Sequential Coevaporation and Deposition of Antimony Selenosulfide Thin Film for Efficient Solar Cells

Abstract Antimony selenosulfide (Sb 2 (S,Se) 3 ) is an emerging low‐cost, nontoxic solar material with suitable bandgap and high absorption coefficient. Developing effective methods for fabricating high‐quality films would benefit the device efficiency improvement and deepen the fundamental understanding on the optoelectronic properties. Herein, equipment is developed that allows online introduction of precursor vapor during the reaction process, enabling sequential coevaporation of Sb 2 Se 3 and S powders for the deposition of Sb 2 (S,Se) 3 thin films. With this unique ability, it is revealed that the deposition sequence manipulates both the interfacial properties and optoelectronic properties of the absorber film. A power conversion efficiency of 8.0% is achieved, which is the largest value in vapor‐deposition‐derived Sb 2 (S,Se) 3 solar cells. The research demonstrates that multi‐source sequential coevaporation is an efficient technique to fabricate high‐efficiency Sb 2 (S,Se) 3 solar cells.