www.sciencemag.org/content/350/6265/1222/suppl/DC1

Supplementary Materials for Overcoming the electroluminescence efficiency limitations of perovskite

light-emitting diodes

Himchan Cho, Su-Hun Jeong, Min-Ho Park, Young-Hoon Kim, Christoph Wolf, Chang-Lyoul Lee, Jin Hyuck Heo, Aditya Sadhanala, NoSoung Myoung, Seunghyup Yoo, Sang

Hyuk Im, Richard H. Friend, Tae-Woo Lee*

*Corresponding author. E-mail: twlee@postech.ac.kr, taewlees@gmail.com

Published 4 December 2015, Science 350, 1222 (2015) DOI: 10.1126/science.aad1818

This PDF file includes:

Materials and Methods Supplementary Text Figs. S1 to S13 Tables S1 to S5 References

Materials and Methods Preparation of MAPbBr3 solutions

MABr was synthesized by reacting 50 mL of hydrobromic acid (48 % in water, Aldrich) and 30 mL of methylamine (40 % in methanol, Junsei Chemical Co. Ltd.) at 0 °C for 2 h while stirring. Removing solvents by heating at 50 °C for 1 h yielded a white precipitate. Purification of the products was conducted by dissolving in ethanol, recrystallizing from diethyl ether, and drying at room temperature in a vacuum oven for 24 h. MAPbBr3 solutions (40 wt.%) were prepared by dissolving MABr and PbBr2 with varying molar ratio (MABr:PbBr2 = 1.1:1, 1.07:1, 1.05:1, 1.03:1, 1.02:1, 1:1, 1:1.05) in DMSO at 60 °C while stirring. Self-organized conducting polymer (SOCP) layer preparation

High-conductivity SOCP is composed of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (CleviosTM PH500), perfluorinated ionomer, tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer (PFI) (PEDOT:PSS:PFI = 1:2.5:11.2 (w:w:w)), and a small amount of DMSO additive. On top of the cleaned glass or polyethylene terephthalate substrates, the high-conductivity SOCP was spin-coated to fabricate a layer of 100-nm thickness, then baked on a hot plate at 200 °C for 10 min in air. Low-conductivity SOCP for MAPbBr3 film analysis is composed of PEDOT:PSS (CleviosTM P VP AI4083) and PFI (PEDOT:PSS:PFI = 1:6:25.4 (w:w:w)). The low-conductivity SOCP was spin-coated to fabricate a layer of 40-nm thickness, then baked on a hot plate at 150 °C for 30 min in air. Perovskite light-emitting diode (PeLED) fabrication

Glass substrates were cleaned in acetone and isopropyl alcohol (IPA) for 15 min by sonication, then boiled on a hot plate at 300 °C in IPA to evaporate the solvent quickly from the substrates. The cleaned glass substrates were UV-ozone treated for 15 min to make the surface hydrophilic, then high-conductivity SOCP was spin-coated on the glass substrate and used as an anode. To form MAPbBr3 layers, MAPbBr3 solutions were spin-coated onto the SOCP layers in glove box, then baked at 90 °C for 10 min. Particularly, MAPbBr3 nanograin layers could be fabricated by S-NCP or A-NCP, which use dripping of chloroform or chloroform:TPBI solution onto the spinning layers during spin-coating of MAPbBr3 solutions (Fig. S3). After transferring the specimens to a high vacuum thermal evaporator (< 10-7 Torr), the fabrication of PeLEDs was completed by depositing TPBI (50 nm), LiF (1 nm) and Al (100 nm) in sequence with deposition rates of 1, 0.1 and 3 Å s-1, respectively. PeLEDs were encapsulated before measurement in inert atmosphere. MAPbBr3 films used for characterization were not encapsulated unless indicated otherwise. PeLED characterization

The current-voltage-luminance characteristics of PeLEDs were measured by using a computer-controlled source-measurement unit (Keithley 236) and a spectroradiometer (Minolta CS2000).

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X-ray photoelectron spectroscopy and (XPS) and ultraviolet photoelectron spectroscopy (UPS)

XPS and UPS spectra of MAPbBr3 layers on Glass/ITO/SOCP (low-conductivity) were measured by using a photoelectron spectrometer (Kratos Inc., AXIS-Ultra DLD). A monochromatic Al-Kα line (1486.6 eV) was used for XPS, and He I radiation (21.2 eV) was used for UPS. Steady-state PL measurement

The steady-state PL of MAPbBr3 layers on Glass/SOCP (low-conductivity) was measured by using a spectrofluorometer (JASCO FP6500). Time-correlated single photon counting (TCSPC) measurement

The PL decay of MAPbBr3 films on Glass/SOCP (low-conductivity) was investigated using a TCSPC system. A pulsed diode-laser head (LDH−P-C-405, PicoQuant) coupled with a laser-diode driver (PDL 800-B, PicoQuant) was used as an excitation source with a pulse width < 70 ps and a repetition rate of 5 MHz. The excitation wavelength was 405 nm. The fluorescence was spectrally resolved using a monochromator (SP-2150i, Acton) and its time-resolved signal was measured by a TCSPC module (PicoHarp, PicoQuant) with a microchannel plate photomultiplier tube (MCP-PMT, R3809U-59, Hamamatsu). The total instrument response function (IRF) was < 130 ps, and the temporal resolution was < 10 ps. The deconvolution of the decay curve, which separates the IRF and actual decay signal, was performed using fitting software (FluoFit, PicoQuant) to deduce the time constant associated with each exponential decay curve. Photoluminescence quantum efficiency (PLQE) measurement

The PLQE of the thin film samples (Glass/SOCP (low-conductivity)/MAPbBr3) was measured using an integrating sphere method, described elsewhere (35). A continuous-wave 407-nm blue diode laser with an excitation power of 30 mW and a focused beam spot of ∼0.3 mm2 was used to photo-excite the samples. Emission was measured using an Andor iDus DU490A InGaAs detector. The samples were encapsulated between two glass cover slips before measurements.

Supplementary Text A. Efficiency summary of visible PeLEDs using OIP films

To the best of our knowledge, the highest reported EQE in visible PeLEDs using pure OIP films is ~ 0.8 % (15). The CE = 42.9 cd A-1 (EQE = 8.53%) of our PeLED lies well beyond all the PeLEDs (Table S1, Fig. S1). The achievement of high CE indicates that solution-processed PeLEDs can compete even with phosphorescent OLEDs in display and lighting. Furthermore, many advantages of PeLEDs (very high color purity, simply-tunable bandgap with a reasonable ionization energy, and low material cost) make them even more attractive than OLEDs. We expect that our work showing high efficiency will greatly inspire researchers and trigger the intensive study of PeLEDs.

3

B. Self-organized conducting polymers (SOCPs) We used two kinds of SOCPs for analysis (Table S2). High-conductivity SOCP was

used as an anode in PeLEDs. SOCPs have excellent exciton-buffering and hole-injection capabilities because the spin-coating of PEDOT:PSS:PFI solutions leads to the self-organization of components and concomitant gradient WF profiles with PFI-rich surfaces (7). MAPbBr3 films on a low-conductivity SOCP/glass substrate were used for measurement of XPS, UPS, XRD, PL, TCSPC, and PLQE.

C. Nanocrystal pinning (NCP) process

NCP is devised to fabricate MAPbBr3 nanograin films with reduced grain size (Fig. S3). Two steps of spin-coating speed were used (500 rpm for 7 s, 3000 rpm 90 s). After spin speed accelration (stage 1), MAPbBr3 solution in dimethyl sulfoxide was being spin-cast (stage 2). When 60 seconds passed, or at the end of stage 2, nanocrystal pinning occurred by chloroform or chloroform:TPBI solution. In stage 3, the residual solvents were evaporated.

D. MAPbBr3 grain size calculation (Fig. S4) & effect

A-NCP created much smaller MAPbBr3 grains than did S-NCP. Increased total area of grain boundaries in MAPbBr3 layers can be harmful for the charge transport due to charge traps, and for EL in PeLEDs due to quenching of excitons. However, this demerit of larger grain boundary area can be compensated by stronger spatial confinement of excitons. The reduced grain size can be a strong merit for PL and EL because excitons are more strongly confined in smaller grains than in larger grains, thereby reducing exciton dissociation and enhancing radiative recombination (6). Furthermore, because the metallic Pb atoms at grain boundaries were greatly reduced in our modified MAPbBr3 layers (MABr:PbBr2 = 1.05:1), luminescence quenching effect at grain boundaries was reduced significantly, which also compensate the adverse effect of increased grain boundary area caused by the decrease in grain size.

E. X-ray diffraction (XRD) analysis

We calculated the MAPbBr3 crystallite size using Scherrer equation 𝐿 = 𝐾𝜆

𝐵𝑐𝑜𝑠𝜃,

where L is the crystallite size [nm], 𝐾 is the Scherrer constant [dimensionless], 𝜆 is

the X-ray wavelength [nm], 𝐵 is full width at half maximum [rad] of a XRD peak and 𝜃 is X-ray angle [rad]. We assumed that MAPbBr3 crystallites were spherical; i.e., 𝐾 = 0.94 (37). The crystallite size was averaged over four largest peaks ((100), (110), (200) and (210)) (Table S3).

F. X-ray photoelectron spectroscopy (XPS) analysis

The Br:Pb atomic ratios were calculated considering the areas of Pb4f and Br3d peaks and the atomic sensitivity factors (8.329 for Pb, 1.055 for Br) as described elsewhere (7). The Br:Pb atomic ratios were 2.64 for the film of 1.05:1, 2.32 for 1:1 and 2.10 for 1:1.05. The deviation from an ideal ratio of 3 can be ascribed to unintended losses of Br atoms or to incomplete reactions between MABr and PbBr2 (25).

4

In the Br3d spectra (Fig. S7, A to B), two peaks were observed at 68.6 and 69.7 eV, which were assigned to Br3d5/2 and Br3d3/2, respectively (38). The positions and intensities of the peaks were not affected by the stoichiometric changes (Fig. S7A). The N1s spectra exhibited a peak at 402.4 eV which was assigned to a C-N+* bond (27). The intensities of N1s spectra gradually increased with increasing molar proportion of MABr; this change can confirm the changes in the MABr:PbBr2 ratio.

G. PL decay mechanism

In our decay mechanism model, the fast decay is related to trap-assisted recombination at grain boundaries, whereas the slow decay is related to radiative recombination inside the grains. Two different cases are explained depending on the presence of metallic Pb atoms (strong quenchers) (Fig. S9). When metallic Pb atoms are absent (MABr:PbBr2 = 1.05:1), the dominant decay channel is radiative recombination inside the nanograins (slow decay). However, when metallic Pb atoms in the emission layer of MABr:PbBr2 = 1:1 are mainly present at grain boundaries rather than in the grains, non-radiative recombination dominates due to the presence of many accessible quenching sites.

H. Exciton diffusion length modelling

We follow the diffusion model introduced by Stranks et al. (33) but introduced a bi-exponential decay model because it agrees better with our experimental data than the one by Stranks et al. We chose n(t) = 1

𝑛(0)∑ ni ∙ exp (−𝑏𝑖,𝑡𝑜𝑡𝑡)2𝑖=1 which yields a decay

function of

g(t) =−1𝑛(0)

�𝑛𝑖 ∙ 𝑏𝑖,𝑡𝑜𝑡exp (−𝑏𝑖,𝑡𝑜𝑡𝑡)2

𝑖=1

,

so our radiative decay equation reads (39)

f(t) =1

𝑛(0)�𝑛1𝑏1,𝑟𝑎𝑑 exp�−𝑏1,𝑡𝑜𝑡𝑡� + 𝑛2𝑏2,𝑟𝑎𝑑exp (−𝑏2,𝑡𝑜𝑡𝑡)�,

where n1 and 𝑛2 describe the respective density of two exciton species and is set

according to the fractional intensity obtained from TCSPC measurement, 𝑏𝑖,𝑟𝑎𝑑 is the radiative decay rate which is set to 20% (40), and 𝑏𝑖,𝑡𝑜𝑡 the total decay rate, including nonradiative decay which is inversely proportional to the species’ lifetime.

The decay model is used as described before; higher-order terms ∝ 𝑛2 and higher are neglected (41) and the 1-D diffusion equation reads

𝜕𝜕𝑡𝑛(𝑥, 𝑡) = 𝐷

𝜕2

𝜕𝑥2𝑛(𝑥, 𝑡) − 𝑔(𝑡)𝑛(𝑥, 𝑡),

where 𝐷 [m2 s-1] is the diffusion coefficient and 0 ≤ x ≤ L is the linear dimension [m]

of the active material. The initial condition is set by absorption according to Beer-

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Lambert law 𝑛(𝑥, 𝑡 = 0) = exp(−α𝑥) where α was calculated from the complex dielectric function. Forward and backward excitation were compared, and forward excitation data was used in the modelling. The difference between forward and backward excitation data was negligible. Excitons that reach the perovskite/air interface are considered to be quenched perfectly 𝑛(𝑥 = 𝐿, 𝑡) ≡ 0; this is a simplification but no detailed quenching model is currently known. Excitons at the polymer/perovskite interface are reflected back into the active region, i.e., ∂n(x=0,t)

∂x= 0 (42).

The quality of the fit was evaluated by calculating the Pearson's correlation r2 between modelled and the measured data (deconvoluted, IRF = 0.120 ns) and varying the diffusion coefficient until r2 > 0.995 was obtained. The residuals were then plotted and carefully evaluated with respect to their random distribution (43). A good degree of randomness was obtained leading to the conclusion that the diffusion model is reliable. After obtaining a diffusion coefficient the diffusion length 𝐿𝐷 = �𝐷 ∙ 𝜏𝑒 was calculated, where 𝜏𝑒 is the time required for the modelled decay curve to reach 1/e of its initial value (Fig. S10).

From variations of film thickness and the precision of the model we estimate LD to be precise down to an order of ±10 nm. In our experience the diffusion simulation is highly sensitive to the film thickness and the fractional intensities of the lifetime components.

I. Angle-dependent emission profile of PeLEDs

Our PeLED showed emission profile very similar to Lambertian. The accurate EQE values were calculated from this emission profile.

6

Fig. S1. Progress of visible PeLEDs.

Progress of visible PeLEDs

14/08

14/09

14/10

14/11

14/12

15/01

15/02

15/03

15/04

15/05

15/06

15/07

15/08

--0

2

4

6

8

10

(18)(17)(15)

(13)(7)

Reported works Our work Our previous work

Our workEQ

E (%

)

Year/Month

(6)

7

Fig. S2. Schematic illustrations of stoichiometry control and nanograin engineering. (A) Stoichiometry control using excess MABr to prevent exciton quenching from metallic Pb atoms. (B) MAPbBr3 nanograin engineering to enhance luminescent properties.

Excess CH3NH3Br

Enhanced LuminescenceExciton quenching by metallic Pb

Removal of metallic Pb

A

BSmaller nanograin sizeLarger nanograin size

Enhanced Luminescence

MAPbBr3 Nanograin Film

8

Fig. S3 NCP process. (A) Schematics of NCP process during spin-coating to fabricate MAPbBr3 nanograin films. (B) Spin-coating speed-time profile. NCP at the end of Stage 2 induces immediate crystallization.

MAPbBr3solution loading

nanocrystal pinningduring spin-coating

MAPbBr3nanograin film

Stage 1 Stage 2 Stage 3

nanocrystalpinning

A

B

0 20 40 60 80 1000

1000

2000

3000

Spin

-coa

ting

spee

d (rp

m)

Time (s)

9

Fig. S4. MAPbBr3 grain size distribution. The grain size distribution of MAPbBr3 nanograin layers of (A) 1:1.05, (B) 1:1, (C) 1.05:1 with S-NCP, and (D) 1.05:1 with A-NCP.

500 nm

500 nm

500 nm

500 nm

B

A

C

D

MABr:PbBr2 = 1.05:1 (S-NCP)

MABr:PbBr2 = 1:1.05 (S-NCP)

MABr:PbBr2 = 1.05:1 (A-NCP)

MABr:PbBr2 = 1:1 (S-NCP)

Average = 99.7 nm

0 50 100 150 200 2500

10

20

30

40

50

60

70

80 MABr:PbBr2 = 1.05:1 (A-NCP)

Coun

t

Size (nm)

0 100 200 300 400 5000

10

20

30

40

Coun

t

Size (nm)

MABr:PbBr2 = 1:1.05 (S-NCP)

0 100 200 300 400 5000

10

20

30

40 MABr:PbBr2 = 1:1 (S-NCP)

Coun

t

Size (nm)

0 100 200 300 400 5000

10

20

30

40

50

60 MABr:PbBr2 = 1.05:1 (S-NCP)

Coun

t

Size (nm)

Average = 182 nm

Average = 164 nm

Average = 192 nm

10

Fig. S5. XRD patterns of MAPbBr3 nanograin layers. (A) Variation in XRD peak positions with varying molar ratio MABr:PbBr2. (B) XRD patterns of MAPbBr3 layers (1.05:1) fabricated by S-NCP and A-NCP.

A

B

1.05:1(S-NCP)

1:1(S-NCP)

1:1.05(S-NCP)

1.05:1 (A-NCP)

10

20

30

40

50

2-th

eta

(deg

ree)

MABr:PbBr2 ratio

(300)(220)

(210)(200)

(110)

(100)

10 20 30 40 50 60

(300)

Norm

alize

d in

tens

ity (a

.u.)

2-theta (degree)

MABr:PbBr2 = 1.05:1 (A-NCP)

MABr:PbBr2 = 1.05:1 (S-NCP)

(100)

(110) (200)

(220)

(210)

(211)

11

Fig. S6. XPS survey and Pb4f spectra. (A) Survey spectra of MAPbBr3 nanograin layers with varying molar ratio MABr:PbBr2. Pb4f spectra of MAPbBr3 nanograin layers of (B) 1.05:1, (C) 1:1 and (D) 1:1.05 after deconvolution. (E) Pb4f spectra of MAPbBr3 nanograin layers with varying molar ratio MABr:PbBr2 and (F) magnified spectra at the peak assigned to metallic Pb.

147 144 141 138 135

MABr:PbBr2 = 1.05:1

Inte

nsity

(a.u

.)

Binding energy (eV)

Raw data Fitted data Background Pb4f5/2

Pb4f7/2

147 144 141 138 135In

tens

ity (a

.u.)

Binding energy (eV)

Raw data Fitted data Background Pb4f5/2

Metallic Pb Pb4f7/2

Metallic Pb

MABr:PbBr2 = 1:1.05

500 400 300 200 100 0

MABr:PbBr2 = 1.05:1 MABr:PbBr2 = 1:1 MABr:PbBr2 = 1:1.05

Inte

nsity

(a.u

.)

Binding energy (eV)

Pb

BrC

N

A

C

147 144 141 138 135

MABr:PbBr2 = 1:1

Inte

nsity

(a.u

.)

Binding energy (eV)

Raw data Fitted data Background Pb4f5/2

Metallic Pb Pb4f7/2

Metallic Pb

B

D

E F

138.0 137.5 137.0 136.5 136.0 135.50

5000

10000

15000

20000 MABr:PbBr2 = 1.05:1 MABr:PbBr2 = 1:1 MABr:PbBr2 = 1:1.05

Inte

nsity

(a.u

.)

Binding Energy(eV)146 144 142 140 138 136

0

20000

40000

60000

80000

100000 MABr:PbBr2 = 1.05:1 MABr:PbBr2 = 1:1 MABr:PbBr2 = 1:1.05

Inte

nsity

(a.u

.)

Binding Energy(eV)

12

Fig. S7. XPS Br3d and N1s spectra. (A) Br3d, (C) N1s spectra of MAPbBr3 nanograin layers with varying molar ratio MABr:PbBr2. (B) Br3d, (D) N1s spectra of MAPbBr3 nanograin layers of 1:1 after deconvolution.

405 404 403 402 401 400

MABr:PbBr2 = 1.05:1 MABr:PbBr2 = 1:1 MABr:PbBr2 = 1:1.05

Inte

nsity

(a.u

.)

Binding Energy(eV)

72 71 70 69 68 67 66

MABr:PbBr2 = 1.05:1 MABr:PbBr2 = 1:1 MABr:PbBr2 = 1:1.05

Inte

nsity

(a.u

.)

Binding Energy(eV)

405 404 403 402 401 400

Inte

nsity

(a.u

.)

Binding energy (eV)

Raw data Fitted data Background C-N+*

72 71 70 69 68 67 66

Inte

nsity

(a.u

.)

Binding energy (eV)

Raw data Fitted data Background Br3d3/2

Br3d5/2

A

C

B

D

13

Fig. S8. UPS spectra. UPS spectra of MAPbBr3 nanograin layers (A) showing secondary cut-offs and (B) offset between WFs and IEs of MAPbBr3 with varying molar ratio MABr:PbBr2.

16.5 16.4 16.3 16.2 16.1 16.0 15.9

~5.12 eV~5.09 eV~5.06 eV~5.02 eV~5.00 eV~4.98 eV

Norm

alize

d In

tens

ity (a

.u.)

Binding energy (eV)

1.1:1 1.07:1 1.05:1 1.03:1 1.02:1 1:1 1:1.05

MABr:PbBr2 WF~4.97 eVA

B

2.0 1.5 1.0 0.5 0.0

~0.89 eV Offset MABr:PbBr2

Norm

alize

d In

tens

ity (a

.u.)

Binding energy (eV)

1.1:1 1.07:1 1.05:1 1.03:1 1.02:1 1:1 1:1.05

14

Fig. S9. PL decay mechanism. A schematic illustration describing two proposed mechanisms of radiative recombination without (left) and with (right) stoichiometric tuning.

A MAPbBr3 grain and crystallites (sub-grains)

+

- exciton trap Metallic Pb

τ1: short lifetime component τ2: long lifetime component

(2) Radiative recombinationinside the grains

(1) trap-assisted recombination at grain boundaries

(3) Exciton quenching

~100 nm

-

+

+-

~100 nm

-+

(1)

MABr:PbBr2 = 1:1 MABr:PbBr2 = 1.05:1

-

+

+-

-+

(1)

-

+

𝐸 = ℎ𝜈 (𝜏2)

(2)

(3)

-+

(3) -+

(3)

-

+

𝐸 = ℎ𝜈 (𝜏2)

(2)-

+

-+

-+

- +

+-

𝐸 = ℎ𝜈 (𝜏2)

(2) (2)

𝐸 = ℎ𝜈 (𝜏2)

-+

-+

-(1)𝐸 = ℎ𝜈 (𝜏1)

- +

+

-

-+

-

+

- +

+

-

(1)-+ (2)

𝐸 = ℎ𝜈 (𝜏2)

15

Fig. S10. Exciton diffusion length modelling. TCSPC (red sphere) and simulated PL data (black solid line) of MAPbBr3 films (1.05:1) with PMMA capping layer. The exciton lifetime τe is extracted from the intersection of the simulated data with the dashed horizontal line that represents a drop of intensity to 1/e of the initial value.

50 1000

1

Inte

nsity

(a.u

.)

time (ns)

16

Fig. S11. Current density-voltage characteristics. Current density of PeLEDs based on MAPbBr3 nanograin emission layers with varying molar ratio MABr:PbBr2.

0 3 6 9 12 1510-710-610-510-410-310-210-1100101102103

1.07:1 1.05:1 1.03:1 1.02:1 1:1 1:1.05 1:1(w/o NCP)Cu

rrent

den

sity

(mA

cm-2)

Voltage (V)

17

Fig. S12. Angle-dependent emission profile of the PeLED.

18

Fig. S13. Photographs of PeLEDs. Photographs of (A) a normal PeLED and (B) a large-area (2 cm by 2 cm pixel) PeLED.

A

B

19

Table S1. Comparison of our work with previous reports.

Previous reports Publication year/month Emission layer Maximum CE

(cd A-1) Maximum EQE

(%) Tan et al. (6) 2014/08 MAPbBr3 0.3 0.1 Kim et al. (7)

(our previous work) 2014/11 MAPbBr3 0.577 0.125

Hoye et al. (12) 2015/01 MAPbBr3 ~ 0.27 not reported

Kumawat et al. (13) 2015/01 MAPbBr3, MAPbI3-xBr3

~ 1.8 × 10-2 (green)

~ 2.8 × 10-4 (red)

~ 6.5 × 10-3 (green)

~ 1.1 × 10-3 (red) Wang et al. (15) 2015/02 MAPbBr3 not reported ~ 0.8

Sadhanala et al. (16) 2015/02 MAPbI3-xClx: MEH-PPV not reported ~ 0.005

Qin et al. (36) 2015/03 MAPbBr3 not reported ~ 0.1 Yu et al. (18) 2015/05 MAPbBr3 0.22 0.051

Kumawat et al. (19) 2015/06 MAPbBr3-xClx ~ 9 × 10-3 (green) ~ 3.5 × 10-4 (blue) ~ 3 × 10-4 (blue)

Our work MAPbBr3 42.9 8.53

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Table S2. Composition, WF and conductivity of SOCPs.

Sample PEDOT / PSS / PFI (w/w/w)

DMSO 5 wt.%

WF (eV) (AC2)

Conductivity (S cm-1)

PEDOT:PSS 1 / 2.5 / 0 O 4.73 300 1 / 6 / 0 X 5.20 6.06 × 10-4

SOCP High conductivity 1 / 2.5 / 11.2 O 5.80 50

Low conductivity 1 / 6 / 25.4 X 5.95 ~ 1 × 10-4

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Table S3. Lattice parameter [nm] and average crystallite sizes [nm] depending on the molar ratio of MABr to PbBr2.

MABr:PbBr2 Lattice parameter Crystallite size Average Standard deviation

1.05:1 5.88 24.9 1.3 1:1 5.89 24.4 2.4

1:1.05 5.88 25.5 1.6

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Table S4. WF (eV), offset (eV) and IE (eV) depending on the molar ratio of MABr to PbBr2.

MABr:PbBr2 WF Offset IE

1.1:1 4.97

~0.89

~5.86 1.07:1 4.98 ~5.87 1.05:1 5.00 ~5.89 1.03:1 5.02 ~5.91 1.02:1 5.06 ~5.95

1:1 5.09 ~5.98 1:1.05 5.12 ~6.01

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Table S5. Fast PL lifetime (τ1), slow PL lifetime (τ2) and average lifetime (τavg) depending on the molar ratio of MABr to PbBr2. The PL decay curve with MABr:PbBr2 = 1.05:1 with PMMA cover and MABr:PbBr2 = 1:1 can also be fitted well by single-exponential decay model.

MABr:PbBr2 Fitting model (exponential

decay) τ1 (ns) f1 (%) τ2 (ns) f2 (%) χ2 τavg (ns)

1.05:1 (PMMA-covered)

Bi- 18.0 9 106.0 91 1.05 98.0

Single- 60.9 100 - - 1.32 60.9

1.05:1 Bi- 13.0 23 62.3 77 1.30 51.0 1.03:1 Bi- 14.3 24 56.7 76 1.27 46.5 1.02:1 Bi- 12.5 20 44.7 80 1.11 38.3

1:1 Bi- 8.11 46 15.6 54 1.50 12.2 Single- 11.3 100 - - 2.02 11.3

1:1.05 Bi- 9.92 13 33.6 87 1.61 30.5

24

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