Defect Study and Modelling of SnX3-Based Perovskite Solar Cells with SCAPS-1D

Recent achievements, based on lead (Pb) halide perovskites, have prompted comprehensive research on low-cost photovoltaics, in order to avoid the major challenges that arise in this respect: Stability and toxicity. In this study, device modelling of lead (Pb)-free perovskite solar cells has been carried out considering methyl ammonium tin bromide (CH₃NH₃SnBr₃) as perovskite absorber layer. The perovskite structure has been justified theoretically by Goldschmidt tolerance factor and the octahedral factor. Numerical modelling tools were used to investigate the effects of amphoteric defect and interface defect states on the photovoltaic parameters of CH₃NH₃SnBr₃-based perovskite solar cell. The study identifies the density of defect tolerance in the absorber layer, and that both the interfaces are 10¹⁵ cm^-3, and 10¹⁴ cm^-3, respectively. Furthermore, the simulation evaluates the influences of metal work function, uniform donor density in the electron transport layer and the impact of series resistance on the photovoltaic parameters of proposed n-TiO₂/i-CH₃NH₃SnBr₃/p-NiO solar cell. Considering all the optimization parameters, CH₃NH₃SnBr₃-based perovskite solar cell exhibits the highest efficiency of 21.66% with the V of 0.80 V, J of 31.88 mA/cm² and Fill Factor of 84.89%. These results divulge the development of environmentally friendly methyl ammonium tin bromide perovskite solar cell.