Ultraviolet-O2 treatment TiO2/Ti anodes for use in Ti grids-based large-area flexible dye-sensitized solar cells

Large-area flexible dye-sensitized solar cells (DSSCs) based on nanocrystalline TiO2/Ti anodes on the Ti foils and platinum/single-wall carbon nanotube (Pt/SWCNT) counter electrodes on the indium-doped tin oxide coated polyethylene naphthalate (ITO/PEN) substrates, were successfully assembled with Ti grids. The resistance of the DSSC could be observably reduced with the Ti grid, which could enhance the fill factor and the efficiency of the DSSC. Ultraviolet-O2 treatment of the TiO2/Ti anode could improve the efficiency of the DSSC, owing to that the passivated Ti foil was enhanced by the ultraviolet-O2 treatment. Based on the optimal preparation conditions, a large-area (40 cm2) flexible DSSC with efficiency of 5.29% was achieved under natural light intensity of 55 mW cm−2 measured outdoors.