Tuning of a graphene-electrode work function to enhance the efficiency of organic bulk heterojunction photovoltaic cells with an inverted structure

We demonstrate the fabrication of inverted-structure organic solar cells (OSCs) with graphene cathodes. The graphene film used in this work was work-function-engineered with an interfacial dipole layer to reduce the work function of graphene, which resulted in an increase in the built-in potential and enhancement of the charge extraction, thereby enhancing the overall device performance. Our demonstration of inverted-structure OSCs with work-function-engineering of graphene electrodes will foster the fabrication of more advanced structure OSCs with higher efficiency. (C) 2010 American Institute of Physics. [doi:10.1063/1.3514551]