Growth of nanocrystalline TiO2 films by pulsed-laser-induced liquid-deposition method and preliminary applications for dye-sensitized solar cells

A novel technique, the pulsed-laser-induced liquid-deposition (PLLD) method, has been employed to grow nanocrystalline TiO 2 films on fluorine-doped tin-oxide-coated (FTO) glass substrates at room temperature. The PLLD method was implemented by directing a pulsed laser into a liquid precursor and depositing the photosynthesized nanocrystalline TiO 2 on an FTO glass substrate immersed in the liquid precursor. The as-grown nanocrystalline TiO 2 films were found to have a rutile crystal structure and consist of a number of flower-like TiO 2 crystal units arrayed together on the FTO glass substrate. Each of the flower-like TiO 2 crystal units was composed of many nanostructured TiO 2 whiskers, and their building blocks were found to be bundles of TiO 2 nanorods with diameter of about 5 nm. The growth of these TiO 2 nanorods is highly anisotropic, with the preferential growth direction along [001]. As-grown nanocrystalline TiO 2 films were annealed at 450°C in air for 30 min for the applications of dye-sensitized solar cells, and the nanostructured characteristics with good porosity were preserved after annealing. A preliminary dye-sensitized solar cell was built based on the annealed nanocrystalline TiO 2 film. The results suggest that the PLLD method is a promising technique for growing nanocrystalline TiO 2 films for photovoltaic applications.