(479f) Ordered TiO2 Nanotube Arrays On Transparent Conducting Oxide for Efficient Dye-Sensitized Solar Cells

Synthesizing highly ordered 1-D TiO2 nanostructures directly on transparent conductive oxides (TCO), which is of key interest for fabricating front-side illuminating dye-sensitized solar cells (DSCs), has been one of the most challenging nanofabrication tasks. Here, we present a process for synthesizing vertically aligned TiO2 nanotube arrays on TCO through a liquid-phase conversion process using ZnO nanowire arrays as a template. The resulting TiO2 nanotube arrays can be easily integrated with the fabrication process of DSCs and lead to significantly improved photovoltaic performance compared to ZnO nanowire-based DSCs. It is also observed that the lifetime of photogenerated electrons in TiO2 nanotubes is more than an order of magnitude larger than that in sintered TiO2 nanoparticles. This result opens up numerous opportunities to further improve DSCs, for example, by employing solid-state electrolytes and redox mediators with faster kinetics, which otherwise would be challenging or impossible to implement by the use of nanoparticlebased DSCs.