Synthesis of Mesoporous Anatase TiO2 Nanotubes by a Hydrothermal Treatment and Their Use in Solid-State Dye-Sensitized Solar Cells

Mesoporous anatase TiO2 nanotubes (NTs) with the diameter of about 7 similar to 12 nm and the length of several hundred nanometers were synthesized by a hydrothermal method on commercial TiO2 particles in NaOH followed by HCl washing. The samples were characterized by X-ray diffraction (XRD), transmitting electron microscopy (TEM), and Brunauer-Emmet-Teller (BET) measurements. The hydrothermal treatment temperature at 130 degrees C was shown to affect not only the extent of particle-to-sheet conversion, and thus the resulting structures of the NTs, but also the anatase-to-rutile transformation. The surface area of the NTs was similar to 200 M(2)g(-1). This value was much higher in comparison to TiO2 nanoparticles of similar to 50 M(2)g(-1). It was also found that the NT photoelectrodes had a pronounced impact on the performance of solar cells as compared to nanoparticle ones. This was probably due to lead to a significantly higher specific dye loading and, for certain hydrothermal treatments, resulting in a doubling of the solar cell efficiency (in our case from 2.84% to 4.03% of AM 1.5 conditions).