学术动态
新加坡南洋理工大学熊启华教授学术报告会
2017-10-19 08:36  

报告题目:Probing Light-Matter Interactions in Perovskite Crystals

报 告 人:熊启华  教授

          新加坡南洋理工大学数理科学学院和电气电子工程学院双聘教授

主 持 人:李金山  教授    西北工业大学材料学院

报告时间:2017年10月20日16:00

报告地点:公字楼334会议室

Abstract:
The interaction of light with matter gives rises to a wide range of linear and nonlinear phenomena that we are familiar with, such as absorption, scattering, spontaneous or stimulated emission, and second harmonic generation. In insulators or semiconductors, the electromagnetic field of light polarizes the matter leading to the formation of elemental excitations such as excitons and exciton polaritons, due to long-range dipolar force as well as additional coupling to the optical fields. In this talk, I will first introduce the background of exciton, exciton polaritons and the electron/exciton-longitudinal optical (LO) phonon interactions in semiconductors. I will then discuss our effort in vapor phase synthesis of high quality inorganic-organic or all-inorganic perovskite crystals. Those crystals exhibit regularly hexagon or square facets with sufficiently large laser damaging threshold while the emission edge can be tuned from ultraviolet to near-infrared. Steady-state and transient spectroscopy approaches can elaborate the exciton binding energy and excitonic emission nature at room temperature. Optically pumped photonic lasing based on the intrinsic whispering gallery mode cavity will then be presented, while the lasing quality factor can be as high as 5000 in all-inorganic perovskite crystals. Lastly, I will introduce our latest work on room temperature exciton-polariton lasing in all-inorganic perovskite CsPbCl3 crystals embedded in optical microcavities. Those crystals have exceptionally large exciton binding energy, strong oscillator strength and can be grown by facile epitaxy-free techniques. Polariton lasing is unambiguously evidenced by a superlinear power dependence, macroscopic ground state occupation, blueshift of ground state emission, and the build-up of long-range spatial coherence. Our work suggests considerable promise of lead halide perovskites towards large-area, low-cost, high performance room temperature polariton devices and coherent light sources extending from the ultraviolet to near infrared range.

 

References:

1.Q. Zhang*, R. Su, W.N. Du, X.F. Liu, L.Y. Zhao, S.T. Ha and Q.H. Xiong*, “Lead halide perovskite nanostructures for small lasers”, Small Methods 1, 1700163 (2017)

2.R. Su et al., “Room temperature polariton lasing in all-inorganic perovskite”, Nano Lett. 17, 3982-3988 (2017)

3.S.T. Ha, et al., “Laser Cooling of Organic-inorganic Lead Halide Perovskites”, Nature Photonics 10, 115–121 (2016)

4.Q. Zhang, et al., “High quality whispering-gallery-mode lasing from cesium lead halide perovskite nanoplatelets”, Adv. Funct. Mater. 26, 6238-6245 (2016)

5.Q. Zhang, et al., “Room-temperature near-infrared high-Q perovskite whispering-gallery planar nanolasers”, Nano Lett. 14, 5995-6001 (2014)

6.S.T. Ha, et al., “Synthesis of organic-inorganic lead halide perovskite nanoplatelets: Towards high performance perovskite solar cells and opto-electronic devices”, Adv. Optical Mater. 2, 838-844 (2014) (highlighted as Best of Advanced Optical Materials – 2014 edition)

 

熊启华教授个人简介

    熊启华教授本硕分别毕业于武汉大学和上海应用物理研究所,在宾夕法尼亚大学取得博士学位,随后在哈佛大学从事博士后研究,现任新加坡南洋理工大学数理科学学院和电气电子工程学院双聘教授。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, 《纳米通讯》,《先进材料》等一系列国际知名杂志上发表了180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6200次,H-因子47。其出色的研究获得了一些奖励和认可,比如新加坡物理学会纳米科技奖(2015),新加坡国立研究基金NRF Investigatorship奖(2014),和南洋理工大学南洋研究卓越奖(2014)等。

 

欢迎广大师生届时参加

 

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