A computational study of lattice dynamics of energy materials

Abstract

Energy materials for photovoltaics and thermoelectrics attract increasing research interest due to their important applications. The thermal property of materials is closely related to the lattice dynamics. In-depth understanding of lattice dynamics and phonon coupling mechanisms is critical for effective engineering of thermal transport. In this presentation, I will speak about the phonon coupling mechanisms in the emerging photovoltaic hybrid perovskite MAPbI3 and the thermoelectric AgCrSe2 based on the results obtained from molecular dynamics simulations. Using the mode decomposition technique, we have obtained the lifetimes of the optical phonon modes of MAPbI3, complementing existing experimental studies. The strong scattering of phonons in AgCrSe2 due to Ag diffusion at elevated temperatures has also been studied in detail to better understand its low lattice thermal conductivity. The pressure effects on the anharmonic lattice dynamics of these energy materials will also be thoroughly discussed in this presentation.