Fabrication of different crystallographically oriented TiO2 nanotube arrays used in dye-sensitized solar cells

Abstract

Different crystallographically oriented TiO₂ nanotube arrays (NTAs) were successfully fabricated via the anodization of Ti film sputtered on indium tin oxide (ITO) glass. The results indicate that the preferred orientation of TiO₂ NTAs with a texture degree f > 0.9 for anatase (004) can be assembled over a wide range of water content in the electrolyte from 1.5 to 6.0 vol%. When the water content is more than 8 vol%, the anatase TiO₂ NTA further transforms to a polycrystal type. When compared to the characteristics of DSSCs based on the different oriented TiO₂ NTAs, the (004) preferred orientation of TiO₂ NTAs possesses the highest power conversion efficiency (PCE) and electron transport rate owing to its excellent orientation.