Enhancing Interfacial Carrier Transport via Chelation Strategy‐Induced 3D/2D Interface Reconstruction in Perovskite

During the crystallization of perovskite, a large number of internal and interfacial defects are generated, posing significant challenges to the performance of perovskite solar cells. A novel chelating strategy using 1,1 ′ ‐carbonyldiimidazole (CDI) is proposed to reduce interfacial nonradiative recombination and provide defect passivation through synergistic passivation with PEABr. The bidentate imidazole group in CDI binds to the uncoordinated Pb 2+ at the upper interface, while the C–N, C=N, and C=O functional groups act as chelators to interact with uncoordinated I − , mitigating the negative impact of PEABr on the interfacial morphology during the formation of the 2D interface. This effectively bridges the perovskite and PCBM interfaces, improves interfacial contact, and promotes charge transfer. As a result, the CDI‐modified device achieves a power conversion efficiency improvement of 24.41%, with a V OC of 1.180 V, J SC of 25.21 mA cm −2 , and fill factor of 82.07%. Additionally, the unencapsulated device exhibits enhanced long‐term stability, maintaining 95% and 90% of its initial efficiency after 1000 h at 25°C in a nitrogen atmosphere and 600 h under humid air conditions, respectively.