Surface modified TiO ₂ nanostructure with 3d urchin-like morphology for dye-sensitized solar cell application

Three-dimensional (3D) urchin-like rutile TiO ₂ powders were synthesized by a mild hydrothermal method without any templates. An individual urchin-like TiO ₂ powder consists of self-assembled nanorods with a length of about 150 nm and width of about 10 nm. Additionally, the urchin-like TiO ₂ nanopowders were coated with an ultra-thin ZnO layer in order to modify the surface properties of the nanopowders, and the ZnO layer was confirmed by high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis. The ZnO-modified TiO ₂ was used as a photoelectrode of a dye-sensitized solar cell (DSSC) and the solar cell performances were investigated. In comparison with bare TiO ₂, ZnO-modified TiO ₂ improved the photovoltaic performances, i.e., energy conversion efficiency, open circuit voltage, and short circuit current were increased. The higher DSSC performance of ZnO-modified TiO ₂ was attributed to its higher dye loading and lower charge recombination rate.