Two-Dimensional Graphene and MXene for Flexible and Stretchable Displays

Two-dimensional materials, such as graphene and MXenes, offer promising alternatives to brittle indium tin oxide (ITO) for flexible and wearable displays. However, their practical application has been impeded by the high electron and hole injection barriers at the electrode/organic interfaces. To overcome this challenge, post-fabrication treatments were employed to modify the work function of 2D electrodes. Electron-withdrawing or electron-donating polymeric overcoating allowed for precise control of charge transfer doping, resulting in improved electroluminescent efficiency with reduced injection barriers. These surface modifications not only enhanced the environmental stability of the 2D electrodes in ambient air but also maintained their electrical properties. Furthermore, to address charge injection issues at stretchable electrode interfaces, a graphene layer can be introduced atop a silver nanowire percolation network, forming a two-dimensional stretchable contact electrode. This approach achieves remarkable current efficiencies among all intrinsically stretchable light-emitting diodes. These advancements in 2D materials establish a solid foundation for the practical implementation of 2D conductive materials in flexible and stretchable displays.