▎ 摘　　要

In this study, graphene nanosheets (GNs) were added into liquid electrolytes to increase their electric conductivity through the exceptional electron mobility of graphene to improve the efficiency of dye sensitized solar cells (DSSCs). The nanostructure of the GNs was analyzed through scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The properties of various electrolytes were examined through conductivity analysis, Raman spectroscopy, Fourier transform infrared spectroscopy, cyclic voltammetry, and the electrochemical impedance spectroscopy of simple symmetric devices. The results indicated that adding graphene to the liquid electrolyte improved the conductivity and electrochemical properties of the electrolyte. Furthermore, DSSCs with various electrolytes were characterized using current density-voltage, incident photon-to-current conversion efficiency, and electrochemical impedance spectroscopy measurements. The results revealed that adding graphene to the electrolyte solutions effectively promoted the efficiency of the DSSC devices; this was because the exceptional electron mobility in the GNs substantially reduced the impedance in the electrolyte solutions. In particular, the DSSC device with the 20-mg graphene electrolyte solution attained the highest efficiency (9.26%), which was 20% higher than that of the device with the non-graphene electrolyte solution. (C) 2017 Elsevier B.V. All rights reserved.