Numerical Simulation Study on the Performance of Sb2(S,Se)3 Solar Cells with CuSCN as Hole Transport Layer

CuSCN is a low-cost inorganic HTL with potentially better ambient stability than Spiro-OMeTAD according to literature. This study explores copper(I) thiocyanate (CuSCN) as a hole transport layer (HTL) to replace the conventional organic material Spiro-OMeTAD in antimony selenosulfide (Sb2(S,Se)3) solar cells. Numerical simulations performed with the Afors-het software reveal that the device structure FTO/CdS/Sb2(S,Se)3/CuSCN/Au incorporating CuSCN achieves improved interfacial energy band alignment. Specifically, the valence band offset (VBO) is reduced to −0.2 eV, which substantially enhances hole extraction efficiency and suppresses interface recombination. Through systematic optimization of key structural parameters, including the absorber layer thickness (350 nm), the CuSCN layer thickness (9 nm), and its p-type doping concentration (1019 cm−3), the device attains a maximum power conversion efficiency (PCE) of 12.03%. This work provides a theoretical foundation and a viable device design strategy for developing low-cost, highly stable, and efficient Sb2(S,Se)3 solar cells.