(a) Characteristic curves of luminance–current density versus drain voltage of GOLED; (b) characteristic curves of current efficiency and power efficiency of GOLED; (c) transfer characteristic curves of current and luminescence intensity of graphene OLED; (d) output characteristic curves of current and luminescence intensity versus drain voltage of graphene OLED; (e) structure and schematic diagram of GVOLEFET; (f) device energy level diagram of graphene OLED; (g) comparison among illuminating images in the same area of graphene OLED.