Improved Performance of Thermally Evaporated Sb₂Se₃ Thin-Film Solar Cells via Substrate-Cooling-Speed Control and Hydrogen-Sulfide Treatment

Antimony selenide is a promising abundant absorber material for solar cells. However, current Sb₂Se₃ photovoltaic devices, which are fabricated via thermal evaporation, tend to have stoichiometric problems and show suboptimal performance. In this paper, we use a modified thermal evaporator to fabricate high-quality Sb₂Se₃ films. By dedicatedly cooling the substrate, we can improve both the Sb₂Se₃ morphology and the Sb₂Se₃/CdS heterojunction interface substantially. We find a suitable annealing atmosphere, H₂S, which can largely compensate for possible deficiencies of Se and remove the antimony-oxide layer on the film surface. Thanks to cooling control and H₂S treatment, we obtain a significantly improved efficiency (6.24%) for the Sb₂Se₃ solar cells. Our results indicate that this thermal evaporation technique is a promising approach to improve the large-scale fabrication of antimony chalcogenide solar cells.