Platinum nanoparticles/graphene composite catalyst as a novel composite counter electrode for high performance dye-sensitized solar cells

We herein describe our use of a water-ethylene method to prepare a composite material consisting of platinum nanoparticles and graphene. Results obtained using XPS and XRD show that the degree of reduction of graphene was increased by the incorporation of Pt, and in addition, the increased concentration of defects was confirmed by the D/G ratio of the Raman spectra obtained. In comparison with Pt films, results obtained using CV and EIS showed that the electrocatalytic ability of the composite material was greater, and afforded a higher charge transfer rate, an improved exchange current density, and a decreased internal resistance. SEM images showed that the morphology of PtNP/GR counter electrodes is characterized by a smooth surface, however, resulting in a lower resistance to diffusion, thereby improving the total redox reaction rate that occurs at the counter electrode. PtNP/GR electrodes have a number of advantages over other electrodes that consist solely of graphene or Pt films, including a high rate of charge transfer, a low internal resistance, and a low resistance to diffusion. In our study, we showed that DSSCs that incorporate platinum-grafted graphene had a conversion efficiency of 6.35%, which is 20% higher than that of devices with platinized FTO.