Electrochromic properties of sol–gel prepared hybrid transition metal oxides – A short review

Abstract

This short review paper revisits the progress achieved in the last 10-15 years in the field of hybrid electrochromic materials, synthesized through sol-gel methods.During the recent decade, new avenues have been opened, exploring new concepts and particularly interesting applications of electrochromism. In this paper, we will discusssome of the new research directions in the field of electrochromism, together with novel applications of many electrochromic hybrid oxides. The most important incentive for enhanced properties of traditional materials has been the advent of nanotechnology. The discoveries in the field of synthesis of nanomaterials enabled to expand the materials and connect the morphological features of nanoparticles to the electrochromic properties at the macro level. This was possible because of the emergence of the new and more elaborate characterization methods, enabling to unveil hitherto unknown structural and morphological properties of electrochromic materials.It is important to mention the development of novel hybrid materials with significantly improved EC properties, where tungsten oxide is associated with carbonaceous materials such as MWCNT or graphene. These hybrid materials with enhanced EC properties, compared to the inorganic hybrids, will be remarkable in the future,for a series of novel applications.Retracing briefly the history of EC hybrid materials and summarizing the principal achievements will be useful not only for researchers in the field but for a wider readership as well.