Fluorine doped tin oxide (FTO) substrates were modified with acicular crystal assembled TiO2 thin films. The thin films increased transparency and decreased reflectance of the substrates. The films had high transparency over 80% in the range from 400 to 850 rim. They were about 8% higher than those of bare FTO substrates. The films had low reflectance of about 11% in the range from 350 to 850 nm. They were about 3% lower than those of bare FTO areas. Nano-sized surface relief structures of the films functioned as antireflection coatings. Additionally, dye adsorption properties of the substrates were improved by formation of the thin films. It was 70 times higher than that of bare FTO substrates and reached 12 times of TiO2 particulate films prepared by TiO2 nanoparticles (P25, Degussa). High transparency and high dye adsorption properties were important factors for sensors and dye-sensitized solar cells. The acicular crystal assembled TiO2 thin films are thus candidate materials for these applications. (C) 2008 Elsevier B.V. All rights reserved.