报告主题：Giant Photostriction in MAPbI3 and Ferroelectric Photovoltaic Effect
报告人：Prof. Junling Wang, School of Materials Science and Engineering, Nanyang Technological University, Singapore
Giant Photostriction in MAPbI3 and Ferroelectric Photovoltaic Effect
School of Materials Science and Engineering
Nanyang Technological University, Singapore, 639798
The past few years witnessed the explosion of research on photovoltaic cells based on the hybrid lead halide perovskites, in particular CH3NH3PbI3. Despite the tremendous progress in device performance, much less is known about the underlying mechanism except that the carrier lifetime and diffusion length are astonishingly long in both thin films and single crystals.
We recently observed a giant photostrictive response, i.e., light-induced dimension change, of more than 1200 ppm in CH3NH3PbI3. This is very similar to what has been observed in conventional ferroelectric oxides. However, the hybrid lead halide perovskites are not ferroelectric despite the large dipole of the CH3NH3 group. On the other hand, in conventional oxide perovskite BiFeO3 with strong ferroelectricity, we observed that the photovoltaic response could be significantly improved by destabilizing the polarization. Combining these observations, we propose a model to explain the photostriction of CH3NH3PbI3, and suggest a strategy to improve the photovoltaic property of conventional ferroelectric materials.
, “Giant Photostriction in Organic-Inorganic Lead Halide Perovskites”, Yang Zhou†, Lu You†, Zhiliang Ku, Hongjin Fan, Shiwei Wang, Daniel Schmidt, Andrivo Rusydi, Lei Chang, Le Wang, Peng Ren, Liufang Chen, Guoliang Yuan, and Junling Wang*, Nat Commun., 2016, 7,11193.
, “Photovoltaic enhancement accompanied by polar-instability: An insight from ferroelectric perovskite solar cells”, Lu You, Fan Zheng, Liang Fang, Yang Zhou, Liang Z. Tan, Zeyu Zhang, Guohong Ma, Daniel Schmidt, Andrivo Rusydi, Le Wang, Peng Ren, Shiwei Wang, Lei Chang, Andrew M. Rappe*, Junling Wang*, submitted (2017).
Professor WANG Junling obtained his B.S. degree from Nanjing University in 1999, and Ph.D. degree from University of Maryland, College Park in 2005. After spending 1.5 years at Pennsylvania State University as a postdoc, he joined Nanyang Technological University, Singapore as an Assistant Professor in 2006. In 2011, he was promoted to Associate Professor with tenure.
Professor Wang Junling’s research activities focus on multifunctional thin films and their applications in nanoelectronic and spintronic devices. In particular, he is interested in perovskites with the chemical formula of ABX3. These materials possess a wide range of exotic properties ranging from highly insulating to superconducting, from dielectric to ferroelectric and multiferroic. His pioneering work on multiferroic BiFeO3 has attracted much attention in the field. His recent work also includes 2D layered materials that possess ferroelectric and/or magnetic properties. He has published over 120 papers in high impact journals, including Science, Nature Communications, NPG Asia Materials, Advanced Materials, PRB and APL. His work has been cited more than 8000 times.
Through materials processing, structural analysis and electrical/magnetic characterizations, he tries to understand the fundamental physics of the perovskite materials at low dimensions and develop new materials/devices for the next generation nanotechnology.