讲座通知：Ab initio simulations of carrier dynamics for bulk defects and hybrid perovskite system
题目：Ab initio simulations of carrier dynamics for bulk defects and hybrid perovskite system
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.