Effect of TiO(2) nanotubes with TiCl(4) treatment on the photoelectrode of dye-sensitized solar cells

In this study, we used the electrochemical anodization to prepare TiO(2) nanotube arrays and applied them on the photoelectrode of dye-sensitized solar cells. In the field emission scanning electron microscopy analysis, the lengths of TiO(2) nanotube arrays prepared by electrochemical anodization can be obtained with approximately 10 to 30 μm. After titanium tetrachloride (TiCl(4)) treatment, the walls of TiO(2) nanotubes were coated with TiO(2) nanoparticles. XRD patterns showed that the oxygen-annealed TiO(2) nanotubes have a better anatase phase. The conversion efficiency with different lengths of TiO(2) nanotube photoelectrodes is 3.21%, 4.35%, and 4.34% with 10, 20, and 30 μm, respectively. After TiCl(4) treatment, the efficiency of TiO(2) nanotube photoelectrode for dye-sensitized solar cell can be improved up to 6.58%. In the analysis of electrochemical impedance spectroscopy, the value of R(k) (charge transfer resistance related to recombination of electrons) decreases from 26.1 to 17.4 Ω when TiO(2) nanotubes were treated with TiCl(4). These results indicate that TiO(2) nanotubes treated with TiCl(4) can increase the surface area of TiO(2) nanotubes, resulting in the increase of dye adsorption and have great help for the increase of the conversion efficiency of DSSCs.