Enhanced Efficiency of Dye-Sensitized Solar Cells Benefited from Graphene Modified by Ag Nanoparticles.

In this paper, graphene modified by Ag nanoparticles was successfully applied into dye sensitized solar cells. The morphologies and compositions of graphene and graphene-Ag nanoparticles were characterized by scanning electron microscope and energy dispersive X-ray spectroscopy. The optical and electrical properties were evaluated by UV-vis-NIR absorption spectroscopy, electrochemical impedance spectroscopy and current-voltage curve. The results indicated that the incorporation of graphene or graphene-Ag nanoparticles can improve the light absorption and decrease the charge recombination. The solar cells with graphene-Ag nanoparticles exhibited short-circuit current density of 14.34 mA cm-2, open-circuit voltage of 709 mV and conversion efficiency of 6.01%, which were higher than those of DSSCs with graphene or pure TiO2.