Highly conductive and dispersible graphene and its application in P3HT-based solar cells.

A simple reduction method without the need for high-temperature annealing is proposed for highly conductive and dispersible graphene sheets. This method consists of the grafting of graphene oxide (GO) with 1-pyrenecarboxylic acid (PCA) and the exothermic reduction of the PCA-grafted GO, followed by an endothermic decarboxylation with refluxing hot water. The PCA-grafted reduced graphene oxide (PCA-rGO) has a high conductivity of similar to 1.52 x 10(5) S m(-1). Upon incorporating the rGO-PCA in active and electron transport layers of organic solar cells, compared to P3HT-only devices (0.18%) a 16-fold increase in the power conversion efficiency (2.85%) is obtained, attributed to a substantial increase in the short-circuit current density from 0.017 to 12.09 mA cm(-2).