Self-Powered Ultraviolet Photodetectors Enabled by Multisite Bonding at Imidazolate Framework–Polyethylenimine Interfaces

Self-powered ultraviolet (UV) photodetectors are attractive for energy-autonomous sensing, but achieving high detectivity with metal-organic frameworks remains challenging due to poor film morphology and leakage currents. Here, we fabricate a vertical photodiode (FTO/ZIF-8@PEI/PEDOT:PSS/Au) using a ZIF-8@polyethylenimine (PEI) hybrid film engineered through multisite Zn ← N coordination and hydrogen bonding. PEI stabilizes ZIF-8 dispersions, produces dense, crack-free films, and introduces a hole-blocking barrier that reduces the dark current. The resulting device exhibits robust self-powered UV photodetection (302 nm) with a responsivity of 37.3 mA/W, detectivity of 8.24 × 10¹² Jones, and rapid rise/decay times of 0.504/0.582 s, maintaining stability after one month of operation. These results highlight the potential of MOF-polymer interfacial engineering as a practical strategy to suppress leakage and enhance the spectral selectivity in MOF-based photodetectors.