Graphene oxide has been synthesized by oxidation of graphite flakes and has been deposited on transparent conductive electrodes by casting of its aqueous suspension. Then it was annealed at different temperatures to produce thermally reduced graphene oxide and thus to be employed as counter electrode in quasi-solid-state dye-sensitized solar cells. A variety of techniques has been employed, namely, XPS, TGA, XRD, Raman, FE-SEM and electrochemical analysis to characterize the different phases of graphene oxide reduction, to determine the temperature of completion of thermal reduction and to optimize graphene oxide film thickness. Employment of thermally reduced graphene oxide as electrocatalyst on counter electrodes gave satisfactory current and voltage but very poor fill factor. Then the conductive polymer PEDOT has been deposited on the graphene oxide film by simple and rapid one-step potentiostatic electrodeposition. The mixed PEDOT/reduced-graphene-oxide film demonstrated a behavior comparable with Pt nanoparticulate electrocatalyst. (C) 2013 Elsevier Ltd. All rights reserved.