A Multifunctional Hydrogen Bond Bridge Interface to Achieving Efficient and Stable Perovskite Solar Cells

Abstract In perovskite solar cells (PSCs), the buried interface between the electron transfer layer (ETL) and perovskite (PVK) layer profoundly affects the charge carrier transfer efficiency, which has significant implications for the efficiency and long‐term stability of the device. Herein, an organic chemical compound 4,6‐diamino‐2‐mercaptosine (DMP) is incorporated into the ETL/PVK interface in order to optimize the interfacial performance through a hydrogen bond bridging junction. DMP is tightly anchored to the ETL surface by forming the intermolecular hydrogen bonding with the structure as N─H∙∙∙N. This bridge connection is beneficial for enhancing the interface contact, further restraining severe nonradiative charge recombination. Synchronously, the interaction of ─SH with uncoordinated Pb 2+ passivates the defects on the bottom layer of perovskite, further regulating the perovskite crystal growth. Overall, the results express that the power conversion efficiency (PCE) of PSCs based on the DMP interface has significantly increased to 21.65% without obvious hysteresis. Meanwhile, the unencapsulated modified devices show superior environmental stability, maintaining over 85% of their initial PCE even after 500 h in an atmospheric environment.