First principles study on electronic structure and optical property of O-doped lead-free perovskite CsSnCl₃

The radii of O²⁻ and Cl⁻ are similar, and O²⁻ can easily replace Cl⁻ into the cell of perovskite CsSnCl₃. Herein, the doping model of O-doped lead-free perovskite CsSnCl₃ is established. The influence of O doping on the electronic structure and optical properties of CsSnCl₃ is studied by first principles calculation based on density functional theory (DFT). The results show that O doping can effectively regulate the band gap of CsSnCl₃, and it also indicates that the incorporation of O is the fundamental reason for the change in bandgap and the increase in light absorption coefficient of CsSnCl₃.