A new way to obtain black electrochromism: appropriately covering whole visible regions by absorption spectra of copolymers composed of EDOT and carbazole derivatives

Güzel, Merve; Karatas, Erhan; Ak, Metin

doi:10.1088/1361-665x/aaf1e3

Cited by 18 publications

(11 citation statements)

References 36 publications

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“…The redox switching a * b * traces for each of the polymers (Figure b) show that ECP–Random25, ECP–Random30, and ECP–Random40 all have a * b * values that lie within the color-neutral range (which we define as a * and b * values not deviating from the origin, i.e., within ±10), while ECP–Random20 has its neutral state a * values lying slight above 10, moving into the region of red hue. Results on previously published neutral hue ECPs have been shown to possess color neutrality in their extreme potentials; however, their a * b * values often lie outside of ±10 at intermediate voltages. ,,, As the vibronic features are bleached at different rates, this results in an increase in a * and/or b * values to above 10 before returning to color neutral as the polymer continues to be oxidized. Similarly in a previous ECP blending study where multiple ECPs are mixed to achieve color neutrality, we also see colored intermediate states resulting from the differences in oxidation potential of the various polymers .…”

Section: Resultsmentioning

confidence: 99%

Fine-Tuning the Color Hue of π-Conjugated Black-to-Clear Electrochromic Random Copolymers

Shen

Reynolds

2019

Macromolecules

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A family of dioxythiophene (DOT)-based conjugated random copolymers, capable of reversibly switching between a neutral black and an oxidized transmissive state, are reported for electrochromic (EC) applications. By replacing 3,4-ethylenedioxythiophene (EDOT) in the previous generation of a core donor–acceptor–donor (D–A–D) terheterocycle with a methyl-alkylated 3,4-propylenedioxythiophene (ProDOT), we enhance the solubility of precursors and monomers in this new generation of broadly absorbing electrochromic polymers (ECPs). By adjusting the newly designed terheterocycle monomer feed ratio, we obtain three polymers with varying hues of color neutrality (a* and b* < ±10) throughout the entire switching voltage range and with integrated contrasts 45–49% throughout the visible region (380–700 nm). The a* values of the polymers ranged between −8 (green hue) and +5 (red hue), with their b* values ranging between −4 and −7 (blue hue) in their neutral states; additionally, the a* and b* values are all below ±8 in their oxidized states. In electrochromic devices (ECDs), we exploit this variation in color hue to achieve color balance with the counter electrode materiala minimal color-changing polymer (MCCP) that is colorless in its fully neutral and oxidized states but light red at intermediate potentials. This red hue was balanced by the green hue of ECP–Random40, leading to an ECD that was color-neutral (a* ranging from −0.8 to −11 and b* ranging from −0.5 to 1.7) throughout the switching voltage range. This family of high-contrast and color-neutral ECPs are scalable with high yielding syntheses for all monomers due to the enhancement of monomer solubility and the usage of commonly available DOT moieties, which will aid in advancing the development of large-scale polymer-based EC window and display applications. This method provides materials that switch from black to transmissive through only gray intermediates as needed for switchable color tinting applications.

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Section: Resultsmentioning

confidence: 99%

Fine-Tuning the Color Hue of π-Conjugated Black-to-Clear Electrochromic Random Copolymers

Shen

Reynolds

2019

Macromolecules

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“…An interesting recent work focuses on electrochemical copolymerisation of EDOT with either of two conjugation restrained, star-shaped triazine-core, carbazole-arm derivatives [ 42 ]. Tuning the monomer feed ratio to optimise colouration efficiency, and tailoring the thickness of electrochromic layers, through careful electropolymerisation conduct, to maximise contrast ratios, afforded multielectrochromic layers, switching from clear to black through at least three intermediate hues.…”

Section: Pursuing the Goalmentioning

confidence: 99%

Transparent to Black Electrochromism—The “Holy Grail” of Organic Optoelectronics

2019

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In the rapidly developing field of conjugated polymer science, the attribute of electrochromism these materials exhibit provides for a multitude of innovative application opportunities. Featuring low electric potential driven colour change, complemented by favourable mechanical and processing properties, an array of non-emissive electrochromic device (ECD) applications lays open ahead of them. Building up from the simplest two-colour cell, multielectrochromic arrangements are being devised, taking advantage of new electrochromic materials emerging at a fast pace. The ultimate device goal encompasses full control over the intensity and spectrum of passing light, including the two extremes of complete and null transmittance. With numerous electrochromic device architectures being explored and their operating parameters constantly ameliorated to pursue this target, a summary and overview of developments in the field is presented. Discussing the attributes of reported electrochromic systems, key research points and challenges are identified, providing an outlook for this exciting topic of polymer material science.

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“…The same authors recently reported the electrochemical polymerization of an original carbazole-thiophene unit substituted with an alkyl chain in position 3, which sterically inhibited one of the processes that occur due to a high potential and resulted in the formation of a material with a more regular structure [47]. In another study, electrochemical copolymerization of carbazole derivatives and ethylenedioxythiophene (EDOT) led to the formation of original materials with electrochromic properties between black and transparent [48]. Similarly, Aydin et al electropolymerized copolymers of carbazoles with thiophene, EDOT and pyrrole [49].…”

Section: Introductionmentioning

confidence: 99%

Electrodeposition and Characterization of Conducting Polymer Films Obtained from Carbazole and 2-(9H-carbazol-9-yl)acetic Acid

et al. 2022

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Electrochemical oxidation of electrolyte solutions containing carbazole (Cz) and 2-(9H-carbazol-9-yl)acetic acid (CzA) monomers was performed in acetonitrile solutions. Different Cz and CzA feed ratios were used to electrodeposit solid polymer films of various compositions, and to study the influence of the monomer ratio on the physicochemical properties (electroactivity, topography, adhesion, stiffness, wettability) of the polymer films. Thus, electrochemical oxidation led to the deposition of a solid film of micrometric thickness, but only for the solutions containing at least 30% of Cz. The proportion of Cz and CzA in the electrodeposited polymer films has little impact on the adhesion strength values measured by AFM. On the contrary, this proportion significantly modifies the stiffness of the films. Indeed, the stiffness of the polymer films varies from 9 to 24 GPa depending on the monomer ratio, which is much lower than the value obtained for unmodified polycarbazole (64 GPa). This leads to the absence of cracks in the films, which all have a fairly homogeneous globular structure. Moreover, among the different polymer films obtained, those prepared from 70:30 and 50:50 ratios in Cz:CzA monomer solutions seem to be the most interesting because these green films are conductive, thick, low in stiffness, do not show cracks and are resistant to prolonged immersion in water.

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A new way to obtain black electrochromism: appropriately covering whole visible regions by absorption spectra of copolymers composed of EDOT and carbazole derivatives

Cited by 18 publications

References 36 publications

Fine-Tuning the Color Hue of π-Conjugated Black-to-Clear Electrochromic Random Copolymers

Fine-Tuning the Color Hue of π-Conjugated Black-to-Clear Electrochromic Random Copolymers

Transparent to Black Electrochromism—The “Holy Grail” of Organic Optoelectronics

Electrodeposition and Characterization of Conducting Polymer Films Obtained from Carbazole and 2-(9H-carbazol-9-yl)acetic Acid

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