A Highly Efficient SnS‐Based Hetero‐Junction Solar Cell Using SnO ₂ and CuSCN: A SCAPS‐1D Optimization Study

Tin monosulfide (SnS) is an excellent candidate for thin‐film solar cell absorbers due to its earth abundance, environmental friendliness, and suitable optoelectronic properties for efficient solar energy conversion. In this study, SnO ₂ /SnS/CuSCN device structure, where SnO ₂ serves as an electron transport and window layer simultaneously, while CuSCN acts as a hole transport layer, has been simulated using SCAPS‐1D. It is found that increasing the shallow acceptor density up to 10 ¹⁷  cm ⁻³ improves collection, while lowering the bulk and interface defect density in SnS is crucial for reducing the recombination. Losses are further reduced by managing resistance levels judiciously. The simulated structure after multiparameter optimization produces a theoretical highest conversion efficiency of 29.06%, with associated photovoltaic parameters of open‐circuit voltage () = 1.01 V, short‐circuit current density () = 33.62 mA/cm ² , and fill factor = 85.89%. The observed parameters are typical of limits reported in literature on SnS absorbers. The main performance boost is due to favourable band alignment offered by SnO ₂ and CuSCN that results in the reduced interface‐associated recombination losses. Overall, this study shows that the SnO ₂ /SnS/CuSCN design has the potential for being an efficient and stable thin‐film solar cell architecture.