▎ 摘　　要

A dispersion of platinum-on-graphene was prepared essentially by a two-step process, involving uniform distribution of graphene nanoplatelets in a cosolvent of ethanol-water in the presence of a polymeric dispersant and subsequent in situ reduction of dihydrogen hexachloroplatinate to metallic platinum on the graphene surface. The process generated platinum nanoparticles (PtNPs) of ca. 4.0-10 nm in diameter on the graphene surface. The platinum-on-graphene dispersion was coated on an FTO glass to prepare a counter electrode (CE) for a dye-sensitized solar cell (DSSC). The hybrid film of platinum nanoparticles and graphene nanoplatelets (PtNP/GN) showed a transparency of 70% at 550 nm, indicating its suitability as a CE material for a rear-illuminated DSSC. The DSSC with the CE having the film of PtNP/GN exhibited a power conversion efficiency (eta) of 8.00%, superior to 7.14% of the DSSC with a conventional sputtered platinum (s-Pt) CE. In the case of rear-illumination the DSSC showed an h of 7.01%, while the DSSC with the conventional s-Pt showed an eta of only 2.36%. HRTEM and FE-SEM were used to observe the dispersion of the hybrid material in the solvent, UV-vis spectroscopy and cyclic voltammetry were used to characterize the films, and IPCE spectra and electrochemical impedance spectra were used to explain the photovoltaic parameters of the DSSCs.