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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.
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Maksym Kovalenko has been a tenure-track Assistant Professor of Inorganic Chemistry at ETH Zurich since July 2011 and Associate professor from January 2017. His group is also partially hosted by EMPA (Swiss Federal Laboratories for Materials Science and Technology) to support his highly interdisciplinary research program. He completed graduate studies at Johannes Kepler University Linz (Austria, 2004-2007, with Prof. Wolfgang Heiss), followed by postdoctoral training at the University of Chicago (USA, 2008-2011, with Prof. Dmitri Talapin). His present scientific focus is on the development of new synthesis methods for inorganic nanomaterials, their surface chemistry engineering, and assembly into macroscopically large solids. His ultimate, practical goal is to provide novel inorganic materials for optoelectronics, rechargeable Li-ion batteries, post-Li-battery materials, and catalysis. He is the recipient of an ERC Consolidator Grant 2018, ERC Starting Grant 2012, Ruzicka Preis 2013 and Werner Prize 2016. He is also a Highly Cited Researcher 2018 (by Clarivate Analytics).
We discuss the discovery and recent developments of colloidal lead halide perovskite nanocrystals (LHP NCs, NCs, A=Cs+, FA+, FA=formamidinium; X=Cl, Br, I) [1-5]. LHP NCs exhibit spectrally narrow (<100 meV) fluorescence, originating form bright triplet excitons [6], and tunable over the entire visible spectral region of 400-800 nm. Cs- and FA-based perovskite NCs are promising for LCD displays, for light-emitting diodes and as precursors/inks for perovskite solar cells. Perovskite NCs also readily form long-range ordered superlattices, which exhibit accelerated coherent emission (superfluorescence) [7]. Unique structure engineerability of perovskites allows for (nearly) independent tuning of the emission color and radiative rates, which can be used in printable unicolor security tags [8].
L. Protesescu et al. Nano Letters 2015, 15, 3692–3696
L. Protesescu et al. J. Am. Chem. Soc. 2016, 138, 14202–14205
L. Protesescu et al. ACS Nano 2017, 11, 3119–3134
M. V. Kovalenko et al. Science 2017, 358, 745-750
Q.A. Akkerman et al. Nature Materials 2018, 17, 394–405
M. A. Becker et al, Nature 2018, 553, 189-193
G. Raino et al. Nature 2018, 563, 671–675
S. Yakunin et al. submitted
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Andrey L. Rogach is a Chair Professor of Photonics Materials at the Department of Physics and Materials Science, and the Founding Director of the Centre for Functional Photonics at City University of Hong Kong. He received his Ph.D. in chemistry (1995) from the Belarusian State University in Minsk, and worked as a staff scientist at the University of Hamburg (Germany) from 1995 to 2002. From 2002–2009 he was a lead staff scientist at the Ludwig-Maximilians-Universität in Munich (Germany), where he completed his habilitation in experimental physics. His research focuses on synthesis, assembly and optical spectroscopy of colloidal semiconductor and metal nanocrystals and their hybrid structures, and their use for energy transfer, light harvesting and light emission. His name is on the list of Top 100 Materials Scientists and on the list of Top 20 Authors publishing on nanocrystals in the past decade by Thomson Reuters, ISI Essential Science Indicators. Andrey Rogach is an Associate Editor of ACS Nano, and holds honorary appointments at Trinity College Dublin (Ireland), Xi’An Jiaotong University, Jilin University and Peking University (China).
Chemically synthesized lead halide perovskite nanocrystals have recently emerged as a new class of efficient light emitting materials. High emission quantum yield, easily tuned emission colors, and high color purity make this class of materials particular attractive for light-emitting devices (LEDs) and display applications. I will review some of our recent synthetic strategies leading to highly luminescent perovskite nanocrystals of different sizes and shapes, which include recently demonstrated elongated nanorods with a strong polarized emission. I will further consider the doping strategies for perovskite nanocrystals, and the interface engineering of perovskite based hybrid films, which allow us to use them in rather efficient charge injection LEDs.
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Jianjun Tian is a professor at Institute for Advanced Materials and Technology, University of Science and Technology Beijing (USTB). He received his PhD in USTB in 2007. During 2011-2012, he studied in University of Washington as visiting professor. He was selected as new century excellent talents of Ministry of Education in 2013, and built the Laboratory of Optoelectronic Materials and Devices in 2016 as leader (PI). He was nominated as director of Functional Materials Institute, USTB in 2015 and vice-dean of Institute for Multidisciplinary Innovation, USTB in 2019. Current research focuses on quantum dots and perovskites, and their applications, including solar cells, light emitting and photodetectors.
Colloidal all-inorganic halide perovskite quantum dots (QDs) are emerging as high-performance materials for optoelectronic applications due to a number of useful characteristics, such as an easy tunability of the bandgap, long carrier lifetime, high charge carrier mobility, high photoluminescence quantum yield (PLQY), and a possibility of a low-cost solution-based processing. However, their poor stability and high trap density, especially for high sensitivity to moisture, and ease of phase transformation and photodegradation in ambient conditions, still prevent their widespread practical applications. Here, I will demonstrate our recent works that aimed at stabilizing halide perovskite QDs and reducing their trap density for improving performance of QDs and their optoelectronics. The effective approaches involve surface chemistry, doping and architecture construction.
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Lianzhou Wang is Professor and Australian Research Council (ARC) Laureate Fellow in School of Chemical Engineering, Director of Nanomaterials Centre (Nanomac), and Senior Group Leader of Australian Institute for Bioengineering and Nanotechnology, the University of Queensland (UQ). His research focuses on the design and application of semiconductor nanomaterials for renewable energy conversion/storage applications including photocatalytsts for solar hydrogen production, low cost solar cells and batteries. He has contributed 15 edited books and chapters, > 400 journal publications, and 17 patents, with >24000 citations. He won some prestigious Fellowships/awards including ARC QEII Fellowship, Future Fellowship and Laureate Fellowship, UQ Research Excellence Award and Research Supervision Award, Scopus Young Researcher Award, RACI Research Excellence Award in Chemical Engineering. He is the fellow of Royal Society of Chemistry and was named in the list of the Clarivate’s Highly Cited Researchers.
Perovskite quantum dots (QDs) have the advantages of quantum confinement effect, defect-tolerant nature, and the capability of developing lightweight and flexible films, thus attracting much recent research focus for a variety of functional device developments including QD solar cells. Here we report our recent progress on a novel surface ligand engineering strategy in designing perovskite QDs, which led to a record power conversion efficiency of 16.6% in quantum dot solar cells. In normal practice, the long carbon-chain ligands on the surface of QDs not only confine the growth of QDs, but also play an important role in passivating the surface defects. However, these long-chain ligands are insulating and limiting the transport of charge carriers within QD film. To improve the electronic coupling between QDs, we discovered that increasing the concentration of oleic acid ligands during the formation of mixed-cation perovskite QDs facilitates preserve high radiative efficiency by suppressing surface defects. This new finding allowed us not only fundamentally understand the optoelectronic working mechanism of the QDs, but also remarkably improve the optoelectronic quality of the perovskite QDs. The new classes of perovskite quantum dots have been used as building blocks in Quantum Dot Solar Cells with a certified record efficiency of 16.6% (https://en.wikipedia.org/wiki/Solar_cell_efficiency). By using QDs as light absorbing materials, the QD based photocatalysts also exhibited good performance in photocatalytic gaseous hydrogen production.
Keywords：perovskites quantum dots, power conversion efficiency, water splitting