We report morphologic characterization of the anodic titanium oxide (ATO) films with highly-ordered titania (TiO 2 ) nanotube (NT) arrays grown perpendicularly to a titanium (Ti) foil. The length of the ATO arrays was controlled by various electrolytes and anodic periods at a constant applied voltage. In order to enhance the pathways for electron percolation, the ATO film was annealed in an air furnace, forming anatase TiO 2 . After TiCl 4 post-treatment to enhance the ruthenium-based dye loading on the ATO surface, the optimized ATO arrays were used as a photoanode in a dye-sensitized solar cell (DSSC). The best performance of the NT-DSSC device was achieved with aNH 4 F-based ATO film at length of 15 μm, giving J SC = 12.15 mAcm -2 , V OC = 0.74 V,FF= 0.69, andη = 6.2% under backside illumination.