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

TL;DR

This study uses first-principles calculations to analyze BaZrS$_3$, revealing its moderate electron mobility, intrinsic n-type behavior, limited p-type doping potential, and some defect tolerance, guiding future optimization for photovoltaic applications.

Contribution

It provides a comprehensive first-principles analysis of carrier transport and defect properties in BaZrS$_3$, highlighting its limitations and potential for solar cell use.

Findings

Electron mobility is 37 cm$^2$/Vs for electrons and 11 cm$^2$/Vs for holes.

BaZrS$_3$ is intrinsically n-type due to shallow sulfur vacancies.

It exhibits some defect tolerance with few deep intrinsic defects.

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.