题目:
PerovLight: What Perovskite Semiconductors Offer Beyond Solar Cells?
讲座人:
熊启华 教授
南洋理工大学数理科学学院
南洋理工大学电气电子工程学院
清华大学访问教授
时间:
5月8日（周三）16:30-18:00
地点:
卢嘉锡楼202报告厅
报告摘要：
Halide perovskites have recently attracted tremendous attention due to their remarkable properties in thin film solar cells, with the recent certified efficiency >23.0%. On the other hand, perovskite semiconductors are excellent optical gain materials, which have manifested exceptional promise in light-emitting diodes, photodetectors and many other optoelectronic applications. In this talk, I will first review our recent progress in the investigation of halide perovskite materials as excellent optical gain materials, which can be synthesized by either physical or chemical ways. Steady-state and transient spectroscopy approaches can elaborate the large exciton binding energy higher than room temperature thermal excitation energy, and exciton dynamics. High crystalline quality supports the optically pumped photonic lasing based on the intrinsic whispering gallery mode cavity, while the lasing quality factor can be as high as 5000 in all-inorganic perovskite crystals. Next, I will present our experimental realization of room-temperature polariton lasing in all-inorganic cesium lead chloride perovskite crystals embedded in two distributed Bragg reflectors. The perovskite crystals possess efficient polariton-polariton scattering due to the Wannier-Mott exciton nature with large binding energy. The polariton lasing is evidenced by a superlinear power dependence, macroscopic ground state occupation, and increase of the temporal coherence, suggesting stable polariton Bose-Einstein condensate at room temperature. Finally, we will present our recent results using perovskite materials towards highly efficient light-emitting diode (LED) applications, with a recent record high >20% conversion efficiency in green emission region. This talk will be ended up with perspective outlook in polariton artificial lattices at room temperature and electrically pumped polariton laser.
嘉宾介绍：
熊启华，美国物理学会会士。2006年于宾夕法尼亚州立大学获得博士学位，师从Peter C. Eklund教授。2006-2009年在哈佛大学Charles Lieber研究组从事博士后研究。2009年加入南洋理工大学，2014-2019年起担任数理科学学院副院长，先后主管科研，研究生教育和教职事务。主要研究领域是以稳态和瞬态光谱学为主要实验手段，以光和物质相互作用为研究主题, 着重研究低维半导体纳米材料基于光子-声子-电子耦合作用的物理机制和量子调控。他在纳米光子学和表面等离子体学，激光制冷，以及二维半导体材料光学性质等一系列前沿课题做出了一系列有影响的工作。在《自然》及子刊等一系列国际知名杂志上发表了200多篇文章，并被世界知名杂志及大众媒体所报道，总引用次数超过9800次，H-因子59。2019年1月起加入清华大学物理系。
化学化工学院 能源材料化学协同创新中心
2019年5月6日
