Excited state properties of anodic TiO2 nanotubes

Charge carriers, that is, holes as well as trapped and “free” electrons were investigated by means of time resolved spectroscopy in anodic TiO2 nanotubes that were heat treated at different temperatures. The lifetimes of the charge carrier were compared with those generated in reference layers of Solaronix Ti-Nanoxide D and Degussa P25 nanoparticles. Remarkably long lived “free” electrons were only noted in the TiO2 nanotubes. These findings have significance in view of any photoelectrochemical applications of TiO2 nanotubes.