Electrochromic solid-state devices using organic-metallic hybrid polymers

Organic-metallic hybrid polymers are formed by the complexation of metal ions with organic modules bearing two coordination sites. The hybrid polymers consisting of bis-terpyridines and metal ions such as Fe(II) or Ru(II) have a specific color based on the metal-to-ligand charge transfer (MLCT) absorption. Cyclic voltammograms of the polymers exhibit a reversible redox wave according to the redox reaction of the metal ions. Interestingly, a polymer film cast on an indium tin oxide (ITO) electrode exhibits excellent electrochromic properties; the color of the film disappears when a higher potential as compares to the redox potential of the metal ions is applied to the polymer film. In addition, multicolor electrochromic changes appear on introducing two types of metal ions to the polymer. Electrochromic solid-state devices are successfully fabricated by using these polymers.