Solution-processable reduced graphene oxide as a novel alternative to PEDOT:PSS hole transport layers for highly efficient and stable Polymer solar cells

The potential of a flexible, roll-to-roll manufacturing process has made bulk-heterojunction (BHJ) organic solar cells (OSCs) very attractive as a promising solution to energy and environmental issues. ^[1-8] In polymer solar cells, device characteristics such as fill factor (FF), short-circuit current density (J _sc ) and open-circuit voltage (V _oc ) as well as the cell life-time all are highly dependent on the interface properties between the electrodes and the active layers and on the bulk properties of the materials. ^[9] For these reasons, numerous modifications of electrodes by introduction of an interfacial layer have been studied intensively for high-performance and stable OSCs, ^[10-15] and several key factors such as transparency, conductivity, passivation property, film morphology, stability, and solution-processability have been considered for uses of these promising interfacial layers. ^[9-15].