Dye-sensitized solar cells based on multilayered ultrafine TiO2 nanowire photoanodes

A low-temperature hydrothermal method was used to synthesize ultrafine TiO₂ nanowires with the diameter of 4–6 nm. The ultrafine nanowires tend to gather together, forming nanowire bundles. The length of the nanowires is about 1–4 μm, depending on the growth time. Multilayered TiO₂ nanowires with the height more than 10 μm have been synthesized by a multi-step growth process. Furthermore, the dye-sensitized solar cells (DSSCs) are assembled using single-layered, double-layered and triple-layered TiO₂ nanowires as photoanode respectively. The DSSC based on triple-layered TiO₂ nanowires shows the highest power conversion efficiency of 3.96 % among the prepared samples. The relatively high energy conversion efficiency is attributed to the large surface area, which enhances the absorption of dye molecules.