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The systematic study of two ionic porous organic polymers (iPOPs) based on viologens and their first applications in the electrochromic field are reported. The viologen-based iPOPs are synthesized by electrochemical polymerization with cyano groups, providing a simple and controllable method for iPOPs that solves the film preparation problems common to viologens. After the characterization of these iPOPs, a detailed study of their electrochromic properties is conducted. The iPOP films based on viologens structure exhibit excellent electrochromic properties. In addition, the resulting iPOP films show high sensitivity to electrolyte ions of different sizes in the redox process. Electrochemical and electrochromic data of the iPOPs explain this phenomenon in detail. These results demonstrate that iPOPs of this type are ideal candidates as electrochromic materials due to their inherent porous structures and ion-rich properties., (© 2024 Wiley‐VCH GmbH.)

Electrochromic polymers (ECPs) have great application potential in flexible displays, and there is an increasing expectation of using green methods to form ECP films. Herein, we propose a modified microemulsion method to prepare cyan/magenta/yellow (C/M/Y) water-dispersed electrochromic polymer nanoparticles (WDEN) systems. Three polymer films (WDECP-C/M/Y) maintain similar electrochemical properties compared to their corresponding organic solvent-based polymer films. It is intriguing that WDECP-C/M/Y exhibit better electrochromic properties in terms of higher cycling stability (97.24%, 95.05%, and 52.84%, respectively) and faster switching time (0.94 s, 1.09 s, and 1.34 s for coloring time, respectively) due to the introduction of nanoparticles. In addition, it can achieve various desired colors by blending the C/M/Y WDEN systems in different ratios. The calculated chromaticity coordinates of the blending polymer films show close values to the experimental observation, and the calculated Δ E * ab values range from 2.6 to 10.3, which may provide theoretical guidance for precisely color control. Finally, large-scale and patterned devices were assembled, which can achieve colored-to-colorless reversible electrochromism at a low driving voltage of 0–1.5 V. This work puts forward a universal and environmentally sustainable strategy to prepare WDEN systems, demonstrating their wide range of applications in display devices and electronic tags. [ABSTRACT FROM AUTHOR]

Electrochromic supercapacitors (ECSCs) that combine electrochromism and energy storage characters enable visual monitoring of the energy storage state of the device. In this work, two triphenylamine-based polymers pTPACB and pTTPACB were prepared by electrochemical polymerization. Both polymers exhibit multi-step redox behavior due to the presence of multiple triphenylamine and carbazole units. Correspondingly, pTPACB and pTTPACB can be switched from neutral colorless state to multicolored changes at different potentials. Compared with pTPACB, pTTPACB presents faster switching time and higher optical contrast. It is more intriguing that pTTPACB shows much more outstanding pseudocapacitive behavior with ultrahigh areal specific capacitance (6.64 mF‧cm-2) at a current density of 0.05 mA‧cm-2 due to the smaller nanoparticles size and loose aggregated structure. In addition, the asymmetric electrochromic supercapacitor devices based on pTTPACB can light a display panel or blue LED for 30 s accompanied with color changes from blue-green to colorless in the process of power supply. Hence, this work achieves a novel triphenylamine-based polymer for high-performance electrochromic supercapacitors, which shows great potential in electronic tags and display devices. [Display omitted] • Two triphenylamine-based polymers were prepared by electrochemical polymerization. • Two polymers present colorless to multicolored changes under different potentials. • pTTPACB exhibits remarkable electrochromic properties and higher specific capacitance. • Electrochromic supercapacitor exhibits robust cyclic stability over 30000 cycles. [ABSTRACT FROM AUTHOR]

Quinacridone (QA) dye shows great potential applications in organic optoelectronics owing to the large π-conjugated system, good photothermal stability, and high charge carrier transport behavior. In this work, two quinacridone-based monomers QA-B-CZ and QA-6C-CZ were designed and synthesized, and their polymers pQA-B-CZ and pQA-6C-CZ were prepared by electrochemical polymerization. Both pQA-B-CZ and pQA-6C-CZ exhibit multicolored electrochromic properties at different potentials. It is more intriguing that the pQA-6C-CZ bearing with the flexible long alkyl chain preserves multiple stimuli-responsive characteristics compared to pQA-B-CZ containing benzene unit. pQA-6C-CZ film exhibits reversible and robust acidichromic behavior switched from the initial pink color to purple color, implying its potential as a hydrochloric acid sensor. Besides, pQA-6C-CZ presents reversible orange fluorescence and it disappears in response to electric-/acid-stimulation. The multiple stimuli-responsive behaviors should be ascribed to that the flexible long alkyl chains break the conjugated structure between QA and carbazole, which is beneficial for developing their inherent characters, respectively. The work puts forward a new design strategy for the preparation of multifunctional optoelectronic materials based on QA dye. • Two polymers based on QA dye were designed and prepared via electrochemical polymerization. • Both polymers exhibit multicolored electrochromic properties at different potentials. • pQA-6C-CZ exhibits electrochromic, acidichromic as well as fluorescence properties. • The multiple stimuli-responsive behaviors should be ascribed to conjugated-broken strategy. [ABSTRACT FROM AUTHOR]

A core–shell composite of porous ZnO nanosheets and a multichromic conducting polymer poly(4,4′,4′′-tris[4-(2-bithienyl)pheny]amine) (PTBTPA) was prepared by electrodeposition combined with the electropolymerization method. The composite film exhibits noticeable electrochromism with reversible color changes from orange, olive green to dark gray. An optical contrast of 68.7% and a switching time of 0.96 s are obtained for the composite film, better than that of the pure PTBTPA film, 51.8% and 1.95 s. The cyclic stability studies reveal that the composite film exhibits much more enhanced durability and retains 70% of the electroactivity even after 1000 cycles. However, the pure PTBTPA film loses almost most of its electroactivity after 1000 cycles. The core–shell composite structure is believed to be responsible for the observed enhanced electrochromic performance. On one hand, porous ZnO nanosheets with loose inner space can facilitate the penetration of counterions into the polymer film and shorten the diffusion distance, resulting in the higher optical contrast and faster switching speed; on the other hand, the larger contact area can enhance the adhesion between the polymer and the ITO electrode, contributing to better electrochemical stability. [ABSTRACT FROM AUTHOR]

Abstract: Two new electrochromic materials consisting of carbazole and phenyl-methanone units, 4-(9H-carbazol-9-yl)-phenyl-methanone (CPM) and 4-(3,6-di(thiophen-2-yl)-9H-carbazol-9-yl)-phenyl-methanone (TCPM), were synthesized and characterized. Both the compounds show well-defined oxidation and reduction processes. Spectroelectrochemical analysis reveals that their polymers display reasonable optical contrast (25%,41%) and fast switching time (3s,2s). Cyclic voltammogram study confirms that the polymer with the existence of thiophene units is more stable in electrochemical environment. [Copyright &y& Elsevier]

[Display omitted] • A soluble conjugated polymer with reversible change from yellow to light green. • The polymer shows ultrafast coloring time (0.21 s) and a high coloring efficiency. • The polymer can be used as a ion detection to detect Fe3+ with a low detection limit. • Such soluble conjugated polymers are reported firstly to detect Ru3+ (8.07 μM). The design of soluble electrochromic materials with fast responsivity for use in flexible displays and electronic papers remains a challenge. Most of the materials explored properties such as excellent contrast and rich color variation, while fast responsivity is also one of the key properties, which together push electrochromic materials into everyday life. Here we report a soluble electron conjugated polymer PDT-BTz, i.e., poly[3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b] [1,4] dioxepine-alt-(2-(heptan-3-yl)benzo[d]thiazole], which was designed to be highly redox active polymeric backbone for electrochromism and constructed to engineer with chelating sites for metal ion detection, via direct (hetero)arylation polymerization of 3, 4-propenyldioxythiophene with benzothiazole derivative. The resultant PDT-BTz exhibited a pair of distinct redox peaks in the range of 0.41–––1.20 V, corresponding to a clear color change in the visible region between yellow and light green as revealed by cyclic voltammetry. PDT-BTz is easily casted into thin film and is highly responsive to visible light to achieve a very short response time of only 0.21 s, which is much far superior to other polymers reported so far. Remarkably, this electrochromic PDT-BTz is highly luminescent and enables to selectively detect iron Fe (III) and Ru (III) ions, via built-in C–S and C = N chelating units, with exceptional rate constants and detection limits. Together with the high thermal stability, the electron polymer opens a way to a novel class of soluble conjugated polymer that can merge dual functions of electrochromism with ion detection capability into one material. [ABSTRACT FROM AUTHOR]

A new dithienylpyrrole derivative, namely terphenyl bridged-di[2,5-di (2-thienyl)-1H-pyrrole] (TPhSNS), was designed and synthesized, then it was further prepared into cross-linked polymer (pTPhSNS) or copolymer (pTPhSNS-EDOT) with 3, 4-ethylenedioxythiophene (EDOT) via electrochemical polymerization. The cyclic voltammetry curves show that both the obtained pTPhSNS polymer and pTPhSNS-EDOT copolymer possess the excellent reversible oxidative properties. The UV–vis absorption spectra of pTPhSNS-EDOT at neutral state exhibits the similar character to pTPhSNS with very little redshift observed. After being applied at the positive voltage, the pTPhSNS-EDOT copolymers present a grey-blue color at the oxidation state, which is also close to the grey color of pTPhSNS (oxidized). Surprisingly, the pTPhSNS-EDOT copolymers exhibit the faster coloring time of 0.58 s and discoloring time of 0.38 s (at 1100 nm) compared with the pTPhSNS homopolymer films. Besides, the copolymers present a reasonable optical contrast of 40% (1100 nm). These results indicate that the introduction of EDOT into TPhSNS by copolymerization maybe help to form the expected cross-linked polymer structure with excellent electrochromic properties. Interestingly, both pTPhSNS and pTPhSNS-EDOT films present the electrochromic color memory behavior with excellent color stability at the oxidative state. The excellent electrochromic properties and color memory behavior enable TPhSNS with great potential applications in electrochromic area. [ABSTRACT FROM AUTHOR]