Flexible and Transparent Graphene Electrode Architecture with Selective Defect Decoration for Organic Light-Emitting Diodes

Abstract

Graphene produced by chemical vapor deposition (CVD) has attracted great interest as a transparent conducting material, due to its extraordinary characteristics such as flexibility, optical transparency, and high conductivity, especially in next-generation displays. Graphene-based novel electrodes have the potential to satisfy the important factors for high-performance flexible organic light-emitting diodes (OLEDs) in terms of sheet resistance, transmittance, work function, and surface roughness. In this study, flexible and transparent graphene electrode architecture is proposed by adopting a selective defect healing technique for CVD-grown graphene, which results in several benefits that produce high-performance devices with excellent stabilities. The proposed architecture, which has a multi-layer graphene structure treated by a layer-by-layer healing process, exhibits significant improvement in sheet resistance with high optical transparency. For improving the charge transport property and mechanical robustness, various defect sites of the CVD-grown graphene are successfully decorated with gold nanoparticles through a simple electroplating (EP) method. Further, a graphene-based OLED device that integrates the proposed electrode architecture on flexible substrates is demonstrated. Therefore, this architecture provides a new strategy to fabricate graphene electrode in OLEDs, extending graphene's immense potential as an advanced conductor toward high-performance, flexible, and transparent displays.