Performance improvement of Sb2Se3 thin-film solar cells through ultraviolet ozone treatment

Antimony selenide (Sb2Se3) is a promising photovoltaic thin-film absorber material that has been widely studied in recent years. In Sb2Se3 thin-film solar cells, cadmium sulfide (CdS) is generally used for the fabrication of electron collection layers because of its high electron affinity, electronic mobility, and environmental stability. This study demonstrates the effects of ultraviolet ozone (UVO) treatment of chemical-bath-deposited CdS thin films on film crystallinity, surface morphology, and photoelectric properties. We find that UVO treatment not only enhances the crystallinity, transmittance, and conductivity of the CdS film, but it also decreases residual organic impurities on the CdS surface significantly, substantially improving the overall device performance. The efficiency of the superstrate CdS/Sb2Se3 heterojunction solar cell reaches to 4.66%. This UVO treatment is a facile, low-cost, and fast process, which can be performed at room temperature. Our study demonstrates a good method for optimizing the performance of CdS/Sb2Se3 solar cells and is expected to find wide applications in the future.