Ion Migration in Metal Halide Perovskites

Abstract

Metal halide perovskites are promising photovoltaic materials, but they still have some issues that need to be solved. Hysteresis is a phenomenon that strongly is correlated with ion migration; thus, a fast, easy, and low-temperature method for measuring ion migration is required. Through selective blocking, ion migration can be measured separately, apart from electron migration. In this study, ion migration in metal halide perovskites was measured using a vertical device. At different temperatures, ionic activation energies were obtained for a range of perovskite compositions such as MAPbI 3 , FAPbI 3 , CsPbI 3 , and MAPbBr 3 . By comparing the measured ionic activation energies with the theoretical values, we conclude that among other possibilities, I - is the migrating ion in MAPbI 3 , FAPbI 3 , CsPbI 3, and Br - is the migrating in MAPbBr 3 .