High-Efficiency Sb2Se3 Solar Cells Modified by Potassium Hydroxide

Antimony selenide (Sb2Se3) has attracted considerable attention for its simple composition, nontoxic nature, and abundance. However, the efficiency of Sb2Se3 solar cells is limited by the low carrier concentration and high recombination rate at the interface between Sb2Se3 and the Au layer. For this paper, the KOH solution used as the etchant was used to increase the efficiency of Sb2Se3 solar cells. The KOH solution not only reacts with (etching the surface) but also diffuses inside the Sb2Se3 film. This study unexpectedly demonstrates that KOH also increases the doping density and improves the back contact (the thin Sb2O3 layer exists with the etching of the KOH solution) of Sb2Se3 solar cells. Lastly, the best power conversion efficiency of 7.16% is demonstrated with a high open-circuit voltage of 0.407 V; we believe our work can serve as a guide for further development of high-efficiency Sb2Se3 solar cells.