The mechanical, electronic and optical properties of BiPX4 (X = S, Se): a theoretical study

Abstract Bi-based semiconductor materials have emerged as potential solar absorbers for application in solar cells. In this study, we theoretically have investigated the mechanical, electronic and optical properties of BiPX4 (X = S, Se) based on first-principles calculations. The calculated results have suggested that these compounds are mechanically stable, and they also display the feature of ductile material. The PBE functional can give an accurate band gap of BiPS4. The spin-orbit coupling (SOC) effect has a significant influence on the electronic structure of Bi-based material. A suitable band gap value (1.05 eV) is obtained for BiPSe4, and there is no parity-forbidden transition at the Γ piont in BiPSe4. Importantly, BiPSe4 also exhibits higher absoprtion coefficient in the visible light range than that of BiPS4.