Interfacial modification strategy by lead chloride post-treatment enables 8.05% efficient Sb₂S₃ solar cells

Antimony sulfide (Sb₂S₃) is a competitive photovoltaic material, especially for tandem solar cells. However, the quasi-intrinsic carrier concentration and deep work function of Sb₂S₃ cause serious extraction problem at Sb₂S₃/hole-transport-layer (HTL) interface. In this study, we proposed an efficient strategy to modify the Sb₂S₃/HTL interface by lead chloride (PbCl₂) post-treatment. Our results demonstrated that Cl incorporation could passivate the defect of sulfur vacancy (V_S) and antisite (Sb_S), and Pb enabled effective p-type doping at the Sb₂S₃ interface with the Cl help of V_S removal. The synergistic effect of Pb and Cl elements matched well with HTL energy level, facilitated hole extraction and enhanced the interface conductivity. By employing PbCl₂ treatment, the resulting devices obtained a high fill factor (FF) of 66.02%, and a top power conversion efficiency (PCE) of 8.05%. This work provides valuable insights into improving the Sb₂S₃ interface for enhancing solar cell performance.