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 Ω cm2. 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.

► MoS2/graphene flake composite was characterized as CE in Pt-free DSSCs.
► The MoS2/graphene flake CE showed the low Rct of 2.17 Ω cm2.
► The efficiency of the Pt-free DSSC reached 5.98% based on the MoS2/graphene flake CE.