文摘
Although the power conversion efficiency of the lead-halide perovskite solar cells boost to >20%, the toxicity of lead hinders their large-scale implementation. Tin based perovskite have less toxicity, however its air stability is a big challenge. In this study, the air stability of tin based perovskite is improved by doping cobalt. The cobalt doped tin based perovskite thin films (GASn1−xCoxI2−2xCl1+2x) with cubic structure are prepared by one-step spin coating method. All GASn1−xCoxI2−2xCl1+2x (0.025≤x≤0.15) perovskite materials exhibit strong absorption in the visible light spectrum range. According to voltammetric measurement, the highest occupied molecule orbit (HOMO) and the lowest unoccupied molecule orbit (LUMO) of GASn1−xCoxI2−2xCl1+2x (x=0.15) are −5.45 and −3.99xA0;eV, respectively, and the bandgap is calculated to be 1.46xA0;eV. The binding energy increase of Sn3d and I3d for the cobalt doped tin based perovskite thin film might be the reason for enhanced air stability.