Dual-functional Cu-MOF modifies buried interfaces for high-performance and stable MAPbI3 photodetectors

Lead halide perovskites have emerged as promising materials for high-performance optoelectronic devices due to their exceptional optoelectronic properties. Nevertheless, defect states of perovskite thin films severely degrade the device performance and stability. Herein, we report a buried interface engineering strategy based on Cu-based metal-organic frameworks (Cu-MOF) to fabricate high-quality MAPbI3 thin films. The results reveal that the carbonyl groups (C=O) in Cu-MOF effectively passivate undercoordinated Pb2+ at the buried interface through strong coordination interactions, while simultaneously modulating crystallization dynamics to yield enlarged grain sizes and reduced grain boundaries. Furthermore, Cu2+ ions released from the MOFs occupy Pb2+ vacancies in MAPbI3. According to this, the crystalline quality of MAPbI3 thin films has been improved. The enhancement in device performance further demonstrated the crucial roles of Cu-MOF. This work provides a multifunctional interface modification approach for improving the performance of optoelectronic devices.