Self-ordered, vertically aligned, titanium oxide (TiO2) nanotubes were grown on an electropolished titanium foil by anodic oxidation in a viscous organic electrolyte. We chose two different anodization times to obtain nanotubes of approximately 9 and 17 pm in length. Some of the TiO2 nanotubes were post-treated with TiCl4 or hydrothermally with TiO2 P25. Their structure and morphology were investigated with field-emission scanning electron microscopy (FSEM) and transmission electron microscopy (TEM). To improve the sensitizing of the high-aspect-ratio nanotubes with dye we used a new approach in which the TiO2 arrays were immersed into the dye solution at elevated temperature in an autoclave. The current voltage characteristics of the assembled DSSCs gave an average energy-conversion efficiency of 5.7% for the untreated nanotubes. (C) 2016 Elsevier Ltd. All rights reserved.