| TiO2 nanomaterials have been widely studied due to their unique electrical and electrochemical properties which are suitable for sensing, catalysis and solar cells. In recent years, TiO2 nanotubes with high surface-to-volume ratios have received considerable attention because of their potential applications of highly efficient photocatalysis and photovoltaic cells. If the TiO2 nanotube membranes could be transferd onto the FTO substrates, the transparent and conductive TiO2/FTO photoelectrode would have a better application in the photoelectric conversion filed. This dissertation titled"Highly ordered TiO2/FTO nanotube array photoelectrode:fabrication, modification of CdS and its optical properties"mainly describes the following work and results:1. The large-scale (18 mm×11 mm), highly-ordered, vertically-oriented free-standing TiO2 nanotube membranes were fabricated by three-step anodization Ti foils(0.2 mm) in ethylene glycol containing 0.25 wt.% NH4F. It is found that the optical energy gap (Eg) of TiO2 nanotube membranes could not only have high transmissivity (4002500 nm), but also be effectively modulated by different anodic voltage. Obviously, this work would be beneficial to apply in organic-inorganic photovoltaic devices.2. Then the as-prepared free-standing membranes were transferred to FTO-coated glass substrates with TiO2 sol, and the semitransparent TiO2/FTO photoelectrode was obtained after annealing treatment.3. The TiO2/FTO photoelectrode was modified with CdS by the sequential-chemical bath deposition (S-CBD) method in order to extend the optical absorption range of bare TiO2/FTO. The measurement results show that the band-gaps decrease from 3.22 eV for bare TiO2/FTO to 2.43 eV for CdS-modified TiO2/FTO. Meanwhile, the optical absorption band-edges of CdS-modified TiO2/FTO have efficiently shifted from 380 nm to 554 nm, which could lead to an extended optical absorption range from the ultraviolet to the visible.
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