High-performance polymer light emitting diodes with interface-engineered graphene anodes

Recently, graphene-based organic light emitting diodes (OLEDs) were successfully demonstrated using graphene as anodes. However, the graphene electrodes have not been utilized for polymer light emitting diodes (PLEDs) yet, although the simpler device structure and the solution-based fabrication process of PLEDs are expected to be more advantageous in terms of time and cost. Here we demonstrate high-performance polymer light emitting diodes (PLEDs) with simple two-layer structures using interface-engineered single-layer graphene films as anodes. The single-layer graphene synthesized by chemical vapor deposition methods was transferred onto a glass substrate utilizing an elastic stamp, and its work function was engineered by varying the duration and the power of ultraviolet ozone (UVO) treatment. Thus, we were able to optimize the contact between silver electrodes and the graphene anodes, leading to the considerable enhancement of light-emitting performance.