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

This short review revisits the progress achieved in the last 10–15 years in the field of hybrid electrochromic materials, synthesized through sol–gel methods. New research directions in the field of electrochromism (EC), together with novel applications of many electrochromic hybrid oxides are discussed here. Among them, 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. The development of novel hybrid materials with significantly improved EC properties, where tungsten oxide is associated with carbonaceous materials such as MWCNT or graphene is also reported. These hybrid materials with enhanced EC properties, compared to the inorganic hybrids, will be remarkable in the future for a series of novel applications.