Effect of Ni-doping on the structural and electronic properties of metal halide perovskite CsSnBr₃: A DFT study

The structural and electronic properties of pure and Ni-doped perovskite CsSnBr 3 in unit cell and supercell were computed using density functional theory at ambient pressure. Computed formation energy values of undoped and Ni-doped CsSnBr 3 compounds show that these structures are stable. We used both standard DFT and HSE06 calculation in electronic band structure of pure and Ni-doped CsSnBr 3 compounds. Since the band gap of undoped and Ni-doped CsSnBr 3 compounds is located at the R symmetry point in the Brilloun zone, these compounds are materials with a direct band gap. In the HSE06 calculation, it was found that the band gap of 12.5% Ni doped-CsSnBr 3 increased significantly from 1.1162 eV to 1.4343 eV. The electron charge density, Bader charge analysis and density of states reveal a strong covalent bond between Sn-Br (Ni-Br) and a strong ionic bond between Cs-Br. The direct electronic band gaps of undoped and Ni-doped CsSnBr 3 perovskites in the visible energy range show that these compounds can be used effectively in optical applications.