Electrochimica Acta, Vol.247, 754-763, 2017
Preparation of Ti foil-based TiO2 film containing rutile sea urchin-like microspheres covered with anatase nanotubes self-organized layer and its application in dye-sensitized solar cells
Ti foil-based TiO2 films containing rutile sea urchin-like hierarchical microspheres covered with self-organized anatase nanotubes layer were fabricated through two-step hydrothermal processes. The first-step hydrothermal treatment of TiCl4 solution caused a thick rutile film on Ti foil, in which the sea urchin-like rutile microspheres (RMS) with mean size of 5-6 mu m are composed of nanorods with similar to 200 nm diameter and 1-2 mu m length. After the second-step hydrothermal treatment, a thin self-organized layer of anatase nanotubes (ANT) with similar to 10 nm diameter formed on those RMS to form Ti foil-based RMS/ANT composite film. The corresponding dye-sensitized solar cell using the Ti foil-based RMS/ANT film as photoanode achieved an efficiency of 5.42%, much better than that (0.73%) of the single RMS film-based one. The thin ANT layer on the RMS film can not only enhance the dye-loading, but also retard the charge recombination. All these lead to higher photocurrent and better photovoltaic conversion efficiency than the single RMS film-based solar cell. The above results present an efficient approach to improve the photovoltaic performance of the rutile-based solar cells by designing photoanode materials with hierarchical structures to counterbalance rutile's inherent shortages such as low dye-loading and poor conductivity as compared with anatase. (C) 2017 Elsevier Ltd. All rights reserved.
Keywords:Ti foil-based dye-sensitized solar cell;Rutile sea urchin-like microsphere;Anatase nanotube;Hydrothermal process;Photovoltaic conversion