title: A dual electrochrome of poly-(3,4-ethylenedioxythiophene) doped by N,N'-bis(3-sulfonatopropyl)-4-4'-bipyridinium--redox chemistry and electrochromism in flexible devices.
abstract: An electrochromic zwitterionic viologen, N,N'-bis(3-sulfonatopropyl)-4-4'-bipyridinium, has been used for the first time for doping poly (3,4-ethylenedioxythiopene) (PEDOT) films during electropolymerization. Slow and fast diffusional rates for the monomer at deposition potentials of +1.2 and +1.8 V, respectively yielded the viologen-doped PEDOT films with granular morphology and with dendrite-like shapes. The dual electrochrome formed at +1.8 V, showed enhanced coloration efficiency, larger electrochemical charge storage capacity, and superior redox activity in comparison to its analogue grown at +1.2 V, thus demonstrating the role of dendritic shapes in amplifying electrochromism. Flexible electrochromic devices fabricated with the viologen-doped PEDOT film grown at +1.8 V and Prussian blue with an ionic liquid-based gel electrolyte film showed reversible coloration between pale and dark purple with maximum coloration efficiency of 187 cm2C(-1) at lambda=693 nm. The diffusional impedance parameters and switching kinetics of the device showed the suitability of this dual electrochrome formed as a single layer for practical electrochromic cells.
authors.affiliation: National Physical Laboratory, Dr. K. S. Krishnan road, New Delhi-110012, India.
authors.forename: Shweta
authors.initials: S
authors.lastname: Bhandari
authors.forename: Melepurath
authors.initials: M
authors.lastname: Deepa
authors.forename: Suman
authors.initials: S
authors.lastname: Pahal
authors.forename: Amish G
authors.initials: AG
authors.lastname: Joshi
authors.forename: Avanish Kumar
authors.initials: AK
authors.lastname: Srivastava
authors.forename: Rama
authors.initials: R
authors.lastname: Kant
mesh_terms: D000476:Alkanesulfonates / Q000737:chemistry*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D004563:Electrochemistry; D004573:Electrolytes / Q000737:chemistry; D005295:Ferrocyanides / Q000737:chemistry; D005782:Gels / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014755:Viologens / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D000476:Alkanesulfonates; D019086:Bridged Bicyclo Compounds, Heterocyclic; D004573:Electrolytes; D005295:Ferrocyanides; D005782:Gels; D052578:Ionic Liquids; C553049:N,N'-bis(3-sulfonatopropyl)-4,4'-bipyridinium; D011108:Polymers; D014755:Viologens; C121383:poly(3,4-ethylene dioxythiophene); C000170:ferric ferrocyanide