Facile synthesis of NiS/graphene composite with high catalytic activity for high-efficiency dye-sensitized solar cells

Creation of low-cost and efficient counter electrodes (CEs) is important for developing cost-effective dye-sensitized solar cells (DSSCs). In this report, NiS/graphene (G) nanocomposites have been facilely synthesized by physically mixing NiS nanoparticles with G and used as CE in DSSC. The NiS/graphene nanocomposite integrates the high conductive ability of graphene and well electrocatalytic activity of NiS into a single CE material. By introducing graphene, the NiS nanoparticles are well dispersed on graphene sheets. The effect of graphene additive ratios on electrochemical and photovoltaic performance has been investigated. The resultant CEs follow an order of NiS-G0.6 > Pt > NiS-G0.8 > NiS-G0.4 > NiS-G0.2 > NiS > G. With an optimized weight ratio (1:0.6) of graphene to NiS (NiS-G0.6), a maximal power conversion efficiency of 8.18% was obtained, yielding 17.2% enhancement in comparison to the device with NiS CE.