Electrochromism

About: Electrochromism is a research topic. Over the lifetime, 13097 publications have been published within this topic receiving 294637 citations.

The Dynamics of Mobile Ions in Ionically Conducting Glasses and Other Materials

Abstract: The range of applications for ionically conducting materials in technology is very broad and includes batteries; fuel cells; sensors; electrochromic displays; catalysts, oxygen, and hydrogen pumps; and bionics. In most of these applications, the mobility of the ions is a determining factor for optimum performance. Examples are liquid-electrolyte and plastic Li+ ion batteries for portable electronics, solid oxide fuel cells such as the oxygen ion-conducting stabilized zirconia electrolyte for energy conversion, and exchange of different ions in oxide glasses for the fabrication of micro-optic lenses. Therefore research on the dynamics of ionic transport that clarifies the mechanisms limiting the mobility of the ions is useful. These dynamic processes are also fascinating from a basic research point of view and qualitatively follow general patterns independent of the chemical and physical structures of the materials, suggesting that some fundamental physical mechanism is at work. On a quantitative level, the ionic-transport properties depend on the structures of the materials seemingly in well-defined patterns, which can be used to advantage in choosing materials for specific applications.

Structure and electrochromism of two-dimensional octahedral molecular sieve h’-WO 3

Abstract: Octahedral molecular sieves (OMS) are built of transition metal-oxygen octahedra that delimit sub-nanoscale cavities. Compared to other microporous solids, OMS exhibit larger versatility in properties, provided by various redox states and magnetic behaviors of transition metals. Hence, OMS offer opportunities in electrochemical energy harnessing devices, including batteries, electrochemical capacitors and electrochromic systems, provided two conditions are met: fast exchange of ions in the micropores and stability upon exchange. Here we unveil a novel OMS hexagonal polymorph of tungsten oxide called h'-WO3, built of (WO6)6 tunnel cavities. h'-WO3 is prepared by a one-step soft chemistry aqueous route leading to the hydrogen bronze h'-H0.07WO3. Gentle heating results in h'-WO3 with framework retention. The material exhibits an unusual combination of 1-dimensional crystal structure and 2-dimensional nanostructure that enhances and fastens proton (de)insertion for stable electrochromic devices. This discovery paves the way to a new family of mixed valence functional materials with tunable behaviors.

Fast Switching Water Processable Electrochromic Polymers

Abstract: This paper describes the synthesis of two new blue to transmissive donor–acceptor electrochromic polymers: a polymer synthesized using an alternating copolymerization route (ECP-Blue-A) and a polymer synthesized using a random copolymerization (ECP-Blue-R) by Stille polymerization. These polymers utilize side chains with four ester groups per donor moiety, allowing organic solubility in the ester form, and water solubility upon saponification to their carboxylate salt form. We demonstrate that the saponified polymer salts of ECP-Blue-A and ECP-Blue-R (WS-ECP-Blue-A and WS-ECP-Blue-R) can be processed from aqueous solutions into thin films by spray-casting. Upon the subsequent neutralization of the thin films, the resulting polymer acid films are solvent resistant and can be electrochemically switched between their colored state and a transmissive state in a KNO3/water electrolyte solution. The polymer acids, WS-ECP-Blue-A-acid and WS-ECP-Blue-R-acid, show electrochromic contrast Δ%T of 38% at 655 nm and 3...

Nanostructured inorganic electrochromic materials for light applications

Abstract: Abstract Electrochromism, an emerging energy conversion technology, has attracted immense interest due to its various applications including bistable displays, optical filters, variable optical attenuators, optical switches, and energy-efficient smart windows. Currently, the major drawback for the development of electrochromism is the slow switching speed, especially in inorganic electrochromic materials. The slow switching speed is mainly attributed to slow reaction kinetics of the dense inorganic electrochromic films. As such, an efficient design of nanostructured electrochromic materials is a key strategy to attain a rapid switching speed for their real-world applications. In this review article, we summarize the classifications of electrochromic materials, including inorganic materials (e.g., transition metal oxides, Prussian blue, and polyoxometalates), organic materials (e.g., polymers, covalent organic frameworks, and viologens), inorganic-organic hybrids, and plasmonic materials. We also discuss the electrochromic properties and synthesis methods for various nanostructured inorganic electrochromic materials depending on structure/morphology engineering, doping techniques, and crystal phase design. Finally, we outline the major challenges to be solved and discuss the outlooks and our perspectives for the development of high-performance nanostructured electrochromic materials.