First-principles study of oxygen-doped perovskite CsPbX3 (X = Cl, Br, I)

The electronic structures of perovskite CsPbX3 (X = Cl, Br, I) and O doped CsPbX3 have been studied by first principles based on density functional theory (DFT). The theoretical calculation results show that O doping leads to narrow band gap width of perovskite CsPbX3. For pure CsPbX3, it is found that the 6p states of Pb determines the position of the conduction band bottom and the p states of halogen determines the position of the valence band top; and for O doped CsPbX3, it shows that the incorporation of O is the fundamental reason for the narrowing of band gap and light absorption edge redshifting compared with that of pure CsPbX3.