6月21日学术报告：Non-Adiabatic Molecular Dynamics Investigations on the Ultrafast Charge Dynamics at Interfaces

发布者：系统管理员发布时间：2017-06-12浏览次数：34

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

报告人：赵瑾教授 中国科学技术大学物理系

时间: 6月21号（周三）上午10:30am

地点: 田家炳楼南203室

邀请人： 王金兰

欢迎各位老师、同学参加!

 

报告内容简介：

The ultrafast dynamics of photo-excited charge carriers plays an important in optoelectronics and solar energy conversion. Using nonadiabatic molecular dynamics simulation, we study the ultrafast charge dynamics at CH3OH/TiO2 and MoS2/WS2 interfaces. For CH3OH, we study the forward and backward hole transfer between TiO2 and CH3OH as well as the whole hole relaxation process to valance band maximum (VBM). First, we found that the hole trapping ability of CH3OH depends on the adsorption structure strongly. Second, we found the time scales of forward hole transfer process from TiO2 to CH3O (hole trapping process) and hole relaxation to VBM strongly depend on the temperature. The hole relaxation process to VBM is also slow down significantly. This can be interpreted by the reduction of the non-adiabatic coupling and the phonon occupation. For MoS2/WS2, we show that instead of direct tunneling, the ultrafast interlayer hole transfer is strongly promoted by an adiabatic mechanism through phonon excitation. At room temperature the interlayer charge transfer in MoS2/WS2 is ultrafast with a timescale of 20 fs which is in good agreement with the experiment. This ultrafast hole transfer process can be suppressed by decreasing the temperature to 100K. The atomic level picture of phonon-assisted ultrafast mechanism revealed in our study is valuable both for the fundamental understanding of ultrafast charge carrier dynamics as well as for the design of novel quasi-2D devices.

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。迄今为止赵瑾教授共发表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。