Multi-functional TiO2 nanotubes arrays by anodic oxidation: from energy to bio-sensing

Since the first report of Zwilling and coworkers, vertically aligned titanium dioxide (TiO2) nanotube (NT) arrays by anodic oxidation have been largely investigated as active element for dye-sensitized solar cells, Li-ions batteries, water photoelectrolysis, artificial photosynthesis, biomedical devices, molecular sensors, gas sensors, and photocatalytic degradation of pollutants. Thanks to their quasi one-dimensional arrangement, TiO2 NTs are able to provide high surface area and superior electron transport properties resulting in a performance enhancement in the different fields of application. The electrochemical oxidation of Ti foil in a fluorine-based electrolyte is a simple, cheap and green process, easy to be scaled up towards massive production and with a low energy payback time if used for energy harvesting applications. We present and discuss the integration of these arrays as efficient photoanodes into dye-sensitized solar cells - and as ultra-sensitive SERS substrate for bio-sensing application.