Materials exhibiting reversible color change when a voltage is applied, called electrochromic materials, have been drawing a great attention due to their applications as active materials in organic electronics. Many kinds of organic and inorganic compounds are used for electrochromic applications. Among them the most interesting are conjugated polymers which show high coloration efficiencies, low operating voltage, fast switching capabilities and the wide range of colors in both neutral and charged states, and transition metal complexes combining the electrochromic properties of transition metal ions and organic molecules or polymers. Electrochromic properties of transition metal complexes based on the redox reaction of metal ion or ligand molecule and can be modified by changing the structure of ligand molecule or the metal ion.
We present a new materials for electrochromic applications based on conjugated polymers as well as transition metal complexes. Their synthesis, properties and application as active materials in electrochromic as well as dual-functioning electrochromic and fluorochromic devices will be presented.