Hybrid electrode based on carbon nanotube and graphene for ultraviolet light-emitting diodes

We report on a transparent current-spreading electrode that combines carbon nanotubes (CNTs) and graphene for UV-LEDs. We compared the device performance and long-term stability of this CNT–graphene hybrid electrode (CGE) with those of the silver nanowire–graphene electrode (SGE) reported previously. Both types of electrode offered excellent UV transmittance and reduced sheet resistance through the bridging effect for grain boundaries and defects in graphene by nanotubes or nanowires. UV-LEDs using such electrodes offered reduced forward voltage and enhanced electroluminescence intensity, but the device with the CGE showed excellent stability whereas the SGE degraded with time.