Fabrication of TiO2 nanotubes with extended periodical morphology by alternating-current anodization

Highly uniform TiO2 nanotube arrays with regular periodical sidewall morphology were fabricated by both alternating-voltage (AV) and alternating-current (AC) anodization methods. It was revealed that the AC anodization provided a better control to the sidewall morphology than the AV anodization. Various bamboo-shaped nanotube arrays were prepared by using AC anodization with different current functions. Dye-sensitized solar cells (DSSCs) fabricated using different TiO2 nanotube arrays showed that the AC anodization with square-wave driving current gave the highest photo energy conversion efficiency. (C) 2012 Elsevier B.V. All rights reserved.