Preparation, microstructure and photochromism of a new nanocrystalline WO3 film

• Published in: Journal of materials science letters Vol. 19; no. 16; pp. 1407 - 1409
• Main Authors: MU SUN, NING XU, CAO, Y. W, YAO, J. N, WANG, E. G
• Format: Journal Article
• Language: English
• Published: Dordrecht Kluwer Academic Publishers 01.08.2000
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Small particles; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Inorganic compounds; Photochromism; Colloids; Process control; Transition element compounds; Oxides; Tungsten oxides; Experimental study; Fabrication property relation; Thin films; Crystal growth from solutions; Ultraviolet visible spectrum; Microstructure; TEM; Nanocrystal
• ISSN: 0261-8028
• DOI: 10.1023/A:1006707018994

Uniform nanocrystalline WO3 thin films were prepared by a colloid chemistry method. It is found that the particle size and crystallinity of the films can be tailored by controlling the concentration of oxalic acid in the colloid solution. Exposure of the films to ultraviolet light makes the films blue in color, contradicting the general assumption that coloration occurs most efficiently in highly disordered systems. A blue shift is observed in the absorption spectrum of the films with the increasing oxalic acid concentration, which is ascribed to a quantum size effect. (CSA)