High efficiency Sb₂(S, Se)₃ thin-film solar cells by substrate-temperature-controlled vapor transport deposition method

Antimony chalcogenide (Sb₂(S, Se)₃) semiconductor has recently emerged as a popular photovoltaic material for thin-film solar cells because of its high light absorption coefficient and tunable absorption band gap. The vapour transport deposition (VTD) approach has shown promise in fabricating Sb₂(S, Se)₃ solar cells. However, conventional VTD depends on varying substrate positions for managing the temperature differential between source and substrate. This phenomenon leads to unstable film flaws that trigger a decline in open-circuit voltage (V_OC) and the development of profound-level defects. Therefore, a novel method for fabricating Sb₂(S, Se)₃ solar cells based on a double-temperature evaporation furnace named substrate temperature–controlled vapour transport deposition method (STC-VTD) is presented in this study. The initial application of the modified VTD method yielded a solar cell with a power conversion efficiency (PCE) of 7.56 %, which is the highest PCE obtained through single evaporation VTD. Deep-level transient spectroscopy measurements reveal that the defect levels generated in the solar cells are passivated via the STC-VTD method. This work proposes substrate temperature–independent control for other physical vapour preparation methods, paving a new direction for further applications of vapour transport technology.