Defect and carrier characteristics of chalcogenide perovskite BaZrS3 under thermodynamic stability: a first-principles study for photovoltaic application

Abstract

BaZrS₃ is reported to be an exceptional chalcopyrite perovskite with remarkable stability, making it a key material for the next-generation perovskite-inspired technologies. In this study, the thermodynamic stability of BaZrS₃ was investigated while referencing all potential secondary phases in the Materials Project database. Furthermore, the influence of element doping on both the bands and thermodynamic stability of BaZrS₃ was also studied, the band adjustment efficiency was validated, and experimental synthesis challenges were elucidated. Based on a large supercell, Heyd–Scuseria–Ernzerhof hybrid functional and finite-size effect correction, the concentration properties of defects and charge carriers of BaZrS₃ were then determined in the thermodynamically stable region, from the characteristics of defect formation energy with varied Fermi levels. The results indicate that degenerated semiconductor characteristics exist in BaZrS₃ in the thermodynamically stable region, which should be avoided. The defect transition energy level characteristics of BaZrS₃ were also calculated and identified. Additionally, the properties of deep-level defects S_i with high concentration were analyzed. While S_i (+2/0) exhibits deep-level defect states, S_i (+1/0) does not. The non-radiative and radiative capture coefficients of deep-level defect S_i (+2/0) were calculated at 1.28682 × 10⁻²⁵ and 3.51 × 10⁻¹⁵ cm³ s⁻¹, respectively. The obtained defect and carrier qualities of BaZrS₃ were applied to evaluate its photoelectric conversion efficiency. The manuscript investigates, for the first time, how defects evolve with changes in chemical potential in stable BaZrS₃, providing valuable guidance for the experimentally controllable preparation of high-quality BaZrS₃ films or devices.