Sol-gel chromogenic materials and devices.

In the last few years the sol-gel process has turned into an interesting and promising method of synthesizing materials for obtaining thin or thick films with definite functions. The techniques of film preparation such as dip and spin coating are simple and allow us to prepare coatings with smooth optical surfaces with controlled stoichiometry, structure and texture. In this paper we give an up to date overview of what has been achieved in the field of chromogenic materials such as anodic or cathodic electrochromic coatings, counter or ion storage electrodes, transparent electron conductors and ionic conductors to be used in electrochromic (EC) devices. We also review the sol-gel research in the related areas of photochromic, thermochromic and electrooptic sol-gel materials whose properties are essentially used to modulate the luminous or solar energy as well as sol-gel materials prepared in the form of nanoparticles proposed recently for the development of a new type of solar cell. Finally we stress the future developments in these fast growing fields. [ABSTRACT FROM AUTHOR]