Interfacial Engineering by Self‐Assembled Monolayer for High‐Performance Sb₂S₃ Solar Cells

Antimony chalcogenides films and devices have drawn much attention in recent years because of their notable advantages. Unfortunately, the performance of Sb‐based solar cells is still underdeveloped compared to the theoretical value, which is closely related to charge carrier separation and transfer, highlighting the importance of enhancing the interface quality. In this work, an interfacial engineering by utilizing a self‐assembled monolayer (SAM) of MeO‐2PACz as an interface layer between the Sb 2 S 3 and Spiro‐OMeTAD is developed to assist hole transport. The strong interface interaction between Sb 2 S 3 and MeO‐2PACz is systematically investigated by Raman, X‐ray photoelectron spectroscopy (XPS) measurements, and Density functional theory (DFT) calculations. Through such interfacial engineering, a more uniform surface potential, bigger built‐in potential, better energy‐level match as well as outstanding photoelectric properties are achieved. Finally, the champion power conversion efficiency (PCE = 8.06%) of Sb 2 S 3 solar cells with SAMs is inspiringly enhanced by >13%. It is expected that this effort will bring fresh insights and strategies for improving the performance of Sb‐based solar devices.