Nanocrystalline TiO2 film with textural channels: Exhibiting enhanced performance in quasi-solid/solid-state dye-sensitized solar cells

Novel nanocrystalline TiO2 films with the textural channels are obtained for dye-sensitized solar cells (DSSCs). The textural channels consisting of the cracks on the surface and the nanopores with average diameter of about 41 nm are produced by packaging ZnO nanowires with diameter of 30-50 nm into TiO2 films and subsequently etching ZnO nanowires by hydrochloric acid. The performances of DSSCs based on novel TiO2 films (with the textural channels) and traditional TiO2 films (without the textural channels) are investigated, respectively. When two kinds of typical quasi-solid-state electrolytes and one kind of solid-state electrolyte are used, the energy conversion efficiencies of DSSCs from novel TiO2 films are improved by 20-30% compared to that from traditional TiO2 films. The reasons for the great improvement are investigated chiefly by UV-vis absorption spectra, field emission-scanning electron microscope (FE-SEM) and electrochemical impedance spectroscopy (EIS) technique. The results show that the introduction of the textural channels facilitates better penetration of quasi-solid/solid-state electrolytes into the nanopores of novel TiO2 films and thus results in better interfacial/electrical contact and faster interfacial reaction.