Recent Progress in Dye-Sensitized Solar Cells for Improving Efficiency: TiO₂ Nanotube Arrays in Active Layer

Figure 6

Schematic diagram of the evolution of a nanotube array at constant anodization voltage: (a) oxide layer formation, (b) pit formation on the oxide layer, (c) growth of the pits into scallop-shaped pores, (d) metallic part between the pores undergoing oxidation and field-assisted dissolution, and (e) fully developed nanotube array with a corresponding top view. Reprinted with permission from [44]. Copyright 2006, Elsevier.

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