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 TiO2 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.