Design and function of graphene LEDs and LECs. (a) Device schematics for inorganic LEDs incorporating graphene as a growth substrate and cathode on the left, and as an anode on the right. With graphene forming the surface in contact with the substrate, it becomes easy to move the entire device to a new substrate. Adapted from [146, 147]. (b) Power-dependent electroluminescence of each device, showing strong blue emission spectra over a range of input currents. The left-hand device has been transferred to a plastic substrate. (c) Schematic of an LEC. Adapted from [148], graphic provided by http://www.planet11.com. Blending of the emissive material with an electrolyte solution allows the rearrangement of charge at the electrode interface, facilitating balanced electron-hole injection. As both electrodes are transparent, light is emitted through both surfaces.
