Graphene nanoplatelets outperforming platinum as the electrocatalyst in co-bipyridine-mediated dye-sensitized solar cells

Abstract

Graphene nanoplatelets (GNP) in the form of thin semitransparent films on F-doped SnO 2 (FTO) exhibit high electrocatalytic activity for the Co(bpy) 33+/2+ redox couple in acetonitrile electrolyte solution. The GNP film is superior to the traditional electrocatalyst, that is, platinum, both in charge-transfer resistance (exchange current) and in electrochemical stability under prolonged potential cycling. The good electrochemical performance of GNP is readily applicable for dye-sensitized solar cells with Y123-sensitized TiO 2 photoanodes and Co(bpy) 33+/2+ as the redox shuttle. The dye-sensitized solar cell with GNP cathode is superior to that with the Pt-FTO cathode particularly in fill factor and in power conversion efficiency at higher illumination intensity. © 2011 American Chemical Society.