▎ 摘　　要

Moderately reduced graphene oxide/polypyrrole/PEDOT composite films have been fabricated via a three-step process. Graphene oxide/polypyrrole composites were first composed by in-situ polymerization. Uniform thin films of graphene oxide/polyryrrole were then deposited on transparent conductive electrodes and annealed at 300 degrees C to produce moderately reduced graphene oxide/polypyrrole composite films. Even though, at this temperature loss of polypyrrole begins due to calcination, the presence of polypyrrole facilitates uniform film formation and prepares it for the next step of conductive polymer deposition. Finally, poly(3,4 ethylenedioxythiophene), PEDOT, was deposited on the reduced graphene oxide/polypyrrole film by one-step electrodeposition and was employed as electrocatalyst on counter electrodes in dye-sensitized solar cells. Cells employing this composite electrocatalyst demonstrated power conversion efficiency of 7.1 %, which is comparable to that of Pt-based cells made under similar conditions. These findings support the idea of Pt-free solar cells. (C) 2015 Elsevier Ltd. All rights reserved.