18
1st Chungju-Suzhou International Workshop on Novel Nanomaterials and Nanodevices Soochow University, Suzhou, China 19-22 December 2012
1st Chungju-Suzhou International Workshop on
Novel Nanomaterials and Nanodevices
Soochow University, Suzhou, China
19-22 December 2012
Content
Wednesday, 19th December
Registration
Thursday, 20th December
Time Speaker
9:00-9:10
Welcome Speech
Dean of School of Physical Science and Technology, School of Energy,
Soochow University
9:10-9:40
Invited talk, Prof. Jae-Joon Lee
Quasi Fermi Energy Tuning of Carbon Nanotubes-Incorporated TiO2
Photoelectrode for Dye-Sensitized Solar Cells
9:40-10:10 Invited talk, Prof. Huisheng Peng
Novel Photovoltaic Devices in a Wire Format
10:10-10:20 Tea Break
10:20-10:50
Invited talk, Prof. Joon kyung Jang
Nanopatterns Made from Self-Assembled Monolayer of Alkanethiol:
a Molecular Simulation Study
10:50-11:20
Invited talk, Prof. Baoquan Sun
Organic-inorganic Hybrid Solar Cells Based on Nanostructured
Semiconductor
11:20-11:50 Invited talk, Prof. Zengfeng Di
He bubble superlattice formation in He implanted Au bicrystal
11:50 Lunch
14:00-14:30
Invited talk, Prof. Sanggyu Yim
Molecular Thin Film Growth and Its Application to Small-Molecule
Organic Photovoltaic Cells
14:30-15:00
Invited talk, Prof. Qingwen Li
Assembling Carbon Nanotubes into Strong and Multifunctional
Fibers and Composites
15:00-15:30
Invited talk, Prof. Sangbok Lee
Fast Electrochemistry of Heterogeneous Nanowires for
High-to-Ultrahigh Power Energy Storage
15:30-15:40 Tea Break
15:40-16:10 Invited talk, Prof. Hao Yang
Controllable self-assembly in nanocomposite oxide thin films
16:10-16:40 Invited talk, Prof. Guifu Zou
Carbon Nanotubes Integrated with Superconducting NbC
16:40-17:00 Daily summary of the workshop
17:00 Dinner
Friday, 21st December
9:00-11:00
Open
Discussion
Prof. Yongjun Kim
Konkuk University, Nanotechnology Research Center / Department
of Applied Biochemistry
Prof. Yinghui Sun
School of Energy, Soochow University
Dr. Sung Chan Jo
Principal engineer/ Group leader
Samsung Display Co.
Prof. Jie Zhao
School of Energy, Soochow University
Prof. Gwangmo Noh
Konkuk University, Nanotechnology Research Center / Department
of Nanoscience and Mechanical Engineering
Prof. Sang Jung Ahn
Korea Research Institute of Standards and Science
14:00-16:30 Lab tour
Saturday, 22nd December
9:00-12:00 Visit Shanghai Zhangjiang High Technology Park
14:00-16:30 Visit College of Materials Science and Engineering, Donghua University,
Shanghai
Closing Banquet
Quasi Fermi Energy Tuning of Carbon Nanotubes-Incorporated
TiO2 Photoelectrode for Dye-Sensitized Solar Cells
Jae-Joon Lee1,2*
, Narayan Chandra Deb Nath1
1 Department of Advanced Technology Fusion, Konkuk University, Seoul 143-701,
Korea 2Nanotechnology Research Centre & Department of Applied Chemistry, Konkuk
University, Chungju 380-701, Korea *E-mail: [email protected]
The charge transport across the mesoporous TiO2 electrode is known to be a major
bottleneck limiting energy conversion efficiency of a dye-sensitized solar cell (DSSC).
Even though the well ordered or aligned TiO2 network with one-dimensional
directionality has been suggested for effective electron transport pathways, they were
generally proved to be unsuccessful in enhancing the overall efficiency of DSSCs.
Meanwhile, numerous studies have been reported to incorporate carbon nanotubes
(CNTs) into the TiO2 mesoporous layer to take advantage of highly efficient electron
collection and transporting capability. However, it was found that the net power
conversion efficiency was not enhanced even with the increase of the photocurrent
density due to the significant decay of open circuit voltage (Voc) in DSSCs.1
It was
observed that the back electron transfer process is mainly responsible for the
significant Voc drop when CNTs were deposited at the electron collecting substrate of
the photoelectrode. Moreover, we noted that the recombination process is dependent
on the formation of two different types of surface states or traps at hetero-junction
interfaces of FTO|CNTs and TiO2|CNTs, lying energetically below the Fermi level of
FTOs and the conduction band edge of TiO2 nanoparticles (ECB,TiO2), respectively.
This is generally consistent with the negative shift of the quasi Fermi level of the
photoelectrode due to equilibration with a much lower Fermi level of carbon
nanotubes (-4.64 eV). In this regard, three electrode structures with different spatial
arrangements of carbon nanotubes (CNTs) in the mesoporous TiO2 layer were
employed in dye-sensitized solar cells to study the effect of surface states at the
interface formed by the incorporation of CNTs.2 It was found that the direct contact of
nanotubes with the conducting substrate was mostly the source of back electron
transfer to electrolytes via both TiO2 nanoparticles and conducting substrates
themselves through these surface states. And, it was possible to avoid the Voc decay
by the very simple approach of introducing a thin buffer layer of TiO2 to prevent
nanotubes from direct contact to FTO. However, the conventional design of
CNT-incorporated TiO2 photoelectrode still displayed the decrease of Voc. Therefore,
Invited Abstract
we introduced the sp2 nitrogen-doped carbon nanotubes (N(sp
2)-CNTs) into the
mesoporous TiO2 layer for a new route to allow enhanced photocurrent density
without loss of the Voc.3 Incorporation of the sp
2 selective nitrogen atom, N(sp
2), into
carbon nanotubes has been found to induced a positive shift of Fermi level of the TiO2
photoelectrode. So, the Fermi energy level tuning of the photoanode by extended
N(sp2)-CNTs provides a new insight in fabrication of dye sensitized solar cell
preventing Voc decay suffering from the use of pristine CNTs while the fundamental
efficient charge carrier transport properties of carbon nanotubes are still preserved.
References:
(1). N. C. D. Nath, S. Sarker, A. J. S. Ahammad, M. M. Rahman, S.-S. Lim and J.-J.
Lee, accepted to J. Nanosci. Nanotechnol. (2012).
(2). N. C. D. Nath, S. Sarker, A. J. S. Ahammad, and J.-J. Lee, Phys. Chem. Chem.
Phys., 2012, DOI:10.1039/C2CP00035K.
(3). G. I. Lee, N. C. D. Nath, S. Sarker, W. H. Shin, A. J. S. Ahammad, J. K. Kang
and J.-J. Lee, Phys. Chem. Chem. Phys., 2012, DOI: 10.1039/C2CP40279C.
Novel Photovoltaic Devices in a Wire Format
Tao Chen, Zhibin Yang, Huisheng Peng*
Laboratory of Advanced Materials and Department of Macromolcular Science, Fudan University, Shanghai 200438, China
E-mail: [email protected]
Photovoltaic devices are typically made of a rigid plate which is unfavorable for
various applications, e.g., portable and highly integrated devices and equipments.
Therefore, the development of flexible organic photovoltaics has recently become the
subject of active research as a good solution, but the generally studied flexible films
still could not meet many applications, e.g., electronic textiles where photovoltaic
devices are required to be weaveable. As a result, the devices in a flexible wire format
start to attract attentions, and some attempts to make wire-shaped photovoltaics have
appeared in recent years. However, the photovoltaic wires suffer from poor
performance, particularly, much lower energy conversion efficiency than the
conventional planar photovoltaics, as the often used metal wire, carbon fiber, or
modified polymer fiber as electrode might not be able to fully meet the much stricter
requirements including the combined elaborate surface and high flexibility and
conductivity in the wire cell. Here we first show that continuous carbon nanotube and
graphene fibers function as new electrodes to realize photovoltaic wires with high
energy conversion efficiencies.
References
(1) Peng, H. J. Am. Chem. Soc. 2008, 130, 42.
(2) Peng, H.; Sun, X.; Cai, F.; Chen, X.; Zhu, Y.; Liao, G.; Chen, D.; Li, Q.; Lu, Y.;
Zhu, Y.; Jia, Q. Nature Nanotechnology 2009, 4, 738.
(3) Sun, X.; Chen, T.; Huang, S.; Li, L.; Peng, H. Chem. Soc. Rev. 2010, 39, 4244.
(4) Chen, X.; Li, L.; Sun, X.; Liu, Y.; Luo, B.; Wang, C.; Bao, Y.; Xu, H.; Peng, H.
Angew. Chem. Int. Ed. 2011, 50, 5486.
(5) Wang, W.; Sun, X.; Wu, W.; Peng, H.; Yu, Y. Angew. Chem. Int. Ed. 2012, 51,
4644.
(6) Sun, X.; Wang, W.; Qiu, L.; Guo, W.; Yu, Y.; Peng, H. Angew. Chem. Int. Ed. 2012,
51, 8520.
(7) Chen, T.; Qiu, L.; Yang, Z.; Cai, Z.; Ren, J.; Li, H.; Lin, H.; Sun, X.; Peng, H.
Angew. Chem. Int. Ed. 2012, 51, anie.201207023, online.
Invited Abstract
Nanopatterns Made from Self-Assembled Monolayer of Alkanethiol:
a Molecular Simulation Study
Joonkyung Jang1*
, Joyanta K. Saha1
1 Department of Nanomaterials Engineering, Pusan National University, Busan
609-735, Korea *E-mail: [email protected]
By using molecular dynamics simulation, we studied the nanopatterns carved out of
the self-assembled monolayer (SAM) of octadecanethiol on gold. The present system
is relevant to the nanopatterns of SAM generated by various nanolithographic
techniques such as dip-pen nanolithography and microcontact printing. We show that
the minimum diameter of ordered SAM structures is 1.9 nm at room temperature. For
SAMs larger than 1.9 nm, the tilt direction of the alkyl chain precesses around the
center of the SAM. This precession changes direction on a timescale that increases
from ps to ns as SAM size varies from 2 to 3 nm. The molecular packing structure of
SAM line was examined and compared with those of the bulk SAM. We also studied
how narrow a SAM line can be without being disconnected or losing the compact
packing structure found in the bulk SAM, which is related to the ultimate resolution
of a SAM line pattern. Also investigated is how close two lines can be without
merging, which pertains to the spatial resolution of a SAM pattern. A stable SAM line
must be at least 1.7 nm wide, and two lines merge if they are less than 3.0 nm apart. If
two SAM lines cross each other, each line is further destabilized because the crossing
point tends to become circular in shape to maximize the interchain packing of thiol
molecules.
Invited Abstract
Organic-inorganic Hybrid Solar Cells Based on Nanostructured
Semiconductor
Xiaojuan Shen, Fute Zhang, Tao Song, Baoquan Sun*
Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, 199 Ren’ai Road, Suzhou, 215123, China Electronic mail: [email protected]
Numerous new materials and device structures have been widely explored in order to
cut the cost of photovoltaic (PV) manufacture. Especially, low cost organic PVs are
undergoing rapid development. A certified power conversion efficiency (PCE) of
8.37% was achieved in bulk heterojunction photovoltaic device using low-bandgap
conjugated polymer as donor and fullerene derivative PC71BM as acceptor1. In
addition, the fast-booming nanotechnology allows people to observe and manipulate
materials in sub-nanometer scale. Organic-inorganic hybrid solar cells based on
nanostructured semiconductor have built up in few years ago, which can benefit the
advantages of both organic and inorganic. However, the device performances are
relatively lower than its pristine all-inorganic PV devices, resulting from the
numerous surface defect and improper organic-inorganic phase segregation. In our
group, we have developed various nanostructured semiconductors for
high-performance solar cell, as shown in Figure 1. We have investigated
organic-inorganic hybrid solar cells based on nanostructured semiconductor,
including colloidal semiconductor nanocrystals and silicon nanowire array which act
as acceptor. The donor organic materials can be either small molecules or conjugated
polymers. Here, we demonstrate that hybrid PVs based on organic conjugated
molecular and silicon nanowire (SiNWs) arrays can achieve a high PCE (~10%) by
controlling the phase separation as well as surface passiviation2- 4
.
An advantage of hybrid devices presents the excellent light harvest capability of
SiNWs as well as simple fabrication process. The antireflection property of SiNW
arrays fabricated by chemical etching method is significantly enhanced over wide
spectrum range. In addition, we can passiviate the surface defect by methyl group
termination, which suppress the surface recombination velocity dramatically.
Figure 1 Hybrid solar cell based on organic and
inorganic semiconductor.
Furthermore, we can control the phase separation by tuning the density of SiNWs
array and the shell thickness of polymer. Conjugated organic materials exhibit
low-cost solution processability. PVs employing organic and SiNWs hybrid materials
as photoactive layer exhibit the
potency to benefit from the
advantages of both organic and Si
components. The utilization of the
organic molecular allows hybrid
cells to be superior over
conventional silicon ones in terms of
their cost and scalable solution
processing. Hybrid solar cells attract
wide research interests in the
photovoltaic community. Especially,
hybrid composites of conjugated
organic materials and nanostructured
inorganic materials are potential candidates for cost-effective and efficient
solar-energy-harvesting devices.
Reference
[1]. Z. He, C. Zhong, X. Huang, W.-Y. Wong, H. Wu, L. Chen, S. Su, Y. Cao Adv. Mater. 2011, 23,
4636-4643
[2]. T. Song; S. T. Lee; B. Q. Sun J. Mater. Chem. 2012, 22, 4216-4232
[3] X. Shen; B. Q. Sun; D. Liu; S. T. Lee, J. Am. Chem. Soc. 2011, 133, 19408-19415
[4] F. Zhang, B. Sun, T. Song, X. Zhu, S. Lee Chem. Mater., 2011, 23, 2084-2090
-0.6 -0.3 0.0 0.3 0.615
0
-15
-30
J (
mA
/cm
2)
Voltage (V)
Voc
= 0.527 V
Jsc
= 31.3 mA/cm2
FF = 0.588
PCE = 9.70%
PEDOT:PSS
Metal
Metal
Figure 2 (a) The device structure, (b) The electrical output curves of hybrid photovoltaic device.
(a) (b)
He bubble superlattice formation in He implanted Au bicrystal
Zengfeng Di,a,b,*
Xian-Ming Bai,c Qiangmin Wei,
b Jonghan Won,
c Richard G.
Hoagland,c Yongqiang Wang,
c Amit Misra,
b Blas P. Uberuaga,
c and Michael
Nastasib,d
aState Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem
and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China bMaterials Physics and Applications Division, MPA-CINT, Los Alamos National Laboratory, Los
Alamos, New Mexico, 87545, USA cMaterials Science and Technology Division, MST-8, Los Alamos National Laboratory, Los
Alamos, New Mexico, 87545, USA dNebraska Center for Energy Sciences Research, University of Nebraska-Lincoln, Lincoln,
Nebraska, 68583, USA
*Corresponding author: [email protected]
The compelling demand to reduce reliance on fossil fuels while meeting rapidly
growing energy need has stimulated worldwide interest in advanced fission and fusion
energy. Energetic fission and fusion neutrons displace large numbers of atoms from
their lattice positions, creating excess concentrations of vacancy and self-interstitial
atom (SIA) defects, and generate insoluble helium from transmutation reactions. The
helium and defects lead to complex microstructural evolution, in general, He bubbles
that contribute to both swelling and embrittlement in first wall materials of nuclear
reactor, and degrade the material sustaining properties. Recently, an ingenious
approach, i.e., nanolayered metallic has been proposed to mitigate radiation defects
and suppress helium bubble nucleation and growth. The enhanced radiation damage
tolerance of nanolayered metallic compared to single-phase bulk metals is attributed
to sink effect of interface for radiation-induced defects. Similar effect is also
speculated in grain boundaries (GBs), since nanocrystalline materials, which contain a
large fraction of GBs, have proven to more radiation tolerant compared with their
polycrystalline counterparts. However, how helium bubble nucleate at grain
boundaries and how radiation defects interact with grain boundaries are poorly
undertood due to diverse GBs coexists in nanocrystalline or polycrystalline system,
though atomistic simulation may shed light on one specific GB with limited time and
length scales.
In this letter, we create well-defined grain boundary in gold, i.e., pure twist boundary
with precisely controlled twist angle, and investigate the nucleation and growth of
helium bubbles at the presence of such a specific grain boundary. Interestingly,
helium bubbles preferentially nucleate at the nodes of screw dislocations, which lie in
the plane of twist boundary, and form helium bubble lattice. Different from helium
bubble superlattice intensively studied in last century, which is formed by high
fluence (~1018
cm-2
) helium implantation into metal, and has complete isomorphy with
the host metal, the helium bubble lattice in current study only requires very low
fluence (~1015
cm-2
) helium implantation, and behaves the same symmetry as the
screw dislocation network formed along the twist boundary.
Helium bubble superlattice ordered by the screw dislocation network in Au bicrystal
Molecular Thin Film Growth and Its Application to Small-Molecule
Organic Photovoltaic Cells
Sanggyu Yim1,*
1 Department of Chemistry, Kookmin University, Seoul 136-702, Korea
*E-mail: [email protected]
Organic semiconductors have received growing attention for their potential
importance in a wide range of optoelectronic device applications such as organic solar
cells. The analyses on the growth patterns of organic thin films, however, have not
intensively studied despite the surface morphology and interface structure of the
organic layers are known to play a crucial role in the device performance. In this talk,
the surface analyses on the organic thin films used for small molecular weight organic
solar cells and their growth will be discussed. The surface morphology evolution was
observed using various analytical instruments such as atomic force microscope (AFM)
and the analyses on the growth behavior of the films were performed using height
difference correlation function (HDCF) method. The fabrication, structure, and other
properties of the cells are also presented. Especially, the factors hampering further
enhancement in the power conversion efficiency of the cells such as exciton
recombination, light absorption and interfacial morphology between electron donor
and acceptor layer will be discussed in detail.
Assembling Carbon Nanotubes into Strong and Multifunctional Fibers
and Composites
Qingwen Li
Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Science, Suzhou, China
Carbon nanotubes (CNTs) are the strongest material ever synthesized by mankind. It
has extremely high tensile strength (>60 GPa), high modulus (1 TPa), large aspect
ratio (104 to >10
6), low density (less than 1.4 g/cm3), good chemical and
environmental stability, high thermal conductivity (better than diamond) and
relatively good electrical conductivity. These unique properties make CNTs very
attractive not only for the fabrication of nanoscale devices, but also for broad potential
applications in macroscale, such as strong fibers for body armors and light-weight
aerospace structures, and electronic fibers for smart textiles. However, technological
bottlenecks on CNT dispersion and alignment, especially under high volume fraction
have greatly limited CNT application for practical high-strength composites. In my
talk, I will summarize our recent efforts on how to assemble nanoscale individual
tubes into macroscale fibers and composites with high strength and multifuntionalities.
My talk will cover following five aspects: 1) the mechanical strength of individual
tubes; 2) the self-assembly of carbon nanotubes; 3) solid-state spinning of carbon
nanotube fibers and its potential applications; 4) Strong and functional carbon
nanotube composites by dry-processing; 5) conclusions and prospects
Fast Electrochemistry of Heterogeneous Nanowires for
High-to-Ultrahigh Power Energy Storage
Sang Bok Lee
Department of Chemistry and Biochemistry NEES-Energy Frontier Research Center
University of Maryland Chemistry Building, College Park, MD 20742, USA
School of Nanoscience and Technology (WCU) Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
Fast charge-discharge process of heterogeneous nanostructured materials offers vast
gains in electrical and electrochemical reaction speed by increasing surface area and
reducing path lengths for electron and ion transport. The presentation will discuss both
the electrochemical and electrostatic supercapacitors as high-to-ultrahigh power energy
devices, a newly emerging research area in energy storage research field, especially for
power leveling, management, safety, stability, and longevity of battery packs in energy
grid system. The electrochemical growth and atomic layer deposition of the
heterogeneous composite nanotubes and nanowires will be mainly described with
combination of well-controlled porous films. The fast electrochromics will be briefly
discussed and demonstrated as a proof of the fast redox reaction. The same concept of
fast redox reaction can be applied to high power energy storage device such as
supercapacitor and high-power battery. Heterogenous nanostructured materials
separate the multiple functionalities (large energy storage, rapid ion transport, high
electrical conductivity, high mechanical stability) to different materials, realizing a
combined material structure with much higher synergistic performance.
REFERENCES
1. “Nanoengineering Strategies for Metal–Insulator–Metal Electrostatic Nanocapacitors”,
Lauren C. Haspert, Sang Bok Lee*, and Gary W. Rubloff*, ACS Nano, 2012, 6, 3528–3536.
2. “Highly Flexible Pseudocapacitor Based on Freestanding Heterogeneous MnO2/Conductive
Polymer Nanowire Arrays”, Jonathon Duay, Eleanor Gillette, Ran Liu, and Sang Bok Lee*,
Phys. Chem. Chem. Phys., 2012, 14, 3329 – 3337
3. “Electrochemical synthesis and one step modification of PMProDot nanotubes and their
enhanced electrochemical properties”, Thao M. Nguyen, Seungil Cho, Nitinun
Varongchayakul, Daehyun Yoon, Joonil Seog, Kyukwan Zong and Sang Bok Lee*, Chem.
Commun., 2012, 48, 2725 - 2727
4. “High to Ultra-high Power Electrical Energy Storage”, Stefanie A. Sherrill, Parag Banerjee,
Gary W. Rubloff*, and Sang Bok Lee*, Phys. Chem. Chem. Phys., 2011, 13, 20714 – 20723.
5. “Heterogeneous Nanostructured Electrode Materials for Electrochemical Energy Storage”,
Ran Liu, Jonathon Duay and Sang Bok Lee*, Chem. Comm., 2011, 47, 1384 - 1404.
6. “MnO2/TiN Heterogeneous Nanostructure Design for Electrochemical Energy Storage”,
Stefanie A. Sherrill, Jonathon Duay, Zhe Gui, Parag Banerjee, Gary W. Rubloff, and Sang Bok
Lee*, Phys. Chem. Chem. Phys., 2011, 13, 15221 - 15226
7. “Electrochemical Formation Mechanism for the Controlled Synthesis of Heterogeneous
MnO2/Poly (3,4-ethylenedioxythiophene) Nanowires”, Ran Liu, Jonathon Duay and Sang
Bok Lee*, ACS Nano, 2011, 5, 5608–5619.
8. “Synthesis and Characterization of RuO2/poly (3,4-ethylenedioxythiophene) (PEDOT)
Composite Nanotubes for Supercapacitors”, Ran Liu, Jonathon Duay, Timothy Lane, and Sang
Bok Lee*, Phys. Chem. Chem. Phys., 2010, 12, 4309 - 4316.
9. “Profile Evolution for Conformal Atomic Layer Deposition over Nanotopography”, Erin R.
Cleveland, Parag Banerjee, Israel Perez, Sang Bok Lee and Gary W. Rubloff*, ACS Nano,
2010, 4, 4637–4644.
10. “Redox Exchange Induced MnO2-Nanoparticle Enrichment in
Poly(3,4-ethylenedioxythiophene) Nanowires for Electrochemical Energy Storage”, Ran Liu,
Jonathon Duay, and Sang Bok Lee*, ACS Nano, 2010, 4, 4299–4307.
11. “Nanotubular metal–insulator–metal capacitor arrays for energy storage”, Parag Banerjee,
Israel Perez, Laurent Henn-Lecordier, Sang Bok Lee* and Gary W. Rubloff*, Nature
Nanotech, 2009, 4, 292-296.
12. “MnO2/Poly(3,4-ethylenedioxythiophene) Coaxial Nanowires by One-Step
Coelectrodeposition for Electrochemical Energy Storage,” Ran Liu, Sang Bok Lee*, J. Am.
Chem. Soc., 2008, 130, 2942-2943.
13. “Efficient Nanotube Metrology and Application to Nanodevices Employing Atomic Layer
Deposition”, Israel Perez, Erin Robertson, Parag Banerjee, Laurent Henn-Lecordier, Sang Jun
Son, Sang Bok Lee, Gary W. Rubloff*, Small, 2008, 4, 1223-1232.
14. “High-Power Supercapacitors Based on Poly(3,4-ethylenedioxythiophene) Nanotube Array in
Alumina Template”, Ran Liu, Seung Il Cho, and Sang Bok Lee*, Nanotechnology, 2008, 19,
215710.
15. “Fast Electrochemistry of Conductive Polymer Nanotubes: Synthesis, Mechanism and
Application”, Seung Il Cho and Sang Bok Lee*, Acc. Chem. Res., 2008, 41, 699-707.
Controllable self-assembly in nanocomposite oxide thin films
Hao Yang,1 Haiyan Wang,
2 Judith L. MacManus-Driscoll,
3 and Quanxi Jia
4
1Jiangsu Key Laboratory of Thin Films, School of Physical Science and Technology,
Soochow University, Suzhou 215006, China 2Department of Electrical and Computer Engineering, Texas A&M University,
College Station, Texas 77843-3128, USA 3Department of Materials Science and Metallurgy, University of Cambridge,
Cambridge CB2 3QZ, UK 4Materials Physics and Applications Division, Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, USA
Self-assembly has been approved to be a useful method to fabricate oxide thin films
with a rich variety of periodic nanoscale patterns. Recent efforts have been focused on
how to make the self-assembly controllable. In a film-on-substrate geometry, epitaxial
composite films can be divided into two forms: horizontal and vertical. Success of the
investigation critically replies on obtain and manipulation of these two architectures.
In the present work, horizontally and vertically aligned nanostructures have been
obtained in (YBa2Cu3O7-δ)0.5:(BaZrO3)0.5 and (BiFeO3)0.5:(Sm2O3)0.5 thin films
respectively. And the manipulation between the vertical and horizontal architectures
has been realized in (YBa2Cu3O7-δ)1-x:(BaZrO3)x systems by simply changing the
composition of BaZrO3, which resulted from interplay between surface effect and
bulk phase separation. The nanostructures dependent lattice constants, strain state, and
electrical properties have also been investigated. More details will be presented in the
talk.
Literatures
1. J. L. MacManus-Driscoll, et al., Nature Materials, 7, 314 (2008)
2. H. Yang et al., Advanced Materials, 21, 3794 (2009).
3. H. Yang et al., Journal of Applied Physics, 106, 093914 (2009).
4. H. Yang et al., Applied Physics Letters, 96, 012909 (2010).
5. S. A. Harrington et al., Nature Nanotechnology, 6, 491 (2011).
Carbon Nanotubes Integrated with
Superconducting NbC
G. Zou*1
, H. Luo2, Y. Zhang
3, T. McCleskey
4, L. Civale
4, Y. Zhu
5, A.
Burrell6, and Q. X. Jia
4
1 Soochow University, Suzhou 215000, China.
2 New Mexico State University, Las Cruces, New Mexico 88003, USA.
3 Tsinghua University, Beijing 100083, China
4 Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
5 North Carolina State University, Raleigh, North Carolina 27695, USA.
6 Argon National Laboratory, Argon, Illinois 60439, USA
*EMAIL: [email protected]
The formation of carbon nanotube and superconductor composites makes it
possible to produce new and/or improved functionalities that the individual material
does not possess. In this talk, we will give a brief summary about carbon nanotubes
integrated with superconducting niobium carbide (NbC) by a chemical solution
process. Here, coating well-aligned carbon nanotubes with superconducting NbC does
not destroy the microstructure of the nanotubes in two different ways. NbC also
shows much improved superconducting properties such as a higher irreversibility and
upper critical field. An upper critical field value of ~5 T at 4.2 K is much greater than
the 1.7 T reported in the literature for pure bulk NbC. Furthermore, the aligned carbon
nanotubes induce anisotropy in the upper critical field, with a higher upper critical
field occurring when the magnetic field is parallel to the carbon nanotube growth
direction. These results suggest that highly oriented carbon nanotubes embedded in
superconducting NbC matrix can function as defects and effectively enhance the
superconducting properties of the NbC.
School of Physics Science and Technology School of Energy
Soochow University Suzhou 215000, China
