Rutile TiO₂ nano-branched arrays on FTO for dye-sensitized solar cells

Hierarchical TiO₂ nanostructures would be desirable for preparing dye-sensitized solar cells because of their large amount of dye adsorption and superior light harvesting efficiency, as well as efficient charge separation and transport properties. In this study, rutile TiO₂ nano-branched arrays grown directly on transparent conductive glass (FTO) were prepared by a facile two-step wet chemical synthesis process, using a simple aqueous chemical growth method involving immersing the TiO₂ nanorod arrays in an aqueous TiCl₄ solution as seeds, which were prepared by a hydrothermal method. The dye-sensitized solar cells based on the TiO ₂ nano-branched arrays which were only about 3 μm in length show a short-circuit current intensity of 10.05 mA cm^-2 and a light-to-electricity conversion efficiency of 3.75%, which is nearly three times as high as that of bare nanorod arrays, due to the preferable nanostructure, which not only retains the efficient charge separation and transport properties of the nanorod arrays, but also can improve the amount of dye adsorption due to the increased specific surface area from the nanobranches.