Multi-colour electrochromic properties of Fe/Ru-based bimetallo-supramolecular polymers

Abstract

A series of Fe/Ru-based bimetallo-supramolecular polymers were synthesized by a stepwise coordination of Fe(II) and Ru(II) ions to bis(terpyridyl)benzene (L1). The polymers exhibited multi-colour electrochromic behaviour based on the redox potential of the metal ion. Electrochemical and electrochromic properties of the polymer films were analyzed in acetonitrile with 0.1 M lithium perchlorate as an electrolyte. The polymer films showed high optical contrast and very fast response times, demonstrated by transmittance changes (ΔT) at 508 and 585 nm that were 68% and 37%, respectively, within a few seconds. Coloration efficiencies (η) were established for the first time in a metallo-supramolecular electrochromic system, with values of 242.1 and 188.2 (cm² C⁻¹) at different wavelengths.