Improvements of Organic Light‐Emitting Diodes Using Graphene as an Emerging and Efficient Transparent Conducting Electrode Material

Organic light emitting diodes (OLEDs) have received wide attention and progress in impacting the electronics market. The progress of OLEDs in the market over their inorganic counterpart is principally due to their cost savings, flexibility, and excellent performance. As a result of the rising demands for next-generation electronic devices with increased efficiency, high flexibility, reduced cost, and stretchability, there is a need for improvements of OLEDs. In order to fulfill these requirements, it is necessity to replace the transparent conductive electrode (TCE) with a better alternative. The conventionally used TCE, indium tin oxide (ITO), suffers from the scarcity of indium, increased cost, instability, and brittleness. Graphene is recognized as a suitable alternative to ITO because of its excellent properties including high optical transmittance, outstanding electrical conductivity, stability, and great mechanical flexibility. However, the performance of graphene as the TCE material in OLEDs is limited. Several efforts have been made to improve graphene's performance through electrode modifications. This review covers a summary of fabrication techniques for graphene-based TCEs and their improvements. Finally, the application and performance of graphene-based TCEs in OLED devices and the performance of such OLEDs are discussed.