Navigating the ZnO/metal phthalocyanine interface in OLEDs: Challenges, perspectives, and engineering strategies

Abstract

The interface between inorganic charge injection/transport layers and organic functional layers is the superior interface to the performance and stability of organic light-emitting diodes (OLEDs), since this hybrid structure is the most strategic area when OLEDs operate. Zinc oxide (ZnO) as an efficient electron injection/transport layer and metal phthalocyanines (MPcs) as hole injection/transport and emission layers are individually well-established materials in OLED architectures; however, the direct integration and optimization of their interface suffer from a lack of consideration. This perspective leads to the potential challenges and opportunities associated with the ZnO/MPc interface in OLEDs. This perspective analyzes potential issues such as work function (WF), interface morphology, chemical stability, exciton quenching, and charge trapping by seeking the related material systems and considering the electronic/structural properties of ZnO and MPcs. Additionally, we present a comprehensive view on the promising strategies for interface engineering for ZnO-based interfaces to enhance device performance, aiming to outline the potential device architectures leveraging the unique properties of the ZnO/MPc interface. Finally, we propose key future research directions to show some hidden potential of this material combination for OLED fabrication.