Enhancing Sb2Se3 thin-film solar cell efficiency via CuGaSe2 dual-absorber integration

Antimony selenide (Sb 2 Se 3 ) thin-film solar cells have attracted considerable attention due to their earth-abundant composition, suitable bandgap, and high absorption coefficient. However, their performance remains limited by carrier recombination, interfacial losses, and incomplete spectral utilization. In this work, a CuGaSe 2 -assisted dual-absorber architecture is proposed and investigated using SCAPS-1D simulation to enhance the optoelectronic performance of Sb 2 Se 3 -based solar cells. The reference structure (Mo/MoSe 2 /Sb 2 Se 3 /CdS/ZnO/Al:ZnO) is first calibrated against experimental data, showing excellent agreement in key photovoltaic parameters. A \({\text{CuGaSe}}_{2}\) layer is then introduced between Sb 2 Se 3 and CdS, forming a Mo/MoSe 2 /Sb 2 Se 3 /CdS/ZnO/Al:ZnO heterostructure. The proposed device exhibits a significant improvement in performance, with power conversion efficiency increasing from 10.12 to 19.50%, accompanied by an increase in open-circuit voltage from 0.48 to 0.77 V and short-circuit current density from 30.87 to 35.80 mA cm −2 . This enhancement is attributed to improved optical utilization, enhanced carrier generation, and suppressed recombination losses associated with favorable band alignment and modified interfacial energetics introduced by the CuGaSe 2 layer. Additional analyses reveal an increase in built-in potential and a reduction in recombination activity compared with the reference device. Overall, these results demonstrate that CuGaSe 2 can play a beneficial dual role as both an auxiliary absorber and an interfacial energy-modulating layer in Sb 2 Se 3 -based thin-film solar cells.