Enhanced performance of organic light-emitting diodes by using hybrid anodes composed of graphene and conducting polymer

Graphene films are one of the most favorable candidates for next generation transparent conductive electrodes (TCEs) for electrical devices, because of its unique electronic structure. Furthermore, an optical transparency of graphene films surpasses a transparency of conventional TCE such as indium tin oxide (ITO). However, actual graphene anode for OLEDs and OPVs has several problems owing to its low work function and high sheet resistance. Here, we have demonstrated enhanced performance of OLEDs by using hybrid anodes composed of graphene and conducting polymer (poly(3,4-ethylenedioxythiophene) with poly(styrenesulfonic) (PEDOT:PSS)), which can overcome low work function and high sheet resistance. PEDOT:PSS plays a role in improving the conductivity and forming a work function stairs for smooth hole injection property. As a result, we achieved enhanced OLED efficiencies using graphene-conducting polymer hybrid anode. These results are superior to that in efficiencies of graphene anode devices. Our experimental results indicate that graphene and conducting polymer would be next generation and alternative TCEs for OLED and OPV.