Ultra-long hierarchical bud-like branched TiO2 nanowire arrays for dye-sensitized solar cells

The ultra-long hierarchical bud-like branched TiO 2 nanowire arrays on fluorine-doped tin oxide glass substrate have been prepared via a two-step solution route, which involves the growth of the anatase TiO 2 nanowires with the length of 48   μm on fluorine-doped tin oxide glass substrate, followed by a secondary growth of the rutile TiO 2 nanorods on the as-grown TiO 2 nanowires backbone. The dye-sensitized solar cell based on the hierarchical bud-like branched TiO 2 nanowire arrays shows a power conversion efficiency of 6.00%, which is nearly 2.88 times as high as that of bare TiO 2 nanowire arrays because of the preferable nanostructure , which not only retains the efficient charge separation and transport properties of one-dimensional TiO 2 nanostructures, but also improves the amount of dye adsorption and light-scattering ability due to the branched structure.