A novel sulfur source for biosynthesis of (Ag, S)-modified TiO2 photoanodes in DSSC

The (Ag, S)-modified TiO2 photoanodes were prepared using novel garlic (Allium sativum) as a sulfur source. X-ray photoelectron spectroscopy (XPS) confirmed more sulfur adsorption and the modification of TiO2 by interactions between Ag and S. UV-vis spectral analysis and Electrochemical Impedance Spectroscopy (EIS) measurements showed that (Ag, S)-modified TiO2 photoanodes exhibited a strongly enhanced absorption in the UV-vis region and a clear reduction in charge transport resistance, indicating a higher light-harvesting capacity and more efficient charge transport. Therefore, the photoelectric conversion efficiency of dye-sensitized solar cells (DSSCs) was improved. At the optimal Ag loading of 0.5 wt%, (Ag, S)-modified DSSC gave the best performance. (C) 2014 Elsevier B.V. All rights reserved.