Solution-processable functionalized graphene (SPFGraphene) and functionalized multiwalled carbon nanotubes(f-MWCNTs) are introduced for heterojunction solar cell. The performance of the device has improved by the incorporation of both SPFGraphene and f-MWCNTs. The open-circuit voltage (V(oc)), short-circuit current density (J(sc)), fill factor (FF) and power conversion efficiency (eta) were 0.67 V, 4.7 mA/cm(2), 32%, and 1.05%, respectively. Here, we expect that SPFGraphene acts as exciton dissociation and provide percolation paths for electron transfer, whereas f-MWCNTs provide efficient hole transportation. SPFGraphene and f-MWCNTs incorporation yields better carrier mobility, easy exciton splitting, and suppression of charge recombination, thereby improving photovoltaic action. (C) 2010 Elsevier B.V. All rights reserved.