title: Electrochromic multilayer films of tunable color by combination of copper or iron complex and monolacunary dawson-type polyoxometalate.
abstract: Electrochromic multilayer films consisting of polyoxometalate (POM) cluster alpha-K(10)[P(2)W(17)O(61)].17H(2)O (P(2)W(17)), copper(II) complex [Cu(II)(phen)(2)](NO(3))(2) (phen = 1,10-phenithroline), and iron complex [Fe(II)(phen)(3)](ClO(4))(2) were fabricated on silicon, quartz and ITO substrates by layer-by-layer self-assembly method. The multilayer films, PSS/Cu(II)(phen)(2)/[(P(2)W(17)/Cu(II)(phen)(2))](n) and PSS/Fe(II)(phen)(3)/[(P(2)W(17)/Fe(II) (phen)(3))](n) were characterized by UV-vis spectra, X-ray photoelectron spectra, cyclic voltammetry (CV), chronoamperometric (CA) and in-situ spectral electrochemical measurements. The interesting feature of the electrochromic film is its adjustable color by reduction of both transition metal complex and polyoxometalate at different potentials. The multilayer films also exhibit high optical contrast, suitable response time and low operation potential due to the presence of mono-lacunary-substituted polyoxometalate and transition metal complex. This is the first example that the color of electrochromic film can be adjustable, which gives valuable information for exploring new electrochromic materials with tunable colors.
authors.affiliation: Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
authors.forename: Guanggang
authors.initials: G
authors.lastname: Gao
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.forename: Wenju
authors.initials: W
authors.lastname: Wang
authors.forename: Wenjia
authors.initials: W
authors.lastname: An
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Qiu
authors.forename: Zhenqing
authors.initials: Z
authors.lastname: Wang
authors.forename: Enbo
authors.initials: E
authors.lastname: Wang