Mixed halide hybrid perovskites AMX3 ABX3, A=Cs, CH3NH3, CH2(NH3)2, B=Pb, Sn, X=I, Br, Cl, are excellent light absorbers for perovskite solar cells. However, the photo-induced halide phase segregation degrades photovoltaic performance and impedes their photovoltaic applications in devices.

To study the thermodynamic and the kinetics of the phase segregation, we combine Density Functional Theory (DFT) and kinetic Monte Carlo (kMC) methods. In this project, DFT calculated parameters (determining the energetic/thermodynamic) will be used as input for kMC code to simulate the dynamic processes of the ion diffusion and therefore the phase segregation.

This study will contribute to a fundamental understanding of light-induced halide phase segregation in mixed halide hybrid perovskites and provide materials design rules to mitigate such effect.