报告题目：Non-Adiabatic Molecular Dynamics Investigations on the UltrafastCharge Dynamics at Interfaces

报告人：赵瑾教授

国家优秀青年基金获得者

中国科学技术大学

Abstract:Theultrafast dynamics of photo-excited charge carriers plays an important inoptoelectronics and solar energy conversion. Using nonadiabatic moleculardynamics simulation, we study the ultrafast charge dynamics at CH₃OH/TiO₂and MoS₂/WS₂interfaces. For CH₃OH, we studythe forward and backward hole transfer between TiO₂and CH₃OHas well as the whole hole relaxation process to valance band maximum (VBM).First, we found that the hole trapping ability of CH₃OH depends onthe adsorption structure strongly. Second, we found the time scales of forwardhole transfer process from TiO₂to CH₃O (hole trappingprocess) and hole relaxation to VBM strongly depend on the temperature. Thehole relaxation process to VBM is also slow down significantly. This can beinterpreted by the reduction of the non-adiabatic coupling and the phononoccupation. For MoS₂/WS₂, we show that instead of directtunneling, the ultrafast interlayer hole transfer is strongly promoted by anadiabatic mechanism through phonon excitation. At room temperature theinterlayer charge transfer in MoS₂/WS₂is ultrafast witha timescale of 20 fs which is in good agreement with the experiment. Thisultrafast hole transfer process can be suppressed by decreasing the temperatureto 100K. The atomic level picture of phonon-assisted ultrafast mechanismrevealed in our study is valuable both for the fundamental understanding ofultrafast charge carrier dynamics as well as for the design of novel quasi-2Ddevices.

报告人简介：赵瑾，1998年毕业于中国科学技术大学物理系，2003年于中国科学技术大学理化科学中心获得博士学位（指导教师：侯建国院士，杨金龙教授）。2004年3月起在美国匹兹堡大学HrvojePetek教授组内工作。2008年8月起成为匹兹堡大学物理系研究助理教授，2010年初成为中国科学技术大学物理系及合肥微尺度国家实验室教授，匹兹堡大学兼职教授（adjunct Prof.），并入选百人计划。2013年获基金委优秀青年基金资助。赵瑾教授的研究小组关注于利用第一性原理计算从时间、空间、动量与能量等多个尺度对激发态动力学的超快过程进行描述，同时研究激发态载流子与声子、极化子、缺陷、边界等的相互作用。迄今为止共发表SCI论文70篇，包括3篇Science、4篇Phys. Rev. Lett.、5篇J. Am. Chem. Soc.、2篇Nano Lett.、6篇ACS NANO，他引次数1885次，H因子26。

地点：前卫南区唐敖庆楼C区603报告厅

时间：2017年5月17日（周三）上午10:00

举办单位：超硬材料国家重点实验室

物理学院

吉林省物理学会

中国物理学会高压物理专业委员会