Enhancing the efficiency of Sb2S3 solar cells using dual-functional potassium doping

Antimony sulphide (Sb2S3) thin films have attracted considerable research interest as a photovoltaic absorber material owing to their suitable band gap, large absorption coefficient, and excellent photoelectronic properties. In this study, cadmium sulphide (CdS) films were doped with potassium, which increased their crystallinity and optical transmission. These films were then used as a buffer layer to increase the efficiency of Sb2S3 solar cells. Furthermore, the potassium diffused into the Sb2S3 film, which increased their crystallinity and light absorption and decreased its surface roughness. Dual-functional potassium doping helped improve all of the photoelectric parameters of the Sb2S3 solar cells. Specifically, the device efficiency increased from 4.57% to 6.53% (an increase of 42.89%), and a high current density of 15.29 mA cm−2 was achieved. These findings are expected to facilitate the further development of Sb2S3 thin-film solar cells for industrial applications.