Coral-shaped ZnO nanostructures for dye-sensitized solar cell photoanodes

A highly efficient ZnO photoanode for dye-sensitized solar cells was successfully grown by a simple, low cost, and scalable method. A nanostructured coral-shaped Zn layer was deposited by sputtering onto fluorine-doped tin oxide/glass slices at room temperature and then thermally oxidized in ambient atmosphere. Stoichiometry, crystalline phase, quality, and morphology of the film were investigated, evidencing the formation of a highly porous branched nanostructure, with a pure wurtzite crystalline structure. ZnO-based dye-sensitized solar cells were fabricated with customized microfluidic architecture. Dye loading on the oxide surface was analyzed with ultraviolet-visible spectroscopy, and the dependence of the cell efficiency on sensitizer incubation time and film thickness was studied by current-voltage electrical characterization, incident photon-to-electron conversion efficiency, and impedance spectroscopy measurements, showing the promising properties of this material for the fabrication of dye-sensitized solar cell photoanodes with a solar conversion efficiency up to 4.58%. Copyright (c) 2012 John Wiley & Sons, Ltd.