Hierarchical Oriented Anatase TiO(2) Nanostructure arrays on Flexible Substrate for Efficient Dye-sensitized Solar Cells

The vertically oriented anatase single crystalline TiO(2) nanostructure arrays (TNAs) consisting of TiO(2) truncated octahedrons with exposed {001} facets or hierarchical TiO(2) nanotubes (HNTs) consisting of numerous nanocrystals on Ti-foil substrate were synthesized via a two-step hydrothermal growth process. The first step hydrothermal reaction of Ti foil and NaOH leads to the formation of H-titanate nanowire arrays, which is further performed the second step hydrothermal reaction to obtain the oriented anatase single crystalline TiO(2) nanostructures such as TiO(2) nanoarrays assembly with truncated octahedral TiO(2) nanocrystals in the presence of NH(4)F aqueous or hierarchical TiO(2) nanotubes with walls made of nanocrystals in the presence of pure water. Subsequently, these TiO(2) nanostructures were utilized to produce dye-sensitized solar cells in a backside illumination pattern, yielding a significant high power conversion efficiency (PCE) of 4.66% (TNAs, J(SC) = 7.46 mA cm(−2), V(OC) = 839 mV, FF = 0.75) and 5.84% (HNTs, J(SC) = 10.02 mA cm(−2), V(OC) = 817 mV, FF = 0.72), respectively.