High-throughput screening of the transport behavior of tetragonal perovskites

Abstract

Halide perovskites have attracted attention due to their low cost and excellent optoelectronic properties. Although their optical properties gained widespread consensus, there was still divergence in understanding carrier transport behavior. In this study, the mobility of tetragonal perovskites was investigated by empirical models, including longitudinal acoustic phonon (LAP) and polar optical phonon (POP) models. The results revealed that the mobility predicted from the LAP model was much higher than that from the POP model. A longitudinal optical phonon (LOP) was considered as the decisive scattering source for charge carriers in perovskites. Furthermore, the mobility was extremely sensitive to z-axis strain, and 8 types of perovskites with high carrier mobility were screened. Using the experimental lattice constants, the predicted mobility of CsSnI₃ was μ_e,z = 1428 and μ_h,z = 2310 cm² V⁻¹ s⁻¹, respectively. The tetragonal CsSnI₃ has high mobility and moderate bandgaps, suggesting potential applications in high-efficiency solar cells.