Crystal Growth Promotion and Defect Passivation by Hydrothermal and Selenized Deposition for Substrate-Structured Antimony Selenosulfide Solar Cells

Antimony sulfide-selenide (Sb-2(S,Se)(3)) is a promising light-harvesting material for stable and high-efficiency thin-film photovoltaics (PV) because of its excellent light-harvesting capability, abundant elemental storage, and excellent stability. This study aimed to expand the application of Sb-2(S,Se)(3) solar cells with a substrate structure as a flexible or tandem device. The use of a hydrothermal method accompanied by a postselenization process for the deposition of Sb-2(S,Se)(3) film based on the solar cell substrate structure was first demonstrated. The mechanism of postselenization treatment on crystal growth promotion of the Sb-2(S,Se)(3) film and the defect passivation of the Sb-2(S,Se)(3) solar cell were revealed through different characterization methods. The crystallinity and the carrier transport property of the Sb-2(S,Se)(3) film improved, and both the interface defect density of the Sb-2(S,Se)(3)/CdS interface and the bulk defect density of the Sb-2(S,Se)(3) absorber decreased. Through these above-mentioned processes, the transport and collection of electronics can be improved, and the defect recombination loss can be reduced. By using postselenization treatment to optimize the absorber layer, Sb-2(S,Se)(3) solar cells with the configuration SLG/Mo/Sb-2(S,Se)(3/)CdS/ ITO/Ag achieved an efficiency of 4.05%. This work can provide valuable information for the further development and improvement of Sb-2(S,Se)(3) solar cells.