A catalytic composite film of MoS2/graphene flake as a counter electrode for Pt-free dye-sensitized solar cells

In this study, a composite film of molybdenum sulfide (MoS2)/graphene flake was characterized as the counter electrode (CE) for Pt-free dye-sensitized solar cells (DSSCs). It was found that the enhanced electrocatalytic activity can be demonstrated when high-conductive graphene flake was introduced into MoS2 film. The cyclic voltammograms showed that the cathodic current density of MoS2/graphene CE was higher than those of MoS2, graphene and Pt CEs due to its lamellar structure. Additionally, MoS2/graphene CE exhibited a low charge-transfer resistance of 2.17 Omega cm(2). After the optimization in the thickness of MoS2/graphene CE, the power conversion efficiency of the DSSC assembled with the optimized MoS2/graphene reached 5.98% under AM1.5 illumination of 100 mW cm(-2), which is comparable to that based on the Pt CE. (C) 2012 Elsevier Ltd. All rights reserved.