Achieving Efficiency of up to 27.01% for SnS-Based Heterojunction Solar Cells Through SCAPS-1D Design and Optimization

Tin sulfide (SnS) has emerged as a highly promising absorber material for thin-film solar cells owing to its excellent optoelectronic characteristics and earth-abundant composition properties. However, it is worth noting that the power conversion efficiency (PCE) of SnS-based thin-film solar cells (TFSCs) is still far below their theoretical potential of approximately 32.0%, and the factors leading to poor performance mainly include high recombination rate, short minority carrier lifetime, and unfavorable conduction band offset (CBO) at pn junction interface. In this study, we selected CdS, ZnSe, and ZnS:In as electron transport layers, NiOx, PEDOT: PSS, Spiro-OMeTAD, CuI, and CuSCN as hole transport layers, and compared them through SCAPS-1D simulation to optimize device performance. In addition, the impacts of the SnS absorber layer thickness and doping concentration, bulk defect density, electron transport layer, hole transport layer, and electrode work function on the device performance have been systematically studied using SCAPS-1D. The results show that the solar cell with Al/ITO/ZnS:In/SnS/NiOx/Au/SLG architecture can achieve a maximum PCE of 27.01%. This simulation aims to explore the theoretical performance ceiling of SnS-based architecture rather than predicting experimentally realizable efficiency. This study provides theoretical guidance for the design of high-performance, low-cost SnS-based thin-film solar cells.