Zeolitic Imidazole Framework as Defect Passivation Layer for Enhanced Electron Injection Efficiency in Organic...

Area of Science:

• Materials Science
• Optoelectronics
• Chemistry

Background:

• Interfacial chemistry is crucial for optoelectronic material performance.
• Controlling interfaces in devices like organic light-emitting diodes (OLEDs) presents significant challenges.
• Oxygen vacancies and charge trapping limit device efficiency and stability.

Purpose of the Study:

• To investigate the integration of zeolitic imidazolate framework-8 (ZIF-8) as a passivation layer in inverted OLEDs (iOLEDs).
• To explore the use of ZIF-8 for improving electron transport and energy level alignment at the ZnO interface.
• To establish a metal-organic framework (MOF)-based strategy for enhancing optoelectronic device performance.

Main Methods:

• In situ formation of a ZIF-8 layer on ZnO films via solution-based heterogeneous nucleation.
• Creation of a ZnO:ZIF-8 composite electron-transporting layer (ETL).
• Spectroscopic and electrochemical analyses to characterize interfacial properties and device performance.

Main Results:

• Zn-N coordination at the ZnO:ZIF-8 interface passivates oxygen vacancies and reduces non-radiative recombination.
• Improved energy level alignment and a lower electron injection barrier were achieved.
• Devices with ZnO:ZIF-8 ETL exhibited enhanced luminance (17800 cd m⁻²) and operational stability.

Conclusions:

• ZIF-8 incorporation effectively passivates interfaces and enhances electron transport in iOLEDs.
• MOF-based interfacial coordination is a viable strategy for addressing charge transport limitations.
• This work expands the application of MOFs in advanced optoelectronic devices.