Improving electrochromic properties via copolymerization

Abstract

Copolymers of 5,8-di(1H-pyrrol-2-yl)-2,3-di(thiophen-2-yl)quinoxaline (PTQ) in the presence of 2,2 -bis(3,4-ethylenedioxythiophene) (BiEDOT) and 4,7-bis (2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2-dodecyl-2H-benzo[1,2,3] triazole (BEBT) were synthesized via the potentiodynamic method in a tetrabutylammonium perchlorate/dichloromethane (TBAP/DCM) (0.1 M) solvent-electrolyte couple. P(PTQ-co-BiEDOT) reveals an oxidation potential at +0.45 V and a reduction potential at −0.2 V (figure 1(a)), whereas the homopolymer, P(PTQ) has an oxidation potential of +0.55 V and a reduction potential of +0.1 V. Spectroelectrochemical behaviors and the switching ability of copolymers were investigated by ultraviolet-visible (UV-vis) spectroscopy and cyclic voltammetry. The spectroelectrochemical behaviors of the P(PTQ-co-BiEDOT) and P(PTQ-co-BEBT) in comparison to the homopolymer revealed solid evidence of copolymerization based upon the differences in the spectral signatures. P(PTQ-co-BEBT) reveals 80% optical contrast at 1450 nm whereas the homopolymer achieves only 66% at 1460 nm. Coloration efficiency of P(PTQ-co-BEBT) was found to be 132 cm 2 C −1 compared to 116 cm 2 C −1 of the homopolymer at 100% full switch in the visible region. Switching times of the polymers were evaluated by kinetic studies upon measuring the per cent transmittance (%T ) at the maximum contrast point. P(PTQ-co-BEBT) switches between the two extreme states in 0.5 s compared to 1.2 s for the homopolymer.

Benzotriazole containing conjugated polymers for multipurpose organic electronic applications

“…19 Monomer of compound 19, 4,7-bis(2,3-dihydrothieno [3,4-b] [1,4]dioxin-5-yl)-2-dodecyl-2H-benzo [1,2,3] triazole (BEBT), was used as the comonomer against benzoquinoxaline and pyrrole bearing ones and it has been shown that copolymerization with BEBT increases the optical and kinetic properties of the resulting polymer even more efficiently than simple copolymerization with Bi-EDOT. 20,21 Benzazole-EDOT bearing DA type ECPs, 14 and 15, revealed a green color in their neutral states accompanied by highly transmissive oxidized states. 22,23 They showed two p-p* transitions which was claimed as essential to obtain green colored polymers.…”

Polypyrrole derivatives for electrochromic applications

“…134 The polymer possessed 66% optical contrast in the near IR region with a switching time of 1.2 s. Subsequently, the copolymer of (35) with BiEDOT was synthesized. 135 The resulting polymer had a l max at 525 nm (E g ¼ 1.4 eV) with a purple color in neutral state. The copolymer achieved 10% optical contrast around 2 s in the visible range.…”

Design, Synthesis, and Properties of Donor–Acceptor–Donor′ Asymmetric Structured Electrochromic Polymers Based on Fluorenone as Acceptor Units

“…Polymer electrochromic (PEC) materials have received extensive attention due to their wide variety of structures, rich color range, high optical contrast, good processability, adjustable band, and fast response and are considered as one of the development directions for the next generation of EC materials. − At present, the multicolor display properties of PEC materials are generally achieved through molecular structure design and modification such as donor–acceptor (D–A) structure design and the copolymerization of different monomers. − Copolymerization is an effective structural adjustment method that can combine the advantages of two or more monomers to improve the electrochromic properties of polymers. , We have used copolymerization to synthesize a series of multicolor display polymer materials. − However, the randomness of the copolymerization is not conducive to the in-depth study of the relationship between the molecular structure and the discoloration properties of the PEC material.…”