Efficient Sb2(S,Se)3 solar cells via monitorable chemical bath deposition

Abstract

The efficiency of Sb₂(S,Se)₃ solar cells prepared via hydrothermal methods recently broke the bottleneck of 10%. However, limited by the black-box hydrothermal process, important experimental details, such as the real-time chemical reaction process, precursor temperature and pH in the hydrothermal reactor, have not been acquired accurately until now. Moreover, the hydrothermal method is unfavorable for fabricating large-area devices. Herein, we develop a simple and monitorable chemical bath deposition (CBD) method to fabricate an Sb₂(S,Se)₃ absorber layer. Owing to the open space of CBD, the physical and chemical processes during the whole film deposition could be studied based on the real-time precursor color, pH and temperature. The comprehensive understanding of CBD further guided the optimization of Se/S composition and film thickness. Finally, a champion efficiency of 8.27% with an open-circuit voltage of 0.625 V, a short-circuit current density of 22.98 mA cm⁻² and a fill factor of 57.6% were achieved, representing the highest efficiency among all CBD-based antimony chalcogenide solar cells.