Enhanced absorption of TiO₂nanotubes by N-doping and CdS quantum dots sensitization: insight into the structure

Abstract

A simple two-step procedure to shift the absorption of TiO2 nanotubes to the visible range.

The Anodization of Thin Titania Layers as a Facile Process towards Semitransparent and Ordered Electrode Material

“…This can address the spectral mismatch between the photoanode and the solar incident radiation [ 3 ]. For example, a red shift of the absorption edge from 397 nm to 575 nm has been reported by Bjelajac et al [ 4 ] when investigating the absorption spectra of TNTs sensitized with CdS quantum dots grown by anodic oxidation on fluorine doped tin oxide (FTO) considered there as a semitansparent conducting substrate. This indicates a significant improvement in the absorption capacity towards the visible range of the semitransparent material after CdS quantum dots decoration.…”

“…After describing both the physical deposition methods and various strategies investigated to improve the adhesion of Ti films to TCO, this section presents the different models already presented in the literature to explain the mechanism of TNTs formation through anodic oxidation. The growth of TNTs via electrochemical anodization is a simple and highly reproducible technique, enabling control over the geometry of the produced TNTs [ 4 ]. Moreover, this method does not need sophisticated facilities.…”

“…TNTs exhibit numerous advantages as compared to titania nanoparticles, or other one-dimensional geometry materials such as nanofibers, nanowires and nanorods. TNTs vertically oriented with an average length in order of micrometer significantly enhance the visible light scattering and absorption [ 4 ]. Additionally, electrons transport is much faster along nanotubes as compared to the randomly distributed nanoparticle networks [ 5 , 6 ].…”

“…This means that the decoration can be done by incorporating nanoparticles on the outer and inner tube walls. The modification of TNTs can be realized by: (1) immersing the formed TNTs after anodization in the heteroatom solution, (2) thermal post-treatment of the anodized materials with reactive heteroatom gases, (3) anodizing the substrates in electrolyte mixed with heteroatom salts [ 4 ]. Recently, titania nanotubes-based materials synthesized by depositing Ti films onto TCO, and subsequent anodization to obtain semitransparent TNTs are widely explored, taking advantage of the synergistic effect between the high ordering degree of TNTs, and the excellent transparency of TCO.…”

Sn-doped TiO2 nanotubular thin film for photocatalytic degradation of methyl orange dye

“…In a previous study, we noted that the diffusion of Sn from FTO to TiO 2 can be promoted by annealing [19]. The aim of this work is to intensify this effect in order to obtain Sn-doped TiO 2 thin film that can then be used as an improved photocatalyst with respect to undoped TiO 2 [20].…”