Zeolitic Imidazole Framework as Defect Passivation Layer for Enhanced Electron Injection Efficiency in Organic Light‐Emitting Diodes

Understanding and controlling interfacial chemistry remains a critical challenge in optoelectronic materials. This study demonstrates that incorporating a zeolitic imidazolate framework‐8 (ZIF‐8) can be succesfully integrated as a coordination‐driven passivation layer in inverted organic light‐emitting diodes (iOLEDs). The ZIF‐8 layer is in situ formed on ZnO films via a solution‐based heterogeneous nucleation process to yield a ZnO:ZIF‐8 composite electron‐transporting layer (ETL). Spectroscopic and electrochemical analyses confirm that Zn‐N coordination at the interface effectively passivates oxygen vacancies, suppresses electron trapping, and reduces non‐radiative recombination. The incorporation of ZIF‐8 also modifies the surface potential of ZnO for better energy level alignment to the adjacent organic emissive layer and lowers the electron injection barrier. Devices incorporating the ZnO:ZIF‐8 ETL achieve a maximum luminance of 17800 cd m −2 with significantly enhanced operational stability under high voltages. The work establishes a MOF‐based interfacial coordination strategy to address charge transport limitations in optoelectronic devices and expands the use of MOFs in advanced optoelectronic applications.