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Open Access Nano Express

Effect of TiO2 nanotubes with TiCl4 treatment on the photoelectrode of dye-sensitized solar cells

Teen-Hang Meen1*, Yi-Ting Jhuo1, Shi-Mian Chao2, Nung-Yi Lin3, Liang-Wen Ji3, Jenn-Kai Tsai1, Tien-Chuan Wu1, Wen-Ray Chen1, Walter Water1 and Chien-Jung Huang4

Author Affiliations

1 Department of Electronic Engineering, National Formosa University, Yunlin, 632, Taiwan

2 Department of Electrical Engineering, Hsiuping University of Science and Technology, Taichung, 412, Taiwan

3 Institute of Electro-Optical and Materials Science, National Formosa University, Yunlin, 632, Taiwan

4 Department of Applied Physics, National University of Kaohsiung, Kaohsiung, 811, Taiwan

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Nanoscale Research Letters 2012, 7:579  doi:10.1186/1556-276X-7-579

Published: 23 October 2012

Abstract

In this study, we used the electrochemical anodization to prepare TiO2 nanotube arrays and applied them on the photoelectrode of dye-sensitized solar cells. In the field emission scanning electron microscopy analysis, the lengths of TiO2 nanotube arrays prepared by electrochemical anodization can be obtained with approximately 10 to 30 μm. After titanium tetrachloride (TiCl4) treatment, the walls of TiO2 nanotubes were coated with TiO2 nanoparticles. XRD patterns showed that the oxygen-annealed TiO2 nanotubes have a better anatase phase. The conversion efficiency with different lengths of TiO2 nanotube photoelectrodes is 3.21%, 4.35%, and 4.34% with 10, 20, and 30 μm, respectively. After TiCl4 treatment, the efficiency of TiO2 nanotube photoelectrode for dye-sensitized solar cell can be improved up to 6.58%. In the analysis of electrochemical impedance spectroscopy, the value of Rk (charge transfer resistance related to recombination of electrons) decreases from 26.1 to 17.4 Ω when TiO2 nanotubes were treated with TiCl4. These results indicate that TiO2 nanotubes treated with TiCl4 can increase the surface area of TiO2 nanotubes, resulting in the increase of dye adsorption and have great help for the increase of the conversion efficiency of DSSCs.

Keywords:
TiO2 nanotube arrays; dye-sensitized solar cells; TiCl4 treatment