Seminar & Colloquium
[세미나: 3월 18일(월), 오후 2시] Prof. Bin Hu, University of Tennessee
Title
Abnormal Electron-Phonon Coupling and Intersystem Crossing Effects Towards Enhancing Light-Emitting Properties in Metal Halide Hybrid Perovskites
Speaker
Prof. Bin Hu, University of Tennessee
* Biography
Dr. Bin Hu is a full professor in the Department of Materials Science and Engineering at the University of Tennessee (Knoxville). He received his Ph.D in condense matter physics in Chinese Academy of Sciences in 1991. After his postdoc and research scientist positions in the Department of Polymer Science and Engineering at the University of Massachusetts (Amherst) and senior research scientist at SICPA Product Security Incorporation, Dr. Bin Hu joined University of Tennessee in 2002 as assistant professor, associate professor and then full professor. Dr. Bin Hu’s research interest includes spintronics, orbitronics, and photophysics in organic molecules, organic-inorganic hybrid materials, nanomaterials, and organic crystals. His research has been focusing on orbital dynamics, spin dynamics, and spin-orbital coupling dynamics at different length and time scales in both spontaneous and stimulated regimes in light-emitting, photovoltaic, infrared sensing, and radiation detecting applications. Dr. Bin Hu received research achievement award multiple times at University of Tennessee in 2022, 2019, 2017, 2014, 2012, 2010, 2008. In 2008, Dr. Bin Hu received career development award from National Science Foundation on organic spintronics. Dr. Bin Hu serves in International Advisory Committee on Organic spintronics. He has published more than 200 research articles in Nature Materials, Nature Communications, Advanced Materials, Advanced Energy Materials, Advanced Functional Materials, Advanced Optical Materials, Joule, JACS, ACS Nano, Nano Energy, Small, and JPCL. The h-index is 48 with the total citations over 11000.
| Date | Monday March 18th , 2024
| Time | 14:00 ~
| Venue | 33동 222호(DB세미나실)
[Abstract]
Electrons and phonons are inevitably interacting especially in light-emitting semiconductors, leading to electron-phonon coupling. Normally, electron-phonon coupling causes the energy transfer from excitons to lattice vibrations, consequently generating nonradiative emission that functions as primary loss to light emission. This is known as normal electron-phonon coupling effects where a higher light emission corresponds to photoluminescence a longer lifetime. Within normal electron-phonon coupling effects, longer photoluminescence lifetimes are often used as a key parameter to indicate a lower loss. We found abnormal electron-phonon coupling effects where a higher light emission corresponds to a shorter photoluminescence lifetime, opposite to normal electron-phonon coupling effects. Importantly, abnormal electron-phonon coupling effects provide an important mechanism to enhance light emission in metal halide perovskite upon introducing dipolar polarization.
Intersystem crossing refers to the phenomenon that the light-emitting excitons are transferred between spin-up and spin-down band structures in metal halide perovskites. In principle, intersystem crossing must require momentum conservation between different band structures. We found that intersystem crossing can essentially tuned by external spin polarization in metal halide perovskites, leading to spin-switchable intersystem crossing. This spin-switchable intersystem crossing provides a vital mechanism to convert non-emissive excitons into emissive excitons, presenting an important method to enhance light-emitting properties in metal halide perovskites.
This presentation will discuss both abnormal electron-phonon coupling and intersystem crossing effects towards enhancing light-emitting properties in metal halide perovskites.
| Host | 이태우 교수(02-880-8021)