Highly-ordered dye-sensitized TiO2 nanotube arrays film used for improving photoelectrochemical electrodes

Thin titanium oxide nanotube arrays (TNAs) films were synthesized by anodization of titanium foil in an aqueous dimethyl sulfoxide solution using a platinum foil counter electrode. TNAs up to 6.8 μm in length, 120 nm in inner pore diameter, and 20 nm in wall thickness were obtained by 40 V potentials anodization for 24 h. Their microstructures and surface morphologies were characterized by XRD, TEM, SAED and UV-vis spectroscopy. The photoelectrochemical properties of as-prepared unsensitized and dye-sensitized TNAs electrodes were examined under simulated solar light (AM 1.5, 100 mW/cm²) illumination. The results showed that the photocurrent of the dye-sensitized TNAs electrodes reached 6.9 mA/cm², which was 6 times more than that of the dye-sensitized TiO₂ nanoparticles (TNPs) electrodes. It implied that the electron transport process and the charge recombination suppression within TNAs electrodes were much more favorable in comparison with that in the TNPs electrodes. Electrodes applying such kind of titania nanotubes will have a potential to further enhance the efficiencies of TNAs-based dye-sensitized solar cells.