Pyridine-Anchored Small Molecule Interlayer Enables Defect Passivation and Enhanced Carrier Transport for Perovskite Solar Cells

Engineering of the interface between the perovskite and hole transport layer (HTL) has been crucial to achieving high performance. In this study, two interfacial materials, MN-CZ and CN-CZ, are designed by systematically regulating the group substitution site to study the relationship between spatial conformation and the passivation effect. The passivation groups of CN-CZ molecules exhibit a stronger "vector addition" effect, resulting in larger molecular dipoles and enhanced defect passivation and energy level regulation effects. Consequently, the CN-CZ-based perovskite solar cell (PSC) shows a high efficiency of 23.8%, which is much higher than that of the reference device. Meanwhile, the humidity and thermal stability of the unencapsulated device have been significantly improved.