Synergistic Passivation on Buried Interface for Highly Efficient and Stable p–i–n Perovskite Solar Cells

Abstract The properties of an interface at the hole transport layer (HTL)/perovskite layer are crucial for the performance and stability of perovskite solar cells (PVSCs), especially the buried interface between HTL and perovskite layer. Here, a molecular named potassium 1‐trifluoroboratomethylpiperidine (3FPIP) assistant‐modified perovskite bottom interface strategy is proposed to improve the charge transfer capability and balances energy level between HTL and perovskite. BF 3 − in the 3FPIP molecule interacts with undercoordinated Pb 2+ to passivate iodine vacancies and enhance PVSCs performance. Furthermore, the infiltration of K + ions into perovskite molecules enhances the crystallinity and stability of perovskite. Therefore, the PVSCs with the buried interface treatment exhibit a champion performance of 24.6%. More importantly, the corresponding devices represent outstanding ambient stability, remaining at 92% of the initial efficiency after 1200 h. This work provides a new method of buried interface engineering with functional group synergy.