AVS 53rd International Symposium
    Nano-Manufacturing Topical Conference Tuesday Sessions
       Session NM-TuP

Paper NM-TuP4
Fabrication of Titanium Oxide Nanotubes by Anodization

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Nano-Manufacturing Poster Session
Presenter: K. Ishibashi, Tohoku University, Japan
Authors: K. Ishibashi, Tohoku University, Japan
H. Sato, Tohoku University, Japan
R. Yamaguchi, Tohoku University, Japan
Y. Kimura, Tohoku University, Japan
M. Niwano, Tohoku University, Japan
Correspondent: Click to Email
Dye-sensitized solar cells (DSSCs) have been an attractive device with their simple structure and cost effectiveness. DSSCs were generally constructed with a TiO@sub2n@ electrode, electrolyte containing iodine and a Pt counter electrode. It is important to adsorb a lot of dyes on the TiO@sub2n@ electrode for fabricating high-effective DSSCs and the TiO@sub2@ electrode with large surface area is required. Using the TiO@sub2@ electrode with porous structures is a solution to it. On the other hand, several groups have reported that diffusion coefficients of electron in mesoporous TiO@sub2n@ are much lower than those in the bulk crystal because of electron scattering due to grain boundaries between TiO@sub2@ nanoparticles, oxygen defects, and amorphous layers. Therefore, TiO@sub2@ nanotubes or nanowires are a promising class of materials to improve energy conversion efficiency of DSSCs because they have a large surface area comparable to mesoporous TiO@sub2@ and few grain boundaries. In fact, it was reported that the use of TiO@sub2@ nanowires improves the energy conversion efficiency. However, production of those TiO@sub2@ nanotubes requires high temperature and a reaction time of several dozens hours. In this study, we demonstrate that TiO@sub2@ nanotubes can be synthesized at room temperature for several minuets using an electrochemical process. We prepared a sheet of 99.5% Ti and anodized it at a potential of 40 V in a mixture of perchloric acid and ethanol using Pt as a counter electrode. The length and the diameter of the TiO@sub2@ nanotubes we obtained were more than 10 µmm and about 70 nm, respectively.