题目：Ab initio simulations of carrier dynamics for bulk defects and hybrid perovskite system

报告人：Lin-Wang Wang

时间：2018年1月3日上午10：00

地点：betway必威动力与机械学院报告厅

欢迎各位师生踊跃参加！

Abstract text:

Carrier dynamics is important problem which determines the efficiency of electric optical devices and other ultrafast properties. In this talk, I will present some recent progress in using ab initio calculation methods to study the carrier dynamics in bulk defects hybrid perovskite system. The multi-phonon process will be simulated via the calculation of the electron-phonon coupling constants. A new algorithm is developed to calculate the coupling coefficient s efficiently. The non-radiative decay rate calculated in such a way agrees with experiment and can be used to explain the time optical spectroscopy. The carrier dynamics can also be studied using non-adiabatic molecular dynamics and rt-TDDFT. I will show how such simulations can be used to study various ultrafast processes and hot carrier relaxation, as well as electron mobility in the hybrid perovskite system.

About the lecturer:

   Lin-Wang Wang:  Senior Staff Scientist, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S.  Dr. Wang has 25 years of experience in large scale electronic structure calculations. He has worked in O(N) electronic structure calculations in early 1990s. Worked with Alex Zunger, he invented the folded spectrum method which pushed the limit of nonselfconsistent electronic structure calculations from 100 atoms to thousands of atoms. He developed a linear combination of bulk bands (LCBB) method for semiconductor heterostructrure electronic structure calculations, which allows the calculation of  million atom devices. He developed generalized moments method which calculates the density of state and optical absorption spectra of a given system without explicit calculation of its eigenstates. He also developed a popular parallel total energy plane wave pseudopotential program (PEtot). He invented a charge patching method, which enables the ab initio accuracy thousand atom calculations for nanosystems. He has developed a linear scaling three dimensional fragment method (LS3DF), which can be used to selfconsistently calculate systems with tens of thousands of atoms. Recently, he developed a new algorithm for real-time time-dependent DFT calculations which accelerates the traditional algorithms by hundreds of times.

汪林望教授现任美国劳伦斯伯克利国家实验室资深研究员。1985年获上海交通大学物理学学士学位，1991年获康奈尔大学物理学博士学位。1991年至1995年先后在康奈尔大学物理系和美国再生能源国家实验室从事博士后研究。汪林望教授主要从事的研究领域有：计算物理学、计算材料科学、纳米材料科学, 以及能源材料科学等。至今共发表SCI论文250余篇，包括8篇Science和Nature，40余篇PRL、JACS、NanoLett。论文总引用次数达13000余次，H-index为54。在计算方法和跨尺度材料计算领域已发展了十多种算法和程序，如现已广泛使用的PEtot、Escan、LCBB、LS3DF等。汪林望教授于2008年获得戈登贝尔奖。