Graphene coated alumina-modified polypyrrole composite films as an efficient Pt-free counter electrode for dye-sensitized solar cells

Polypyrrole (PPy) with graphene coated Al2O3 (GCA) composite films with different levels of graphene were fabricated via a two-step process. GCA was first prepared. A dispersed solution of monomeric pyrrole and GCA was deposited on a fluorine doped tin oxide film by one-step electrodeposition and used as an electrocatalyst on the counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). The DSSCs fabricated from these CEs were characterized by the current density-voltage, incident photon-to-current conversionss efficiency, cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel measurements. The DSSCs containing the 3 wt.% PPy/GCA (PPy/GCA) CE exhibited an efficiency of 7.33%, whereas the DSSCs with a CE having Pt as the catalytic material showed an efficiency of 7.57%. The results show that the PPy/GCA composite film is a potential catalyst for replacing the expensive, conventional Pt in DSSCs. (C) 2016 Elsevier Ltd. All rights reserved.