Metallopolymer electrochromic film prepared by oxidative electropolymerization of a Fe(II) complex with arylamine functionalized terpyridine ligand

The oxidative electropolymerization of [Fe(L)(2)](PF6)(2) = 4'-{[p-(N-butyl-N-phenyl)aminol-phenyl)-2,2':6',2 ''-terpyridine) has been conducted by continuous cycling of the working electrode potential from 0 to 1.8 V in 0.1 mol.L-1 Bu4NClO4/CH3CN solution containing 5.0 x 10(-4) mol.L-1 monomer. The purple hybrid polymer film exhibits a non-diffusional charge transfer behavior of Fe(III)/Fe(II) couple and an irreversible redox process of phenylamine moiety on the Pt working electrode, as well as high stability in monomer-free electrolytic solution. The film thickness is easily tuned by controlling the number of potential sweeping cycle, and the AC impedance of as-formed film increases with cycling number. Morphological characterization of the film on indium tin oxide (ITO) has been provided by scan electron microscopy (SEM). The donor-acceptor (D-A) polymer film on ITO shows a broad and red-shifted (MLCT)-M-1 wave in the UV-vis spectrum and a clearly electrochromic behavior from purple to pale yellow with the times of 1.1 s for the coloration step and 2.2 s for the bleaching step, the optical contrast of 20.3% and the coloration efficiency of 164 C-1.cm(2). (C) 2013 Elsevier B.V. All rights reserved.