Post-treatment has been regarded as an important strategy in thin-film fabrication, which surmounts the limitations in directly deposited films through manipulating the chemical, electrical, morphological, and defect properties. In terms of the emerging photovoltaic material antimony selenosulfide (Sb2(S,Se)3), conventional hydrothermal synthesis of Sb2(S,Se)3 thin film has achieved great improvement toward 10% efficiency bottleneck in solar cell applications. However, this fabrication method fails to achieve desirable carrier transport and defective properties. In this study, we develop an InCl3-based post-treatment method to enhance the carrier transport and passivate the deep-level defects, including S and Se vacancies and anti-site defects (SbS(e)3). We find that the indium ions generated by post-treatment preferentially diffuse into the interstitial sites of (Sb4S(e)6)n ribbons, leading to the formation of In-S(e) chemical bonds. These atomic interactions facilitate efficient carrier transport across the entire film. Furthermore, the synergistic effects of energy level alignment optimization, deep-level defect passivation, and interfacial trap inhibition effectively suppress non-radiative carrier recombination and improve photovoltaic performance. Consequently, this post-treatment enables the Sb2(S,Se)3 solar cell to achieve a remarkable power conversion efficiency of 10.55%. This study provides a novel post-treatment method for defect passivation, electronic structure regulation, and carrier transport management for high-performance antimony selenosulfide solar cells.
Mei et al. (Sun,) studied this question.