A surface science perspective on TiO2 photocatalysis

http://nathan.instras.com/ResearchProposalDB/doc-131.pdf

Photochromism in composite and hybrid materials based on transition-metal oxides and polyoxometalates

Optical properties of anatase TiO2 thin films prepared by aqueous sol–gel process at low temperature

TiO2 thin films - Influence of annealing temperature on structural, optical and photocatalytic properties

A transparent, high purity, amorphous titanium dioxide thin film composed of densely packed nanometer-sized grains has been successfully deposited on a glass substrate at room temperature from an aqueous peroxotitanate solution using a simple, inexpensive, reproducible, and environmentally friendly method. The as-deposited thin film was 117 nm thick and composed of closely packed particles of 10–15 nm in diameter, but they aggregated into large grains of 50–100 nm in diameter. The aqueous peroxotitanate solution was obtained by dissolving metatitanic acid (H2TiO3) in a mixture of concentrated H2O2 and NH3·H2O. An anatase TiO2 thin film was obtained by heating the as-deposited thin film at 500 °C for 1 h in air. A chemical composition of TiO1.4(O2)0.5(OH)0.2·1.34H2O is proposed for the as-deposited thin film, based on XPS, FT-IR and TG-DTA data. Band gap energies of 3.20 eV for indirect transition and 3.63 eV for direct transition were obtained for the anatase TiO2 film.

http://www.titanshield.com/pdf/E/articles/TiO2-JMC-(2003(13)).pdf

Room temperature deposition of a TiO2 thin film from aqueous peroxotitanate solution

Deposition of SrTiO3 (STO) thin films by radio-frequency magnetron sputtering in an ultrahigh vacuum system at a low substrate temperature (∼200 °C) was performed in order to produce high-quality STO/p-Si (100) interfaces and STO insulator layers with dielectric constants of high magnitude. The STO films were identified as polycrystalline by x-ray diffraction, and were approximated with a layered structure according to the best fitting results of raw data from both Rutherford backscattering spectroscopy and variable angle spectroscopic ellipsometry. Room-temperature current–voltage and capacitance–voltage (C–V) measurements on Al/STO/p-Si diodes clearly revealed metal–insulator–semiconductor behavior, and the STO/p-Si interface state densities were of the order of 1011 eV−1 cm−2. The dielectric constant of the STO film was 65, and the dielectric loss factor varied between 0.05 and 0.55 for a frequency range of 1 kHz–10 MHz. For a 387 nm thick STO film, the dielectric breakdown field was 0.31 MV cm−1, and ...

Electrical properties of SrTiO3 thin films on Si deposited by magnetron sputtering at low temperature

Metallic Mo powder and Ti(OBun)4 were separately dissolved in H2O2 solution and the solutions obtained mixed in different Mo/Ti atomic ratios to prepare precursor solutions. Fresh gels obtained from the precursor solutions with > 40% Mo became blue upon exposure to ambient light. X-Ray photoelectron spectroscopy (XPS) was used to examine the chemical states and compositions of the resultant blue-tinged xerogel powders. Based on the XPS results, it is proposed that TiO2 particles and surface species, including adsorbed water and organic residue, all contribute to the photochromic effect of MoO3. Mo–Ti oxide films were spin-coated on ITO-coated glass substrates using a precursor solution containing 70% Mo. The cycling behaviours of the films annealed at 150 °C for 1 h were studied using cyclic voltammetry (CV) in propylene carbonate solution containing 1 mol L−1 LiClO4. The electrochromic properties of the films upon lithium intercalation were investigated by in situ monochromatic transmittance measurements during the CV process, as well as ex situ in the UV/Vis region. The Mo–Ti oxide films were found to possess excellent electrochromic properties upon Li+ ion insertion/extraction.

Peroxo sol–gel preparation: photochromic/electrochromic properties of Mo–Ti oxide gels and thin films

FeSO4·7H2O was precipitated with ammonia solution in the presence of H2O2 as an oxidant. The precipitate was washed slightly with deionized water and then peptized with acetic acid (ca. 60 mol %) t...

High Li+-Ion Storage Capacity and Double-Electrochromic Behavior of Sol−Gel-Derived Iron Oxide Thin Films with Sulfate Residues

Deposition of SrTiO3 (STO) thin films by ultra-high vacuum rf magnetron sputtering was performed in order to produce high-quality STO/p-Si (1 0 0) interfaces and STO insulator layers with high diel 

Zhongchun Wang

Papers

Optical properties of anatase TiO2 thin films prepared by aqueous sol–gel process at low temperature

Electrical properties of SrTiO3 thin films on Si deposited by magnetron sputtering at low temperature

Peroxo sol–gel preparation: photochromic/electrochromic properties of Mo–Ti oxide gels and thin films

High Li+-Ion Storage Capacity and Double-Electrochromic Behavior of Sol−Gel-Derived Iron Oxide Thin Films with Sulfate Residues

Electrical characterisation of SrTiO3/Si interfaces