First principle study on hybrid organic-inorganic perovskite ASnBr3 (A = Formamidinium, Dimethylammonium and Azetidinium)

The Organic-Inorganic halide perovskites of ABX(3) type (A: Organic cation, B: Metal cation, X: Halide anion) have exceptional electronic properties which attract broad interest. The widely studied Methylammonium Lead Iodide (MAPbI(3)) is toxic and less stable. Hence there is a need to find potential alternative materials. We report in this study, the density functional theory calculations for the tin-based hybrid perovskite ASnBr(3) (where A is an organic molecule: Formamidinium, Dimethylammonium or Azetidinium). We considered 106 different combinations of the constituent element/molecules and shortlisted three potential structures based on the factors like material abundance, bandgap, toxicity and stability. The structures were systematically analysed for their structural and electronic properties based on Density Functional Theory (DFT) calculations using Generalized Gradient Approximation (GGA) functional and GW approximations. Wide tunable bandgap with the range of 2.09 to 4.9 eV and corresponding changes in the optical absorption properties obtained by substituting different organic cations. The tin-based organic-inorganic halide perovskite may find application in tandem solar cells, which may enhance the efficiency of solar energy conversion.