Effects of counter ions on electrochromic behaviors of asymmetrically substituted viologens

Pande, Gaurav K.; Kim, Namhyeon; Choi, Jin Hui; Balamurugan, Gopal; Moon, Hong Chul; Park, Jong Soo

doi:10.1016/j.solmat.2019.04.004

Cited by 43 publications

(20 citation statements)

References 40 publications

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“…[ 9 ] For large‐scale applications, thinner devices would require less material and weigh less, while lower concentrations mean cheaper production. This contrast ratio is also higher than a variety of previously reported viologens [ 7,12,15,17 ] and polymers. [ 2,4,20,21 ]…”

Section: Electrochromismcontrasting

confidence: 52%

“…[ 6 ] Although inorganic materials possess some of these qualities, there is currently a larger focus on organic materials because of high contrast, [ 7 ] fast response, [ 7 ] processability, [ 8,9 ] and cost‐efficiency. [ 9 ] Previously researched EC organic molecules include benzonitriles, [ 10 ] symmetric and asymmetric viologens, [ 7,9,11–17 ] thioxathone viologens, [ 18 ] and the heterocycle in this study, thiazolothiazoles (TTz's). [ 19 ] There has also been a large interest in EC polymers, including those utilizing TTz, [ 4,5,20 ] thiophene, [ 21 ] and benzothiadiazole moieties.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Obtaining Reversible, High Contrast Electrochromism, Electrofluorochromism, and Photochromism in an Aqueous Hydrogel Device Using Chromogenic Thiazolothiazoles

Adams

Brotherton

Molai

et al. 2021

Adv Funct Materials

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There have been an increasing number of materials developed that show multifunctional chromogenic properties (such as electrochromism, electrofluorochromism, or photochromism), but to date, few materials have shown all three properties. Materials that are electrochemically and optically active are attractive for a diverse set of applications that include smart‐windows, lighting, sensing, energy production, and conservation. This is especially attractive for building developers interested in adaptive or environmentally responsive façades. Achieving systems made from cost‐effective, readily synthesized materials will make them easy to utilize in a variety of fields. Low‐cost devices are developed using water‐soluble, chromogenic thiazolo(5,4‐d)thiazole (TTz) dyes that show high device performance in three areas: electrochromism, electrofluorochromism, and photochromism and are all contained within a highly fluorescent aqueous polyvinyl alcohol/borax hydrogel device. The dyes incorporate a rigid, heterocyclic TTz structure that enables the development of devices with excellent reversibility and stable cycling for 250 cycles. The TTz hydrogel‐containing devices also exhibit photochromism under illumination, which can be electrochemically cycled back to the colorless state. In addition, coupling photochromism with electrochromism lowers the power necessary for a comparable electrochromic color change. Last, the hydrogel‐containing devices also show electrofluorochromism, where fluorescence can be turned off by > 90%.

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Section: Electrochromismcontrasting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Obtaining Reversible, High Contrast Electrochromism, Electrofluorochromism, and Photochromism in an Aqueous Hydrogel Device Using Chromogenic Thiazolothiazoles

Adams

Brotherton

Molai

et al. 2021

Adv Funct Materials

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“…However, the signals obtained from the remaining compounds studied in the presence of 1 and 3 equiv of NH 4 PF 6 salt exhibited a similar behavior to the one detected for the MV bis(hexafluorophosphate) compound dissolved in NaCl (Figure D), which is also consistent with the electrogeneration process of radical cations that attach to the electrode surface. Methyl viologens have also been extensively used in supramolecular chemistry as selective anion recognition elements. , Ji et al , studied the anion recognition of a methyl viologen derivative for ions 2Br – , 2I – and 2PF 6 – , reporting the following binding constants for interactions in a pH = 7 phosphate buffer solution: 2.37 × 10 5 , 3.37 × 10 4 and 1.92 × 10 5 mol L –1 , respectively. Based on this data and our cyclic voltammetry results, we believe that adding enough NH 4 PF 6 salt to the solutions of the compounds studied generates an ion-exchange process.…”

Section: Resultsmentioning

confidence: 99%

Concentration Effects on the First Reduction Process of Methyl Viologens and Diquat Redox Flow Battery Electrolytes

Martínez‐González

Flores‐Leonar

Amador‐Bedolla

et al. 2021

ACS Appl. Energy Mater.

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Analyte concentration effects on the first reduction process of methyl viologens and diquat redox flow battery electrolytes were examined by cyclic voltammetry in aqueous media. A simple one-electron transfer mechanism to form radical cations was detected for diquat, 4,4′-dimethyl diquat, and bis(3trimethylammonio)-propyl viologen compounds. The radical cations attach to the electrode surface when the source of their electrogeneration is methyl viologen molecules bearing PF 6 − ions as a counterpart. However, this inner sphere reduction mechanism was not observed in methyl viologen having an I − counterion. For the latter compound, as well as for 5,5′-dimethyl diquat and 1,1′bis(3-sulfonatopropyl)-4,4′-bipyridinium, a piece of experimental evidence for unexpected, fast, and reversible dimerization interactions between their electrogenerated radical cations is presented. To get information on these bimolecular interactions, a screening methodology (using different levels of theory) was employed in finding suitable dimeric structures and their related interaction energies. By using diquat as a reference system, a relationship between calculated interaction energies and the corresponding experimental dimerization constants was obtained. The examination of redox-active molecules using this experimental and theoretical approach will allow a better selection of redox flow battery electrolytes.

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“…55 To achieve multiple colors and enhance the functionality of all-in-one type EC devices the incorporation of several EC chromophores is inevitable. 56 They can achieve the simplest device configuration because of the facile fabrication using versatile solution processes (e.g., spin coating and printing) and easily tunable device characteristics such as transmittance contrast, color, operating voltage, and cyclic stability by varying the concentration of chromophores 57,58 and tuning the electrochemical properties 59 or molecular structures 60,61 of redox species. To this end, 1,1′-disubstituted-4,4′-bipyridinium salts known as viologens have been extensively studied because their optical and electrochemical properties can be easily tunable by modifying their substituents.…”

Section: Introductionmentioning

confidence: 99%

Advanced developments in nonstoichiometric tungsten oxides for electrochromic applications

et al. 2021

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Effects of counter ions on electrochromic behaviors of asymmetrically substituted viologens

Cited by 43 publications

References 40 publications

Obtaining Reversible, High Contrast Electrochromism, Electrofluorochromism, and Photochromism in an Aqueous Hydrogel Device Using Chromogenic Thiazolothiazoles

Obtaining Reversible, High Contrast Electrochromism, Electrofluorochromism, and Photochromism in an Aqueous Hydrogel Device Using Chromogenic Thiazolothiazoles

Concentration Effects on the First Reduction Process of Methyl Viologens and Diquat Redox Flow Battery Electrolytes

Advanced developments in nonstoichiometric tungsten oxides for electrochromic applications

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