Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

The surface science of titanium dioxide

Transparent conductors as solar energy materials: A panoramic review

Electrochromic tungsten oxide films: Review of progress 1993–1998

Metal oxides are the key ingredients for the development of many advanced functional materials and smart devices. Nanostructuring has emerged as one of the best tools to unlock their full potential. Tungsten oxides (WOx) are unique materials that have been rigorously studied for their chromism, photocatalysis, and sensing capabilities. However, they exhibit further important properties and functionalities that have received relatively little attention in the past. This Feature Article presents a general review of nanostructured WOx, their properties, methods of synthesis, and a description of how they can be used in unique ways for different applications. Tungsten oxides (WOx) are unique functional materials that can be obtained in a vast variety of nanostructured forms. This Feature Article presents a comprehensive review on the properties of WOx that goes beyond chromism and photocatalysis, for which they are usually investigated for. This is followed by a survey of their synthesis methods and implementations for different applications.

Nanostructured Tungsten Oxide – Properties, Synthesis, and Applications

Study of sol–gel prepared nanostructured WO3 thin films and composites for electrochromic applications

Nanocrystalline titania films were prepared by a complexing agent-assisted sol-gel dip-coating process. The effect of acetylacetone, diethanolamine and polyethylene glycol on the structure of the heat-treated titania films was examined by Raman and FTIR spectroscopy and X-ray diffraction. The effect the complexing agents have on the anatase to rutile phase transition during the heat treatment process is studied. The understanding of this effect is expected to enhance our capacity to tailor the composition and morphology of films and thus their properties. The Raman and the infrared spectra of nanocrystalline titania films and the changes induced by the heat treatment were also investigated. We have also studied the size of the crystallites in TiO2 films and its dependence on the type of complexing agent used.

Study of anatase to rutile phase transition in nanocrystalline titania films

The electrochromic behavior of all‐solid‐state device, Au/a‐WO3/LiF/Au has been studied as a function of the thickness of LiF as electrolyte. Thickness‐dependent coloration and response time have been observed. The electrochromic coloration takes place at different stages, and a significant change in the transmittance of the tandem over a wide wavelength range (500–1000 nm) occurs. Hence, the performance of this configuration suggests the possible application of the tandem in all‐solid‐state ‘‘switchable windows’’.

Electrolyte thickness dependence of the electrochromic behavior of ‘‘a‐WO3’’ films

TiO2 nanocrystalline thin films with varying degree of porosity have been prepared using a low temperature method. TiO2 films of the anatase form have been obtained by using a polyethylene glycol (PEG) modified sol-gel method. Densification and crystallization of the films was found to result from the thermal treatment of the dip coated films in boiling water. The films have been characterized by Raman, XRD, FTIR, AFM and optical methods. Highly transparent films with transmission in excess of 85% and porosity as high as 58% are formed predominantly of anatase crystallites of dimensions of the order of 5 nm. Initial results on lithium intercalation into these films resulting in an efficient optical modulation in the visible and near infrared regions demonstrate a good potential of these films for electrochromic applications.

P. V. Ashrit

Papers

Study of sol–gel prepared nanostructured WO3 thin films and composites for electrochromic applications

Study of anatase to rutile phase transition in nanocrystalline titania films

Electrolyte thickness dependence of the electrochromic behavior of ‘‘a‐WO3’’ films

Low Temperature Sol-Gel Preparation of Nanocrystalline TiO2 Thin Films

Novel electrochromic devices based on complementary nanocrystalline TiO2 and WO3 thin films