Electrochemistry of poly(3,4-ethylenedioxythiophene)-polyaniline/Prussian blue electrochromic devices containing an ionic liquid based gel electrolyte film

Abstract

Electrochromic devices based on poly(3,4-ethylenedioxythiophene) (PEDOT) as the cathodic coloring electrode and polyaniline (PANI) or Prussian blue (PB) as the counter electrode containing a highly conductive, self-supporting, distensible and transparent polymer-gel electrolyte film encapsulating an ionic liquid, 1-butyl-1-methylpyrrolidiniumbis-(trifluoromethylsulfonyl)imide, have been fabricated. Polarization, charge transfer and diffusion processes control the electrochemistry of the functional electrodes during coloration and bleaching and these phenomena differ when PEDOT and PANI/PB were employed alternately as working electrodes. While the electrochemical impedance response shows good similitude for PEDOT and PANI electrodes, the responses of PEDOT and PB were significantly different in the PEDOT-PB device, especially during reduction of PB, wherein the overall amplitude of the impedance response is enormous. Large values of the coloration efficiency maxima of 281 cm 2 C À1 (l = 583 nm) and 274 cm 2 C À1 (l = 602 nm), achieved at À1.0 and À1.5 V for the PEDOT-PANI and PEDOT-PB devices have been correlated to the particularly low magnitude of charge transfer resistance and high polarization capacitance operative at the PEDOT-ionic liquid based electrolyte interface at these dc potentials, thus allowing facile ion-transport and consequently resulting in enhanced absorption modulation. Moderately fast switching kinetics and the ability of these devices to sustain about 2500 cycles of clear-to-dark and dark-to-clear without incurring major losses in the optical contrast, along with the ease of construction of these cells in terms of high scalability and reproducibility of the synthetic procedure for fabrication of the electrochromic films and the ionic liquid based gel electrolyte film, are indicators of the promise these devices hold for practical applications like electrochromic windows and displays.

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

“…The switching times are larger than previously reported values for PEDOT based films [20,38] and devices. [39,40] The high sheet resistance of the underlying conducting substrate (< 350 W sq À1 ), the interfacial resistance of the PEDOT/electrolyte, or PB/electrolyte interface are possible reasons for slow kinetics.…”

Cobalt Hexacyanoferrate-Decorated Titania Nanotube: CoHCF@TNT Modified GCE as an Electron Transfer Mediator for the Determination of Hydrazine in Water Samples

“…For instant, sol-gel method, by using perm selective coating using nafion and other polymers and direct coating in presence of conducting polymer are some of the few examples [13,14]. Recently mesoporous carbons [15], carbon nanotube [16], and graphene [17] have been utilized to stabilize PB and analogues.…”

3D Nanostructured Conjugated Polymers for Optical Applications

“…In particular, the optical response caused by a chemical trigger is often diffusion limited, causing relatively slow response times. [ 5 ] The structure formation of these materials on small length scales greatly enhances their specifi c surface area, which typically improves properties that arise from surface chemistry or interdiffusion processes. [6][7][8] The formation of 3D nanostructures in soft organic materials holds several challenges, particularly with respect to mechanical stability and resistance to plasticization by small molecules.…”