Electro-chromic device

Electrochemical applications of polyanilines comprise - electro chromic devices, - electrochemical sensors, and bioelectrochemical devices (- biosensors, - biofuel cells). 

Argun, A.A. and J.R. Reynolds. 2005. Line patterning for flexible and laterally configured electro-chromic devices. J Mater Chem 15 1793-1800. 

The electrochemical behavior of redox molecules in polymer films and gels has been investigated [4,7,18,23,61-66], but such behavior has usually been studied by using a modified electrode coated with a polymer film or gel in the presence of an outer electrolyte solution. In a few examples, entirely solid-state voltammetry was also achieved, but by using a microelectrode array [65,66] composed of working, counter, and reference electrodes because of the slow ionic or molecular diffusion in the soHd matrices. The apparent diffusion coefficient (Dapp) of a redox substrate in the films or solids coated on an electrode was very small [4,7,18,23,62-66], usually of the order of less than 10 cm s Another example of solid state votammetry is a report on the electrochemistry of Prussian blue in silica sol-gel electrolytes [67], but only Pt gauze working and counter electrodes for a - 1 mm-thick silica solid were used. Moreover, it is well known that solid electrolytes have been used on various sensors, electro chromic devices, etc. [68,69]. However, in spite... 

Based on conducting polymer nanomaterials, various apphcations are reviewed in the final section. These applications include chemical sensor and biosensor, transistor and switch, data storage, supercapacitor, photovoltaic cell, electro chromic device, field emission display, actuator, optically transparent conducting material, surface protection, and substituent for carbon nanomaterials (Fig. 1). Because large amounts of research have been dedicated to this field, it is very difficult to cover whole apphcation fields of conducting polymers. Some comprehensive review articles related to applications of conducting polymers are available [67-73]. 

FIGURE 12 Schematic design of (a) a rechargeable lithium battery and (b) an electro-chromic device. 

Randin, J. R, 1982, Ion-containing polymers ass semisolid electrolytes in WO -based electro-chromic devices, J. Electrochem Soc. 129 1215-1220. 

Draw out the most common Transmission-mode and Reflectance mode electro-chromic device constructs. Investigate optimized placements of a third, reference electrode in each, and alternative placements of the counter electrode. 

There is increasing interest in optical devices commonly called electro-chromic (smart) windows (EWs), i.e. ECDs which allow electrochemically... 

Considering their possible applications in fuel cells, hydrogen sensors, electro-chromic displays, and other industrial devices, there has been an intensive search for proton conducting crystals. In principle, this type of conduction may be achieved in two ways a) by substituting protons for other positively charged mobile structure elements of a particular crystal and b) by growing crystals which contain a sufficient amount of protons as regular structure elements. Diffusional motion (e.g., by a vacancy mechanism) then leads to proton conduction. Both sorts of proton conductors are known [P. Colomban (1992)]. 

Probable applications in various fields like electro chromic displays, electronic devices, modified electrodes, chemical- and bio-sensors etc. [ 133] may be envisaged. Potentially, nanodimensional oxide- (Si02, Mn02 and Zr02) based composites of these polymers have shown promise as optical materials [50]. Conducting polymer-coated low Tg latexes of sub-micron (50-500 nm) dimensions are reported to find use in antistatic and anticorrosion applications [ 113]. In the light of this information it would be of interest to explore the usability of the corresponding MMT-based composites in these directions. 

PANI is suited to the production of very fa.st devices, because the time necessary for the colour changes is about one order of magnitude shorter than in electro-chromic oxides [34]. In fact, it is the cell resistance which controls the switching speed of the device, and if it were possible to take into account just the transport inside the film, it would be possible to obtain response times as short as 100 ps [17]. 

Rauh, R.D., F. Wang, J.R. Reynolds, and D.L. Meeker. 2001. High coloration efficiency electro-chromics and their application to multi-color devices. Electrochim Acta 46 2023-2029. 

FIGURE 16.18. Change in optical density as a function of time for an electrochromic device of the type shown in the inset. The data are based on measured reflectance R. (From Granqvist, C., Handbook of Inorganic Electro-chromic Materials, Elsevier Science, 1995. With permission.)... 

A novel type of device configuration first apparently proposed by Inganas and Lundstrom [865], and developed to a considerable degree of refinement by Chandrasekhar et al. [866], is one which is based on interfacing a CP to an inorganic semiconductor (SC). This utilizes the well known electrochromic properties of the CP. The SC may be a material such as CdS or Ai-Si. In this context, it should be noted that the CP, in its doped form, is also a SC, but its semiconducting properties are not the primary focus of interest in such SC/CP interfaces- rather, its electro-chromic properties are. 

The ion storage layer acts in a similar active redox manner as the electro-chromic layer. During switching this layer incorporates and releases lithium ions, but in the opposite direction of the electrochromic layer. Usually this layer does not change its optical absorption during switching. Metal oxides or metal oxide combinations have been proposed as ion storage layers such as oxides based on cerium and titanium oxide as well as nickel oxides or vanadium oxides. Metal oxides suffer from their brittle nature, which limits their use in flexible devices. 

DE PAOU, M.A., NOGUEiRA, A.F., MACHADO, D.A., CONGO, c., All-polymcric electro-chromic and photoelectrochemical devices new advances, Electrochim. Acta,... 

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