their Fast Anion Exchange Angewandte Chemie International Edition v

55 n 29 p 8328ndash8332 jul 2016a

WANG L et al Pressure-Induced Structural Evolution and Band Gap Shifts of Organometal

Halide Perovskite-Based Methylammonium Lead Chloride The Journal of Physical Chemistry

Letters v 7 n 24 p 5273ndash5279 15 dez 2016b

WANG L WANG K ZOU B Pressure-Induced Structural and Optical Properties of

Organometal Halide Perovskite-Based Formamidinium Lead Bromide Journal of Physical


WANG P et al Solvent-controlled growth of inorganic perovskite films in dry environment for

efficient and stable solar cells Nature Communications v 9 n 1 p 2225 8 dez 2018a

WANG Y et al Pressure-Induced Phase Transformation Reversible Amorphization and

Anomalous Visible Light Response in Organolead Bromide Perovskite Journal of the American

Chemical Society v 137 n 34 p 11144ndash11149 2015

WANG Y et al Solution-Grown CsPbBr 3 Cs 4 PbBr 6 Perovskite Nanocomposites Toward

Temperature-Insensitive Optical Gain Small v 13 n 34 p 1701587 set 2017

WANG Y et al Bright Luminescent Surface States on the Edges of Wide-bandgap Two-

dimensional Lead Halide Perovskite p 1ndash16 mar 2018b

XIE L-Q et al Organicndashinorganic interactions of single crystalline organolead halide perovskites

studied by Raman spectroscopy Phys Chem Chem Phys v 18 n 27 p 18112ndash18118 2016

YANG R X et al Spontaneous octahedral tilting in the cubic inorganic cesium halide perovskites

CsSnX3and CsPbX3(X = F Cl Br I) Journal of Physical Chemistry Letters v 8 n 19 p

4720ndash4726 2017

YIN J et al Supporting Information Intrinsic Lead Ion Emissions in Zero-dimensional Cs 4 PbBr

6 Nanocrystals [sd]

YIN J et al Molecular behavior of zero-dimensional perovskites Science Advances v 3 n 12

p e1701793 2017a

57

YIN J et al Intrinsic Lead Ion Emissions in Zero-Dimensional Cs4PbBr6 Nanocrystals ACS

Energy Letters v 2 n 12 p 2805ndash2811 2017b

ZEWEN XIAO C et al Materials Horizons rsclimaterials-horizons Searching for promising new

perovskite-based photovoltaic absorbers the importance of electronic dimensionality Searching

for promising new perovskite-based photovoltaic absorbers the importance of electronic v 4 p

206 2017

ZHANG B BIN et al The preparation and characterization of quasi-one-dimensional lead based

perovskite CsPbI3crystals from HI aqueous solutions Journal of Crystal Growth v 498 n May

p 1ndash4 2018a

ZHANG H et al Pure zero-dimensional Cs4PbBr6 single crystal rhombohedral microdisks with

high luminescence and stability Physical Chemistry Chemical Physics v 19 n 43 p 29092ndash

29098 2017

ZHANG L et al Pressure-Induced Structural Evolution and Optical Properties of Metal Halide

Perovskite CsPbCl3 The Journal of Physical Chemistry C p acsjpcc8b05397 15 jun 2018b

ZHANG L ZENG Q WANG K Pressure-Induced Structural and Optical Properties of

Inorganic Halide Perovskite CsPbBr3 Journal of Physical Chemistry Letters v 8 n 16 p

3752ndash3758 2017a

ZHANG Q YIN Y All-Inorganic Metal Halide Perovskite Nanocrystals Opportunities and

Challenges 2018

ZHANG Z et al Growth characterization and optoelectronic applications of pure-phase large-

area CsPb2 Br5 flake single crystals Journal of Materials Chemistry C v 6 n 3 p 446ndash451

2018d

2




Msc thesis presented to the Post-Graduation

Course in Physics of the Federal University of

Cearaacute as part of the requisites for obtaining the

Degree of Master in Physics

Advisor Prof Dr Alejandro Pedro Ayala

FORTALEZA

2018

3

4










BANCA EXAMINADORA

___________________________________________________________



___________________________________________________________



___________________________________________________________



5

Acknowledgements








investigation







microscopy and EDX








6

Abstract













7

Resumo














hidrostaacutetica

8

List of Figures


















34





positions 39










and intensity 47

9

List of tables





38





10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

3

4










BANCA EXAMINADORA

___________________________________________________________



___________________________________________________________



___________________________________________________________



5

Acknowledgements








investigation







microscopy and EDX








6

Abstract













7

Resumo














hidrostaacutetica

8

List of Figures


















34





positions 39










and intensity 47

9

List of tables





38





10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

4










BANCA EXAMINADORA

___________________________________________________________



___________________________________________________________



___________________________________________________________



5

Acknowledgements








investigation







microscopy and EDX








6

Abstract













7

Resumo














hidrostaacutetica

8

List of Figures


















34





positions 39










and intensity 47

9

List of tables





38





10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

5

Acknowledgements








investigation







microscopy and EDX








6

Abstract













7

Resumo














hidrostaacutetica

8

List of Figures


















34





positions 39










and intensity 47

9

List of tables





38





10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

6

Abstract













7

Resumo














hidrostaacutetica

8

List of Figures


















34





positions 39










and intensity 47

9

List of tables





38





10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

7

Resumo














hidrostaacutetica

8

List of Figures


















34





positions 39










and intensity 47

9

List of tables





38





10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

8

List of Figures


















34





positions 39










and intensity 47

9

List of tables





38





10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

9

List of tables





38





10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

10








11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

11

Contents

Introduction 12


Chapter 1 20


Materials 20


Cs4PbBr6 20

CsPb2Br5I 21

(DMA)11Pb4Br19 21

(DMA)14RbPb4Br23 21

(DMA)9S4Pb5Br27 21




Chapter 2 27


Chapter 3 35


Chapter 4 42



Conclusions 49

References 52

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

12

Introduction





























13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

13


















14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

14














2018a)

















15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

15












factors



small


size


B ion interstices


ionic radii

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

16


DAVID B MITZI 2016)





17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

17






























18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

18































19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

19






20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

20

Chapter 1





Materials










Cs4PbBr6






21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

21

CsPb2Br5I






(DMA)11Pb4Br19





(DMA)14RbPb4Br23





(DMA)9S4Pb5Br27





22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

22







119899120582 = 2119889ℎ119896119897 sin 120579 (1)



















23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

23


24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

24

Raman spectroscopy















25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

25
















studied compound 40

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

26






27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

27

Chapter 2

















(DMA)9S4Pb5Br27







composition

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

28








29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

29





30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

30










31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

31






octahedrons






















32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

32






Empirical

formula



2018)


3

(DMA)9S4Pb5Br2

7

Formula

weight

235006 276538 305640 335828

Temperatur

e

275(2) K 302(2) K 273(2) K 273(2) K


Crystal

system



Unit cell

dimensions

a=170859(3) Ǻ

b=196358(3) Ǻ

c=164307(3) Ǻ

β=105719(1)

a=108017(3) Ǻ

b=278009(8) Ǻ

c=248172(7) Ǻ

β=914880(10)

a=43899(3) Ǻ

b=156404(10) Ǻ

c=145021(9) Ǻ

a=109761(4) Ǻ

b=329494(12) Ǻ

c=151073(6) Ǻ

β=972490(10)

Volume 530627(16) Ǻ3 74500(4) Ǻ3 99571(11) Ǻ3 54200(4) Ǻ3

Z 4 2


Absorption

coefficient

23967 mm-1 19225 mm-1 16472 mm-1 17774 mm-1

F(000) 4168 4808 5288 2875


6 mm3

0214x0185x013

mm3

028x0164x016

mm3

Theta range

for data

collection

1615 to 2639

235 to 2385

237 to 2742

252 to 2367

Refinement

method


R indices

(all data)

R1=01816 wR2=01765

R1=0951

wR2=01207

R1=01504

wR2=03752

R1=00854

wR2=02090

Type of

chain


33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

33













34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

34



perovskite

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

35

Chapter 3















- layers are






36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

36







37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

37
















38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

38




CsPb2(Br085I015)5


Pb 8ℎ 1198622119907prime 1198601119892⨁1198602119892⨁1198602119906⨁1198611119892⨁1198611119906⨁1198612119892⨁119864119892⨁2119864119906

Cs 4119886 1198634 1198602119892⨁1198602119906⨁119864119892⨁119864119906

Br1 4119888 1198624ℎ 1198601119906⨁1198602119906⨁2119864119906

Br2I 16119897 119862119904119889 21198601119892⨁1198601119906⨁1198602119892⨁21198602119906⨁1198611119892⨁21198611119906⨁21198612119892⨁1198612119906⨁3119864119892⨁3119864119906

Γ119879119874119879 = 31198601119892⨁21198601119906⨁31198602119892⨁51198602119906⨁21198611119892⨁31198611119906⨁31198612119892⨁1198612119906⨁5119864119892⨁8119864119906

Γ119860119888 = 1198602119906⨁119864119906

Γ119868119877 = 41198602119906⨁7119864119906

Γ119877119886119898119886119899 = 31198601119892⨁21198611119892⨁31198612119892⨁5119864119892

Γ119878119894119897 = 21198601119906⨁31198611119906⨁1198612119906


39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

39















are reversible


phonon positions

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

40















disordered site
















41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

41







18 and 53 GPa

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

42

Chapter 4



halide perovskite



4minus
















119914119956120783 6a 1198633

Pb 6b 1198786

119914119956120784 18e 1198622

Br 36f 1198621

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

43
















44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

44














40 60 80 100 120 140 160 180 200 220 240 260 280 300

Ram

an I

nte

snsi

ty (

au

)

Wavenumbers (cm-1)

Experimental

Lorenztian

Calculated

45

4856

61

6975

84

107

124

136

153

179




45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

45












or 1205842 with 119864119892 symmetry


















46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

46



















phase transitions

0 1 2 3 4 5 6 7 8 9 10 11 1240

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

Wa

ve

nu

mbe

rs (

cm

-1)

Pressure (GPa)

(036 500)

40 60 80 100 120 140 160 180 200 220 240 260 280

ʋ1ʋ5

036 GPa

Release

1085 GPa

1015 GPa

968 GPa 921 GPa

758 GPa

708 GPa 680 GPa

657 GPa 632 GPa 600 GPa 550 GPa

514 GPa 473 GPa

390 GPa 428 GPa

353 GPa

325 GPa


150 GPa 123 GPa 100 GPa

071 GPa

0 GPa

Ram

an I

nte

nsi

ty(a

u)

Wavenumber (cm-1)

ʋ5

(a) (b)

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

47






high pressure












48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

48











49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

49

Conclusions

















-4 group












50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

50







for CsPb2Br5
























51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

51





52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

52

References





2016



5628 2013











2018b










10 n 19 p 3746ndash3749 2017


vibrations 1972

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

53







6 p 3215ndash3222 2018



842 2014


2018



2795 ago 2014









v 141 p 377ndash382 2015









2017


54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

54











2017b






p 54ndash62 2018



15 p 5309ndash5312 2017











56 n 19 p 11552ndash11564 2017



55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

55













2018


Students [sl sn]









2727 2013a









56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

56

v 536 n 7616 p 312ndash317 2016







55 n 29 p 8328ndash8332 jul 2016a




















4720ndash4726 2017


6 Nanocrystals [sd]


p e1701793 2017a

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

57






206 2017



p 1ndash4 2018a



29098 2017





3752ndash3758 2017a


Challenges 2018



2018d

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