Efficiency enhancement of Sb2Se3 solar cells based on electron beam evaporation CdS film with variable deposition temperature

Abstract In our previous work, the detailed crystal structure, optical and electrical properties of evaporated CdS (hexagonal CdS) and chemical bath deposition CdS (cubic CdS) were discussed. The hexagonal CdS film is more suitable as the buffer layer for Sb2Se3 film solar cells compared with its cubic counterpart. However, in our experiments, the influence of high annealing temperature on hexagonal CdS is difficult to control. Moreover, hexagonal CdS is unsuitable for large-area industrial production of Sb2Se3 solar cells. In this study, an electron beam evaporation-prepared CdS buffer layer (hexagonal CdS) with high quality, uniformity and low-temperature treatment was introduced in Sb2Se3 thin film solar cells. The influence of different substrate temperatures during electron beam evaporation on the crystal structure, surface morphologies, and optical properties of CdS and Sb2Se3 films was investigated. The device performance improvement from 3.52% to 5.89% was obtained after the surface roughness of the CdS film and the heterojunction interface were optimised. Lastly, the efficiency of the Sb2Se3 solar cells was obtained to be 6.71% based on the structure of FTO/EB-CdS/Sb2Se3/MoO3/Au.