title: High-Performance Electrochromic Devices Based on Poly[Ni(salen)]-Type Polymer Films.
abstract: We report the application of two poly[Ni(salen)]-type electroactive polymer films as new electrochromic materials. The two films, poly[Ni(3-Mesalen)] (poly[1]) and poly[Ni(3-MesaltMe)] (poly[2]), were successfully electrodeposited onto ITO/PET flexible substrates, and their voltammetric characterization revealed that poly[1] showed similar redox profiles in LiClO4/CH3CN and LiClO4/propylene carbonate (PC), while poly[2] showed solvent-dependent electrochemical responses. Both films showed multielectrochromic behavior, exhibiting yellow, green, and russet colors according to their oxidation state, and promising electrochromic properties with high electrochemical stability in LiClO4/PC supporting electrolyte. In particular, poly[1] exhibited a very good electrochemical stability, changing color between yellow and green (λ = 750 nm) during 9000 redox cycles, with a charge loss of 34.3%, an optical contrast of ΔT = 26.2%, and an optical density of ΔOD = 0.49, with a coloration efficiency of η = 75.55 cm(2) C(-1). On the other hand, poly[2] showed good optical contrast for the color change from green to russet (ΔT = 58.5%), although with moderate electrochemical stability. Finally, poly[1] was used to fabricate a solid-state electrochromic device using lateral configuration with two figures of merit: a simple shape (typology 1) and a butterfly shape (typology 2); typology 1 showed the best performance with optical contrast ΔT = 88.7% (at λ = 750 nm), coloration efficiency η = 130.4 cm(2) C(-1), and charge loss of 37.0% upon 3000 redox cycles.
authors.forename: Marta
authors.initials: M
authors.lastname: Nunes
authors.forename: Mariana
authors.initials: M
authors.lastname: Araújo
authors.affiliation: CeNTI , Rua Fernando Mesquita, 2785, 4760-034 Vila Nova de Famalicão, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Fonseca
authors.forename: Cosme
authors.initials: C
authors.lastname: Moura
authors.affiliation: Department of Chemistry, University of Leicester , Leicester LE1 7RH, United Kingdom.
authors.forename: Robert
authors.initials: R
authors.lastname: Hillman
authors.forename: Cristina
authors.initials: C
authors.lastname: Freire
keywords: conducting polymers; electrochromism; metal salen complexes; solid-state electrochromic cell; spectroelectrochemistry