Assessing carrier mobility, dopability, and defect tolerance in the chalcogenide perovskite BaZrS${}_3$

Abstract

The chalcogenide perovskite BaZrS${}_3$ has attracted much attention as a promising solar absorber for thin-film photovoltaics. Here, we use first-principles calculations to evaluate its carrier transport and defect properties. We find that BaZrS${}_3$ has a phonon-limited electron mobility of 37 cm${}^2$/Vs comparable to that in halide perovskites but lower hole mobility of 11 cm${}^2$/Vs. The defect computations indicate that BaZrS${}_3$ is intrinsically n-type due to shallow sulfur vacancies, but that strong compensation by sulfur vacancies will prevent attempts to make it p-type. We also establish that BaZrS${}_3$ shows some degree of defect tolerance, presenting only few low formation energy, deep intrinsic defects. Among the deep defects, sulfur interstitials are the dominant nonradiative recombination centers but exhibit a moderate capture coefficient. Our work highlights the material's intrinsic limitations in carrier mobility and p-type doping and suggests focusing on suppressing the formation of sulfur interstitials to reach longer carrier lifetime.