Novel dual-colored 1,1′,1″,1‴-tetrasubstituted (4,4′,4″,4‴-tetrapyridyl) cyclobutane with rapid electrochromic switching

Cross-Linked and Surface-Modified Cellulose Acetate as a Cover Layer for Paper-Based Electrochromic Devices

We studied the surface and microstructure of cellulose acetate (CA) films to tailor their barrier and mechanical properties for application in electrochromic devices (ECDs). Cross-linking of CA was carried out with pyromellitic dianhydride to enhance the properties relative to unmodified CA: solvent resistance (by 43% in acetone and 37% in DMSO), strength (by 91% for tensile at break), and barrier (by 65% to oxygen and 92% to water vapor). Surface modification via tetraethyl orthosilicate and octyltrichlorosilane endowed the films with hydrophobicity, stiffness, and further enhanced solvent resistance. A detailed comparison of structural, chemical, surface, and thermal properties was performed by using X-ray diffraction, dynamic mechanical analyses, Fourier-transform infrared spectroscopy, and atomic force microscopy. Coplanar ECDs were synthesized by incorporating a hydrogel electrolyte comprising TEMPO-oxidized cellulose nanofibrils and an ionic liquid. When applied as the top layer in the ECDs, cross-linked and hydrophobized CA films extended the functionality of the assembled displays. The results indicate excellent prospects for CA films in achieving environmental-friendly ECDs that can replace poly(ethylene terephthalate)-based counterparts.

Multichromic Monolayer Terpyridine-Based Electrochromic Materials

The article describes novel electrochromic materials (ECMs) that are based on a monolayer consisting of two or three isostructural metal complexes of 4'-(pyridin-4-yl)-2,2':6',2''-terpyridine simultaneously deposited on surface-enhanced support. The support was made by screen printing of indium tin oxide (ITO) nanoparticles on ITO-glass and has a surface area sufficient for a monolayer to give color visible to the naked eye. The ability to separately electrochemically address the oxidation state of the metal centers on the surface (i.e., Co²⁺/Co³⁺, Os²⁺/Os³⁺, and Fe²⁺/Fe³⁺) provides an opportunity to achieve several distinct color-to-color transitions, thus opening the door for constructing monolayer-based multicolor ECMs.

Multicolored electrochromic and electrofluorochromic materials containing triphenylamine and benzoates

Multicolored electrochromic and electrofluorochromic materials containing triphenylamine and benzoates were developed.

Viologen-Based Electrochromic Materials: From Small Molecules, Polymers and Composites to Their Applications

Organic materials have gained considerable attention for electrochromic (EC) applications owing to improved EC performance and good processability. As a class of well-recognized organic EC materials, viologens have received persistent attention due to the structural versatility and property tunability, and are major active EC components for most of the marketed EC devices. Over the past two decades, extensive efforts have been made to design and synthesize different types of viologen-based materials with enhanced EC properties. This review summarizes chemical structures, preparation and EC properties of various latest viologen-based electrochromes, including small viologen derivatives, main-chain viologen-based polymers, conjugated polymers with viologen side-chains and viologen-based organic/inorganic composites. The performance enhancement mechanisms are concisely discussed. The current marketed viologens-based electrochromic devices (ECDs) are briefly introduced and an outlook on the challenges and future exploration directions for viologen-based materials and their ECDs are also proposed.

Dual-colored 4,4′,4′′,4′′′-(cyclobutane-1,2,3,4-tetrayl)-tetrabenzoate electrochromic materials with large optical contrast and coloration efficiency

This paper reports novel ester-containing electrochromic materials, 4,4′,4′′,4′′′-(cyclobutane-1,2,3,4-tetrayl)tetrabenzoate derivatives, with dual-colored electrochromism, high color contrast and coloration efficiency.

Multifunctional polyurethanes synthesized from different triarylamine units with electrochromic, photogeneration, memory storage and sensing properties

Herein, we report three multifunctional polyurethane materials, which exhibit excellent electrochromic, photoelectric, memory and sensing properties, and also have good mechanical properties.

A novel organic electrochromic device with hybrid capacitor architecture towards multicolour representation

A multicolour novel electrochromic device containing both anodic and cathodic EC materials was fabricated with the simple hybrid capacitor architecture.