Polythiophene -viologen bilayer for electro-trichromic device

et al. 2021

IET Nanodielectrics

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A nanostructured film of NiCo 2 O 4 has been prepared using a hydrothermal technique by simply using separate precursors to obtain nanoneedle-like architecture for electrochromic applications. A homogeneous film consisting of packed nanoneedles with moderate density, appearing translucent white in colour, has been obtained and characterized using XRD and Raman spectroscopy techniques for confirming the composition and structure. Electrochemical analysis of the film reveals that the film shows good electrochromic properties under the anodic scan of potential with strong stability. The mechanism of the electrode under the transformation from natural white to opaque dark brown colour has been understood with the help of an in situ optical absorption spectroscopy technique. The electrode is found electrochromically active with a bias of up to 2 V and shows 50% optical contrast which makes it a good candidate for application in a solid state electrochromic device. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Section: Introductionmentioning

confidence: 99%

Low voltage colour modulation in hydrothermally grown Ni‐Co nanoneedles for electrochromic application

et al. 2021

IET Nanodielectrics

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“…Electrochromism, the phenomenon of bias‐induced reversible color change, is one of the most exploratory areas. [ 1–12 ] Any material may have electrochromic (EC) properties [ 13 ] but only the ones with appreciable switching time, [ 14 ] coloration efficiency, [ 15 ] contrast ratio, [ 16 ] and quality factor may be used in an actual device in smart windows, displays, etc. and often depend upon the active materials’ properties.…”

Section: Introductionmentioning

confidence: 99%

“…A better EC counter electrode will be one which not only enables the active electrode's optical switching but also change color in the due course as it will be advantageous and will help improving the overall EC performance. [ 28 ] An EC electrode can be synthesized using electropolymerization, [ 29 ] spin coating, [ 12,14 ] drop‐casting, [ 30 ] etc. Recently, electrodes containing nanomaterials are being fabricated and found to be advantageous, [ 31 ] mainly by improving electron transport during the redox process which not only depends on the morphology but also gives an option to tailor it by appropriately designing nanomaterial‐based electrodes.…”

Section: Introductionmentioning

confidence: 99%

Chronopotentiometric Deposition of Nanocobalt Oxide for Electrochromic Auxiliary Active Electrode Application

Physica Status Solidi (a)

et al. 2020

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A dense nanofilm of Co 3 O 4 is synthesized using constant current electrodeposition on a conducting transparent electrode that works not only as a counter electrode but also shows electrochromic (EC) properties on its own. The isolated active nano-Co 3 O 4 electrode shows reduction in the redox potential and good color contrast between its yellowish transparent and dark states at different bias conditions. The electrode shows improved color contrast, stability, and cycle life. In situ spectroelectrochemical studies of the nanoelectrode reveals that the biasinduced redox activity of the metal oxide leads to the color change between yellowish and opaque states. The bias-induced color change makes it an active EC counter-ion electrode for appropriate solid-state EC devices.

“…In situ Raman spectroscopy has been carried out on both the devices in backscattering geometry. The Raman spectra of device, under different bias conditions, containing PPB shows (Figure 5(a)) peaks at 925 cm −1 (marked by #) 2152 cm −1 (marked with '&') corresponding to [53] EV 2+ and PB, respectively. A bias of −1.5 V, reduces partial PB to PW form as evident with peak shifting to 2104 cm −1 and 2132 cm −1 (violet curve, Figure 5(a)) [54] whereas, the EV peak remains unaltered at 925 cm −1 .…”

Section: Resultsmentioning

confidence: 99%

Improved ionic solid/viologen hybrid electrochromic device using pre‐bleached Prussian‐blue electrode

et al. 2021

IET Nanodielectrics

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The authors demonstrate how a simple step of loading an electrochromically active Prussian blue (PB; an ionic solid) electrode with Li + ions can help in achieving a more efficient viologen based solid state hybrid electrochromic device. To accomplish this, two different devices, with and without Li + ion loaded PB electrodes, have been fabricated. These devices have been compared in terms of their current-voltage response, bias dependent optical modulation and corresponding colour switching to establish the role of Li + ion in charge transport and charge balancing involved during bias induced redox mediated colour switching of the two devices. The Li + containing PB electrode device exhibits a superior performance with twice (40%) the value of colour contrast (20%), quick response switching (1.3 s), excellent stability (8400 s) and better power efficiency as compared to the device containing as-synthesised PB electrode. A mechanism has been proposed to explain the role of the Li + ion which is later substantiated using biasdependent in situ Raman spectroscopic evidences.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.