Figure 3From: Conical islands of TiO2 nanotube arrays in the photoelectrode of dye-sensitized solar cells FESEM images of the conical island structure composed of TiO 2 nanotube arrays grown by anodic oxidation. At a constant voltage of 60 V in 0.5 wt% NH4F- and 0.2 vol% H2O-containing ethylene glycol solution; at magnifications of (a) × 4,000, (b) × 15,000, (c) × 50,000, and (d) × 50,000.Back to article page