Numerical Investigation of MASnI₃-Based Lead-Free Perovskite Solar Cells: Impact of Hole Transport Layers on Device Performance

Abstract

Tin-based perovskites have emerged as promising lead-free alternatives for photovoltaic applications, but their efficiency remains limited by rapid carrier recombination and interfacial energy mismatches. In this work, we replicate a reported MASnI₃/In₂S₃ perovskite solar cell structure using SCAPS-1D and investigate the impact of various hole transport layers (HTLs) on device performance. The reference device employing Spiro-OMeTAD yielded a power conversion efficiency (PCE) of ~10%, consistent with literature. Substituting the HTL with inorganic materials demonstrated significant improvements: CuSCN achieved the highest performance (Voc = 0.85 V, Jsc = 33.0 mA cm⁻², FF = 69.2%, η = 19.4%), followed by NiOx (η = 17.9%) and CuI (η = 16.9%). In contrast, PEDOT:PSS exhibited poor band alignment with MASnI₃, leading to suppressed Voc (0.50 V) and the lowest efficiency (7.2%). Energy band analysis revealed that the superior performance of CuSCN stems from its favorable valence band alignment with MASnI₃, which reduces interfacial recombination and enhances hole extraction. These findings highlight the potential of inorganic HTLs for optimizing lead-free perovskite devices, offering both improved efficiency and better stability prospects compared to conventional organic counterparts.