A review of electrochromic (EC) polymers and their applications in absorption/transmission, reflective, and patterned electrochromic devices (ECDs) is presented. Fundamental properties of EC materials such as optical contrast, coloration efficiency, switching speed, and stability are described along with the commonly used characterization methods. The origin of electrochromism in conjugated polymers is explained in terms of the electronic structure changes in the backbone upon doping/dedoping. The ability to tailor the EC properties of conjugated polymers and tune their color states via modification of the polymer structure is demonstrated. Multicolor electrochromic materials can be obtained by substitution of a parent polymer and controlled polymerization of comonomers and with blends and laminates of homopolymers. Absorption/transmission-type ECDs from complementarily colored polymers and reflective-type ECDs on metalized substrates are illustrated with several examples from the literature. Finally, sev...

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Multicolored Electrochromism in Polymers: Structures and Devices

This paper presents a review of the redox and electrocatalytic properties of transition metal oxide electrodes, paying particular attention to the oxygen evolution reaction. Metal oxide materials may be prepared using a variety of methods, resulting in a diverse range of redox and electrocatalytic properties. Here we describe the most common synthetic routes and the important factors relevant to their preparation. The redox and electrocatalytic properties of the resulting oxide layers are ascribed to the presence of extended networks of hydrated surface bound oxymetal complexes termed surfaquo groups. This interpretation presents a possible unifying concept in water oxidation catalysis – bridging the fields of heterogeneous electrocatalysis and homogeneous molecular catalysis.

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Redox and electrochemical water splitting catalytic properties of hydrated metal oxide modified electrodes

A series of dual polymer electrochromic devices (ECDs) based on 12 complementary pairs of conducting polymer films have been constructed using 3,4-ethylenedioxythiophene-containing conducting polymers. Poly[3,6-bis(2-(3,4-ethylenedioxythiophene))-N-methylcarbazole] (PBEDOT-NCH3Cz), poly[3,6-bis(2-(3,4-ethylenedioxythiophene))-N-eicosylcarbazole] (PBEDOT-NC20H41Cz), and poly[4,4‘-bis(2-(3,4-ethylenedioxythiophene))biphenyl] (PBEDOT-BP) were utilized as anodically coloring polymers that electrochemically switch between an oxidized deep blue absorptive state and a transmissive (orange or yellow) reduced state. Poly(3,4-ethylenedioxythiophene) (PEDOT) and its alkyl derivatives (PEDOT-C14H29 and PEDOT-C16H33) have been used as high-contrast cathodically coloring polymers that switch between a deep blue absorptive state in the reduced form and a sky blue, highly transmissive state in the oxidized form. The dual polymer ECDs were constructed by separating complementary pairs of EC polymer films, deposited on ITO...

High Contrast Ratio and Fast-Switching Dual Polymer Electrochromic Devices

A short survey of technological aspects of electrochromism with various electroactive species is given. Different approaches with inorganic and organic materials have been pursued in the past. So far widespread usage of this technology for large area applications has not been achieved. Nevertheless one major technical product, self-darkening rear-view mirrors for cars, is already well established. This article reviews some research results on electroactive polythiophenes, especially poly(3,4-alkylenedioxythiophenes). Some promising results with the commercially available electrically conducting polymer Baytron P (PEDT/PSS) are presented. It is demonstrated that an all solid-state electrochromic multilayer assembly based on a polymeric electrochromic material might be close to technical realization. The coating of large area substrates with aqueous poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) dispersion can be a way to an economically viable product.

J. C. Lacroix

Papers

Polyaniline: A Very Fast Electrochromic Material