Enhancement of Sb2Se3 thin-film solar cell photoelectric properties by addition of interlayer CeO2

Antimony selenide (Sb 2 Se 3 ) thin films are light-absorbing materials used for low-cost, highly efficient thin-film solar cells. However, because it is deposited onto a comparatively rough substrate, stacking growth of a Sb 2 Se 3 thin film negatively impacts formation of the heterojunction. For this study, Sb 2 Se 3 thin-film solar cells were fabricated in a FTO/CdS/CeO 2 /Sb 2 Se 3 /Au configuration. An ultrathin layer of cerium dioxide (CeO 2 ) was deposited onto the CdS surface by evaporation, and the thickness of the CeO 2 interlayer was optimized to improve the photoelectric properties of the solar cells. Compared to the CdS surface in conventional Sb 2 Se 3 thin-film solar cells (FTO/CdS/Sb 2 Se 3 /Au), the surface of the CdS buffer in our solar cells was smoothed by the CeO 2 layer, which induced columnar growth of the Sb 2 Se 3 grains. Furthermore, diffusion of Ce 4+ into Sb 2 Se 3 enhanced its crystallinity and improved the evenness of the Sb 2 Se 3 thin-film surface. The photo-conversion efficiency (PCE) of a solar cell with a 2-nm thick CeO 2 interlayer reached 5.14%.