Optical absorption, photoelectrochemical, and ultrafast carrier dynamic investigations of CdSe quantum dot sensitized TiO2 electrodes composed of nanotubes and nanowires

In this paper, we prepared TiO₂ electrodes composed of nanotubes and nanowires following a surfactant template method reported by M. Adachi et al. (2003) and sensitized them with CdSe QDs reported in Q. Shen and T. Toyoda (2004). We studied the optical absorption and the incident photon to current conversion efficiency (IPCE) of the electrodes using photoacoustic (PA) and photoelectrochemical (PEC) methods. The PA method is a powerful tool for characterizing the optical absorption of opaque and scattered samples as presented in A. Rosencwaig and A. Gersho (1976). In addition, we studied ultrafast carrier dynamics of TiO₂ films composed of nanotubes and nanowires using lens-free heterodyne detection transient grating (LF-HD-TG) technique based in M. Katayama et al. (2003).