Electrochromic thin films of organic-metallo hybrid polymers

Organic-metallo hybrid polymers attract considerable attention in terms of designing and fabricating materials since metals and ligands of polymer components can be easily changed. One of the goals to design the molecular materials is the development of reversible and efficient molecular switches for optical and electronic applications, and electrochromic materials and devices are of major subject. We are interested in tepyridine-metal hybrid polymers because terpyridine ligands posses an excellent ability to coordinate metal ions. Self-assembly of 1,4-bis(2,2':6',2"-terpyridin-4'-yl)benzene and Fe(II) or Co(II) results in metallosupuramolecular polyelectrolytes (MEPE). Thin films of both Fe(II)- and Co(II)-MEPE showed reversible oxidation to Fe(III) or Co(III), and reduction to Fe(II) or Co(II). Fe-MEPE showed high redox respond, followed by dramatic color change between blue and colorless clear. Here, electrochromic properties of those thin films are reported.