Program
 
Sun Jan 28 2018
16:00 - 17:00
Registration
17:00 - 18:00
Welcome Drink
 
Mon Jan 29 2018
08:00 - 08:40
Registration
08:40 - 08:45
Announcement of the Day
08:45 - 09:00
Opening
Session G1
Chair: Hiroshi Segawa
09:00 - 09:45
G1-K1
Graetzel, Michael
École Polytechnique Fédérale de Lausanne EPFL
Molecular Photovoltaics and Perovskite Solar Cells
Michael Graetzel
École Polytechnique Fédérale de Lausanne EPFL, CH

Professor of Physical Chemistry at the Ecole Polytechnique Fédérale de Lausanne (EPFL) Michael Graetzel, PhD, directs there the Laboratory of Photonics and Interfaces. He pioneered research on energy and electron transfer reactions in mesoscopic systems and their use to generate electricity and fuels from sunlight. He invented mesoscopic injection solar cells, one key embodiment of which is the dye-sensitized solar cell (DSC).  DSCs are meanwhile commercially produced at the multi-MW-scale and created a number of new applications in particular as lightweight power supplies for portable electronic devices and in photovoltaic glazings. They engendered the field of perovskite solar cells (PSCs) that turned our to be the most exciting break-through in the recent history of photovoltaics. He received a number of prestigious awards, of which the most recent ones include the RusNANO Prize, the Zewail Prize in Molecular Science, the Global Energy Prize, the Millennium Technology Grand Prize, the Samson Prime Minister’s Prize for Innovation in Alternative Fuels, the Marcel Benoist Prize, the King Faisal International Science Prize, the Einstein World Award of Science and the Balzan Prize. He is a Fellow of several learned societies and holds eleven honorary doctor’s degrees from European and Asian Universities. According to the ISI-Web of Science, his over 1500 publications have received some 230’000 citations with an h-factor of 219 demonstrating the strong impact of his scientific work.

 

Authors
Michael Graetzel a
Affiliations
a, Laboratory of Photonics and Interfaces Ecole Polytechnique Fédérale de Lausanne, Suisse
Abstract

A planetary emergency has arisen from the continued depletion of fossil fuels, producing green house warming and unprecedented environmental pollution. Future energy options for renewable and carbon-free sources will need to fill the terra-watt gap that will open up during the next few decades due to the growth of the world population. A promising development is the recent emergence of a new generation of low cost and highly efficient photovoltaic converters based on molecular sensitizers and perovskite pigments as light harvesters. Dye sensitized solar cells are meanwhile found applications as flexible light weight power supplies for portable electronics as well as electric power producing glass panels their market being presently in the multi-megawatt range. Perovskite solar cells (PSCs) [1] have directly evolved from DSCs. They have attracted enormous interest due to their low cost ease of preparation and ha certified solar to electric power conversion efficiency (PCE) exceeding already the performance polycrystalline silicon solar cells. Present efforts focus on scale up of the device size [2] and achieving operational stability [3]. The high photovoltage (Voc > 1.2 V) attained with these systems renders them very attractive for the generation of fuels from sunlight, e.g. by the splitting of water into hydrogen and oxygen [4] and the cleavage of CO2 into CO and 1/2 O2.

References:

[1] M. Grätzel, The light and shade of perovskite solar cells., Nature Materials 2014, 13, 838-842.

[2] X. Li, D. Bi, C. Yi, J.-D. Décoppet, J. Luo, S.M. Zakeeruddin, A. Hagfeldt, M. Grätzel,

A vacuum flash–assisted solution process for high-efficiency large-area perovskite solar cells,

Science, 353, 58-62 (2016)

[3] N. Arora, M.I. Dar, A. Hinderhofer, N. Pellet, F. Schreiber, S.M. Zakeeruddin, M. Grätzel, Perovskite solar cells with CuSCN hole extraction layers yield stabilized efficiencies greater than 20%., Science, 358, 768-771 (2017)

[4] J. Luo, J.-H. Im, M.T. Mayer, M. Schreier, Md.K. Nazeeruddin, N.-G. Park, S.D.Tilley, H.J. Fan, M. Grätzel. Water photolysis at 12.3% efficiency via perovskite photovoltaics and Earth abundant catalysts. Science 2014, 345, 1593-1596.

09:45 - 10:15
G1-I1
Ginger, David
University of Washington
Approaching the Shockley-Queisser Limit with Interface Control in Halide Perovskites
David Ginger
University of Washington, US
Authors
David Ginger a
Affiliations
a, Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700
Abstract

Experiments suggests that electrical heterogeneity in both the perovskite active layer, as well as the perovskite/electrode interface, can affect carrier diffusion and non-radiative recombination processes within perovskite solar cells. In this talk we will describe both confocal and conductive atomic force microscopy (cAFM) to explore the role of heterogeneities and grain boundaries on lateral carrier transport, and will demonstrate varying degrees of grain boundary opacity to carrier transport depending on the structure. In this talk, we will also discuss both ligand exchange and cation exchange experiments in the context of tailoring the properties of halide perovskite thin films. We show that with controlled passivation of the perovskite surfaces we are able to obtain carrier lifetimes and PL intensities in solution-processed thin films that rival those in the best single crystals, achieving over 90% PL internal quantum efficiency and quasi-Fermi level splittings that exceed 96% of the Shockley-Queisser limit under illumination. Combining these results with experiments demonstrating contact-induced losses in many common perovskite architectures, we then explore new contact materials and their potential for increased efficiency.

10:15 - 10:45
G1-I2
Diau, Eric Wei-Guang
National Chiao Tung University Hsinchu, Taiwan
Tin-Rich and Lead-Free Perovskite Solar Cells
Eric Wei-Guang Diau
National Chiao Tung University Hsinchu, Taiwan

Eric Wei-Guang Diau received his Ph.D. in Physical Chemistry from National Tsing Hua University, Taiwan, in 1991. Before joining at Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan, as a faculty member since 2001, he worked as a postdoctoral fellow at Emory University (1993-1995), University of Queensland (1995-1996), Stanford Research Institute, International (1996-1997) and California Institute of Technology (1997-2001).  He is interested on studying relaxation kinetics in condensed matters, in particular interfacial electron transfer and energy transfer dynamics in many solar energy conversion systems. His current research is focusing on the developments of novel functional materials for next-generation solar cells, including perovskite solar cells (PSC). He received “Outstanding Research Award” from MRS Spring Meeting & Exhibit on April, 2014 and “Sun Yat Sen Academic Award” from Sun Yat Sen Academic and Cultural Foundation on October, 2014. He has published over 180 peer-reviewed papers with H-index 51. He has been granted over 14 patents. He is currently Distinguished Professor at Department of Applied Chemistry and Science of Molecular Science, National Chiao Tung University.

Authors
Eric Wei-Guang Diau a
Affiliations
a, Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 300, Taiwan
Abstract

Perovskite solar cells (PSC) have attracted much attention in recent years due to the rapid progress on the performance of PSC to attain PCE over 22 % within 5 years. However, conventional perovskite light absorbers contain the toxic lead element that should be replaced by other environmentally benign elements. Herein we report both tin-rich and pure tin-based PSC based on various device configurations. For the tin-rich perovskites, we designed and synthesized alloyed Sn-Pb mixed halide perovskites by dipping the precursor solutions on the mesoporous films with the TiO2/Al2O3/C configuration to form solar cells free of organic HTM. The photovoltaic performance was further improved on adding 30 mol % of tin fluoride (SnF2) with device configuration FTO/TiO2/Al2O3/NiO/C producing best power conversion efficiency 5.2 % with great reproducibility and intrinsic stability. To make a stable pure tin perovskite free of lead, we varied SnCl2/SnBr2 ratios to yield tin perovskites with three halides (I, Br and Cl) co-crystallized inside the tin-perovskite crystals (MASnIBr2-xClx) according to the stoichiometric ratios of the precursors. When the SnCl2 proportion was equal to or greater than 50 % (x  1), phase separation occurred to generate MASnI3-yBry and MASnCl3-zBrz according to the stoichiometric proportions of their precursors, confirmed with the corresponding XRD analysis. A device with MASnIBr1.8Cl0.2 (SnCl2 = 10 %) showed the best photovoltaic performance: JSC = 14.0 mA cm-2, VOC = 380 mV, FF = 0.573 and PCE = 3.1 %, with great reproducibility and long-term stability. The devices made of 2D tin-based PSC will also be introduced and discussed.

10:45 - 11:15
Coffee Break
11:15 - 11:45
G1-I3
Dai, Songyuan
North China Electricity Power University
Preparation and Optimization of Materials for Efficient Perovskite Solar Cells
Songyuan Dai
North China Electricity Power University, CN

Songyuan Dai is the Professor and Dean of Renewable Energy School, North China Electric Power University. He received his BS in Department of Physics from Anhui Normal University in 1987. And got his MS, and PhD degrees in Institute of Plasma Physics Chinese Academy of Sciences, in 1991, and 2001, respectively. He works as a chief scientist of National Key Basic Research Project (973 project) during 2006-2010,2011-2015, and 2016~2020. He published over 200 peer-reviewed papers regarding dye-sensitized solar cells, quantum-dot solar cell and perovskite solar cell

Authors
Songyuan Dai a, b, Xu Pan b, Linhua Hu b, Jianxi Yao a
Affiliations
a, Beijing Key Laboratory of Novel Thin Film Solar Cells,Renewable Energy School, North China Electric Power University, Beijing, 102206, P. R. China
b, Key Laboratory of Novel Thin Film Solar Cells, Institute of Applied Technology, Chinese Academy of Sciences, Hefei, 230031, P. R. China.
Abstract

A novel mesoporous ETL based on La doped BaSnO3 (LBSO) is investigated here. The LBSO nanoparticles are synthesized under relatively mild conditions and proved to be a suitable material for mesoporous ETL. After optimization, solar cells using mesoporous LBSO show the best power conversion efficiency of 15.1%.

A uniform, pinhole-free and incomplete pore filling in porous TiO2 film of PbI2-free perovskite layer was prepared by the sandwich structure MAI-PbI2-MAI precursor film. Compare to the conventional two-step method, the devices fabricated from the sandwich structure MAI-PbI2-MAI precursor films shown a dramatic improvement for all the performance parameters, and a promising efficiency of 17.8% was achieved.

A new class of hole-transporting materials (HTM) containing tetraphenylmethane (TPM) core have been developed. After thermal, charge carrier mobility, and contact angle tests, it was found that TPA-TPM (TPA: arylamine derivates side group) showed higher glass-transition temperature and larger water-contact angle than spiro-OMeTAD with comparable hole mobility.By adopting low pressure vapor assisted process (LP-VASP), we systematic studied the effect of the type of A cation, the type of X halide, and the structure on the photovoltaic properties. In LP-VASP, the evolution of crystal structure and mechanism of carriers transport showed many different results compared with that of the PSC prepared by solvent approaches. We achieved PCE of 17.40% in planar PSCs with mixed halide sources. There are some studies going on based on LP-VASP, such as the introduction the pseudohalogen into the structure of ABX3.

References

X. Zhang, J. Ye, L. Zhu, H. Zheng, X. Liu, X. Pan and S. Dai, ACS Appl. Mater. Interfaces, 2016, 8, 35440-35446.

L. Zhu, Z. Shao, J. Ye, X. Zhang, X. Pan and S. Dai, Chem. Commun., 2016, 52, 970.

L. Zhu, J. Ye, X. Zhang, H. Zheng, G. Liu, X. Pan and S. Dai, J. Mater. Chem. A, 2017.

T. Du, N. Wang, H. Chen, H. Lin, H. He, ACS Appl. Mater. Interfaces 2015, 7 (5), 3382-3388.

11:45 - 12:15
G1-I4
Kubo, Takaya
The University of Tokyo
Solution-Processed Colloidal-Quantum-Dot Solar Cells Operating in the Infrared Region
Takaya Kubo
The University of Tokyo, JP
Authors
Takaya Kubo a, Haibin Wang a, Jotaro Nakazaki b, Hiroshi Segawa a, b
Affiliations
a, Reseach Center for Advanced Science and Technology, The University of Tokyo
b, Graduate School of Arts and Sciences, The University of Tokyo
Abstract

Efficient utilization of a wide range of the solar spectrum is essential to construct ultra-high efficiency solar cells. So far, several different concepts for ultra-high efficiency have been proposed, which use multiple exciton generation, hot-carrier extraction, multi-junction and so forth. Most of them are, however, still under fundamental investigation. Although multi-junction solar cells based on III-V semiconductors are the only solar cells that have achieved a power conversion efficiency well over the single-junction limit (-30% under one-sun illumination), the solar cells rely heavily on high cost solar cell technology, which makes it difficult for the solar cells to be used widely. Organic photovoltaics made up of conjugated small molecules and/or polymers, and perovskite solar cells composed of organometal halide perovskite compounds (e.g. CH3NH3PbI3) are promising candidate for the top and/or middle cells of multi-junction solar cells. This is because the solar cells can be constructed with low-temperature and solution-based methods, and because the solar cells are able to capture visible and near-infrared photon energy efficiently. However, there are few materials to choose from for the bottom cells, as few materials harvest solar energy in the short-wave infrared. The development of low cost and efficient short-wave infrared solar cells is therefore essential to construct the bottom cell of multijunction cells. Lead chalcogenide colloidal quantum dots (CQDs), such as PbS and PbSe, appear promising for use as the middle and/or bottom cells. This is because the absorption bandgap of bulk PbS is located in the infrared region (3.1 mm) and can be readily tuned by controlling quantum dot synthesis conditions. Most importantly, CQDs are compatible with low-temperature solution-based technologies.

We have focused on CQD/ZnO nanowire (NW) structures (NW-type), with the aim of simultaneous enhancement in carrier transport and light harvesting efficiency. We also used PbS CQDs with the first exciton absorption peak locating between the near-infrared and short-wave infrared region. Our recent study revealed that NW-type solar cells give a carrier diffusion length of over 1 µm, and a record high EQE of 40% (at 1.6 mm) in the short-wave infrared region. In this presentation, we investigate the performance of PbS QD/ZnO NW solar cells using PbS CQDs absorbing photons in a wide range of solar spectrum, and discuss the potential for low-cost multi-junction solar cells with PbS CQD/ZnO NW hybrid structures.

12:15 - 12:45
G1-I5
Li, Yongfang
Soochow University
Side-Chain Engineering of Photovoltaic Materials for High Performance Polymer Solar Cells
Yongfang Li
Soochow University, CN

Yongfang Li is a professor in Institute of Chemistry, Chinese Academy of Sciences (ICCAS) and in Soochow University. He received his Ph. D. degree in department of Chemistry from Fudan University in 1986, and did his postdoctoral research at ICCAS from 1986 to 1988. He became a staff in 1988 and promoted to professor in 1993 in ICCAS, and elected as member of Chinese Academy of Sciences in 2013. He did his visiting research in Institute for Molecular Science, Japan from 1988 to 1991 and in University of California at Santa Barbara from 1997 to 1998. His present research interests are photovoltaic materials and devices for polymer solar cells. He has published more than 600 papers and the published papers were cited by others for more than 28000 times with h-index of 86.

Authors
Yongfang Li b
Affiliations
a, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190
b, Soochow University, CN
Abstract

Polymer solar cells (PSCs) have attracted great attention in the past decade, because of the advantages of simple device structure, light weight and capability to be fabricated into flexible and semitransparent devices. The key photovoltaic materials of PSCs are conjugated polymer donors and the fullerene or non-fullerene acceptors. Recently, the nonfullerene n-type organic semiconductor (n-OS) (such as the low bandgap n-OS ITIC) acceptors have attracted great attention for their high photovoltaic performance. To match with the low bandgap ITIC acceptor, we developed a series of medium bandgap 2D-conjugated D-A copolymer donors based on bithienyl-benzodithiophene (BDTT) as donor unit and fluorobenzotriazole (FBTA) as acceptor unit. The D-A copolymer donors possess complementary absorption spectra and matching electronic energy levels with ITIC acceptor. By side chain engineering (alkyl-thienyl1, alkylthio-thienyl2, trialkylsilyl-thienyl3 or alkyl-difluorothienyl4 substitution) on the thiophene conjugated side chains of the medium bandgap polymers, the power conversion efficiency (PCE) of the PSCs with the polymers as donor and ITIC as acceptor reached 9.26%~11.63%. By side chain isomerization of ITIC, the PCE of the nonfullerene PSCs was further improved to 11.77%5~12.05%6. The results indicate that the side chain engineering of the conjugated polymer donors and n-OS acceptors are effective way to improve photovoltaic performance of the PSC.

References:

1. L. Gao, Z.-G. Zhang, H. J. Bin, L. Xue, Y. Yang, C. Wang, F. Liu, T. P. Russell, Y. F. Li, Adv. Mater., 2016, 28, 8288–8295.

2. H. Bin, Z.-G. Zhang, L. Gao, S. Chen, L. Zhong, L. Xue, C. Yang, Y. F. Li, J. Am. Chem. Soc., 2016, 138, 4657–4664.

3. H. Bin, L. Gao, Z.-G. Zhang, Y. K. Yang, Y. Zhang, C. Zhang, S. Chen, L. Xue, C. Yang, M. Xiao, Y. F. Li, Nature Commun, 2016, 7, 13651.

4. L. Xue, Y. K. Yang, J. Xu, C. Zhang, H. Bin, Z.-G. Zhang, B. Qiu, X. Li, C. Sun, L. Gao, J. Yao, X. Chen, Y. X. Yang, M. Xiao, Y. F. Li, Adv. Mater., 2017, 1703344.

5. Y. K. Yang, Z.-G. Zhang, S. Chen, H. J. Bin, L. Gao, L. Xue, C. Yang, Y. F. Li, J. Am. Chem. Soc., 2016, 138, 15011–15018.

6. H. Bin, Y. K. Yang, Z. Peng, L. Ye, J. Yao, L. Zhong, C. Sun, L. Gao, H. Huang, X. Li, B. Qiu, L. Xue, Z.-G. Zhang, H. Ade, Y. F. Li, Adv. Energy Mater., 2017, 1702324.

12:45 - 13:00
Industries: Greatcellsolar & TCI
13:00 - 14:30
Lunch
Session A1
Chair: Eric Wei-Guang Diau
14:30 - 15:00
A1-IS1
Han, Hongwei
Huazhong University of Science and Technology
Printable Mesoscopic Perovskite Solar Cell: From Cell to Module
Hongwei Han
Huazhong University of Science and Technology, CN

Dr. Hongwei Han is Professor at Huazhong University of Science and Technology (HUST) / Wuhan National Laboratory for Optoelectronics (WNLO), and Distinguished Professor of ‘ChangJiang Scholars Program’. He obtained his bachelor degree from the College of Chemistry and Molecular Science in 2000 and his doctor degree from the School of Physics and Technology in 2005 at Wuhan University. And then, Dr. Han continued his research work at Monash University of Australia as Postdoc. After that he joined HUST and WNLO in 2008 and began to establish his group of Printable Mesoscopic Photovoltaics & Optoelectronics. Since 2000, Dr. Han has worked on the fully printable mesoscopic solar cells. The characteristic of such device is to print nanocrystalline layer, spacer layer and counter electrode layer on a single conductive substrates layer-by-layer, and then sensitized with dye and filled with electrolyte (or filled with perovskite materials directly). In 2015 his group fabricated 7m2 fully printable mesoscopic perovskite solar module. His more than 60 peer-reviewed publications in Science、 Nature Chemistry、 Nature Communications、J. Am. Chem. Soc.、Energy Environ. Sci. et al. have been published and 15 Patents have been applied within past five years.

Authors
Hongwei Han a
Affiliations
a, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road Wuhan 430074, P.R. China, Wuhan, 4300074, CN
Abstract

The fully printable perovskite solar cells was developed with triple mesoscopic layers, where the TiO2 nanocrystalline layer, the ZrO2 spacer layer and the mesoporous carbon counter electrode were printed on a single conductive substrate layer by layer, and then filled with an organic-inorganic perovskite materials under atmospheric condition. The bifunctional molecules were introduced into the perovskite materials to enhance the performance of fully printable perovskite solar cells. The results indicated that the interface engineering plays a key role of stability with directing the crystal formation and growth during the infiltration and precipitation of the perovskite within the mesoporous oxide scaffold. The fully printable mesoscopic perovskite solar cell presents no obvious decay within over 1000h light soaking and high efficiency of more than 16%. Meanwhile, the characterization of the mesoscopic perovskite solar cells under the UV light soaking condition was performed. Moreover, 3600 cm2 mesoscopic perovskite solar panel was also fabricated. These results offer a promising prospect for its commercial application.

15:00 - 15:15
A1-O1
Kapil, Gaurav
The University of Tokyo
Study to realize the effect of multiple monovalent cation for lead/tin mixed perovskite solar cells
Gaurav Kapil
The University of Tokyo, JP
Authors
Gaurav Kapil a, Kengo Hamada b, Yuhei Ogomi b, Takeru Bessho a, Takumi Kinoshita a, Qing Shen c, Taro Toyoda c, Takurou N Murakami d, Hiroshi Segawa a, Shuzi Hayase b
Affiliations
a, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, JP
b, Kyushu Institute of Technology, Japan
c, The University of Electro-Communications, Japan
d, National Institute of Advanced Industrial Science and Technology (AIST), Japan, JP
Abstract

Lead/Tin(Sn/Pb) mixed perovskite solar cells give advantages such as reduced amount of lead content and improved photon harvesting towards higher wavelength [1]. Inspite of these benefits, Sn/Pb possess low air stability due to rapid oxidation of Sn2+ to Sn4+, which results in immediate degradation of solar cell performance and makes even difficult to correctly evaluate the performance. To solve the issue we tried to explore the role of multiple monovalent cations such as rubidium (Rb+)cesium(Cs+), formamidinium [(CH3(NH2)2+, FA+], methylammonium [(CH3NH3)+, MA+] etc. on the A position of ABX3 perovskite crystal structure[2], which has been reported as an approach to improve the stability and reproducibility of Pb based perovskite solar cells. The present research work discusses about the difference in performance of double and triple cation based perovskites  answered by  X-ray diffraction (XRD) pattern, thermogravimetric analysis (TGA), scanning electron microscopy etc. Solar cells fabricated were (FASnI3)0.6(MAPbI3)0.4 as (FAMA), (CsI)x[(FASnI3)0.6(MAPbI3)0.4]1-x as (Cs)x(FAMA)1-x. The optimized solar cell performance of ~16% will be reported with the further discussion on effect of addition of more monovalent cations at A position of ASn/PbX3 perovskite solar cell.

 

Reference

1. Y. Ogomi & S. Hayase et al, J. Phys. Chem. Lett., 2014, 5, 1004-1011.

2. M. Saliba & M. Gratzel et al, Energy & Environ. Sci., 2016, 9, 1989-1997.

15:15 - 15:30
A1-O2
Jain, Sagar Motilal
Swansea University
Vapour Assisted Morphological Tailoring of Lead-Free Bismuth Based Perovskite Solar Cells for Improved Performance and Stability
Sagar Motilal Jain
Swansea University, GB
Authors
Sagar Jain a
Affiliations
a, SPECIFIC IKC, College of Engineering, University of Swansea, Swansea, U.K
Abstract

Abstract

We present a controlled, stepwise formation of methylammonium bismuth iodide (CH3NH3)3Bi2I9 perovskite films prepared via the vapor assisted solution process (VASP) by exposing BiI3 films to CH3NH3I (MAI) vapours for different reaction times, (CH3NH3)3Bi2I9 semiconductor films are obtained of which the optoelectronic properties can be fine tuned. Solar cells prepared using mesoporous TiO2 substrates yielded efficiencies upto 2% with good reproducibility. The good performance is attributed mainly to the homogeneous surface coverage, improved stoichiometry, metallic content, and optoelectronic properties of absorber material. Solar cells prepared using pure BiI3 films achieved power conversion efficiency of 0.34%. The non-encapsulated devices found to be stable for as long as > 60 days of time with a bare loss of 0.1% in efficiency. These results on (CH3NH3)3Bi2I9 ­show the benefit of VASP technique to optimize material stoichiometry, morphology, solar cell performance, and long-term durability.

Broader context:  The rapid efficiency improvement of lead based perovskite photovoltaic. have competed with traditional photovoltaic materials such as silicon and CdTe in terms of efficiency, However, toxicity, and long-term stability remains a hurdle for their commercialization. It is a challenging task to remove toxic lead from solar cells. In this direction, we report here pure bismuth iodide based solar cells yielding 0.34% efficiency. A two-step VASP method was used to systematically react BiI3 with MAI vapours. The solar cells were prepared at different reaction time in order to find the optimized composition, reduce metallic states for solar cells and obtained power conversion efficiency of 2%, which is highest efficiency reported so far for the MAI_BiI3 type of cells. Also, the devices made shown > 60 days long term stability. The finding of this work and the methodology applied could be extended to improve the performance and stability of other lead free (e.g. antimony and tin) based perovskite solar cells by facile fabrication means.

15:30 - 15:45
A1-O3
Varadwaj, Arpita
The University of Tokyo
Haloammonium Halide Perovskites: A Class of Newly Identified Compounds for Photovoltaics
Arpita Varadwaj
The University of Tokyo, JP
Authors
Arpita Varadwaj a, b, Pradeep R. Varadwaj a, b, Koichi Yamashita a, b
Affiliations
a, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, JP
b, CREST-JST, 7 Gobancho, Chiyoda-ku, Tokyo, 1020076, JP
Abstract

Methylammonium metal triiodide perovskites are among the largely cultivated soft nanomaterials for application in photovoltaic solar cells.1-2 Because of their stability issues,3 different varieties of such BMY3 compounds (lead-free, lead-based and double perovskites, etc.) have been theoretically modelled, experimentally synthesized, and eventually proposed as possible candidates for photovoltaics4 since they display better geometrical stabilities and solar power conversion efficiencies (up to 22%),5 among several other things. BMY3 conceives a variety of B, M and Y site ions, where B = organic/inorganic monovalent cation (CH3NH3+/Cs+), M = divalent metal cation (Pb2+/Sn2+), and Y = monovalent halide anion (Y = Cl, Br, I). We have been involved in the rationale design of such materials computationally using periodic and non-periodic density functional theories. We mainly examine the geometries, energetics, electronic band structures, density of states spectra and carrier effective masses (the latter associated with the parabolic curvatures of the valence and conduction band extrema) to examine a variety of BMY3 hypothetical perovskite structures. In this presentation, I discuss in a nut-shell a small part of our group research that will center on the electronic structures and materials properties of a new series of haloammonium assisted all-inorganic halide perovskites that are found to be structurally diversified. They display characteristic features analogous with those of the CH3NH3PbY3 (Y = Cl, Br, I) series, thereby these may be possible new materials for photovoltaics.

 

References 

[1] a) W.-Q. Wu, D. Chen, R. A. Caruso, Y.-B. Cheng, J. Mater. Chem. A, 2017, 5, 10092-10109; b) X. Qin, Z. Zhao, Y. Wang, J. Wu, Q. Jiang, J. You, J. Semicond. 2017, 38, 011002.

[2] A. Varadwaj, P. R. Varadwaj, K. Yamashita, J. Comput. Chem. 2017, DOI:10.1002/jcc.25073.

[3] T. A. Berhe, W.-N. Su,C.-H. Chen, C.-J. Pan, J.-H. Cheng, H.-M. Chen, M.-C. Tsai, L.-Y. Chen, A. Aregahegn Dubale, B.-J. Hwang, Energy Environ. Sci. 2016, 9, 323.

[4] G. Volonakis,et al., J. Phys. Chem. Lett. 2017, 8, 772. 

[5] National Renewable Energy Laboratory (NREL) Best Research-Cell Efficiency chart. https://www.nrel.gov/pv/assets/images/efficiency-chart.png.

15:45 - 16:15
Coffee Break
16:15 - 16:30
A1-O4
Nguyen, Bich Phuong
Ewha Womans University
Influence of iodine-to-bromine ratio on electrical properties of lead-free Sn halide perovskite solar cells
Bich Phuong Nguyen
Ewha Womans University, KR
Authors
Bich Phuong Nguyen a, Trang Thi Thu Nguyen a, Juran Kim a, Hye Ri Jung a, Seokhyun Yoon a, Wiilam Jo a
Affiliations
a, Department of Physics, Ewha Womans University, 52, Ewhayeodaegil, Seodaemungu, , Seoul, 3760, KR
Abstract

Lead-free photovoltaic devices based on methylammonium tin iodide (CH3NH3SnI3) perovskite material is designed as a less toxic alternative to CH3NH3PbI3. CH3NH3SnI3 has a broader absorption to 950 nm and can be easily tuned by adjusting the perovskite composition. Specifically, Bromine (Br) incorporation has been shown to affect the controlling band gap of perovskite absorber layers, leading to cover the visible range of optical spectra. A series of tin-based mixed halide perovskite (CH3NH3Sn(I1-xBrx)3) were fabricated. We found that the optimized Sn-based mixed halide perovskite, CH3NH3Sn(I0.33Br0.67)3 exhibits 3.2% in comparison to original CH3NH3SnI3 (1.17%). In this study, we investigated the local electrical and optical properties of CH3NH3Sn(I1-xBrx)3 (0 ≤ x ≤ 1) thin-films by using scanning probe microscopy and Raman scattering spectroscopy. Based on that, we can describe the electron-hole carrier transport with various I/Br compositional ratio. Consequently, we can suggest the correlation of the local composition and electrical properties in perovskite layer depending on the Br concentration. Thus, we can anticipate the origin of the high efficiency perovskite solar cells with optimal Br concentration.

16:30 - 16:45
A1-O5
Ono, Luis
Okinawa Institute of Science and Technology
Up-Scaling of Organic-Inorganic Hybrid Perovskite Solar Cells and Modules
Luis Ono
Okinawa Institute of Science and Technology, JP
Authors
Luis Ono a, Matthew Leyden a, Sonia Raga a, Yan Jiang a, Longbin Qiu a, Mikas Remeika a, Emilio Juarez-Perez a, Shenghao Wang a, Yabing Qi a
Affiliations
a, Energy Materials and Surface Sciences Unit (EMSS), Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun , Okinawa, 904-0495
Abstract

Organic-inorganic hybrid perovskites have emerged as a promising high-performance, cost-effective solar cell technology. However, most of the best reported efficiencies have been obtained on small active-area devices (~0.1 cm2). To move forward this technology towards commercialization, it is important to develop up-scaling processes with high performance and stability [1]. At OIST, a team of researchers in the Energy Materials and Surface Sciences Unit have been making concerted efforts to develop processes aiming at high PCE, high-throughput, and minimum batch-to-batch variation, and compatible with large-area perovskite solar cells and modules. We will present our progress to use chemical vapor deposition [2-5] and spray coating [6] to fabricate perovskite solar cells and modules. Also, we will introduce a novel methylamine gas induced crystallization process [7, 8], which provides valuable insights into the formation of perovskite films.

[1] L.K. Ono, N.-G. Park, K. Zhu, W. Huang, Y.B. Qi*, Perovskite Solar Cells—Towards Commercialization. ACS Energy Lett. 2 (2017) 1749-1751.

[2] L.K. Ono, M.R. Leyden, S. Wang, and Y.B. Qi*, Organometal Halide Perovskite Thin Films and Solar Cells by Vapor Deposition. J. Mater. Chem. A 4 (2016) 6693-6713.

[3] M.R. Leyden, Y. Jiang, and Y.B. Qi*, Chemical Vapor Deposition Grown Formamidinium Perovskite Solar Modules with High Steady State Power and Thermal Stability. J. Mater. Chem. A 4 (2016) 13125-13132.

[4] M.R. Leyden, M.V. Lee, S.R. Raga, and Y.B. Qi*, Large Formamidinium Lead Trihalide Perovskite Solar Cells Using Chemical Vapor Deposition with High Reproducibility and Tunable Chlorine Concentrations. J. Mater. Chem. A 3 (2015) 16097-16103.

[5] M.R. Leyden, L.K. Ono, S.R. Raga, Y. Kato, S.H. Wang, and Y.B. Qi*, High Performance Perovskite Solar Cells by Hybrid Chemical Vapor Deposition. J. Mater. Chem. A 2 (2014) 18742-18745.

[6] M. Remeika, S.R. Raga, S. Zhang, and Y.B. Qi*, Transferrable Optimization of Spray-Coated PbI2 Films for Perovskite Solar Cell Fabrication. J. Mater. Chem. A 5 (2017) 5709-5718.

[7] S.R. Raga, L.K. Ono, and Y.B. Qi*, Rapid Perovskite Formation by CH3NH2 Gas-Induced Intercalation and Reaction of PbI2. J. Mater. Chem. A 4 (2016) 2494-2500.

[8] Y. Jiang, E.J. Juarez-Perez, Q. Ge, S. Wang, M.R. Leyden, L.K. Ono, S.R. Raga, J. Hu, and Y.B. Qi*, Post-Annealing of MAPbI3 Perovskite Films with Methylamine for Efficient Perovskite Solar Cells. Mater. Horiz. 3 (2016) 548-555.

16:45 - 17:00
A1-O6
Pant, Namrata
Substrate dependent morphological and electronic properties of lead halide perovskite solar cells
Namrata Pant
Authors
Namrata Pant a, Masatoshi Yanagida a, b, Yasuhiro Shirai b, Kenjiro Miyano b
Affiliations
a, University of Yamanashi
b, National Institute for Materials Science(NIMS)
Abstract

Solar cell research has been attracting a lot of attention from researchers worldwide mostly because of the rapidly increasing efficiencies of the perovskite solar cells. From 3.8% in 2009 to 22.1% in 2016, a whopping increase by nearly 6 times, in less than ten years is a remarkable achievement and indeed a breakthrough in this field. The methyl ammonium lead iodide (MAI) perovskites have been considered as the most promising candidates by far. The excellent properties of the MAI perovskite such as their high mobility, broadband light absorption, low exciton binding energy as well as low trap density makes them suitable to be used as an absorber layer in solar cell [1,2]. The typical device architecture consists of perovskite absorber layer sandwiched between a hole transport layer and an electron transport layer, along with additional metal electrode. Perovskite is one of the most important layers of the device, but there are various other factors which contribute in the overall device performance. The substrate plays an influential role in the bulk properties of the perovskite films as well as interfacial properties of the device. Therefore the selection of the substrate on which the perovskite grows is an important step. Studying this layer carefully to understand the role of the interfaces in various mechanisms, including the degradation can help us to address the existing issues related with the perovskite solar cells. In an attempt to understand the role of this layer for the perovskite film, on the overall device performance, we have fabricated devices with different hole transport layers. The difference in the morphology and the crystallinity of the perovskite films coated over different substrates will give us an insight to further understand the differences in other parameters which are significant for the overall device performance. Studies by Md. Bodiul Islam et al [3] and Kunie Ishioka et.al [4] show the influence of substrates on the device stability and hole injection dynamics at the HTL/perovskite interface respectively. Their studies comparing PEDOT:PSS, NiO and PTAA as the hole transport layer motivate us to further investigate the influence of different substrates on the properties of perovskite solar cells.

References:

1. Kojima, et al. J.Am. Chem. Soc., 131, 6050-6051  (2009)

2. Bobo Li, et al. RSC Adv., 6, 38079 (2016)

3. Md. Bodiul Islam, et al. ACS Omega, 2, 2291-2299, (2017)

4. Kunie Ishioka, et al. J. Phys. Chem. Lett., 8, 3902−3907 (2017)

17:00 - 17:15
A1-O7
Wang, Zhiping
University of Oxford
Self-assembled 2D–3D heterostructured butylammonium-caesium-formamidinium lead halide perovskites for stable and efficient solar cells
Zhiping Wang
University of Oxford, GB
Authors
Zhiping Wang a, Qianqian Lin a, Francis Chmiel a, Nobuya Sakai a, Laura Herz a, Henry Snaith a
Affiliations
a, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
Abstract

Self-assembled 2D–3D heterostructured butylammonium-caesium-formamidinium lead halide perovskites for stable and efficient solar cells

Zhiping Wang*, Qianqian Lin, Francis P. Chmiel, Nobuya Sakai, Laura M. Herz and Henry J. Snaith*

Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom

*Correspondence: zhiping.wang@physics.ox.ac.uk; henry.snaith@physics.ox.ac.uk

 

Three-dimensional (3D) organic-inorganic perovskite solar cells have undergone a meteoric rise in cell efficiency to > 22%. However, the perovskite absorber layer is prone to degradation in water, oxygen and UV light. Two-dimensional (2D) Ruddlesden-Popper layered perovskites have exhibited promising environmental stability, but perform less well in solar cells, possibly due to the inhibition of out-of-plane charge transport by the insulating spacer cations. Alternatively, moving away from methylammonium, to the mixed cation formamidinium-caesium based perovskites has led to considerably enhancement of the stability of 3D perovskite absorber layers1. Here we incorporate butylammonium, within the caesium-formamidinium lead halide perovskite2. We observe “plate-like” two-dimensional-phase crystallites standing up between the three-dimensional perovskite grains, and remarkably enhanced crystallinity. We observe inhibition of non-radiative recombination within this “hetero-structured” film, which we postulate to be due to interfacial grain boundary passivation. In complete solar cells, we achieved a stabilised efficiency of 19.5% with a 1.61 eV bandgap perovskite and 17.3% employing a 1.72 eV bandgap perovskite. Additionaally, we observe greatly enhanced stability under simulated sun light, with cells sustaining 80% of their “post burn-in” efficiency after 1,000 hrs in air, and 4,000 hrs when encapsulated. Our work illustrates that engineering heterostructures between 2D and 3D perovskite phases is possible, and can lead to enhancement of both performance and stability of perovskite solar cells.

References

1.        Wang, Z. et al. Efficient and Air-Stable Mixed-Cation Lead Mixed-Halide Perovskite Solar Cells with n-Doped Organic Electron Extraction Layers. Adv. Mater. 29, 1604186 (2017).

2.        Wang, Z. et al. Efficient and ambient-air-stable solar cells with 2D-3D hetero-structured butylammonium-caesium-formamidinium lead halide perovskites. Nat. Energy 2, 17135 (2017).

 

17:15 - 17:30
A1-O8
ZHU, ZONGLONG
Hong Kong University of Science and Technology
Highly Efficient Lead-free or Pb/Sn based Perovskite Solar Cell through Compositional Engineering
ZONGLONG ZHU
Hong Kong University of Science and Technology, HK
Authors
Zonglong Zhu a
Affiliations
a, Department of Chemistry, Hong Kong University of Science and Technology, Hong Kong, HK
Abstract

Organic-inorganic perovskites photovoltaics has created transformative energy generation for achieving the new generation low-cost, large-area and lightweight devices. In my presentation, I would introduce a solution processed 2-step deposition technique realize high-performance FASnI3 PVSCs with a PCE over 7%. Then I would present our recent works on inorganic perovskite which through compositional engineering, wide Eg (1.7~1.8 eV) and low Eg (1.25~1.35 eV) inorganic perovskite has been made successfully and have been utilized to fabricate highly efficient perovsktie device.

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  1 1 1 1 1 1 1 1 1 1  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Session B1
Chair: Hideo Ohkita
14:30 - 15:00
B1-IS1
Qi, Yabing
Okinawa Institute of Science and Technology Graduate University (OIST)
Perovskite Material and Solar Cell Research by Surface Science and Advanced Characterization
Yabing Qi
Okinawa Institute of Science and Technology Graduate University (OIST), JP

Prof. Yabing Qi is Unit Director of Energy Materials and Surface Sciences Unit at Okinawa Institute of Science and Technology Graduate University (https://groups.oist.jp/emssu). He received his B.S., M.Phil., and Ph.D. from Nanjing University, Hong Kong University of Science and Technology, and University of California Berkeley, respectively. Prof. Qi has published 70+ research articles (30+ articles on perovskite solar cells) and is the inventor for 11 patents/patent applications. His research interests include perovskite solar cells, surface/interface sciences, lithium-ion batteries, organic electronics, energy materials and devices.

Authors
Yabing Qi a
Affiliations
a, Energy Materials and Surface Sciences Unit (EMSS), Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun , Okinawa, 904-0495
Abstract

Organic-inorganic hybrid perovskite solar cells have attracted much attention as one of the most promising next generation photovoltaic technologies. For efficient stable solar cells, interfaces are of paramount importance. My group at OIST is making efforts to obtain better understanding about interfaces in perovskite solar cells. In this talk, I will present our recent research findings regarding interface engineering, which provides a viable route to the fabrication of perovskite solar cells with high efficiency and improved stability [1, 2].


[1] Zafer Hawash, Sonia R. Raga, Dae-Yong Son, Luis K. Ono, Nam-Gyu Park*, Yabing Qi*, "Interfacial Modification of Perovskite Solar Cells using an Ultrathin MAI Layer Leads to Enhanced Energy Level Alignment, Efficiencies, and Reproducibility" J. Phys. Chem. Lett. 8, 3947 (2017).

[2] Longbin Qiu, Luis K. Ono, Yan Jiang, Matthew R. Leyden, Sonia R. Raga, Shenghao Wang, Yabing Qi*, "Engineering Interface Structure to Improve Efficiency and Stability of Organometal Halide Perovskite Solar Cells" J. Phys. Chem. B (2017) DOI: 10.1021/acs.jpcb.7b03921

15:00 - 15:15
B1-O1
Ripolles, Teresa
Graduate School of Life Science and Systems Engineering
Origin of Open Circuit Voltage in wide band gap absorbers of all inorganic Cesium Perovskite Solar Cells
Teresa Ripolles
Graduate School of Life Science and Systems Engineering, JP
Authors
Teresa S. Ripolles a, Chi Huey Ng b, Kengo Hamada a, Siow Hwa Teo b, Hong Ngee Lim b, Juan Bisquert c, Shuzi Hayase a
Affiliations
a, Kyushu Institute of Technology Graduate School of Science
b, University Malaysia Sabah
c, Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castellón de la Plana, Castellón, España, Castellón de la Plana, ES
Abstract

Wide band gap absorbers were synthesized based on cesium lead bromide and iodide mixture in perovskite solar cells, CsPbBr3-xIx, where x varies between 0, 0.1, 0.2, and 0.3 molar ratio. High photoconvertion efficiencies were performed of 3.98 % for the perovskite composition of small amount of iodide as CsPbBr2.9I0.1. We observed that the open circuit voltage Voc depends mainly of two factors, which are (i) the band gap of the perovskite and (ii) the work function of the hole transport material HTM. An increment in Voc was observed for the device with larger perovskite band gap, while keeping the electron and hole extraction contacts the same. Additionally, the bilayer P3HT/MoO3 with deeper HOMO level instead of spiro-OMeTAD as HTM, thus increased the Voc from 1.16 V to 1.3 V for CsPbBr3 solar cell, although the photocurrent is lowered due to charge extraction issues. The stability was also investigated which confirmed that the addition of small amount of iodide into the CsPbBr3 perovskite is necessarily to stabilize the cell performance over time.

15:15 - 15:30
B1-O2
Knapp, Evelyne
ZHAW
Physical model for impedance loop and negative capacitance in perovskite solar cells
Evelyne Knapp
ZHAW, CH
Dr. Evelyne Knapp is a research associate at the Institute of Computational Physics at the Zurich University of Applied Sciences in Winterthur, Switzerland. She holds a Diploma and Ph.D. degree in Computational Science and Engineering from ETH Zurich.
Authors
Evelyne Knapp a, Beat Ruhstaller a, Martin Neukom b
Affiliations
a, Institute of Computational Physics, ZHAW, Wildbachstr. 21, Winterthur, 8401, CH
b, Fluxim, Katharina-Sulzer-Platz, 2, Winterthur, CH
Abstract

Negative capacitance and inductive loops in impedance spectroscopy at low or intermediate frequencies in perovskite solar cells have been described in several recent reports [1-4]. The origin of these observations, however, remained unknown so far and is under debate. There are suggestions that the negative capacitance and inductive loop are related to one another as they appear in the same samples but at different applied biases. A direct correlation between the observation of the negative capacitance and a corresponding decrease in performance of the solar cell was reported recently [3]. Similarly, we have demonstrated that ion migration is present even in high-efficiency low-hysteresis perovskite cells [5].

In this contribution, we shed light on the physical mechanisms behind these observations and compare devices with weak and strong hysteresis in the frequency domain at different applied bias. For this purpose, we employ a 1D model that includes electronic transport as well as ionic transport. The model is able to simulate current-voltage curves, transient responses and impedance spectra and naturally produces inductive loops and negative capacitance.

We investigate which factors influence the occurrence of the negative capacitance and the inductive loop by systematically varying the model parameters. The simulations allow us to analyse the charge carrier and ion distributions at different applied bias where the negative capacitance and an inductive loop appear. We compare the simulation results with measurements and are able to correlate the efficiency and the appearance of the negative capacitance and the inductive loop with the help of the simulation.

[1] Inductive Loop in the Impedance Response of Perovskite Solar Cells Explained by Surface Polarization Model, Elnaz Ghahremanirad, Agustín Bou, Saeed Olyaee, and Juan Bisquert, The Journal of Physical Chemistry Letters 2017 8 (7), 1402-1406

[2] Kovalenko, A., Pospisil, J., Zmeskal, O., Krajcovic, J. and Weiter, M. (2017), Ionic origin of a negative capacitance in lead halide perovskites. Phys. Status Solidi RRL, 11: n/a, 1600418.

[3] Deleterious Effect of Negative Capacitance on the Performance of Halide Perovskite Solar Cells, Francisco Fabregat-Santiago, Michael Kulbak, Arava Zohar, Marta Vallés-Pelarda, Gary Hodes, David Cahen, and Iván Mora-Seró, ACS Energy Letters 2017 2 (9), 2007-2013,

[4] Properties of Contact and Bulk Impedances in Hybrid Lead Halide Perovskite Solar Cells Including Inductive Loop Elements, Antonio Guerrero, Germà Garcia-Belmonte, Ivan Mora-Sero, Juan Bisquert, Yong Soo Kang, T. Jesper Jacobsson, Juan-Pablo Correa-Baena, and Anders Hagfeldt, The Journal of Physical Chemistry C 2016 120 (15), 8023-8032

15:30 - 15:45
Abstract not programmed
15:45 - 16:15
Coffee Break
16:15 - 16:30
B1-O3
Qin, Chuanjiang
OPERA, Kyushu University
Degradation mechanism of perovskite solar cells under standard test conditions
Chuanjiang Qin
OPERA, Kyushu University, JP
Authors
Chuanjiang Qin a, b, Toshinori Matsushima a, b, Chihaya Adachi a, b
Affiliations
a, OPERA, Kyushu University, JP
b, Japan Science and Technology Agency (JST), ERATO, Adachi Molecular Exciton Engineering Project
Abstract

Degradation Mechanism of Perovskite Solar Cells under Standard Test Conditions

Chuanjiang Qin,1,2* Toshinori Matsushima,1,2 and Chihaya Adachi1,2*

1OPERA, Kyushu University, 744 Motooka, Nishii, Fukuoka, 819-0395, Japan

2 Japan Science and Technology Agency (JST), ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishii, Fukuoka, 819-0395, Japan

*Corresponding authors. Email: cjqin@opera.kyushu-u.ac.jp;adachi@cstf.kyushu-u.ac.jp

 

Organic-inorganic hybrid halide perovskites have emerged as an interesting class of materials that have excellent photovoltaic properties for application to solar cells. In the last four years, the power conversion efficiency of perovskite solar cells (PSCs) over 20% has recently been realized through systematic optimization of materials and fabrication processes. However, the stability of PSCs is just beginning to be studied, and the actual degradation mechanisms of PSCs are not well understood. Here, we firstly investigate the degradation mechanisms of CH3NH3PbI3-based PSCs using a thermally stimulated current technique, which is a versatile technique used to analyze carrier traps in inorganic and organic materials. We observed that a large density of hole traps is formed in PSCs degraded by continuous solar illumination and that the formation of hole traps is strongly related to the stability.1 We further proved that exposure to moisture could accelerate degradation of perovskite under continous operation condition. One source of the traps is metallic lead resulting from photodegradation of CH3NH3PbI3 under continous light irradiation. By virtue of multifunctional benzoquinone additive which could efficiently suppress the formation of Frenkel defect-metallic lead, we greatly extended the lifetime of PSCs under standard laboratory weathering testing (ISOS-L-1 Laboratory) with a light intensity of 100 mW cm-2 without using a UV filter from 150 hours to 4000 hours.2 Futhermore, we systematically studied the device stability with different perovskites absorbers, and revealed influrence of phase transition on the device stability. Finally, efficient and thermally stable PSCs were realized under standard thermal cycling test (ISOS-T-1 Thermal Cycling).3

 

 

References

[1]  C. Qin, T. Matsushima, T. Fujihara, W. J. Potscavage, Jr., C. Adachi, Degradation mechanisms of solution-processed planar perovskite solar cells: thermally stimulated current measurement for analysis of carrier traps, Advanced Materials, 2016, 28, 466-471.

[2]  C. Qin, T. Matsushima, T. Fujihara, C. Adachi, Multifunctional benzoquinone additive for efficient and stable planar perovskite solar cells, Advanced Materials, 2017, 29, 1603808.

[3]  C. Qin, T. Matsushima, T. Fujihara, C. Adachi, under revision.

16:30 - 16:45
B1-O4
Lin, Xiongfeng
Monash University, Department of Materials Science and Engineering
Dipole-field-assisted charge extraction in metal-perovskite-metal back-contact solar cells
Xiongfeng Lin
Monash University, Department of Materials Science and Engineering, AU
Authors
Xiongfeng Lin a
Affiliations
a, Monash University, Calyton, 3800, AU
Abstract

Hybrid organic-inorganic halide perovskites are low-cost solution-processable solar cell materials with photovoltaic properties that rival those of crystalline silicon. The perovskite films are typically sandwiched between thin layers of hole and electron transport materials, which efficiently extract photogenerated charges. This affords high-energy conversion efficiencies but results in significant performance and fabrication challenges. Herein we present a simple charge transport layer-free perovskite solar cell (PSC), comprising only a perovskite layer with two interdigitated gold back-contacts. Charge extraction is achieved via self-assembled molecular monolayers (SAMs) and their associated dipole fields at the metal/perovskite interface. Photovoltages of approximately 600 mV generated by SAM-modified PSCs are equivalent to the built-in potential generated by individual dipole layers. Efficient charge extraction results in photocurrents of up to 12.1 mA cm-2 under simulated sunlight, despite a large electrode spacing. Full control of the charge extraction process in photovoltaic devices via SAM dipole-fields as shown here renders electronically matched charge extraction layers redundant and has potential application well beyond the field of PSCs.

16:45 - 17:00
B1-O5
Ryan, James
NIMS
Understanding the Voc in Perovskite Solar Cells Using Photo-Induced Transient Optoelectronic Techniques
James Ryan
NIMS, JP
Authors
James Ryan a
Affiliations
a, International Centre for Young Scientists, National Institute for Materials Science
Abstract

While rapid progress has been made in lead halide perovskite solar cells (PSCs) since the seminal papers from Snaith & Miyasaka and Park in 2012,1,2 much of the underlying device physics that makes these devices so efficient is not well understood. In order for PSCs to achieve their maximum efficiency it is necessary to clearly understand the key loss processes that govern their performance. In particular, understanding the origin of the open-circuit voltage (VOC) is vital. In PSCs, the VOC can shift considerably depending on the choice of transport layer and device architecture, be it from improved perovskite film quality or a better interface between the perovskite absorber and transport layer. To probe the recombination dynamics, transient optoelectronic techniques, such as transient photovoltage, transient photocurrent and charge extraction, offer key insights into the non-geminate charge carrier dynamics in solar cells and can explain the difference in VOC between different devices.3 These techniques have been employed with great success in organic and dye-sensitized solar cells but their application in PSCs is not as straightforward due to lead halide perovskites being mixed ionic-electronic conductors. In this talk I will discuss some of the challenges in using these techniques for PSCs and how they can be overcome to understand the origin of the open-circuit voltage as well as derive addional information into the working mechanisms of PSCs. In particular I will discuss the impact of hole-transporting layers on the VOC in inverted PSCs. 

References

1. Lee, Science, 338, 643

2. Kim, Sci. Rep. 2, 591

3. Ryan, Adv. Energy Mater., 7, 1601509

17:00 - 17:15
B1-O6
Patel, Jay
University of Oxford
The Importance of Interface Morphology for Hysteresis-Free Perovskite Solar Cells
Jay Patel
University of Oxford, GB
Authors
Jay Patel a, Jennifer Wong-Leung b, Stephan Van Reenen a, Nobuya Sakai a, Jacob Wang a, Elizabeth Parrott a, Mingzhen Liu a, Henry Snaith a, Laura Herz a, Michael Johnston a
Affiliations
a, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
b, The Australian National University, Canberra ACT 0200, Australia, AU
Abstract

The Importance of Interface Morphology for Hysteresis-Free Perovskite Solar Cells

Jay B. Patel1, Jennifer Wong-Leung2, Stephan Van Reenen1, Nobuya Sakai1, Jacob Wang1, Elizabeth S. Parrott1, Mingzhen Liu1, Henry J. Snaith1, Laura M. Herz1,

Michael B. Johnston1

1 University of Oxford, Oxford, OX1 3PU, United Kingdom

2The Australian National University, Canberra, ACT 2601, Australia

michael.johnston@physics.ox.ac.uk

Hybrid metal-halide perovskite materials show great promise for photovoltaic devices, with power conversion efficiencies (PCE) having recently exceeded 22%. However, hybrid metal-halide perovskite photovoltaic devices have been affected by anomalous hysteresis, whereby the current-voltage (J-V) characteristics are dependent upon both scan rate and direction. [1] Furthermore, discrepancies have been reported between the initial measured solar cell efficiency and measurements taken after holding the device at a sustained bias over a period (stabilised power output). To understand the cause of the anomalous hysteresis, we use optimised thermally evaporated perovskite solar cells and then characterise them with high resolution microscopy and current-voltage scans. [2] We demonstrate using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) that under identical growth conditions the interface affects perovskite morphology and crystallinity. We further correlate this with electron diffraction patterns of the perovskite at the interface. We find that the devices that are hysteretic incorporate amorphous regions of perovskite at the interface with the electron transport layer leading to poor charge collection efficiency, charge recombination, and is likely to result in device hysteresis via an electrical capacitive effect across the amorphous region.[3] However, when the perovskite is grown on top of an organic layer, such as PCBM, the interface consists of only crystalline perovskite. Not only does this lead to a hysteresis free device, it also leads to the device exhibiting a stabilised power output which is comparable to the measured solar cell efficiency from the J-V characterisation.

References

[1] H. J. Snaith, A. Abate, J. M. Ball, G. E. Eperon, T. Leijtens, N. K. Noel, S. D. Stranks, J. T.-W. Wang, K. Wojciechowski, W. Zhang, J. Phys. Chem. Lett. 2014, 5, 1511

[2] J. B. Patel, J. Wong-Leung, S. Van Reenen, N. Sakai, J. T. W. Wang, E. S. Parrott, M. Liu, H. J. Snaith, L. M. Herz, M. B. Johnston, Adv. Electron. Mater. 2017, 3, 1600470

[3] L. Cojocaru, S. Uchida, P. V. V. Jayaweera, S. Kaneko, J. Nakazaki, T. Kubo, H. Segawa, Chem. Lett. 2015, 44, 1750.

17:15 - 17:30
B1-O7
Jung, Hye-Ri
Ewha Womans University
Carrier transport and potential distribution near grain boundaries of perovskite lead halide and tin halide thin films
Hye-Ri Jung
Ewha Womans University, KR
Authors
Hye Ri Jung a, Bich Phuong Nguyen a, William Jo a
Affiliations
a, Department of Physics, Ewha Womans University, 52, Ewhayeodaegil, Seodaemungu, , Seoul, 3760, KR
Abstract

Lead Halide Perovskites need to improve their stability and environmental safety concerns. Tin halide has been considered as a candidate for replacing the demerits of lead halide but not much is known about its electrical properties. In this study, we report carrier transport and potential distribution of lead and tin halide thin films which were grown on mesoporous titanium oxides. Electronic structure was measured via Kelvin probe force microscopy and its optical exciations were also measured under illumination of laser light onto the sample. We are able to obtain interesting reponses which are strongly dependent on grain boundaries. It was reported that carrier transport inn perovskites is related to the band bending of the materials like Cu(In,Ga)S2 solar cells [1]. Conductive atomic force microscopy in order to investigate the roles of the grain boundaries for charge transport in lead and tin halides. We revealed the existence of a potential barrier at grain boundaries demonstrated thorough the charged region between the grain boundaries and intra grains. Hole entrapment near the grain boundaries in the perovskite thin films will have a positive effect on the utilization of solar cells and other applications by improving the electrical quality characteristics, such as the carrier collection and recombination.

[1] G. Y. Kim, S. H. Oh, B. P. Nguyen, W. Jo, B. J. Kim, D. G. Lee, H. S. Jung, "Efficient Carrier Separation and Intriguing Switching of Bound Charges in Inorganic-Organic Lead Halide Solar Cells", Journal of Physical Chemistry Letters, 6, 2355 (2015).

Session C1
Chair: Yabing Qi
14:30 - 15:00
C1-IS1
Han, Liyuan
National Institute for Materials Science (NIMS)
New Approaches for Large Area Perovskite Solar Module
Liyuan Han
National Institute for Materials Science (NIMS), JP

Dr. Liyuan Han is the managing researcher of Center for Green Research on Energy and Environmental Materials, National Institute for Materials Science (NIMS). He received his Ph.D. degree from the University of Osaka Prefecture in 1988. He worked at SHARP Corporation since 1993, and started on the research of dye-sensitized solar cells. He has renewed the world record efficiency of dye-sensitized solar cells (cell and module) for several times. On 2008, he moved to NIMS, and established a research on next generation solar cells. Recently, he moved to research perovskite solar cells and achieved the first certified efficiency of 15% with cell area larger than 1 cm2. He is an inventor in more than 100 patents and an author in ca 200 scientific publications such as Science, Nature Energy, Advanced Materials in the field of next generation solar cells. His current research interests involve fundamental research in perovskite solar cells, dye-sensitized solar cells, and organic solar cells.

Authors
Liyuan Han a, b
Affiliations
a, National Institute for Materials Science, Tsukuba, 305-0047, Japan
b, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dong Chuan Road, Minhang District, Shanghai 200240, China
Abstract

In recent years, perovskite solar cell (PSC) has undergone unprecedented development with efficiency approaching silicon solar cells. The efficiency record of PSC has reached 22.1% with cell size of 0.01 cm2 and the efficiency ca 20% has also been achieve for the cell size > 1cm2. The future challenge is to fabricate large-area perovskite modules and the key issue is to develop new deposition methods suitable for fabricating large-area perovskite films with low defects density.

Here, I will introduce our achievements in this field. A soft-cover deposition method was proposed and was proved to be effective for the fabrication of large-area and uniform perovskite films with large grains. A perovskite film with an area of 51cm2 was successfully obtained and was testified to be uniform with optical measurements. The perovskite solar cells (1 cm2) based on this method achieved an efficiency of 17.6% with high reproducibility which was the highest record for non-spin-coating methods at that time. More importantly, we recently synthesized a new non-solvent perovskite precursor and modified the soft-cover method by loading pressure before peeling off the polyimide film to control the thickness of films. The combination of this new precursor and deposition method led to the successful fabrication of perovskite module with aperture area of 6 x 6 cm2, a certified efficiency of 12.1% was obtained, which was the first perovskite module efficiency record.

 

F. Ye, H. L. Han, et al. Energy Environ. Sci. 2016, 9, 2295-2301.

H. Chen, L. Han, et al. DOI :10.1038nature23877

E. Bi, L. Han, et al. Nat. Commun., 2017, 8

Y. Wu, , L. Han, et al. Adv. Mater. 2017, 1701073.

 

15:00 - 15:15
C1-O1
Mitchell, Valerie
University of Melbourne
Amphiphilic block-copolymers for morphology control in OSCs
Valerie Mitchell
University of Melbourne, AU
Authors
David Jones a, Valerie Mitchell a
Affiliations
a, School of Chemistry, University of Melbourne, Melbourne, Victoria, 3010, AU
Abstract

In this work we report the synthesis, purification, morphological and photovoltaic evaluation of a novel fully-conjugated donor/acceptor block copolymer system based on the P3HT-b-PFTBT scaffold. The incorporation of hydrophilic tetraethylene glycol side-chains into the PFTBT acceptor block generates an amphiphilic species whose properties provide demonstrable benefits over traditional systems. This design strategy facilitates isolation of the block copolymer from homopolymer impurities present in the reaction mixture, and we show that this purification leads to better-defined morphologies. The chemical disparity introduced between donor and acceptor blocks causes spontaneous microphase separation into well-defined domains, which we demonstrate with a combination of spectroscopy, microscopy, and X-ray scattering. The morphological advantages of this system are significant.

[1] Mitchell, V. D., Wong, W. W. H., Thelakkat, M., and Jones, D. J., "The synthesis and purification of amphiphilic conjugated donor–acceptor block copolymers," Polymer Journal, Vol. 49(1), 155-161 (2016). DOI: 10.1038/pj.2016.97

[2] Mitchell, V. D.; Gann, E.; Huettner, S.; Singh, C. R.; Subbiah, J.; Thomsen, L.; McNeill, C. R.; Thelakkat, M.; Jones, D. J., "Morphological and Device Evaluation of an Amphiphilic Block Copolymer for Organic Photovoltaic Applications" Macromolecules 2017, 50 (13), 4942-4951. DOI: 10.1021/acs.macromol.7b00377

15:15 - 15:30
C1-O2
Zhang, Xintong
Northeast Normal University
Interfacial Modification of Three-dimensional Heterojunctional Colloidal Quantum Dot Solar Cell
Xintong Zhang
Northeast Normal University
Authors
Xintong Zhang a, Yinglin Wang a, Shuaipu Zang a, Jinhuan Li a, Yichun Liu a
Affiliations
a, Northeast Normal University
Abstract

    Colloidal quantum dot solar cells (CQDSCs) have been considered as one of the promising photovoltaic devices due to their simple architecture, solution-processed fabrication and well match with the solar spectrum, however, they usually suffer from insufficient carrier diffusion length of quantum-dot film. Developing three-dimensional (3D) CQDSC with ZnO nanowire array could orthogonalize the direction of minority carrier transport with the direction of light absorption, hence, increase the thickness of QD layer for better light-harvesting without obvious decrease of the electron collection efficiency.

    However, the increased interfacial area in the 3D-structural CQDSCs is usually combined with the augment of interfacial charge recombination reactions. In addition, the unbalance among the light-harvesting, electron collection and hole collection processes also restricts the further efficiency improvement of the 3D-structural CQDSCs. Therefore, one of the key points for the performance improvement of 3D-structural CQDSCs is how to efficiently control different carrier-related processes. We modified the surface of ZnO NWs by an ultrathin Mg(OH)2 interfacial layer through a simple solution deposition method which could passivate the surface trap states of ZnO and block the interfacial charge recombination. Thus, this Mg(OH)2  interfacial layer could efficiently increase the photovoltage by 33% and power conversion efficiency (PCE) by 25% compared with the reference cell. Except for the ZnO/PbS interface, we also paid attention to the mismatch band alignment between PbS and Au, which generated a reverse Schottky barrier and blocked the hole collection at PbS/Au interface. An Al2O3 ultrathin layer was atomic layer deposited on PbS-EDT film to increase the work function of PbS film by passivating the trap states of PbS, subsequently reduce the reverse Schottky barrier at PbS/Au interface. As a result, the PCE of CQDSCs with Al2O3 (7.3%) is increased by 31.5% compared with reference cell.

15:30 - 15:45
C1-O3
HAO, XIA
Sichuan University
The effect of cathode buffer in small molecule organic solar cells
XIA HAO
Sichuan University
Authors
Xia Hao a, b, c, Shenghao Wang c, Takeaki Sakurai c, Katsuhiro Akimoto c
Affiliations
a, Institute of New Energy and Low-carbon Technology, Sichuan University
b, Institute of Solar Energy Materials and Devices, College of Materials Science and Engineering, Sichuan University, No.24 South Section 1, Yihuan Road, Chengdu , 610064
c, Institute of Applied Physics, University of Tsukuba
Abstract

Small molecule organic solar cells (OSCs) are very interesting in the photovoltaic field since they are expected to open a novel field of solar cells, that is, flexible, light
weight, and potential low-cost photovoltaic cells. In this work, we fabricated inverted structured  boron subphthalocyanine chloride (SubPc)/fullerene (C60) based small molecule organic solar cells were fabricated. The effect of bathocuproine (BCP)/Ag doped BCP (Ag:BCP) in inverted organic solar cells was investigated. We demonstrated that BCP layer can be used as a buffer layer in inverted structure OSCs and the device performance was greatly improved. Unfortunately, the device exhibited an anomalous kink in the current density-voltage (J–V) characteristics, namely, an S-shaped J–V curve, leading to a low fill factor and low power conversion efficiency (PCE). To improve device performance, Ag:BCP was used to replace the BCP layer. The results showed that the Ag:BCP layer can eliminate the S-kink in the J–V curve, resulting in a large improvement of fill factor and PCE. The origin of the S-shaped J–V curve was demonstrated to originate from the charge accumulation at the C60/BCP interface. On the contrary, the C60/Ag:BCP interface has favorable electronic properties with beneficial gap states for the transport of free carriers. Together with the good conductivity of Ag:BCP layer and the smooth morphology properties, the device performance was greatly improved by Ag:BCP buffer layer. 

15:45 - 16:15
Coffee Break
16:15 - 16:30
C1-O4
Do, Thu Trang
Conjugated 1,8-Naphthalimide Based Solution Processable n-Type Semiconductors for Organic Electronics
Thu Trang Do
Authors
Thu Trang Do a, Hong Duc Pham a, Yasunori Takeda b, Sergei Manzhos c, John Bell a, Shinzo Tokito b, Prashant Sonar a, d
Affiliations
a, School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD-4001, Australia
b, Research Center for Organic Electronics, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510, Japan.
c, Department of Mechanical Engineering, Faculty of Engineering, National University of Singapore, Block EA #07-08, 9 Engineering Drive 1, Singapore 117576
d, Institute of Future Environment, GPO Box 2434, Brisbane QLD 4001
Abstract

Organic semiconductors have received great attention for application in field-effect transistors (OFETs), light-emitting diodes, and solar cells (OSCs). Particularly, solution processing is one of the most attractive features of organic semiconductors due to the advantages such as low cost and large-area device fabrication. In practice, the n-type semiconducting materials are as important as the p-type for high-performance OSCs and OFETs. However the development of n-type semiconductors has lagged far behind that of p-type materials. The imbalanced improvement of organic semiconductors limits the broad applications of organic electronics; therefore there is a growing trend in developing n-type semiconducting materials in OSCs and OFETs fields.

Herein, a series of novel electron deficient small molecular n-type based on 1,8-naphthalimide (NAI) and 9-fluorenone (FN) or 9,10-anthraquinone (ANQ) with different branched alkyl chains are synthesized and characterized. These molecules are based on an acceptor–donor–acceptor–donor–acceptor (A1–D–A2–D–A1) molecular design configuration with NAI as the end-capping acceptor (A1), FN or ANQ as electron-withdrawing central (A2) group, and thiophene ring as a donor (D) unit. These materials are named as NAI-FN-NAI (BO), NAI-FN-NAI (HD), NAI-ANQ-NAI (BO), NAI-ANQ-NAI (HD) and NAI-ANQ-NAI (HD) where BO, HD and DT represent butyloctyl, hexyldecyl and decyltetradecyl alkyl groups, respectively. To further modify energy levels, we converted the weak electron withdrawing ketonic group attached to the FN moiety of NAI-FN-NAI (BO) to a stronger electron withdrawing cyano group to obtain the compound NAI-FCN-NAI (BO). The materials exhibited higher to medium band gaps, low LUMO energy levels, and highly thermally stable properties. The first group materials including NAI-FN-NAI (BO), NAI-FN-NAI (HD), and NAI-FCN-NAI (BO) were utilised as electron acceptor for OSCs; and OSC devices based on NAI-FN-NAI (BO) as an acceptor exhibited the highest performance with VOC of 0.88 V, JSC of 9.1 mAcm–2, FF of 45%, and PCE of 3.6%. This is the first report of 9-fluorenone based nonfullerene acceptor with poly(3-hexylthiophene) donor in the devices with such a promising performance. The second group materials of NAI-ANQ-NAI (BO), NAI-ANQ-NAI (HD) and NAI-ANQ-NAI (HD) were applied for n-type OFETs to investigate the effect of alkyl chain length on device performances. NAI-ANQ-NAI (BO) based device showed the best results with the highest electron mobility of 0.042 cm2V-1s-1.

16:30 - 16:45
C1-O5
Horvath, Endre
École Polytechnique Fédérale de Lausanne EPFL
Organic-inorganic lead halide perovskite nanowires: formation mechanism and optoelectronic applications
Endre Horvath
École Polytechnique Fédérale de Lausanne EPFL, CH
Authors
Endre Horvath a, Massimo SPINA a, Bálint NÁFRÁDI a, Eric BONVIN a, Márton KOLLÁR a, Andrzej SIENKIEVICZ a, Anastasiia GLUSHKOVA a, Alla ARAKCHEEVA a, Zsolt SZEKRÉNYES b, Hajnalka TÓHÁTI b, Katalin KAMARÁS b, Richard GAAL c, László FORRÓ a
Affiliations
a, EPFL SB IPHYS LPMC , station 3, 1015, Lausanne
b, Wigner Research Centre for Physics, 1525, Budapest
c, EPFL SB IPHYS EPSL , station 3, 1015, Lausanne
Abstract

In this talk a common mechanism underlying of hybrid perovskite nanowire formation will be discussed in detail [1]. The central role of the solvatomorph phase as the intermediate phase in crystallization will be highlighted. Next, our latest findings on the guided growth of perovskite nanowires by ‘solvatomorph-graphoepitaxy’ will be presented [2]. This method turned out to be a fairly simple approach to overcome the spatially random surface nucleation. The process allows the synthesis of extremely long (centimeters) and thin (a few nanometers) nanowires with a morphology defined by the shape of nanostructured open fluidic channels. This method might allow the integration of perovskites into advanced CMOS technologies.

CH3NH3PbI3 nanowires in association with carbon nanostructures (carbon nanotubes and graphene) make outstanding composites with rapid and strong photoresponse. They can serve as conducting electrodes, or as central components of detectors. Performance of several miniature photo-field effect transistor devices based on these composite structures will be demonstrated.

Solvatomorph-graphoepitaxy method could open up an entirely new spectrum of architectural designs of organometal-halide-perovskite-based heterojunctions -and tandem solar cells, LEDs, photodetectors and new type of magneto-optical data storage devices [5].

References :

[1] Horváth et al. Nano Letters, 2014, 14 (12), 6761–6766

[2] Spina et al. Scientific Reports, 2016, 6

[3] Spina et al. Small, 2015, 11, 4824-4828

[4] Spina et al. Nanoscale, 2016, 8, 4888

[5] Náfrádi et al. Nature Communications 7, 13406

Acknowledgement:

This work was supported by the ERC Advanced Grant (PICOPROP#670918).

16:45 - 17:00
C1-O6
Liang, Xinxing
University of Bath
Continuous Low Temperature Synthesis of MAPbX3 Perovskite Quantum Dots with Tuneable Luminescence
Xinxing Liang
University of Bath, GB
Authors
Xinxing Liang a, Wentao Deng a, Kejun Wu b, Robert Baker a, Dominic Ferdani a, Laura Torrente-Murciano b, Petra Cameron a
Affiliations
a, Department of Chemistry, University of Bath, Claverton Down, University of Bath, Bath,UK, BA2 7AY, GB
b, Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB2 3RA, UK., Cambridge CB2 3RA, UK, Cambridge, GB
Abstract

Due to the high absorption coefficients, long carrier diffusion lengths, high carrier mobilities and low trap densities, perovskites have been widely investigated as absorbers for solar cells and emitters for light emitting diodes (LEDs).  Along with the development of bulk perovskite materials, perovskite quantum dots (QDs) have also attracted scientific interest because of their size-dependent absorption and emission, narrow emission width and high quantum efficiency. They have been applied as the interlayers or active layers for high performance solar cells and LEDs. Currently, the synthesis of perovskite NCs is mainly based on two methods: ligand-assisted reprecipitation (LARP) and hot injection (HI). These two methods can result in the formation of highly emissive perovskite QDs, but they are normally carried out in batch systems with poor mixing, making scale-up difficult. Besides, high temperatures of over 100°C are normally required especially for HI method. In this work, a simple flow reactor was used to carry out the room temperature synthesis of MAPbX3 perovskite QDs. The resulting QDs showed a narrow size distribution, high stability and excellent emissive properties. Their photoluminescence was tuned by changing the halide composition. 

17:00 - 17:15
C1-O7
YANGUI, Aymen
Institute of Industrial Science, The University of Tokyo
White-Light Emission in two-dimensional Hybrid Perovskites
Aymen YANGUI
Institute of Industrial Science, The University of Tokyo
Authors
Aymen Yangui a, Kamel Boukheddaden b, Smail Triki c, Sebastien Pillet d, Younes Abid e
Affiliations
a, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
b, Groupe d’Etudes de la Matière Condensée, Université de Versailles Saint Quentin En Yvelines, 45 Avenue des Etats-Unis, 78035, Versailles, France
c, Laboratoire de Chimie, Electrochimie Moléculaires, Chimie Analytique, UMR CNRS 6521-Université de Bretagne Occidentale, BP 809, 29285 Brest, France
d, Laboratoire de Cristallographie, Résonance Magnétique et Modélisations, UMR-CNRS 7036, Institut Jean Barriol, Université de Lorraine, BP 239, 54506 Vandœuvre-lès-Nancy, France
e, Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, Route de Soukra km 3.5 BP 1171, 3018 Sfax, Tunisia
Abstract

During the last decades, great attention has been devoted to organic-inorganic hybrid perovskites (OIHP) due to their special structures and important optical and optoelectronic properties. Since 2009, OIHP represented an exciting new class of low-cost solar absorber materials which have revolutionized the photovoltaic landscape by the exceptional growth of their power conversion efficiency from 3.8 % to more than 22 %1,2 in less than ten years. Moreover, their 2D counterparts exhibit strong photoluminescence, even at room temperature, making them promising candidates for the design of organic-inorganic light emitting diodes (OILED).3 Recently, we have observed a strong white-light emission, even at room temperature, in the 2D lead bromide based-OIHP, under UV irradiation.4 The maximum photoluminescence quantum efficiency (PLQE) of this very broad (~ 660 meV) emission was observed around 100K. Later on, we succeeded to partially control the chromaticity of the emission with the choice of halogen and metal.5 The same phenomenon was observed just before by Dohner et al. in some 2D (100)-oriented OIHP and a stable PLQE of 9 % has been measured, even after three months of continuous irradiation.6,7 Our optical and structural investigations suggested that this white-light emission results from self-trapped carriers in a deformable lattice due to the presence a strong electron−phonon coupling. Since these pioneering works, several research groups started exploring deeply this new phenomenon,7-11 which further confirms the great interest of these low-cost single-component white-light emitters in solid state lighting applications.

References

1 A. Kojima et al., J. Am. Chem. Soc., 131(17), 6050–6051 (2009).

2 W.S. Yang et al., Science 356, 1376–1379 (2017).

3 D.B. Mitzi, et al. IBM J Res & Dev 45, 29-45 (2001).

4 A. Yangui, et al. J. Phys. Chem. C, 119(41), 23638-23647 (2015).

5 A. Yangui, et al., J. Alloys Compd. 699, 1122-1133 (2017).

6 E.R. Dohner, E.T. Hoke, H.I. Karunadasa. J. Am. Chem. Soc. 136, 1718-1721 (2014).

7 E.R. Dohner, A. Jaffe, L.R. Bradshaw, H.I. Karunadasa. J. Am. Chem. Soc. 136, 13154-13157 (2014).

8 K. Thirumal et al., Chem. Mater., 29(9), 3947–3953 (2017).

9 D. Cortecchiaet al., J. Am. Chem. Soc, 139(1), 39-42 (2017).

10 L. Mao et al., J. Am. Chem. Soc., 139(34), 11956–11963 (2017).

11 Z. Zhuang et al., Tunable White-Light Emission in Single-Cation-Templated Three-Layered 2D Perovskites (CH3CH2NH3)4Pb3Br10–xClx, Angew. Chem. Int. Ed. DOI: 10.1002/anie.201706660

17:15 - 17:30
C1-O8
Mao, Wenxin
Monash University, Department of Materials Science and Engineering
Controlled Growth of Monocrystalline Organo-Lead Halide Perovskite and Its Application in Photonic Devices
Wenxin Mao
Monash University, Department of Materials Science and Engineering, AU
Authors
Wenxin Mao a
Affiliations
a, Department of Materials Science and Engineering, Monash University
Abstract

Organo-lead halide perovskites (OHPs) have recently emerged as a new class of exceptional optoelectronic materials, which may find use in many applications, including solar cells, light emitting diodes, and photodetectors. More complex applications, such as lasers and electro-optic modulators, require the use of monocrystalline perovskite materials to reach their ultimate performance levels. Conventional methods for forming single crystals of OHPs like methylammonium lead bromide (MAPbBr3) afford limited control over the product morphology, rendering the assembly of defined microcavity nanostructures difficult. We overcame this by synthesizing for the first time (MA)[PbBr3]·DMF (1), and demonstrating its facile transformation into monocrystalline MAPbBr3 microplatelets. The MAPbBr3 microplatelets were tailored into waveguide based photonic devices, of which an ultra-low propagation loss of 0.04 dB um-1 for a propagation distance of 100 um was demonstrated. An efficient active electro-optical modulator (AEOM) consisting of a MAPbBr3 non-linear arc waveguide was demonstrated, exhibiting a 98.4% PL intensity modulation with an external voltage of 45 V. This novel synthetic approach, as well as the demonstration of effective waveguiding, will pave the way for developing a wide range of photonic devices based on organo-lead halide perovskites.

17:30 - 19:00
Posters Exhibition
20:00 - 22:00
Social Dinner
 
Tue Jan 30 2018
08:55 - 09:00
Announcement of the Day
Session G2
Chair: Shuzi Hayase
09:00 - 09:45
G2-K1
Park, Nam-Gyu
Sungkyunkwan University
Halide Perovskite Photovoltaics and X-ray Imaging
Nam-Gyu Park
Sungkyunkwan University, KR

Nam-Gyu Park is professor and SKKU-Fellow at School of Chemical Engineering and adjunct professor at Department of Energy Science, Sungkyunkwan University. He got Ph.D. in Inorganic Solid State Chemistry from Seoul National University in 1995. He worked at ICMCB-CNRS, France, from 1996 to 1997 and at National Renewable Energy Laboratory, USA, from 1997 to 1999 as postdoctoral researchers. He worked as Director of Solar Cell Research Center at Korea Institute of Science and Technology from 2005 to 2009 and as a principal scientist at Electronics and Telecommunications Research Institute from 2000 to 2005 before joining Sungkyunkwan University in 2009. He has been doing researches on high efficiency mesoscopic solar cells including perovskite solar cell and dye-sensitized solar cell since 1997. He is pioneer in solid state perovskite solar cell, which was first developed in 2012. He received awards, including Scientist Award of the Month (MEST, Korea), KyungHyang Electricity and Energy Award (KEPCO, Korea), KIST Award of the Year (KIST, Korea) and Dupont Science and Technology Award (Dupont Korea), SKKU fellowship, and MRS Outstanding Research Award (MRS, Boston) and WCPEC Paper Award (Kyoto, Japan). He published over 230 scientific papers, including Science, Nature Materials, Nature Nanotechnology, Nature Energy and Nature Communications, 80 patent applications and 8 book chapters. He received H-index of 67 as of May, 2017.

Authors
Nam-Gyu Park a
Affiliations
a, School of Chemical Engineering and Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 440-746, KR
Abstract

Since the first report on the solid-state perovskite solar cell with power conversion efficiency (PCE) of 9.7% and 500 h-stability in 2012 by our group, its certified PCE now reaches 22.1%. It is believed that perovskite solar cell is promising next-generation photovoltaics due to superb performance and very low cost. Although high photovoltaic performance was achieved, there are some issues to be addressed. Current-voltage hysteresis is critical because hysteresis can cause instability of perovskite material. In this talk, material and interfacial emerging are introduced to remove hysteresis and thereby improve stability. Doping is found to be effective way in reducing defect. Universal approach toward hysteresis-free perovskite solar cell will be discussed in detail. Organic-inorganic halide perovskite is found to be highly useful material for low-dose, high resolution X-ray imaging. Multicrystalline perovskite crystal (MPC) with enhanced (100) planes was prepared by solution chemistry. We demonstrated 10 by 10 cm2 X-ray imaging using MPC with TFT backplane.

09:45 - 10:15
G2-I1
Mhaisalkar, Subodh
NTU SINGAPORE
Metal-Halide Perovskite Nanocrystals: Unlocking Size Dependent Effects for High Performance Solar Cells and Light-Emitting Devices
Subodh Mhaisalkar
NTU SINGAPORE

Subodh Mhaisalkar is the Tan Chin Tuan Centennial Professor in the School of Materials Science & Engineering at the Nanyang Technological University (NTU), Singapore. Subodh is also the Executive Director of the Energy Research Institute @ NTU (ERI@N), a pan-University multidisciplinary research institute for innovative energy solutions. Prior to joining NTU in 2001, Subodh has over 10 years of research and engineering experience in the microelectronics industry and his areas of expertise and research interests includes semiconductor technology, perovskite solar cells, printed electronics, and energy storage. Subodh received his Bachelors’ degree from IIT-Bombay and his MS/Ph.D. degrees from The Ohio State University.

 

Authors
subodh Mhaisalkar a
Affiliations
a, Materials Science and Engineering, Nanyang Technological University, SG
Abstract

The past five years have witnessed remarkable advances in the field of solar cells and light-emitting devices with the perovskite metal halide, CH3NH3PbI3, and related family of materials. These semiconductors form nearly defect free, crystalline films at low temperatures that exhibit high optical absorption, long-range charge transport, and efficient charge collection, yielding high performance LEDs and solar cells. The prospects for advancing device efficiencies are contingent upon exploring new perovskite compositions and structures. One such structural variant is represented by lower-dimensionality layered perovskite derived from their 3D counterparts (ABX3) by increasing the distance between the interconnected inorganic sheets with the appropriate organic cations. Lower-dimensionality layered perovskites formulations permit for band gaps and exciton binding energy tuning, carrier mobility facilitated by the inorganic moeities, with the organic moieties providing additional controls for stability, light harvesting, and intralayer charge transport. Nanocrystals is yet another variant in perovskites that promises to yield new opportunities in advancing device performance. Perovskites are typically synthesised via wet-chemistry routes, allowing for mixing at a molecular level, and resulting in materials with high phase purity. By carefully controlling the reaction conditions such as temperature, solvent, and ligands, hybrid perovskites of morphologies ranging from 0D quantum dots to 3D single crystals; and sizes stretching 6 orders of magnitude can be prepared. This presentation will outline a broad palette of elemental substitutions, solid solutions, and multidimensional families that will provide the next step towards the advances of the perovskite solar cells and light-emitting devices. Challenges and opportunities in perovskite materials beyond methyl ammonium lead iodide, with emphasis on their recombination dynamics, optoelectronic properties, and integration into solar cells and light-emitting devices, will also be addressed.

References: (1) Chen, W. et al. "Giant five-photon absorption from multidimensional core-shell halide perovskite colloidal nanocrystals”, Nature Communications, 8: 15198, 2017. (2) Li, MJ. et al. "Slow cooling and highly efficient extraction of hot carriers in colloidal perovskite nanocrystals", Nature Communications, 8: 14350, 2017. (3)           Veldhuis SA. et al. Perovskite Materials for Light-Emitting Diodes and Lasers, Advanced Materials, 28(32): 6804-6834, 2016. (4) GC Xing et al. Low-Temperature Solution-Processed Wide Wavelength Tunable Perovskites for Lasing, Nature Materials, 13, 5, 476-480, 2014. (5) Xing, GC. et al. Long-Range Balanced Electron- and Hole-Transport Lengths in Organic-Inorganic CH3NH3PbI3; Science; 342(6156)344-347; 2013 

10:15 - 10:45
G2-I2
Jen, Alex K-Y.
University of Washington
Rational Material, Interface, and Device Engineering for High-Performance and Stable Perovskite Solar Cells
Alex K-Y. Jen
University of Washington, US

Professor Alex Jen obtained his Ph. D. degree from the Department of Chemistry, University of Pennsylvania in 1984. He is currently the Boeing-Johnson Chair Professor and Department Chair of the Materials Science & Engineering at the University of Washington, Seattle. He is also serving as the Chief Scientist of the Clean Energy Institute established by the governor of the Washington State. Dr. Jen’s research interest is focused on utilizing molecular, polymeric and biomacromolecular self-assembly to create ordered arrangement of organic and inorganic functional materials for photonics, opto-electronics, nanomedicine, and nanotechnology. He has co-authored more than 500 publications, given over 400 invited presentations, and has more than 20,000 citations and a H-index of 72. He is also a co-inventor for more than 50 patents and invention disclosures. For his pioneering contributions in organic photonics and electronics, he was elected as Fellow by several professional societies including the MRS Fellow of the Materials Research Society, ACS Fellow of the American Chemical Society, the AAAS Fellow by American Association of the Advancement of Science, the OSA Fellow of Optical Society of America, SPIE Fellow of the International Society of Optical Engineering, and PMSE Fellow of the American Chemical Society’s Polymeric Materials Science & Engineering Division. He was also elected as an Academician of the Washington State Academy of Sciences.

Authors
Alex K-Y Jen a, b
Affiliations
a, Department of Materials Science & Engineering, University of Washington, Seattle, WA 98195
b, Department of Materials Science, City University of Hong Kong, Kowloon, HK
Abstract

Advances in controlled synthesis, processing, and tuning of the properties of peroskites have enabled significantly enhanced performance of hybrid perovskite solar cells. The performance of hybrid perovskite solar cells is strongly dependent on their efficiency in harvesting light, charge transport, and charge collection at the metal/organic/perovskite or the metal/metal oxide perovskite interfaces. In this talk, an integrated approach of combining material design, interface, and device engineering to significantly improve the performance and stability of organic and hybrid perovskite photovoltaic cells (PCE of >20%) will be discussed. At the end, several new device architectures and optical engineering strategies to make tandem cells and OPV/Perovskite hybrid solar cells will be discussed to explore the full promise of perovskite hybrid solar cells.

 1 1 1  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  1 1 1 1   1 1 1 1 1 1 1

10:45 - 11:15
Coffee Break
11:15 - 11:45
G2-I3
Jung, Hyun Suk
Sungkyunkwan University
Interfacial Nanomaterials Engineering in Perovskite Solar Cells
Hyun Suk Jung
Sungkyunkwan University, KR
Hyun Suk Jung is an associate professor in school of advanced materials science & engineering at Sungkyunkwan university (SKKU). He received his BS, MS, and PhD degrees in materials science & engineering from Seoul National University (SNU), in 1997, 1999, and 2004, respectively. He joined Los Alamos National Laboratory (LANL) as a director’s postdoctoral fellow in 2005. He had worked for Kookmin University (KMU) since 2006 and joined SKKU in 2011. He published over 130 peer-reviewed papers regarding synthesis of inorganic nanomaterials and dye-sensitized solar cells. He presently researches perovskite solar cells and flexible solar cells.
Authors
Hyun Suk Jung a
Affiliations
a, School of Advanced Materials Science & Engineering, Sungkyunkwan University, Cheoncheon-dong, Jangan-gu, Suwon-si, Gyeongggi-do, Suwon, 440746, KR
Abstract

All solid-state solar cells based on organometal trihalide perovskite absorbers have already achieved distinguished power conversion efficiency (PCE) to over 22% and further improvements are expected up to 25%. These novel organometal halide perovskite absorbers which possess exceptionally strong and broad light absorption enable to approach the performances of the best thin film technologies. To commercialize these great solar cells, there are many bottlenecks such as long term stability, large scale fabrication process, and environmental issues.

In this presentation, we introduce our recent efforts to improve long term stability and solve environmental issues. For examples, we introduce a recycling technology of perovskite solar cells, which will facilitate the commercialization as well as solve the environmental issues of perovskite solar cells. Also, we are going to show new interfacial layers such as BCP and C60/TiO2 layers that are inserted between Perovkite and TCO. These layers are found to show excellent long-term stability of Perovskite materials as well as good charge transporting properties. Also, stability issue of perovskite materials regarding charge generation and extraction will be discussed. 

11:45 - 12:15
G2-I4
Yang, Yang
Universtiy of California Los Angeles
Controlled Crystal Growth and Defect Passivation for Efficient Planar Perovskite Solar Cells
Yang Yang
Universtiy of California Los Angeles, US

Prof. Yang Yang The Carol and Lawrence E. Tannas Jr. Endowed Chair in Engineering Department of Materials Science and Engineering, UCLA PhD: Physics and Applied Physics, U-Mass.,Lowell, 1992; Advisors: Prof. Sukant Tripathy (deceased) and Jayant Kumar MS.: Physics and Applied Physics, U-Mass.,Lowell, 1988 Advisor: Prof. Y.Y. Teng (deceased) BS.: Physics, National Cheng-Kung University, Taiwan, 1982 Prof. Yang's major researches are in the solar energy and highly efficient electronic devices. He has more than 230 refereed papers (including book chapters); 43 patents (filed or issued), and 120 invited talks. His H-Index is ~82 as January 2014. His major contribution in the organic solar energy is in the understanding of polymer morphology and the influence on device performance; the invention of inverted organic solar cell, and inverted tandem solar cell; and transparent solar cells. In the past few years, Yang has created several record-high efficiencies in polymeric solar cells. Other researches he participated are: organic memory devices, solution processible graphene, and solution processible CIGS/CZTS solar cells. He has a group of 25 student and postdocs. Since 2001, he has produced 28 PhD degrees, 10 MS degrees; among them, 9 of his students have become faculty. His technology has enabled the formation of 5 startups. Honors and Awards: The Carol and Lawrence E. Tannas Jr. Endowed Chair in Engineering, July 2011 Director, Nano Renewable Energy Center of California NanoSystem Inst., UCLA. (2007-now) Top Hot Researcher in 2010, Science Watch (published by Thomas Reuters) Highest cited Paper in 2010, Advanced Functional Materials Highest cited Paper in 2008-2010, Journal of American Chemical Society (JACS) IEEE Photovoltaic Field Expert, 2009. Semiconductor Research Association Invention Award 2008. NSF Career Award: 1998; 3M Young Investigator Award, 1998. Professional EXPERIENCE UCLA (1997-present): The Carol and Lawrence E. Tannas Jr. Endowed Chair in Engineering, July 2011 Nano Renewable Energy Center, California Nano-System Institute, Director, (2007-present). Materials Science and Engineering, Professor (02-now), Asso. Prof. (98-02), Asst. Prof. (97-98) EFL Tech. (Brisbane, Australia), Chair of Scientific Advisory Board (2012-present) EFL Tech is a startup to commercialize the transparent solar cell for portable electronics. Solarmer Energy Inc., Chief Scientist (2006-present) Solarmer Energy Inc. is a startup co-funded by Yang, their business is in the commercialization of polymer solar cells. 1992-1996, UNIAX Corporation (now Du Pont Display) in Santa Barbara Postdoc (92 -93; advisor: Prof. Alan Heeger, Nobel Laureate, 2000) and Staff Scientist (93-96) Participated in research on polymer LEDs, transistors, and conducting polymers. 1991-1992, University of California-Riverside, Chemistry Department Postdoc (supervisor: Prof. B. Kohler (deceased)) Laser spectroscopy and hole-burning experiments. Prof. Yang's Selective Publications His H-index is ~82 as of January 2014 (1) High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends, Gang Li, Vishal Shrotriya, Jinsong Huang, Yan Yao, Tom Moriarty, Keith Emery and Yang Yang, Nature Materials Volume: 4 Issue: 11, 864-868, 2005 Times Cited: 2002 (2) Polymer solar cells with enhanced open-circuit voltage and efficiency, Hsiang-Yu Chen, Jianhui Hou, Shaoqing Zhang, Yongye Liang, Guanwen Yang, Yang Yang, Luping Yu, Yue Wu and Gang Li., Nature Photonics, 3, 11, Pages: 649-653, 2009 Times Cited: 427 (3) Programmable polymer thin film and non-volatile memory device, Jianyong Ouyang, Chih-Wei Chu, Charles R. Szmanda, Liping Ma, Yang Yang, Nature Materials, 3, 12, 918-922, 2004 Times Cited: 322 (4) Polyaniline nanofiber/gold nanoparticle nonvolatile memory, Ricky Jia-Hung Tseng, Jiaxing Huang, Jianyong Ouyang, Richard B. Kaner, and Yang Yang, Nano Letters, 5, 6, 1077-1080, 2005 Times Cited: 319 (5) Synthesis, Characterization, and Photovoltaic Properties of a Low Band Gap Polymer Based on Silole-Containing Polythiophenes and 2,1,3-Benzothiadiazole, Jianhui Hou, Hsiang-Yu Chen, Shaoqing Zhang, Gang Li, and Yang Yang., Journal of the American Chemical Society, 130, 48, 16144-16145, 2008 Times Cited: 284 (6) High-throughput solution processing of large-scale graphene, Vincent C. Tung, Matthew J. Allen, Yang Yang and Richard B. Kaner., Nature Nanotechnology, 4, 1, 25-29, 2009 Times Cited: 254 (7) "Solvent annealing" effect in polymer solar cells based on poly(3-hexylthiophene) and methanofullerenes, Gang Li, Yan Yao, Hoichang Yang, Vishal Shrotriya, Guanwen Yang, and Yang Yang, Advanced Functional Materials, 17, 10, 1636-1644, 2007, Times Cited: 254 (8) Investigation of annealing effects and film thickness dependence of polymer solar cells based on poly(3-hexylthiophene), Gang Li, Vishal Shrotriya, Yan Yao, and Yang Yang., Journal of Applied Physics, 98, 4, 043704(5 pages), 2005 , Times Cited: 229 (9) Recent Progress in Polymer Solar Cells: Manipulation of Polymer: Fullerene Morphology and the Formation of Efficient Inverted Polymer Solar Cells, Li-Min Chen, Ziruo Hong, Gang Li, and Yang Yang, Advanced Materials ,21, 14, 1434-1449, : 2009, Times Cited: 196 (10) Accurate measurement and characterization of organic solar cells, Vishal Shrotriya, Gang Li, Yan Yao, Tom Moriarty, Keith Emery, and Yang Yang., Advanced Functional Materials, 16, 15, 2016-2023, 2006 , Times Cited: 181 (11) Low-Temperature Solution Processing of Graphene-Carbon Nanotube Hybrid Materials for High-Performance Transparent Conductors; Tung, VC; Chen, LM; Allen, MJ; Kaner, R., and Yang, Y., Nano Letters, 9 (5), 1949-1955 (2009); Times Cited: 114 (12) Synthesis of a Low Band Gap Polymer and Its Application in Highly Efficient Polymer Solar Cells; Hou, JH; Chen, HY; Zhang, SQ; Yang, Y.et al; JACS, 131(43), 15586- 629 (2009); Times Cited: 136 (13) Effect of solvent mixture on the nanoscale phase separation in polymer solar cells; Yao, Y; Hou, JH; Xu, Z; Li, G., Yang, Y.; Adv. Func. Mat., 18, 1783-1789 (2008). Times Cited: 106 (14) Manipulating regioregular poly(3-hexylthiophene): [6,6]-phenyl-C-61-butyric acid methyl ester blends - route towards high efficiency polymer solar cells; Li, G; Shrotriya, V; Yao, Y; Huang, J., Yang, Y.; Journal of Materials Chemistry, 17 (30), 3126-3140 (2007), Times Cited: 120 (15) Patterning organic single-crystal transistor arrays, A. L. Briseno, S. Mannsfeld, M. M. Ling, S. Liu, R. J. Tseng, C. Reese, M. E. Roberts, Y. Yang, Z. Bao; Nature, 444, 913, (2006). Times Cited: 272 (16) Digital memory device based on tobacco mosaic virus conjugated with nanoparticles; Tseng, RJ; Tsai, CL; Ma, LP; Ouyang, J., Ozkan, C.S., Yang, Y.; Nature Nanotech, 1, 72, (2006) Times Cited: 145 (17) Efficient inverted polymer solar cells; Li, G; Chu, CW; Shrotriya, V; Huang, J., and Yang, Y. Appl. Phys. Lett., 88, Pages: 253503-253505 (2006), Times Cited: 85 (18) Regioregular copolymers of 3-alkoxythiophene and their photovoltaic application; Shi, CJ; Yao, Y; Yang, Y; Pei, Q.; JACS, 128, 27, p. 8980-8986 (2006); Times Cited: 137 (19) Electrical switching and bistability in organic/polymeric thin films and memory devices, Yang, Y; Ouyang, J; Ma, LP; et al.; Adv. Func. Mat. 16, 1001-1014 (2006). Times Cited: 184 (20) Achieving high-efficiency polymer white-light-emitting devices; Huang, JS; Li, G; Wu, E; Yang, Y.Adv. Mat. 18, 114-117, (2006). Times Cited: 163 (21) Transition metal oxides as the buffer layer for polymer photovoltaic cells; Shrotriya, V; Li, G; Yao, Y; Yang, Y.; Applied Physics Letters: 88(7), Pages: 073508-510 (2006); Times Cited: 132 (22) High-performance organic thin-film transistors with metal oxide/metal bilayer electrode; Chu, C.W., Li, S-H., Chen, C-W., Shrotriya, V., & Yang, Y., Appl. Phys. Lett., 87,193508 (2005) Times Cited: 100 (23) Investigation of annealing effects and film thickness dependence of polymer solar cells based on P3HT; Li, G; Shrotriya, V; Yao, Y; & Yang, Y., JAP 98, 043704, (2005). Times Cited: 229 (24) Organic donor-acceptor system exhibiting electrical bistability for use in memory devices; Chu, CW; Ouyang, J; Tseng, HH; Yang, Y.; Adv. Mat. 17 (11) p. 1440 (2005) Times Cited: 140 (25) Nonvolatile electrical bistability of organic/metal-nanocluster/organic system, Ma, LP; Pyo, S; Ouyang, J; Yang, Y., Appl. Phys. Lett. 82, 1419-21, (2003). Times Cited: 213 (26) High-performance polymer light-emitting diodes doped with a red phosphorescent iridium complex, Chen, FC; Yang, Y; Thompson, ME; Appl. Phys. Lett., 80, 2308 (2002). Times Cited: 155 (27) Organic electrical bistable devices and rewritable memory cells, Ma, LP; Liu, J; Yang, Y; Applied Physics Letters, 80, 16, p. 2997-2999 (2002). Times Cited: 260 (28) Solvation-induced morphology effects on the performance of polymer-based photovoltaic devices, Liu, J; Shi, YJ; Yang, Y, Adv. Func. Mat., 11 (6), p. 420-424, (2001), Times Cited: 150 (29) Device performance and polymer morphology in polymer light emitting diodes: The control of device electrical properties and metal/polymer contact, Liu, J; Shi, YJ; Ma, LP; Yang, Y J. Appl. Phys., 88, 605, (2000). Times Cited: 95 (30) Device performance and polymer morphology in polymer light emitting diodes: : the control of thin film morphology and device quantum efficiency;; Shi, Y; Liu, J; Yang, Y; J. Appl. Phys., 87, 4254 (2000). Times Cited: 249 (31) Polymer electroluminescent devices processed by inkjet printing: I. Polymer light-emitting logo, Bharathan, J; Yang, Y, Appl. Phys. Lett., 72, 2660, (1998). Times Cited: 255 (Citation number is from: www.researchid.com)

Authors
Yang Yang a, Jin-Wook Lee a, Lijian Zuo a, Qifeng Han a, Yao-Tsung Hsieh a, Sang-Hoon Bae a, Nicholas De Marco a, Pengyu Sun a
Affiliations
a, Department of Materials Science and Engineering and California NanoSystems Institute, University of California, Los Angeles, California 90095, United States
Abstract

Tremendous research efforts have been focused on perovskite solar cells over the last few years that have resulted in a rapid evolution of certified power conversion efficiencies (PCEs) up to 22.7%. Recent studies have suggested that a key for further improvement of PCE is to improve microscopic inhomogeneity in photovoltaic performance of perovskite solar cells. Such microscopic inhomogeneity in PCE has been attributed to i) prevailing defects in polycrystalline perovskite films that induce non-radiative charge recombination losses and ii) inhomogeneous interfacial contact with selective charge transporting layers that results in poor charge collection. Therefore, methods for reducing defects and improving interfaces are essential for further enhancement of PCE.

In this presentation, I will report our recent achievements on methods for controlling crystal growth and passivation of defects. Crystallization kinetics of the perovskite layer was controlled by engineering of intermediate phases, which resulted in significant enhancement in crystallinity with reduced defects. The inevitable defects at grain boundaries and interfaces were effectively passivated by a self-assembly monolayer or additives. Significant enhancement in photoluminescence lifetime and charge extraction evidenced reduced defects at the perovskite layer and interfaces. Owed to the reduced defects and improved interfaces, a PCE exceeding 20% (steady-state PCE >19%) was achieved for a planar heterojunction perovskite solar cell.

In addition, I will also report our progresses on perovskite tandem solar cells. A high performance perovskite tandem solar cell was achieved by engineering of the tunneling junction, where a certified power conversion efficiency over 20% was demonstrated.

 

12:15 - 12:45
G2-I5
Ohkita, Hideo
Kyoto University
Device Analysis of Lead-Halide Perovskite Solar Cells
Hideo Ohkita
Kyoto University, JP

Hideo Ohkita is a Professor in the Department of Polymer Chemistry at Kyoto University.  He obtained a Doctoral degree in 1997 at Kyoto University.  He became an Assistant Professor in 1997, was promoted to Associate Professor in 2006, and to Professor of Department of Polymer Chemistry at Kyoto University in 2016.  He concurrently worked as an academic visitor with Professor Durrant at Imperial College London from 2005 to 2006, and as a researcher in the Precursory Research for Embryonic Science and Technology (PRESTO) program “Photoenergy Conversion Systems and Materials for the Next Generation Solar Cells”, Japan Science and Technology Agency (JST), from 2009 to 2015.  His research interests include studying photophysics and photochemistry in polymer systems.  His current research focuses on spectroscopic approach to polymer solar cells.

Authors
Hideo Ohkita a, Hyung Do Kim a
Affiliations
a, Kyoto university, JP
Abstract

Lead-halide perovskite solar cells have made rapid progress in the last few years.  Currently, the power conversion efficiency (PCE) has been improved up to more than 20%.  We have recently shown that the device performance is improved with increasing grain size of perovskite materials and with decreasing thickness of the hole-transporting layer (HTL).[1,2]  In this talk, we will discuss the photovoltaic parameters in CH3NH3PbI3 perovskite solar cells.  All the photovoltaic parameters were improved with increasing grain sizes of CH3NH3PbI3 perovskite materials.  The improvement in JSC is simply because the absorption efficiency is increased owing to the thicker active layer.  For the device with an active layer thickness of ~500 nm, the external quantum efficiency was as high as more than 90%, suggesting no loss in the current generation.  The improvement in VOC was well analyzed by direct and trap-assisted (Shockley−Read−Hall) SRH recombination model.  As a result, we found that VOC is mainly limited by the trap-assisted SRH recombination.  If trap density was reduced to less than 1013 cm−3 so that the trap-assisted recombination is negligible, VOC would be improved up to 1.27 V.  The fill factor was improved with decreasing HTL thickness as mentioned above.  As a result, the best performance was obtained for the device with an active layer thickness of ~500 nm and an HTL thickness of 170 nm: JSC = 23.8 mA cm−2, VOC = 1.07 V, FF = 0.770, and PCE = 19.6%.[2]  This improvement in FF can be explained by an empirical equation for FF with a reduced series resistance RS.  On the basis of the empirical equation, FF would be improved up to more than 0.8 for the highest VOC and lowest RS.  Consequently, we conclude that PCE could be improved up to more than 25%.

 

References:

1) H. D. Kim, H. Ohkita, H. Benten, and S. Ito, Adv. Mater., 28, 917–922 (2016).

2) H. D. Kim and H. Ohkita, Sol. RRL, 1, 1700027 (2017).

Invited Speaker Session
Chair: Shuzi Hayase
12:45 - 13:15
Session-IS1
Meredith, Paul
Swansea University
Commentary on the Scaling Physics of Printable Organic and Perovskite Thin Film Solar Cells
Paul Meredith
Swansea University, GB

Professor Meredith is professor of materials physics at the University of Queensland in Brisbane, Australia. He is currently an Australian Research Council Discovery Outstanding Research Award Fellow, co-director of the Centre for Organic Photonics and Electronics, and Director of the UQ Solar Initiative. His research involves the development of new sustainable high-tech materials for applications such as solar energy and bioelectronics, and he particularly specialises in the transport physics and electro-optics of disordered semiconductors. Professor Meredith is also the co-founder of several start-up companies including XeroCoat and Brisbane Materials Technology. He is the recipient of numerous awards including the Premier of Queensland’s Sustainability Award (2013) and is widely recognised for his contributions to innovation and the promotion of renewable energy in Australia. He serves on several advisory boards including the Premier of Queensland’s Climate Change Council, the Australian Solar Thermal Research Initiative Strategic Advisory Board, and the Australian Renewable Energy Agency Technical Advisory Board. He originally hails from South Wales, was educated at Swansea University and Heriot-Watt University, and was DTI Postdoctoral Fellow at the Cavendish Laboratory in Cambridge before spending 6 years as an industrial scientist with Proctor and Gamble.

Authors
Paul Meredith a
Affiliations
a, Sêr Cymru Chair in Sustainable Advanced Materials Department of Physics, Swansea University, Singleton Park Swansea SA2 8PP
Abstract

Organic solar cells and organohalide perovskite solar cells share several common electro-optical operating principles [1]. Both families of devices operate within the thin film, low finesse cavity limit and there are also commonalities in electrodes and ancillary layer materials and structures [2]. It is therefore not surprising that organic and organohalide perovskite solar cells are subject to the same scaling physics considerations, i.e. the physical mechanisms that come into play in retaining performance and efficiency in large area devices, particularly those deposited by printing or other solution processing methods. A simple example of such physics is the limitation in the size of ‘maximum carrier collection path length’ which is dominated by the sheet resistance of the transparent conducting electrode and shown to be ~ 1-2 cm for commonly used 15 ohm/sq indium tin oxide [3]. This phenomenon has meant that the majority of large area organic solar cells are invariably serially interconnected thin strips.

In my talk I will review these scaling physics considerations and explain their basic origin in terms of electro-optics and transport phenomena in both organic and organohalide perovskite solar cells. I will explore how the limitations of scaling physics can potentially be overcome and demonstrate so-called large area ‘monolithic architectures’ which retain their fill factor and hence power conversion efficiency up to 5 cm x 5 cm. Addressing the scaling physics in next generation thin film solar cells is an essential part of endeavors to create viable modules and hence progress low cost manufacturing and ultimately commercialization of printed solar cells [4].

[1] Lin et al. Nature Photonics, 9, 106-112 (2015);

[2] Armin et al. ACS Photonics, 1(3), 173-181 (2014);

[3] Jin et al. Advanced Energy Materials, 2(11), 1338-1342 (2012).

Armin & Meredith, “The Scaling Physics of Thin Film Organic Solar Cells”, in World Scientific Handbook of Organic Optoelectronics, Volume 2 Organic Photovoltaics, Chapter 7 (edited F. So & B. Thompson), World Scientific Publishing, New York (2017).

13:15 - 14:30
Lunch
Session A2
Chair: Hyun Suk Jung
14:30 - 15:00
A2-IS1
Takayuki, Negami
Panasonic Corporation
Improvement on Thermal Stability of Perovskite Solar Cells and Fabrication of Modules for Practical Use
Negami Takayuki
Panasonic Corporation, JP
Authors
Takatyuki Negami a
Affiliations
a, Panasonic Corporation, 1006 Kadoma, Kadoma, Osaka 571-8501, JP
Abstract

Perovskite solar cells have achieved high efficiencies over 20%. Production costs of the perovskite solar cells are expected to drastically decrease by the solution based processes with a low temperature annealing under atmospheric. However, It is required not only to establish the process of the high efficiency solar cells but to ensure stability of the performance for practical use. Production processes of large area modules are also needed to be established. I will report on improvement of the stability under high temperature exposure, and fabrication of the modules with a 20 x 20 cm2 size. The stability of performance under high temperature exposure was improved by suppression of dopant diffusion from hole transport layers and phase changes of perovskite absorbers. The cell composed of (Cs, FA,MA)Pb(I,Cl)3 and PTAA showed a stable efficiency of 11% after exposure at 85 C for 1000 h. 20 x 20 cm2 size modules were fabricated using laser and mechanical scribing for monolithic series interconnection on the substrate. The 35 series connected module showed an efficiency of 12.6% with a Voc of 38.6 V.

15:00 - 15:15
A2-O1
Khadka, Dhruba B.
National Institute for Materials Science(NIMS)
Efficient Wide Bandgap Mixed Halide Perovskite Solar Cells Tuning with Electron Transport Layers
Dhruba B. Khadka
National Institute for Materials Science(NIMS)
Authors
Dhruba Khadka b, Yasuhiro Shirai a, Masatoshi Yanagida a, Kenjiro Miyano a
Affiliations
a, National Institute for Materials Science, Tsukuba, 305-0047, Japan
b, International Centre for Young Scientists, National Institute for Materials Science
Abstract

We report high performance of wide bandgap (WBG) perovskite device using hybrid halide to widen the bandgap to 1.72 eV by tuning the bromine composition in perovskite. We employed various C60 chained electron transport layers (ETLs) on wide bandgap perovskite-based solar cell devices. The WBG perovskite device tuning with C60-fused N-methylpyrrolidine-meta-C12 phenyl (C60MC12) demonstrated an enhanced efficiency of 16.7% with promising open circuit voltage of 1.24 V. The increase in device efficiency was found to be governed by high interface quality and reduction of energy disorder of wide bandgap perovskite layer with C60MC12 as carrier transport layer. We observed that the long-chain alkyl-substituted C60MC12 has better crystallinity over PCBM which is favorable for efficient carrier transport and formation of better interface with perovskite layer. The analysis of J-V characteristics and capacitance spectroscopy revealed impacts on optoelectronic properties of WBG perovskite devices with PCBM and C60MC12 as an ETL. These results corroborate that WBG perovskite device coupled with proper carrier transport layer is crucial to achieve high-efficiency top cell for tandem device integrated with silicon solar cell.

Keywords: Wide bandgap perovskite, ETLs, interface quality, efficiency

15:15 - 15:30
A2-O2
Liu, Jiewei
Institute for Chemical Research, Kyoto University
High Purity Solvent-Coordinated Tin Halide Complexes for Lead Free Perovskite Solar Cells
Jiewei Liu
Institute for Chemical Research, Kyoto University, JP
Authors
Masashi Ozaki a, Jiewei Liu a, Yukie Katsuki a, Taketo Handa a, Ryosuke Nishikubo b, Yoshihiko Kanemitsu a, Akinori Saeki b, Yasujiro Murata a, Atsushi Wakamiya a
Affiliations
a, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
b, Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 566-0871, Japan
Abstract

Organic-inorganic hybrid halide perovskite has emerged as one of the most promising photovoltaic (PV) material since 2012, with the power conversion efficiency (PCE) of perovskite solar cells (PSCs) rising from 10% to over 22% with intense research from PV research community around the world. However, the toxicity of lead (Pb), which is commonly applied in high efficiency PSCs, remains to be a serious problem that hampers the wide application of this magic material. Therefore, there has been a continued effort to study the replacement of Pb2+ with other environmentally friendly cations, such as tin (II) (Sn2+), germanium (II) (Ge2+), and bismuth (III) (Bi3+), etc. Theoretical calculations have proved the possibility of perovskite crystal structure formation after metal cation substitution, showing suitable band gap and optoelectronic properties. However, the PCEs obtained from lead-free perovskite devices are well below that of their lead counterpart. Although the lead-free PSC using MASnI3 as absorber was first demonstrated in 2014, the highest PCE achieved for lead-free PSCs is only around 9% so far. In addition, the Sn2+ suffers from rapid oxidation to Sn4+ in ambient atmosphere, leading to higher carrier density and conductivity and subsequently severe electric shorting of the fabricated devices. Therefore, it is necessary to conduct the whole device fabrication and measurement process under inert atmosphere. In this work, we synthesized a series of solvent-coordinated tin halide complexes as purified precursors for tin halide perovskite, including [SnI2(dmf)], [SnI2(dmso)], and [SnI2(dmso)2]. We performed MAS (magic-angle spinning) NMR spectroscopy and thermogravimetric analysis (TGA) measurements, the results of which suggest the Sn2+ purity of our materials is much higher than the real purity of commercially available sample of SnI2. We then prepared film samples of FASnI3 and MASnI3 using purified precursors. We performed photoelectron yield spectroscopy and photoluminescence spectroscopy under inert atmosphere to check the valence band (VB) and conduction band (CB) position. The results show much higher VB and CB position comparing to previously reported results, suggesting the possibility that the reported value might come from partially oxidized samples. These data are important guidance for selection of electron transporting material and hole transporting material with suitable CB and VB for device fabrication. We then fabricated perovskite solar cells with our purified material and achieved agreeable performance.

15:30 - 15:45
A2-O3
Hou, Qicheng
Monash University
Revealing the Relationship between Design and Performance of Back-Contact Perovskite Solar Cells with Honeycomb Charge Collecting Electrode
Qicheng Hou
Monash University, AU
Authors
Qicheng Hou b, Dorota Bacal b, Askhat Jumabekov a, Wei Li b, Ziyu Wang c, Xiongfeng Lin b, Soon Hock Ng c, Boer Tan b, Qiaoliang Bao c, Anthony Chesman a, Yi-Bing Cheng c, e, Udo Bach b, d, e
Affiliations
a, CSIRO Manufacturing, Clayton, Victoria 3168
b, Department of Chemical Engineering, Monash University
c, Department of Materials Science and Engineering, Monash University
d, Melbourne Centre for Nanofabrication, Australia
e, ARC Centre of Excellence in Exciton Science, Monash University
Abstract

Perovskite solar cells (PSCs) experienced dramatic increase in efficiency from less than 4% in 2009 to higher than 22% in 2016. Sandwich structure is commonly employed as the device structure where the perovskite light absorber is sandwiched in between of the anode and cathode. This requires incident light passing through one of the electrode, which is usually transparent conductive oxide (TCO), before reaching the perovskite layer. In this case, shading caused by the electrode can introduce parasitic absorption to the solar cells. However, shading caused by the front electrode is completely eliminated by using back-contact (BC) design, in which the two sets of electrodes are located at the same side of the light absorber, to replace the conventional configuration. In this work, we present a unique design of BC PSCs acquiring the idea of quasi-interdigitated electrode (QIDE), namely the electron-collecting electrode and hole-collecting electrode are separated at two planes with an insulator in between. Most importantly, our QIDE is designed to honeycomb structure, which has higher structural robustness, better defect tolerance and improved charge collecting efficiency, with which we achieved high short-circuit current and stabilized power output. In addition to the minimized parasitic absorption from the front electrode, PSCs with the BC architecture also allow the direct observation of the perovskite layer during solar cell operation , which might open a window to the research of PSCs. A schematic diagram of the device is shown in the attachment.

15:45 - 16:15
Coffee Break
16:15 - 16:30
A2-O4
McMeekin, David
Oxford University
Crystallization kinetics and morphology control of formamidinium-cesium mixed-cation lead mixed-halide perovskite via tunability of the colloidal precursor solution
David McMeekin
Oxford University, GB
Authors
David McMeekin a, Zhiping Wang a, Waqaas Rehman a, Federico Pulvirenti b, Jay Patel a, Nakita Noel a, Seth Marder b, Laura Herz a, Henry Snaith a
Affiliations
a, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom
b, Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
Abstract

Title: Crystallization kinetics and morphology control of formamidinium-cesium mixed-cation lead mixed-halide perovskite via tunability of the colloidal precursor solution

David P. McMeekin,1 Zhiping Wang,1 Waqaas Rehman,1 Federico Pulvirenti,2 Jay B. Patel,1 Nakita K. Noel,1 Michael B. Johnston,1 Seth R. Marder,2 Laura M. Herz,1 Henry J. Snaith1*

1 Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK

2 School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA 30332-0400

* Corresponding author E-mail: henry.snaith@physics.ox.ac.uk

 

The meteoric rise of the field of perovskite solar cells has been fueled by the ease with which a wide range of high-quality materials can be fabricated via simple solution processing methods. However, to date, little effort has been devoted to understanding the precursor solutions, and the role of additives such as hydrohalic acids upon film crystallization and final optoelectronic quality. Here, a direct link between the colloids concentration present in the [HC(NH2)2]0.83Cs0.17Pb(Br0.2I0.8)3 precursor solution and the nucleation and growth stages of the thin film formation is established. Using dynamic light scattering analysis, the dissolution of colloids over a time span triggered by the addition of hydrohalic acids is monitored. These colloids appear to provide nucleation sites for the perovskite crystallization, which critically impacts morphology, crystal quality, and optoelectronic properties. Via 2D X-ray diffraction, highly ordered and textured crystals for films prepared from solutions with lower colloidal concentrations are observed. This increase in material quality allows for a reduction in microstrain along with a twofold increase in charge-carrier mobilities leading to values exceeding 20 cm2 V−1 s−1. Using a solution with an optimized colloidal concentration, devices that reach current–voltage measured power conversion efficiency of 18.8% and stabilized efficiency of 17.9% are fabricated.

 

16:30 - 16:45
A2-O5
Filonik, Oliver
Technical University of Munich
Investigating the perovskite crystallization in fully printable mesoscopic perovskite solar cells
Oliver Filonik
Technical University of Munich, DE
Authors
Oliver Filonik a, Margret Thordardottir a, Jenny Lebert a, Stephan Proeller a, Sebastian Weiss a, Jia Haur Lew b, Anish Priyadarshi b, Nripan Mathews b, Peter Müller-Buschbaum c, Eva M. Herzig a, d
Affiliations
a, Technische Universität München, Munich School of Engineering, Lichtenbergstr. 4a, 85748 Garching, Germany
b, Energy Research Institute @ NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive 637553, Singapore
c, Technische Universität München, Physik-Department, Lehrstuhl für Funktionelle Materialien, James-Franck-Str. 1, 85748 Garching, Germany
d, Universität Bayreuth, Physikalisches Institut, Herzig Group – Dynamik und Strukturbildung, Universitätsstr. 30, 95447 Bayreuth
Abstract

Organometal halide perovskite based solar cells have emerged as the fastest-advancing photovoltaic technology to date, reaching certified solar cell efficiencies up to 22.1%. Recently, the focus of research broadened beyond high efficiencies to key values like prolonged device lifetime and stability that are required for industrial implementation. A novel perovskite cell architecture utilizing a mesoporous scaffold with embedded perovskite addresses these challenges and is furthermore adaptable for industrial scale production. However, little is known about the perovskite crystal formation in such mesoscopic scaffolds.

In this project, we fabricate a mesoscopic scaffold comprised of a triple-layer of titania, zirconia and carbon by screenprinting. We investigate the influence of the processing additive 5-ammonium valeric acid iodide (5-AVAI) on the perovskite formation and resulting device performance. Additionally, we determine the perovskite backfilling by cross sectional scanning electron microscopy (SEM) and perovskite crystallization dynamics by time-resolved grazing incidence wide angle x-ray scattering (GIWAXS). Our results grant us a better understanding of the perovskite crystallization processes within the mesoscopic scaffold and are of key importance for further developments.

16:45 - 17:00
A2-O6
Futscher, Moritz
AMOLF
Performance Limitations and Prospects of Perovskite/Silicon Tandem Solar Cells
Moritz Futscher
AMOLF, NL
Authors
Moritz Futscher a, Bruno Ehrler a
Affiliations
a, AMOLF, science park 104, amsterdam, 1098, NL
Abstract

Perovskite solar cells have entered the research field of photovoltaics by storm, already reaching efficiencies close to highly optimized silicon solar cells. Coupling perovskite and silicon solar cells in a tandem configuration has the potential to considerably out-perform conventional solar cells. Under standard test conditions, perovskite/silicon tandem solar cells already outperform the silicon single-junction solar cell alone. Under realistic conditions, however, tandem solar cells made from current record cells are hardly more efficient than the silicon solar cell alone. We model the performance of realistic perovskite/silicon tandem solar cells under real-world climate conditions, by incorporating parasitic cell resistances, nonradiative recombination, and optical losses into the detailed-balance limit. We show quantitatively that when optimizing these parameters in the perovskite top cell, perovskite/silicon tandem solar cells could reach efficiencies above 38% under realistic conditions, even while leaving the silicon cell untouched. Despite the rapid efficiency increase of perovskite solar cells, our results emphasize the need for a concerted effort in material development, careful device design, and light management strategies, all necessary to further increase the efficiency of perovskite cells, and develop highly efficient perovskite/silicon tandem solar cells.

17:00 - 17:15
A2-O7
Wang, Ruiyao
University of Liverpool
Study of Organolead Halide Perovskite Film Formation Mechanism from the View of Coordination Chemistry
Ruiyao Wang
University of Liverpool, GB
Authors
Tianhao Yan a, Ruiyao Wang a
Affiliations
a, Department of Chemistry, Xi'an Jiaotong-Liverpool University
Abstract

Recently, organo-lead-halide perovskite solar cells have attracted growing and widely attention due to their remarkable photoelectric properties, low cost and ease of fabrication. However, the development of perovskite solar cells is still limited by several factors like strict fabrication conditions, low stability, small active area and poor reproducibility. We argue that the nature of perovskite film formation is a process of a series of chemical reactions and the crystallization, where the Pb(II) coordination chemistry involves in. We thus set out to study the perovskite film formation process from the view of Pb(II) coordination chemistry. In this study, the formation process of the perovskite films were examined in situ using microscope and powder XRD techniques. Four intermediates were identified and structurally characterized using single crystal X-ray crystallography. The intermediates were characterized by XRD, UV-Vis, IR and TGA/DSC. The film formation mechanisms from the different precursors, such as PbCl3/MAI (1:3), PbI2/MAI (1:1 and 1:3) and PbBr2/MAI (1:3) were proposed.

Key Words: solar cell, perovskite, mechanism, intermediate, crystal structure, solvent engineering

Session B2
Chair: Takaya Kubo
14:30 - 14:45
B2-O1
Barbe, Jeremy
1SPECIFIC, College of Engineering, Swansea University Bay Campus, Fabian Way, SA1 8EN Swansea, United Kingdom
Origin of dark electrical bias-induced degradation of inverted methylammonium lead iodide perovskite solar cells
Jeremy Barbe
1SPECIFIC, College of Engineering, Swansea University Bay Campus, Fabian Way, SA1 8EN Swansea, United Kingdom
Authors
Jeremy Barbe a, Vikas Kumar b, Michael Newman a, Harrison Lee a, Sagar Jain a, Hu Chen c, Cecile Charbonneau a, Cornelia Rodenburg b, Chung Tsoi a
Affiliations
a, SPECIFIC IKC, College of Engineering, University of Swansea, Swansea, U.K
b, The University of Sheffield, Department of Chemistry
c, King Abdullah University of Science and Technology(KAUST), KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), Material Science and Engineering Program (MSE), King Abdullah University of Science and Technology, Thuwal, 23955-6900, SA
Abstract

Emerging lead halide perovskite materials have enormous potential for a range of optoelectronic devices, such as solar cells, light emitting diodes, transistors and lasers. However, the large-scale commercialization of these technologies will depend on the ability of the active material to be stable under environmental and operating conditions. Perovskite can be degraded by many factors such as humidity, light, oxygen and temperature. More recently, electrical stress has also been shown to be detrimental for the stability of perovskite solar cells (PSCs). However, the origin of such degradation, which has been attributed to either ion migration or superoxides formation, is not clear and needs further investigations. Besides, there is no study on perovskite devices with the inverted structure although it can be radically different from the standard structure as the electric field is opposite in that case and other types of interlayers are used. Inverted PSCs have several advantages over standard top-anode devices such as less hysteresis and lower processing temperatures, while record efficiencies are getting comparable to the standard architecture. In this work, the electrical bias-induced degradation of inverted perovskite solar cells in the dark is systematically investigated in four different environments, which allowed us to conclude that humidity coupled with electrical bias results in fast degradation of CH3NH3PbI3 into PbI2.

Micro-Raman and photoluminescence show that the degradation starts from the edge of the cell due to moisture ingress. By using novel local Raman-transient photocurrent measurements, we were able to probe local ion migration at the degraded region and non-degraded region with micro-meter resolution and found that the formation of PbI2 can passivate perovskite by reducing ion migration. The degradation is far from uniform across different grains as revealed by secondary electron hyperspectral imaging, an advanced microscopy technique which allows to probe the composition of individual grain from the cross-section. By using potential step chronoamperometry, we also found that the humidity – mediated bias degradation agrees well with the increased density of mobile ion defects.

The unique combination of a number of established methods with several novel analytical tools from nano-scale to cell level demonstrates the impact played by ion migration on the bias degradation of inverted perovskite solar cells. Importantly, these advanced techniques will be useful for studying perovskite solar cells in general, while the dark bias degradation has significant insight to other perovskite based (opto-)electronic devices.

14:45 - 15:00
B2-O2
Uratani, Hiroki
The University of Tokyo
Inorganic Lattice Fluctuation Induces Charge Separation in Lead Iodide Perovskites: Theoretical Insights
Hiroki Uratani
The University of Tokyo, JP
Authors
Hiroki Uratani a, b, Koichi Yamashita a, b
Affiliations
a, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, JP
b, CREST-JST, 7 Gobancho, Chiyoda-ku, Tokyo, 1020076, JP
Abstract

Lead halide perovskites-based photovoltaic devices are attracting much interest for their high photoconversion efficiency, which may be attributed to the remarkable carrier properties in this class of materials, e.g. long carrier lifetime and long carrier diffusion length. These properties should be ascribed to the efficient charge separation; electrons and holes are well separated so that the recombination is suppressed.

However, the mechanism of such efficient charge separation is still under debate. Especially, role of the molecular cation component of the perovskites is a controversial problem in this research field.

In this work, through first-principles molecular dynamics simulations for four types of lead iodide perovskites (MAPI, FAPI, GAPI, and CsPI), we demonstrated that the structural fluctuation of the inorganic (lead iodide) part of the perovskites decreases the spatial overlap between the valence band maxima (VBM) and the conduction band minima (CBM), i.e. enhances the charge separation.

Also, we discussed the mechanism of the structural fluctuation-induced charge separation. First, based on a simple model (a one-dimensional tight-binding model), we proposed that the charge separation is induced by fluctuation of electrostatic potential. Second, we confirmed the above discussion by first-principles. We calculated the electrostatic part of the energy of holes and electrons, and found that the electrostatic stabilization of the carriers determines the spatial overlap between VBM and CBM. Third, we demonstrated that the fluctuation of electrostatic potential mainly comes from the structural fluctuation of the inorganic part.

Considering the above, we propose a possible mechanism of the charge separation in this kind of material; the structural fluctuation of the inorganic part induces the fluctuation of electrostatic potential inside the materials, and the fluctuation of the electrostatic potential causes the charge separation.

Our results indicate that the charge separation is governed by the inorganic part and the organic cations may not be the dominant factor, suggesting that all-inorganic lead halide perovskites-based photovoltaic devices might be able to rival the organic-inorganic lead halide perovskites-based ones in performance.

15:00 - 15:15
B2-O3
Uchida, Satoshi
The University of Tokyo
Perovskite Solar Cells: Crystal Structure and Interface Architecture with High Resolution TEM Observations
Satoshi Uchida
The University of Tokyo, JP

Prof. Satoshi Uchida is a professor (born in 1965) in Research Center for Advanced Science and Technology (RCAST), The University of Tokyo.  He received his PhD from Tohoku University in 1995 and moved to current position in 2006.  For more than 15 years his research focused on the field of dye-sensitized solar cells (DSSCs), specifically cell assembling technique such as full-plastic, light-weight, film type as a ubiquitous power source.  He is now also showing strong activity of Perovskite Solar Cells research based on the crystallography, surface engineering and electronic simulation.

Authors
Satoshi Uchida a, Tae Woong Kim a, Ludmila Cojocaru a, Takashi Kondo a, Hiroshi Segawa a
Affiliations
a, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, JP
Abstract

Recently, organometal halide perovskite solar cells (PSCs) have received great attention. The power conversion efficiency (PCE) of PSCs have shown a dramatic increase and certified PCEs adopting mixed organic cations and halide anions have reached up to 22%. The PCE is considerably affected by photovoltaic property of each component of a PSC. Particularly, because crystal quality of materials is strongly concerned with the electronic properties such as carrier transport, investigation of detailed crystallographic information of the perovskite light absorber is essential. In spite of the significance in the crystallographic information, however, microstructural observation for crystal structure analysis of the perovskite layer has not been actively conducted. In this talk, we will report a microstructural observation about phase coexistence in the perovskite light absorber through transmission electron microscope (TEM) observation.

To obtain the crystallographic information of the perovskite light absorber, a pure methylammonium lead iodide (MAPbI3) layer was formed through spin-coating method assisted by antisolvent in a planar type PSC (Au/Spiro-MeOTAD/ MAPbI3/TiO2/FTO/Glass). MAPbI3 precursor solution used is 1.4 M and the spin-coated MAPbI3 film was annealed at 100oC for 30 min.

Surprisingly, during the high resolution (HR) TEM observation, we found coexistence of tetragonal and cubic structures in the same perovskite layer. This new observation is expected to be an important clue of the enhancement of perovskite crystal quality for highly efficient PSCs.

15:15 - 15:30
B2-O4
Bretschneider, Simon
Max Planck Institute For Polymer Research
Trap-Free Hot Carrier Relaxation in Lead-Halide Perovskite
Simon Bretschneider
Max Planck Institute For Polymer Research, DE
Authors
Simon Bretschneider a, Frédéric Laquai b, Mischa Bonn a
Affiliations
a, Max Planck Institute For Polymer Research, Max Planck Institute for Polymer Research Ackermannweg 10, Mainz, DE
b, King Abdullah University of Science and Technology(KAUST), KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), Material Science and Engineering Program (MSE), King Abdullah University of Science and Technology, Thuwal, 23955-6900, SA
Abstract

Photovoltaic devices that employ lead–halide perovskites as photoactive materials exhibit power conversion efficiencies of 22%.1 One of the potential routes to go beyond the current efficiencies is to extract charge carriers that carry excess energy, that is, nonrelaxed or “hot” carriers, before relaxation to the band minima is completed. Lead–halide perovskites have been demonstrated to exhibit hot-carrier relaxation times exceeding 100 ps for both single- and polycrystalline samples.2 Here, we demonstrate, using a combined time-resolved photoluminescence and transient absorption study supported by basic modeling of the dynamics, that the decay of the high-energy part of the photoluminescence occurs on a time scale (∼100 ps) very similar to the repopulation of the band minima when excited with a photon energy larger than 2.6 eV.3 The similarity between the two time scales indicates that the depopulation of hot states occurs without transient trapping of electrons or holes.

 

[1]Yang, W. S. et al.: Science 2017, 356 (6345), 1376-1379.

[2]Niesner, D. et al.: Journal of the American Chemical Society 2016, 138 (48), 15717-15726.

[3]Bretschneider, S. A. et al.: The Journal of Physical Chemistry C 2017, 121 (21), 11201–11206

15:30 - 15:45
B2-O5
Marronnier, Arthur
Paris-Saclay University
Anharmonicity and Disorder in the Black Phases of CsPbI3
Arthur Marronnier
Paris-Saclay University

Arthur Marronnier is a PhD Candidate and a Teaching Fellow in Solar Energy at Ecole Polytechnique , Paris-Saclay University. He obtained his first Graduate Degree in Solid State Physics from Ecole Polytechnique in 2013. Arthur also holds a Master of Science in Materials Science from Stanford University (2014) and an Advanced Master's degree in Public Policy from Ecole des Ponts (2015). After working for SunPower as a consultant in Public Affairs for Photovoltaics, he was awarded an exceptional grant from the French Department of Energy to pursue a PhD in the field of New Perovskite Solar Cells. His current research is focused on anharmonicity, instabilities and oxygen defects in halide perovskites for photovoltaics. He has published two articles on this topic and given several oral presentations at international conferences. Arthur recently won the “My PhD in 6 Minutes” competition and the Best Oral Presentation Award at the 2017 French Conference on Perovskites. In September 2017, he was appointed Siebel Scholar in Energy Science.

Authors
Arthur Marronnier a, Heejae Lee a, Bernard Geffroy a, b, Yvan Bonnassieux a, Jacky Even c, Guido Roma d
Affiliations
a, LPICM, CNRS, Ecole Polytechnique, Université Paris Saclay, 91128, Palaiseau, FR
b, LCSEN, NIMBE, CEA, Paris-Saclay University, 91191 Gif Sur Yvette
c, Fonctions Optiques pour les Technologies de l’Information (FOTON), Institut National des Sciences Appliquées (INSA) de Rennes, CNRS, UMR 6082, Rennes, FR
d, SRMP, CEA, Paris-Saclay University, 91191 Gif Sur Yvette
Abstract

Hybrid organic-inorganic perovskite materials have emerged over the past five years as absorber layers for new high-efficiency yet low-cost solar cells that combine the advantages of organic and inorganic semiconductors. Despite this sky rocketing evolution, the physics behind the electronic transport in these materials is still poorly understood.

Here, employing the linear response (DFPT) approach of Density Functional Theory (DFT) and frozen phonon calculations, we reveal strong anharmonic effects in the inorganic CsPbI3 perovskite structure and found a double-well instability at the center of the Brillouin zone for both cubic and orthorhombic phases. We show that previously reported1 soft modes are stabilized at the actual lower symmetry equilibrium structure, which occurs in a very flat energy landscape. Our results highlight the anharmonic behavior of CsPbI3, showing that this perovskite structure can oscillate between two equilibrium states at room temperature, and allow us to give an anharmonicity-corrected value for its band gap. These results are coherent with previsouly reported low energies of the whole accoustic phonon at 80 C and unusually large Debye-Waller factors. If further taken into account into the models used for electron-phonon interactions2 and band gap calculations3, these anharmonic effects could lead to a better understanding of the electrical transport properties of perovskite solar cells (PSCs).

As for hybrid perovskites, the PSC community has for some time had trouble agreeing on CH3NH3PbI3 (MAPbI3)’s exciton binding energy, and on whether it behaves more like organic compounds (high exciton binding energy, low dielectric constant) or vice-versa like inorganic compounds. Using the phonon spectrum obtained for the pseudocubic phase of MAPbI3 and performing ellipsometry measurements, we here confirm that MAPbI3, similar to inorganic semiconductors, has a rather high relative dielectric constant (≈ 18) at low frequencies, suggesting a low exciton binding energy and confirming the electrical behavior of hybrid perovskites as free-carrier devices4-5-6.

 

[1] H. Kawai et al., Nano Letters, vol. 15, pp. 3103-3108, 2015.
[2] L. D. Whalley et al., Phys. Rev. B, vol 94, 220301, 2016.
[3] C. E. Patrick et al., Phys. Rev. B, vol 92, 201205, 2015.
[4] J. Even et al., J. Phys. Chem. C, vol. 119, pp. 10161-10177, 2015.
[5] A. Miyata et al., Nature Physics, vol. 11, pp. 582-587, 2015.
[6] M. Shirayama et al., Phys. Rev. Applied, vol 5 (1), 014012, 2016.

15:45 - 16:15
Coffee Break
16:15 - 16:30
B2-O6
Lim, Jongchul
Oxford university
Effective Lateral Mobility and Diffusion Length Determined by Refractive Index Change of Perovskite at the Sub-Bandgap : Photoinduced Reflection Spectroscopy
Jongchul Lim
Oxford university
Authors
Jongchul Lim a, Henry J. Snaith a
Affiliations
a, Photovoltaic and Optoelectronic Device Group, Department of Physics, Oxford University, Clarendon Laboratory, Parks Road, Oxford, GB
Abstract

We set up and developed a new spectroscopy apparatus for measuring the photo-induced change in the reflection and transmission from thin films of optoelectronic materials. We then carry out a photophysical study on charge transport phenomena at the perovskite solar cell absorber materials. By focusing on changes in spectra below band-edge of perovskite materials, we observe a sub bandgap bleaching [1], band filling [2], and free carrier absorption [3]. Changes in transmittance and reflectance of materials at sub-bandgap is originated from charge density changes in perovskite. A simulation data set of fractional changes in transmission and reflection was obtained through transfer-matrix method based on Kramer-Kronig relationship [3], and this simulation data clearly supports our suggestion from experimental data that the charge generation in perovskite is strongly related to refractive index change. It is possible to combine with photoconductivity for mobility calculation. Thus effective mobility was obtained by calculating carrier density from Drude model and quasi steady state photoconductivity. This work lead to a much improved understanding of the electronic processes occurring at sub-bandgap of photovoltaic junction. Scientific findings through advanced spectroscopy apparatus may provide some clues to understand optoelectronic properties of heterogeneous interfaces as well as fundamental properties of perovskite, by analysing those complicated sets of experimental data, considering many possible explanations, and employing experimental methodology.

References

[1] M. B. Price, J. Butkus, T. C. Jellicoe, R. H. Friend and F. Deschler, Nat. Commun. (2015), 6, 9420.

[2] J. S. Manser and P. V. Kamat, Nature Photon. (2014), 8, 737.

B. R. Bennett, R. A. Soref and J. A. Del Alamo, IEEE J. Quantum Electron. (1990), 26, 113.

16:30 - 16:45
B2-O7
Wang, Shufeng
Peking University
Revealing subgrain morphology in organolead perovskite films by spectroscopic method
Shufeng Wang
Peking University, CN
Authors
Shufeng Wang a
Affiliations
a, Physics Department, Peking University, Beijing, China
Abstract

For highly developing field of organolead perovskite based solar cells, there is a fundamental question still stay mysterious. That is, the mechanism for charge separation. Unlike the p-n junction based solar cells, or the organic solar cells with bulk heterojunction, the thick working layers (300-500nm) of organolead perovskite themselves efficiently separate the electrons and holes, without noticeable internal morphology for separation and transportation. In addition, the density of carriers can be high, while it is quite strange that the recombination rate is extremely low. For well-prepared films, the lifetime for carriers can be up to 1 microsecond. The morphological basis for understanding such phenomena is still missing.

Recently, we developed a density-resolved spectroscopic method, for observing the photoproducts inside the films. The firm experimental proof shows that the commonly accepted exciton-free carrier co-existing model is only true in non-heated samples and single crystals. For working layers in real devices, which experience heat annealing as a general step, a significant exciton-carrier collision replace the co-existence. According to the photoproduct-morphology relationship, it indicates the tetragonal phase of perovskite crystalline structure has new subgrain structure after heat annealing. To our knowledge, this is the only report discovering the generality of subgrain structure in real working layers. Then it provides the basis for mechanism analysis starting from a new level of morphology. The new photoproduct relation, subgrain morphology, and relative analysis show that the subgrain structure is possibly the key to solve the mystery.

16:45 - 17:00
B2-O8
Sugimoto, Manabu
Kumamoto University
Chemistries of Materials in Perovskite Solar Cells Revealed by Electronic-Structure Informatics
Manabu Sugimoto
Kumamoto University
Authors
Manabu Sugimoto a, Jing-Shuang Dang b, Wei-Wei Wang b, Ryota Jono b, Hiroshi Segawa b
Affiliations
a, Kumamoto University
b, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, JP
Abstract

Computational studies on electronic structures of materials used in perovskite solar cells (PSCs) are reported. The main concern in this presentation is on chemical characteristics of metal-halide perovskite compounds, organic hole-transport materials, and their interface because carrier transports across these materials are considered to be the bottleneck in PSCs. We perform first-principles calculations at the density-functional-theory level and apply some cheminformatics methods in order to have better understanding and prediction of their chemistries. In the presentation, we will discuss the following four issues: (1) some electronic properties calculated by the DFT method can be used as descriptors of hole mobility in statistical analyses. Based on the informatics study, we suggest some organic compounds for efficient hole transport. (2) Pb-free perovskite-type compounds with a reasonably wide band gap are suggested on the basis of our own materials design, which is justified by the DFT calculations. (3) The rate constant of the photo-induced hole injection at interface are evaluated and is shown to be surface dependent. (4) Surface fabrication of metal halide perovskite by pi-conjugated molecules is expected to be useful to enhance carrier transport by removing harmful effects by lattice defects beneath the interface.

 

17:00 - 17:15
B2-O9
Fabregat-Santiago, Francisco
Institute of Advanced Materials (INAM), Universitat Jaume I
Electrical properties of perovskite solar cells
Francisco Fabregat-Santiago
Institute of Advanced Materials (INAM), Universitat Jaume I, ES

Francisco Fabregat-Santiago is Associate Professor at Physics department of Universitat Jaume I de Castelló. He obtained his BSc (1995) in Physics at Universitat de Valencia and Univerity of Leeds and received his PhD (2001) at the Universitat Jaume I where he is an active member of the Photovoltaics and Optoelectronic devices group that is focused on the development of materials and devices for the production and storage of energy from renewable sources. He is an expert in electro-optical characterization of devices and particularly known by his works in the use of the impedance spectroscopy to model, analyze and interpret the electrical characteristics (charge accumulation, transfer reactions and transport) of devices and films including ZnO and TiO2 nanostructured films (nanocolloids, nanorods and nanotubes), dye sensitized solar cells, electrochromic materials and liquid and solid state hole conductors. He is also active in the fields of QD and perovskite solar cells, photoinduced water splitting, bio-energy and bio-sensors. He has published 103 papers that accumulate more than 9500 citations with an index h of 46, and acts as referee for numerous scientific journals.

Authors
Ramon Arcas a, Elena Mas-Marza a, Francisco Fabregat-Santiago a
Affiliations
a, Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castellón de la Plana, Castellón, España, Castellón de la Plana, ES
Abstract

 

Along last years, perovskite solar cells have shown an impressive progress both in the performance and in stability, what has made this technology a candidate with high probabilities of accessing soon to practical applications.1-3 However, the description ofof their fundamental electrical properties still present some aspects that are not completely understood. In this work impedance spectroscopy analysis will be used to study charge transport, transfer and accumulation properties of the different components of perovskite solar cells and at the interfaces between them. Special attention will be focused in the description of the contribution of each of these elements in the current-voltage curve which is used to determine the performance of the solar cells. Effects such humidity absorption or negative capacitance will be also described. 4, 5

 

References.

1. Saliba, M.; Matsui, T.; Seo, J.-Y.; Domanski, K.; Correa-Baena, J.-P.; Nazeeruddin, M. K.; Zakeeruddin, S. M.; Tress, W.; Abate, A.; Hagfeldt, A.; Gratzel, M. Energy & Environmental Science 2016, 9, (6), 1989-1997.

2. Yang, W. S.; Park, B.-W.; Jung, E. H.; Jeon, N. J.; Kim, Y. C.; Lee, D. U.; Shin, S. S.; Seo, J.; Kim, E. K.; Noh, J. H.; Seok, S. I. Science 2017, 356, (6345), 1376-1379.

3.  Bisquert, J.; Juárez-Pérez, E. J.; kamat, P. V., Hybrid Perovskite Solar Cells: the Genesis and Early Developments 2009-2014. Fundacio Scito: Valencia, 2017.

4. Anaya, M.; Zhang, W.; Hames, B. C.; Li, Y.; Fabregat-Santiago, F.; Calvo, M. E.; Snaith, H. J.; Miguez, H.; Mora-Sero, I. Journal of Materials Chemistry C 2017, 5, (3), 634-644.

5.  Fabregat-Santiago, F.; Kulbak, M.; Zohar, A.; Vallés-Pelarda, M.; Hodes, G.; Cahen, D.; Mora-Seró, I. ACS Energy Letters 2017, 2, (9), 2007-2013.

 

Session C2
Chair: Alex K-Y. Jen
14:30 - 15:00
C2-IS1
Shen, Qing
The University of Electro-Communications
Charge Transfer Dynamics and Photovoltaic Properties of Perovskite Solar Cells: Effects of the Energy Level Alignment of Zn1-xMgxO Electron Selective Layer
Qing Shen
The University of Electro-Communications, JP

Prof. Qing Shen received her Bachelor’s degree in physics from Nanjing University of China in 1987 and earned her Ph.D. degree from the University of Tokyo in 1995. In 1996, she joined the University of Electro-Communications, Japan and became a full professor in 2016. In 1997, she got the Young Scientist Award of the Japan Society of Applied Physics. In 2003, she got the Best Paper Award of the Japan Society of Thermophysical Properties and the Young Scientist Award of the Symposium on Ultrasonic Electronics of Japan. In 2014, she got the Excellent Women Scientist Award of the Japan Society of Applied Physics. She has published nearly 140 peer-reviewed journal papers and book chapters. Her current research interests focus on solution processed nano-materials and nanostructures, semiconductor quantum dot solar cells and perovskite solar cells, and especially the photoexcited carrier dynamics (hot carrier cooling, multiple exciton generation, charge transfer at the interface) in perovskite solar cells, quantum dot and dye sensitized solar cells, organic-inorganic hybrid solar cells.

Authors
Qing Shen a, e, Chao Ding a, Yaohong Zhang a, Feng Liu a, Shuichiro Fujino a, Yuhei Ogomi b, Taro Toyoda a, e, Kenji Yoshino c, e, Takashi Minemoto d, e, Shuzi Hayase b, e
Affiliations
a, The University of Electro-Communications, Japan
b, Kyushu Institute of Technology, Japan
c, Miyazaki Unversity, Miyazaki 889-2192, JP
d, Ritsumeikan University, Japan
e, CREST, Japan Science and Technology Agency (JST), Japan
Abstract

Recently, perovskite solar cell has attracted much attention as a next generation solar cell. In the solar cell, besides absorber layer material, the electron-selective layer (ESL) material is also very important. The ESL is not only crucial to achieving high photovoltaic conversion efficiency (PCE), but also for the device stability. Compared with other metal oxide, ZnO is a particularly promising ESL, because of its high transparency, suitable work function, and high electron mobility.In addition, low-content doping/modification of metal oxides has been considered as a way of improving the selectivity of ESLs. In this talk, we will focus on our recent research results of MAPbI3 perovskite (PVK) solar cells using Zn1-xMgxO thin film as ESLs. We find that the photovoltaic performance, especially Voc depends greatly on x. The devices based on Zn0.9Mg0.1O ESL exhibited the best photovoltaic performance and a PCE of ~15.5% was achieved.Electron injection and recombination dynamics at the interface have been characterized. The electron injection time is almost the same around 6 ns for all of FTO/Zn1-xMgxO/PVK (x: 0 – 0.2). However, the recombination time becomes longer as x increases from 0 to 0.1, and then becomes shorter with x increases up to 0.2. We find that the recombination process is affected by two factors:(1) the conduction band position of Zn1-xMgxO, which increases as x becomes larger; (2) the defect intensity in Zn1-xMgxO, which is smallest at x=0.1 and increases as x increases. These results indicate that the energy level alignment and physical properties of the electron selection layer in the perovskite solar cells are very important for improving the energy conversion efficiency. 

15:00 - 15:15
C2-O1
Turkevych, Ivan
Central Chemical Research Base (CEREBA)
Strategic advantages of reactive polyiodide melts for scalable perovskite photovoltaics
Ivan Turkevych
Central Chemical Research Base (CEREBA)
Authors
Ivan Turkevych a, Said Kazaoui b, Nikolai A. Belich c, Aleksei Y. Grishko c, Sergey A. Fateev c, Andrey A. Petrov c, Toshiyuki Urano a, Shinji Aramaki a, Sonya Kosar d, Michio Kondo b, Eugene A. Goodilin e, Michael Graetzel f, Alexey B. Tarasov c
Affiliations
a, Chemical Materials Evaluation and Research Base (CEREBA), AIST Central 5-2, Tsukuba, 305-8565, Japan
b, National Institute of Advanced Industrial Science and Technology (AIST), AIST Central 5-2, Tsukuba, 305-8565, Japan
c, Laboratory of New Materials for Solar Energetics, Department of Materials Science, Lomonosov Moscow State University (MSU),, Moscow, RU
d, Okinawa Institute of Science and Technology (OIST), 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
e, Chemistry Department, Lomonosov Moscow State University (MSU), Lenin Hills, Moscow, RU
f, Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015 Lausanne, Switzerland
Abstract

Despite tremendous progress in efficiency and stability of hybrid perovskite solar cells, perovskite photovoltaics still faces the challenge of upscaling. In my presentation I will reveal unique advantages of reactive polyiodide melts for the development of an innovative solvent-free technology that automatically ensures 100% coverage and excellent optoelectronic quality of hybrid perovskite films over large areas. Reaction of organic CH3NH3I (MAI) or mixed iodide salts containing MAI, NH2CHNH2I (FAI) and CsI with elementary iodine vapor produces liquid polyiodide phases that readily convert metallic Pb to hybrid perovskites at near room temperature. The conversion reaction is very fast, proceeds without byproducts and does not involve usage of extrinsic media. Furthermore, a large overall volume increase during Pb conversion into perovskite guarantees formation of pin‑hole free layers. I will demonstrate applicability of this synthetic route to the fabrication of single- and multi-cation hybrid perovskite thin films and solar cells. In addition to providing comparative argumentation about strategic advantages of our method for scalable perovskite photovoltaics, I am going to stress about its fundamental importance, universality and advanced implications not only for photovoltaics, but also for all kinds of thin film optoelectronic devices based on hybrid perovskites, such as LED, UV-Vis and soft x-ray photodetectors.

From the fundamental point of view, only two methods for the fabrication of hybrid perovskite thin films were known so far:

1) Crystallization from extrinsic media: MAPbI3(Sol) ® MAPbI3(S) + Sol (i.e. solutions in organic solvents or excessive amine liquids)

2) Combination reaction of two halides: PbI2(S/V) + MAI(S/Solv/V) ® MAPbI3(S) (i.e. dipping PbI2 layers into MAI solution in isopropanol (IPA), annealing of PbI2 in MAI vapor in hybrid CVD, co-evaporation of PbI2 and MAI, etc. )

These two basic methods are implemented in various ways and flavors, however, in none of them hybrid perovskite films are obtained directly through a redox reaction. In our method, hybrid perovskite films are obtained through a direct redox reaction between metallic Pb and reactive polyiodide melts, MAI3(L) or mixed MA(Cs,FA)I3(L), that changes oxidation states of Pb0 ® Pb2+ and I3 ® 3I- and creates a strong driving force for the conversion process.

Thus, our method is a third fundamental method for the fabrication of hybrid perovskite thin films. For that reason, we believe that being fundamentally distinct it opens an entire new field of research on hybrid perovskites with broad opportunities.

15:15 - 15:30
C2-O2
AICH, Badrou Reda
National Research Council Canada
Sustainable ink formulated using non-toxic solvents for organic solar cells
Badrou Reda AICH
National Research Council Canada
Authors
Badrou Reda Aїch a, Jianping Lu a, Salima Alem a, Neil Graddage a, Raluca Movileanu a, Eric Estwick a, Ye Tao a
Affiliations
a, Information and Communications Technologies Portfolio, National Research Council of Canada, Ottawa, ON, Canada, K1A 0R6, National Research Council of Canada, ON, Canada
Abstract

The power conversion efficiencies of Bulk-heterojunctions organic solar cells using a blend of low band-gap polymers and fullerene derivatives have gradually improved up to 11% due to intensive developments such as, the synthesizing of efficient semiconducting donor polymers, the controlling of the morphology of the active layers, the introducing of additional interfacial layers, and the designing of the devices architectures [1]. However, most of these optimizations were done using chlorinated solvents such as chloroform, dichlorobenzene or even trichlorobenzene [2]. These chlorine containing solvents are highly toxic and environmentally hazardous, which limit their usage in the industry. Recently, some research teams started to work on a new processing strategy for the inks formulation by using more benign solvents which meet the industrial standard. Unfortunately, most of the existing low band-gap polymers exhibited a very poor solubility in these non-toxic solvents. The inability to solubilize these polymers in these solvents complicates their use in making inks for large scale organic solar cells. The second limitation for the industrialization of the majority of the champion cells reported so far is mainly due to most films deposition techniques used are based on spin coating [3] instead of more scalable techniques for the industry like blade coating, slot die coating, and roll-to-roll printing. Thus, today the challenge is more on how to prepare efficient inks using non-toxic solvent and adapt these inks to the existing industrial process.

In this work, we report a process for the preparation of a new environment-friendly ink formulation. We first selected a high performance donor polymer the Poly[(5,6-dihydro-5-octyl-4,6-dioxo-4H-thieno[3,4-c]pyrrole-1,3-diyl)[4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′;]dithiophene-2,6-diyl]] PDTSTPD [4] in order to prepare the active layer ink. This polymer has already showed a very good compatibility with several non-toxic solvents [5]. In this work, 1,2,4-trimethylbenzene (TMB) instead chlorobenzene (CB) was selected and used as new host solvent in the ink preparation. The films prepared using this new ink was deposited using blade coating method. The solar cells realized provide performances up to 4% using inverted solar cell structure.

[1] T. H. Lee et al RSC. Adv, 7 (2017) 7476.

[2] P-T. Tsai et al, Org. Electon, 15 (2014) 893.

[3] G. Yu, et al, Science, 270 (1995) 178.

[4] T. Chu et al, J Am Chem Soc. 133 (2011) 4250.

[5] B. R. Aïch et al, Org. Electon 15 , (2014) 543.

15:30 - 15:45
C2-O3
Andricevic, Pavao
École Polytechnique Fédérale de Lausanne EPFL
Vertically aligned carbon nanotube-perovskite light emitting electrochemical cells
Pavao Andricevic
École Polytechnique Fédérale de Lausanne EPFL, CH
Authors
Pavao Andricevic a, Xavier Mettan a, Márton Kollár a, Bálint Náfrádi a, Andrzej Sienkiewicz a, Tonko Garma b, Klára Hernádi c, László Forró a, Endre Horváth a
Affiliations
a, École Polytechnique Fédérale de Lausanne EPFL, Lausanne, CH
b, Power Engineering Department, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Split
c, Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1, HU-6720 Szeged
Abstract

We demonstrate that single crystals of methylammonium lead bromide (MAPbBr3) could be grown directly on vertically aligned carbon nanotube (VACNT) forests. The fast-growing MAPbBr3 single crystals engulfed the protogenetic inclusions in the form of individual CNTs, thus resulting in a three-dimensionally enlarged photosensitive interface. Photodetector devices were obtained, detecting low light intensities (~20 nW) from UV range to 550 nm. Moreover, a photocurrent was recorded at zero external bias voltage which points to the plausible formation of a p-n junction resulting from interpenetration of MAPbBr3 single crystals into the VACNT forest.[1]

Moreover, bright green electroluminescence of the MAPbBr3 single crystals, using symmetrical VACNT electrodes, was observed at room temperature for both polarities. The electroluminescence spectra and light intensity was recorded from room temperature to cryogenic temperatures (20 K). The underlying mechanism behind the light emission is the well documented ion migration. In fact charged ions or vacancies inside the perovskite, drift under an external electric field accumulating at the cathode and anode, forming a p-i-n heterojunction structure. These characteristics have a strong similarity with the operational mechanism of polymer light-emitting electrochemical cells (LECs), especially the device structure and the involvement of mobile ions for efficient electroluminescence.[2] 

This reveals that vertically aligned CNTs can be used as electrodes in operationally stable perovskite-based optoelectronic devices and can serve as a versatile platform for future selective electrode development.

 

[1] Andričević, Pavao, et al. "3-Dimensionally Enlarged Photoelectrodes by a Protogenetic Inclusion of Vertically Aligned Carbon Nanotubes into CH3NH3PbBr3 Single Crystals." The Journal of Physical Chemistry C (2017).

[2] Bade, Sri Ganesh R., et al. "Fully printed halide perovskite light-emitting diodes with silver nanowire electrodes." ACS nano 10.2 (2015): 1795-1801.

 

15:45 - 16:15
Coffee Break
16:15 - 16:30
C2-O4
Pandey, Shyam
Prospects and Challenges with Dye-Sensitized Solar Cells utilizing Far-red Sensitive Dyes and Cobalt Complex Redox Electrolyte
Shyam Pandey
Authors
Shyam S. Pandey a, Anusha Pradhan a, Maryala Saikiran a, Shuzi Hayase a
Affiliations
a, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu 808-0196
Abstract

Recent past has witnessed that a logical molecular design of sensitizers in combination of cobalt complex based redox electrolytes has led to the photoconversion efficiency (PCE) > 14 % with nearly quantitative photon harvesting in the visible wavelength region. This imparts a hope for the further enhancement in the PCE by design and development novel near-infra-red (NIR) dyes by panchromatic photon harvesting. Although iodine based redox electrolyte (I3-/I-) has been widely utilized since the inception of DSSC but its corrosiveness geared the search for alternate redox electrolytes. Cobalt complex based redox shuttles are less colored, less corrosive and exhibit relatively deeper redox potential providing them as a legitimate alternative to the commonly used I3-/I- redox electrolytes. In spite of several merits of cobalt based electrolytes for DSSCs, to their bulkier nature and slow ionic diffusion make them relatively more prone to charge recombination. This has compelled to the judicious selection of not only the suitable sensitizers but also strict surface passivation of conducting substrate (FTO) as well as mesoporous TiO2. Importance of cobalt redox shuttle with visible sensitizers have already been demonstrated aiming towards high efficiency DSSCs but with NIR dyes such reports are rare. It has been found that dyes having multiple and long alkyl chains out-perform with cobalt electrolyte due to the effective surface passivation by dye molecules. We have recently shown that there was tremendous enhancement in the photon harvesting of DSSCs using NIR dyes when both of the FTO substrate and mesoporous TiO2 were subjected to surface treatments using aqueous TiCl4 forming compact TiO2 layer. Using unsymmetrical squaraine dyes as a representative of NIR dyes, efforts have also been directed to investigate the implication of various compact metal oxides for their effectiveness towards surface passivation and implication of final device performance. Synergistic and panchromatic photon harvesting was also demonstrated utilizing our newly designed NIR dye (SQ-110) with complementary light harvesting commercial dye (D-35). Our results reveled that TiCl4 treatment on both of the FTO and TiO2 perform better as compared to other metal oxides under investigation. Optimization of surface passivation utilizing a dye cocktail of SQ-110 and D-35 indicated that a single layer of compact TiO2 on FTO and a bilayer of compact TiO2/MgO was optimum for surface passivation leading to PCE of 7.2% which was much higher as compared to the DSSCs utilizing single constituent dyes.

16:30 - 16:45
C2-O5
Kamarudin, Muhammad Akmal
Kyushu Institute of Technology
Introduction of “spike-like” conduction band of TiO2 compact layer for perovskite solar cells
Muhammad Akmal Kamarudin
Kyushu Institute of Technology, JP
Authors
Muhammad Akmal Kamarudin a, Yuhei Ogomi a, Shen Qing b, Taro Toyoda b, Kenji Yoshino c, Takashi Minemoto d, Shuzi Hayase a
Affiliations
a, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu 808-0196
b, Graduate School of Informatics and Engineering, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, JP
c, Miyazaki University, 1-1 Gakuen, Kibanadai-nishi, Miyazaki 889-2192, JP
d, Ritsumeikan Universitry, 1-1, Tourohigashi, Kusatsushi, 525-8577, JP
Abstract

The good matching of the energy levels between different components in perovskite solar cells (PSCs) is one of the reasons that contributes to the high efficiency of the device. However, the electron transfer mechanism is limited by the electron mobility and the trap density of the TiO2 compact layer. Modification of the electron transporting layer (ETL) could improve the electron mobility, reduce the electron trapping and decrease the electron recombination reaction. This modification could be achieved through a slightly higher (spike-like) conduction band of the ETL compared to that of perovskite layer rather than the normal cliff-like structure. The spike-like energy structure is not new where it is already used in the Copper Zinc Tin Sulfide (CZTS) and Copper Indium Gallium Selenide (CIGS) solar cells. In this study, Mg-doping was used to tune the conduction band of the TiO2 compact layer forming a spike-like structure. Comparing the un-doped PSCs, the doped PSCs showed increasing power conversion efficiency from 9.35% to 11.12% together with an increase in the JSC and VOC. The lower trap-state density of the doped PSCs has been determined from Thermally Stimulated Current measurement. Through this doping process, the conduction band has been increased from 3.46 eV to 3.60 eV and thus helped to increase the VOC. It is believed that the surface of the TiO2 has been passivated by the Mg which allowed for the reduction of the back-recombination reaction as determined from the dark current measurement. However, it is found that if the band offset is too high, the electron transfer will become impossible and lead to lower efficiency. We found that a band offset of less than 0.3 eV between the CB of the TiO2 and perovskite material is good in terms of electron transfer mechanism. The modification of the ETL using cliff-like structure will provide another aspect of improving the efficiency of PSCs which could simultaneously reduce back-recombination reaction while enhancing the electron mobility.

16:45 - 17:00
C2-O6
Khan, Ammar
Lahore University of Management Sciences
Liquid crystalline physical-gel electrolytes for stable dye sensitized solar cells
Ammar Khan
Lahore University of Management Sciences
Authors
Ammar Khan a, Muhammad Akmal Kamarudin b, Sehrish Iqbal a, Hafiyya Malik a, Habib-ur Rehman a, Timothy Wilkinson b
Affiliations
a, Lahore University of Management Sciences
b, Department of Engineering, University of Cambridge, 9 JJ Thomson Ave, Cambridge, CB3 0FA, United Kingdom, JJ Thomson Avenue, 9, Cambridge, GB
Abstract

Organic-inorganic hybrid devices such as perovskite and dye sensitized solar cells (DSSCs) are promising candidates for future renewable energy applications[1][2]. Fabrication using solution processing and the utilization of low-cost materials promise low-cost and scalability. However, despite more than two decades of work on DSSCs (and more recently perovskites), stability and reliability challenges have hindered commercialization. DSSCs suffer from stability problems because of solvent evaporation, electrolyte-driven oxidation of electrical contacts, and dye degradation. Among these challenges solvent evaporation is perhaps the most severe and numerous solutions have been proposed. Examples include the use of non-volatile solvents/ionic liquids, polymer electrolytes and substituting the liquid electrolyte with amorphous small-molecule solid-state hole transport layers. However, nearly all the solutions lead to lower ionic (or hole) conductivity when compared with acetonitrile and thus exhibit lower photovoltaic performance.

In this research we present progress towards the development of thermally-reversible liquid crystal (LC) based physical-gel electrolytes[3]. In particular, we utilize discotic LCs[4] (triphenylene HAT6 and HAT5) that form hexagonal columnar mesophases to form a three-dimensional interconnected network of liquid crystalline fibre bundles to make physical (non-covalently bonded) gel electrolytes. Gel-formation is achieved in-situ using capillary filling, allowing fabrication methods similar to conventional liquid electrolyte DSSCs. The iodide tri-iodide redox electrolyte is confined within the network, limiting bulk flow, but ionic diffusion within the network is not impeded due to phase separation between the gelators and electrolyte.

Gel formation is characterized using polarizing optical microscopy and differential scanning calorimetry. Measurements of ionic conductivity, diffusion coefficients and electrochemical impedance spectroscopy are performed and gel-based photovoltaic devices are fabricated. In comparative studies, the devices exhibit significantly improved stability, competitive ionic conductivity and improved electron lifetime in the mesoporous TiO2 (˜8.4 ms in reference liquid electrolyte and ˜11.4 ms in the physical-gels) due to charge screening by the LC fibers. Our results show that LC-based self-assembled gelators are promising materials for DSSC applications[3] and ongoing work on understanding the driving mechanisms of gel formation as well as the parameter space of compatible solvents is discussed.

[1] B. E. Hardin, H. J. Snaith, M. D. McGehee, Nat. Photonics 2012, 6, 162.
[2] W. Zhang, G. E. Eperon, H. J. Snaith, Nat. Energy 2016, 1, 16048.
[3] A. A. Khan, M. A. Kamarudin, M. M. Qasim, T. D. Wilkinson, Electrochim. Acta 2017, 244, 162.
[4] R. J. Bushby, K. Kawata, Liq. Cryst. 2011, 38, 1415.

17:00 - 17:15
C2-O7
Yang, Fengjiu
Institute of Advanced Energy, Kyoto University
Roles of Polymer Layer in Interfacial Engineering Perovskite Solar Cells with High Photovoltaic Performance
Fengjiu Yang
Institute of Advanced Energy, Kyoto University
Authors
Fengjiu Yang a, HongEn Lim a, Masashi Ozaki b, Ai Shimazaki b, Yuhei Miyauchi a, Atsushi Wakamiya b, Yasujiro Murata b, Kazuanri Matsuda a
Affiliations
a, Institute of Advanced Energy, Kyoto University
b, Institute for Chemical Research, Kyoto University, Gokasyo, Uji, 611, JP
Abstract

Organic–inorganic metal halide perovskite solar cells (PSCs) have recently attracted enormous attention because their power conversion efficiency (PCE) has been drastically increased from 3.8% when first reported1 to 22.1%2 within a few years only. The striking advances rapid in the photovoltaic performance of PSCs is mainly attributable to the development of perovskite photoactive layer materials with superior properties3-6. However, a serious bottleneck for further development of PSCs has been encountered, since the quality of perovskite layer quite effects the photovoltaic performance of PSCs via carrier recombination, interface connection, anti-humidity/oxgen, and so on. Therefore, exploring effective approaches to engineering the interfaces of perovskite layers is strongly required for further improvement of the photovoltaic performance and stability of PSCs, such as self-induced passivation and solvent treatments.

 

In this work, we investigated the enhancement of photovoltaic performance of PSCs by incorporating a poly(methyl methacrylate) (PMMA) layer on the perovskite (CH3NH3PbI3) surface. The current-voltage (J-V) PCE of PSCs have been significantly improved from 16.8 to 20.4% in reverse scan condition. The stabilized power output PCE and stability of PMMA incorporated PSCs also have been much improved from 14.9 to 19.9%. These results are much better than our previously obtained values7 and highest value in CH3NH3PbI3-PSCs. Moreover, the detailed working mechanism of PMMA incorporated in PSCs has been studied via photoluminescence and impedance spectroscopy.

 

References

[1] A. Kojima, et al. J. Am. Chem. Soc. 2009, 131, 6050-6051.

[2] NREL chart, http://www.nrel.gov/ncpv/images/efficiency_chart.jpg, Accessed 13.03.2016, 2016.

[3] G. Xing et al. Science 2013, 342, 344-347.

[4] Q. Lin et al. Nat. Photonics 2015, 9, 106-112.

[5] S. D. Strank et al. Science 2013, 342, 341-344.

[6] C. Wehrenfennig et al. Adv. Mater. 2013, 26, 1584-1589.

[7] F. Wang et al. J. Phys. Chem. C 2017, 121, 1562-1568.

Session G3
Chair: Juan Bisquert
17:15 - 17:45
Abstract not programmed
17:45 - 18:15
G3-I1
Miyasaka, Tsutomu
Toin University of Yokohama
Towards developnment of heat tolelant and durable perovskite solar cells with stable high efficiency
Tsutomu Miyasaka
Toin University of Yokohama, JP

Tsutomu (Tom) Miyasaka received his Doctor of Engineering from The University of Tokyo in 1981. He joined Fuji Photo Film, Co., conducting R&Ds on high sensitivity photographic materials, lithium-ion secondary batteries, and design of an artificial photoreceptor, all of which relate to electrochemistry and photochemistry. In 2001, he moved to Toin University of Yokohama (TUY), Japan, as professor in Graduate School of Engineering to continue photoelectrochemistry. In 2006 to 2009 he was the dean of the Graduate School. In 2004 he has established a TUY-based company, Peccell Technologies, serving as CEO. In 2005 to 2010 he served as a guest professor at The University of Tokyo.

His research has been focused to light to electric energy conversion involving photochemical processes by enhancing rectified charge transfer at photo-functional interfaces of semiconductor electrodes. He has contributed to the design of low-temperature solution-printing process for fabrication of dye-sensitized solar cells and solid-state hybrid photovoltaic (PV) cells. Since the discovery of the organic inorganic hybrid perovskite as PV material in 2006 and fabrication of high efficiency PV device in 2012, his research has moved to R&Ds of the lead halide perovskite PV device. He has promoted the research field of perovskite photovoltaics by organizing international conferences and by publishing many papers on enhancement of PV efficiency and durability, overall citation number of which is reaching more than 5,000 times. In 2009 he was awarded a Ministry of Science & Education prize on his achievements of green sustainable solar cell technology. In 2017 he received Chemical Society of Japan (CSJ) Award. He is presently directing national research projects funded by Japan Science and Technology Agency (JST) and Japan Aerospace Exploration Agency (JAXA).

Authors
Tsutomu Miyasaka a
Affiliations
a, Toin university of Yokohama, 1614 Kurogane-cho, Aoba-ku, Yokohama, 225, JP
Abstract

Research of perovskite solar must be directed to ensure compatibility of stable efficiency and high durability for practical applications.1 Industrialization requires large area manufacture process, in which sinter-less high-speed coating technology enables remarkable reduction of process cost. We have been focused on low temperature fabrication process using heat-resistant metal oxide materials. I-V hysteresis of the metal oxide-based cells was improved by ensuring void-less high quality interfaces of perovskite crystals in contact with charge transport layers, which suppress recombination and enable high voltage output. Using TiO2 as electron transporter, triple-cation based perovskite cells give hysteresis-free high performance with efficiency of 20-21%, which is reproduced under ambient air fabrication processes.2 High open-circuit voltage (Voc) of perovskite cells (1.1-1.2V vs band gap energy of 1.6 eV) is the advantage superior to existing solar cells. Intensity dependence of Voc shows that ideality factor of perovskite solar cells is in a range of 1.4 to 1.9, depending on the structure and size of cell.2 Ideality factor high enough over 1.0 indicates the presence of trap-assisted charge recombination. In other word, there is still a room to improve Voc and efficiency.  

Heat tolerant and durable device that industrialization requires can be made by using MA-free perovskite such as CsFAPbI3 and CsFAPbI3-xBrx. Low-temperature process is applicable to Cs/FA perovskites. Stable and hysteresis-less high efficiency (>18%) was obtained by aging of the device in suitable dry atmosphere.3 When low temperature fabrication was applied to thin plastic film as substrate, perovskite solar cell achieves efficiency over 17% by tuning the quality of TiO2 compact and mesoporous layer.4 Perovskite solar cell fully made by low temperature processes yielded stable high efficiency over 21% with Voc of 1.18V. Stability of the device also largely depends on the qualities of hole transporting material. We chose P3HT as heat-resistant material and examined the cell stability against impacts of temperature changes (-100 to +100oC) and radiation of high energy electron and proton beams. Despite low efficiency compared to spiro-OMeTAD, device showed high stability to corroborate the heat and radiation tolerance of perovskite solar cells.

[1] N. -G. Park, M. Gratzel, T. Miyasaka, K. Zhu, and K. Emery, Nature Energy, 2016, 1, 16152.

[2] T. Singh and T. Miyasaka, Adv. Energy Mat., 2017, 1700677.

[3]Y. Numata, Sanehira, and T. Miyasaka, submitted.

[4] T. Singh and T. Miyasaka, submitted.

18:15 - 18:30
Closing Ceremony
 
Posters
Masatoshi Yanagida, Md Bodiul Islam, Namrata Pant, Yasuhiro Shirai, Kenjiro Miyano
Effect of NiOx Properties as Hole Transport Layer on Lead Halide Perovskite Solar Cells
Quang-Duy Dao, Akihiko Fujii, Ryotaro Tsuji, Masanori Ozaki
Improving stability and efficiency of perovskite solar cell utilizing phthalocyanine-tetrabenzoporphyrin hybrid macrocycle hole transport layer
Said Kazaoui
Environmental Stability of Mixed Perovskite Solar Cells at 1 sun
Pradeep R. Varadwaj, Arpita Varadwaj, Koichi Yamashita
Halogen in Materials Design: Perovskite Solar Cell Semiconductors as Prototypes
Kazuhiro Marumoto, Miki Namatame, Yuhei Ogomi, Shuzi Hayase
Direct observation of dramatically enhanced hole formation in a perovskite-solar-cell material spiro-OMeTAD by Li-TFSI doping
Putao Zhang, Kengo Hamada, Gaurav Kapil, Fu Yang, Shuzi Hayase
Application of a quartz crystal microbalance to measure interface structure between carbon and perovskite materials for carbon based perovskite solar cells
Kumiko Yamamoto, Satoshi Iikubo, Jun Yamasaki, Yuhei Ogomi, Shuzi Hayase
First-principles study of partially substituted perovskite Solar Cells
Chu Zhang, Tingli Ma, Zhanglin Guo, Liguo Gao, Shuai Zhao
Design and Synthesis of a New Lead-free Double Perovskite Cs2NaBiI6
Hong Duc Pham, Hongwei Hu, Zhifang Wu, Thu Trang Do, Luis K. Ono, Krishna Feron, Sergei Manzhos, Hongxia Wang, Nunzio Motta, Yeng Ming Lam, Yabing Qi, Sagar Motilal Jain, Prashant Sonar
Novel Low Cost Triphenylamine Derivatives based Hole Transporting Organic Materials for Highly Efficient and Stable Perovskite Solar Cells
Yueh-Chien Lee, Sheng-Yao Hu, Cheng-Han Wu, Tzu-Fan Hsu
Effects of Rose Bengal Dye on the Photovoltaic Performance of Dye-sensitized ZnO Solar Cell
Mi-Ra Kim
Photovoltaic Effects of TiO2 Pastes for Low-Temperature Process for Dye-Sensitized Solar Cells
Kengo Hamada, Ryo Tanaka, Qing Shen, Taro Toyoda, Yuhei Ogomi, Shuzi Hayase
Effect of TiO2 surface passivation on perovskite solar cells
Md Emrul Kayesh, Towhid Hossain Chowdhury, Kiyoto Matsuishi, Ashraful Islam
Effects of reducing salt on Sn-based perovskite films and their solar cell performance
Yuta Shirogane, Suguru Tanaka, Takeo Suga, Hiroshi Segawa, Hiroyuki Nishide
Perovskite Layer Formation with Polymer-Scaffold: Grain Structure Analysis and in-situ Conductive AFM Characterization
Mayu Yamaguchi, Kenichi Oyaizu, Hiroshi Segawa, Hiroyuki Nishide
Arylamine Polymer as the Hole-Transporting Material for a Perovskite Solar Cell with 1 cm2 Active Area
Yoshiyuki Seike, Daiki Tangiku, Hiroto Katsuta, Taichi Ishikawa, Tatsuo Mori
Influence of Metal Contamination in the Organic Active Layer of the Organic Thin Film Solar Cell
Molang Cai, Ishida Nobuyuki, Liyuan Han, Takeshi Noda
Electrical Potential Distribution for High Performance Perovskite Solar Cells
Zhanglin Guo, Chu Zhang, Liguo Gao, Tingli Ma
Design and fabrication of two-dimensional materials based perovskite solar cells
Greyson Christoforo
Spray Deposited Nanoparticle Films for Perovskite and Organic Solar Cells
Ryo Tanaka, Kengo Hamada, Qing Shen, Taro Toyoda, Yuhei Ogomi, Shuzi Hayase
Improvement of efficiency for mixed metal Sn/Pb perovskite solar cells
Dae Woon Lee, Su-Kyo Jung, O-Pil Kwon, Jong H. Kim
Investigations on Molecular Stacking and Charge Transport Properties of Naphthalene diimide-Based Small Molecules for Solar Cell Applications As an Electron Transport Layer
Hidenori SAITO, Daisuke AOKI, Shinichi MAGAINO, Katsuhiko TAKAGI, Shuzi HAYASE
Photoelectric conversion performance, stability and durability evaluation of Perovskite solar cell performance under the controlled atmosphere conditions.
Masashi Ozaki, Ai Shimazaki, Naoki Maruyama, Mina Jung, Alwani Rafiehm, Yumi Nakaike, Tomoko Aharen, Takahiro Sasamori, Norihiro Tokitoh, Yasujiro Murata, Atsushi Wakamiya
Fabrication of Efficient Perovskite Solar Cells and Module by a Solution Process Using a CH3NH3PbI3·DMF as a Key Precursor
Daisuke AOKI, Keita ANDOU, Hidenori SAITO, Shinichi MAGAINO, Katsuhiko TAKAGI
Study on Evaluation Methods of Perovskite Solar Cells
Kwan-Woo Ko, Sungjun Hong, Soon-Gil Yoon, Chi-Hwan Han
Enhanced Efficiency of Hole-conductor Free Perovskite Solar Cells with carbon electrode
Daiki Tangiku, Tatsuo Mori, Yoshiyuki Seike
Performance Enhancement of Organic Photovoltaic Cell by Electrospray Method
Yong Woon Han, Jun Young Choi, Ran Hee Choi, Hyoung Seok Lee, Sung Jae Jeon, Eui Jin Ko, Doo Kyung Moon
Efficient Organic-inorganic Hybrid Hole Extraction Layers to Enhancing Performance and Stability of Hybrid Organic Solar Cells
Jae Sung Yun
Humidity Induced Degradation via Grain Boundaries of HC(NH2)2PbI3 Planar Perovskite Solar Cells
Nozomi ITO, Koichiro Chijiiwa, Shen Qing, Yuhei Ogomi, Shuzi Hayase
Pb free Sn perovskite solar cells
Kenji Yoshino, Himeka Tominaga, Yuhei Ogomi, Takashi MInemoto, Qing Shen, Shuzi Hayase
High quality of FTO films grown by spray pyrolysis for perovskite-based solar cell
Xing Zhao, Jiangzhao Chen, Nam-Gyu Park
Dependence of Photovoltaic Performance on NiO Thin Layers Annealed at Different Atmospheres
Sung Jae Jeon, Doo Hun Kim, Jeong Eun Yu, Ye Jin Lee, Yong Woon Han, Young Hun Kim, Doo Kyung Moon
Desin of Chemical Structure Based on D-A copolymers via Tuning the Alkyl Side Chain in Efficient Polymer Solar Cells
Su-Kyo Jung, Jin Hyuck Heo, Dae Woon Lee, Seung-Chul Lee, Hoseop Yun, Sang Hyuk Im, O-Pil Kwon
Non-fullerene electron transporting materials based on naphthalene diimides for inverted perovskite solar cells
Ryuji Kaneko, Guohua Wu, Kosuke Sugawa, Ashraful Islam, Joe Otsuki
Synthesis and fabrication of NiOx based hole transporting layer for high efficiency low temperature processed perovskite solar cells
Jong-Hoon Lee, Soyeong Jeong, Byoungwook Park, Kwanghee Lee
Reinforcing the built-in field for efficient charge collection in polymer and perovskite solar cells
Soyeong Jeong, Hongkyu Kang, Byoungwook Park, Seok Kim, Kwanghee Lee
Novel ultra-thin silver electrodes using an amine-containing nucleation inducer for organic solar cells
Seok Kim, Hongkyu Kang, Soonil Hong, Jinho Lee, Soyeong Jeong, Byoungwook Park, Kwanghee Lee
A VERSATILE SELF-ORGANIZATION PRINTING METHOD TO SIMPLIFY TANDEM ORGANIC PHOTOVOLTAICS WITH FOUR-LAYER STRUCTURE
Haibin Wang, Takaya Kubo, Jotaro Nakazaki, Hiroshi Segawa
Efficient infrared solution-processed PbS quantum dot / ZnO nanowire solar cells
Ashish Kulkarni, Tsutomu Miyasaka
Solvent Engineering to Improve the Morphology and Enhance the Conversion Efficiency of Silver-Bismuth Halide Light Absorbing Materials for Efficient Lead Free Perovskite Solar Cells.
Jisu Hong, Hyojung Cha, Yonghwa Baek, Heok-jin Kwon, James R Durrant, Tae Kyu An, Yun-Hi Kim, Chan Eon Park
DTBDT-Based Small Molecule Solar Sells Incorporating Fullerene and Non-Fullerene Acceptors: Characterization of Nanoscale Morphology and Charge Carrier Dynamics
Anusha Pradhan, Gaurav Kapil, Shuzi Hayase, Shyam Pandey
Synthesis and characterization of positively charged NIR dyes for Cobalt electrolyte based dye-sensitized solar cells.
Naohiko Kato, Shinya Moribe, Masahito Shiozawa, Ryo Suzuki, Kazuo Higuchi, Akira Suzuki, Mareedu Sreenivasu, Katsuya Tsuchimoto, Koji Tatematsu, Katsuyoshi Mizumoto, Shoichi Doi, Tatsuo Toyoda
Improved Conversion Efficiency of 10% for Solid-State Dye Sensitized Solar Cells Utilizing P-type CuI and Multi-Dye Consisting of Novel Double Porphyrin and Organic Dyes
Xin Li, Junyou Yang, Qinghui Jiang, Weijing Chu, Dan Zhang, Zhiwei Zhou, Jiwu Xin
Synergistic Effect to High Performance Perovskite Solar Cells with Reduced Hysteresis and Improved Stability by Introduction of Na-treated TiO2 and Spraying-deposited CuI as Transport Layers
Towhid Hossain Chowdhury, Md.Emrul Kayesh, Jae-Joon Lee, Ashraful Islam
Stable and Enhanced Performance of Low Temperature Processed Inverted Planar Perovskite Solar Cells with CuSCN Interlayer at r-GO/Perovskite Interface
Bianka Puscher, Simon Dowland, Meera Stephen, Andres Osvet, Christoph Brabec, Roger Hiorns, Hans-Joachim Egelhaaf, Dirk Guldi
Electron Transfer Dynamics in Fullerene-Diketopyrrolopyrrole Copolymers for Organic Photovoltaics
Xie Shun-Lai, Wei Tzu-Chien
MAPbI3 Perovskite Film Fabricated Using Aqueous Lead Nitrate Precursor via Vapor-Assisted Deposition Process
Mitsuhiro Adachi, Rie Watanabe, Akira Suzuki, Takayuki Shimizu, Mareedu Sreenivasu, Devoju Harinada Chary, Katsuya Tsuchimoto, Tatsuo Toyoda, Takeru Bessho, Zeguo Tang, Keishi Tada, Hiroshi Segawa
Effects of Modified Phthalocyanine as Hole-Transporting Materials in Perovskite Solar Cells
Tae Woong Kim, Satoshi Uchida, Tomonori Matsushita, Ludmila Cojocaru, Ryota Jono, Kohei Kimura, Takashi Kondo, Hiroshi Segawa
Self-organized superlattice and phase coexistence in thin film organometal halide perovskite
Yasuhiro Shirai, Md Bodiul Islam, Masatoshi Yanagida, Kenjiro Miyanno
Sputtered NiOx Hole Transport Layer for Perovskite Solar Cells with Improved Stability
Soonil Hong, Hongkyu Kang, Kwanghee Lee
A New Series Connection Architecture for Large-Area Printed Organic Photovoltaic Modules
Youhei Numata, Yoshitaka Sanehira, Ryo Ishikawa, Hajime Shirai, Tsutomu Miyasaka
Methylammonium-free formamidinium-cesium-rubidium based triple cation perovskite solar cell
Yihe Miao, Ryosuke Nishikubo, Morteza Eslamian, Akinori Saeki
Exploration of Mixed-Cation Sn-based Perovskites by Time-Resolved Microwave Conductivity
Tomoya Hirano, Takeru Bessho, Ryota Jono, Keishi Tada, Chie Nishiyama, Zeguo Tang, Fumiyasu Awai, Miwako Furue, Masato Maitani, Hiroshi Segawa
Optical properties of organometal halide perovskite with different composition of A-site cations
Yi-Hsin Cheng, Tzu-Sen Su, Tzu-Chien Wei
A study on the morphology of MAPbI3 film made from electrodeposited PbI2
Tzu Sen Su, Tzu Chien Wei
Electrodeposition of Nb-doped TiO2 electron transporting layer for perovskite solar cell
Gyu Min Kim, Tsutomu Miyasaka
High perfomance multi-cation/halide perovskite solar cells by controlling evaporation kinetics of intermediate states
Mi-Jen Kuo, Yu-Chieh Liu, Hsien-Hsin Chou, Chen-Yu Yeh, Tzu-Chien Wei
Copper-based redox couple for Acetylene-Bridged 9, 10-Conjugated Anthracene Sensitized Solar Cell with >1.0V open circuit voltage
Zeguo Tang, Takeru Bessho, Fumiyasu Awai, Takumi Kinoshita, Haibin Wang, Masato Maitani, Ryota Jono, Jotaro Nakazaki, Takaya Kubo, Satoshi Uchida, Hiroshi Segawa
Key factors to eliminate the I-V hysteresis of lead halide perovskite solar cells
Moritz Futscher, Jumin Lee, Tianyi Wang, Azhar Fakharuddin, Lukas Schmidt-Mende, Bruno Ehrler
Quantification of Ion Migration in CH3NH3PbI3 Perovskite Solar Cells by Deep Level Transient Spectroscopy
Masahide Kawaraya, Tatsuo Toyoda, Shoichi Doi, Daisuke Kitazawa, Hidenori Saito, Hiroshi Segawa, Katsuhiko Takagi
Development of Emergency Self Emitting Guide Device using the Organic Solar Cells
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