Electrochromism displays

Fast-Ion-Gonducting Glasses. One possible appHcation of fast-ion-conducting glasses is in soHd-state batteries (qv) for automobiles. The glasses might also be used in electrochromic displays or as sensors (qv) (25). 

Optics Electrochromic displays, optical filters (windows with adjustable transparency), materials with non-linear optical properties... 

Wlieii thiomethoxymethyl hexachloroaiitimoiiate was treated with pyridine, a methylthio derivative 28 was isolated in low yield in addition to the expected chlorinated sulfides (71T4209). Several A, A -haloalkyl-bis-4,4 -pyridiniumethenes 29 have been reported in a Japanese patent (80JAP75479). Tliese compounds are promising candidates for the construction of electrochromic display devices (Scheme 7). 

There are various ways in which CMEs can benefit analytical applications. These include acceleration of electron-transfer reactions, preferential accumulation, or selective membrane permeation. Such steps can impart higher selectivity, sensitivity, or stability to electrochemical devices. These analytical applications and improvements have been extensively reviewed (35-37). Many other important applications, including electrochromic display devices, controlled release of drugs, electrosynthesis, and corrosion protection, should also benefit from the rational design of electrode surfaces. 

The enormous efforts put into the basic research and development of conducting polymers are naturally related to hopes of feasible technical apphcations The starting point of this development was the discovery that PA can fimction as an active electrode in a rechargeable polymer battery. Since then, the prospects of technical application have grown considerably Apart from the battery electrode, conducting polymers are discussed as potential electrochromic displays... 

Polynuclear transition metal cyanides such as the well-known Prussian blue and its analogues with osmium and ruthenium have been intensely studied Prussian blue films on electrodes are formed as microcrystalline materials by the electrochemical reduction of FeFe(CN)g in aqueous solutionThey show two reversible redox reactions, and due to the intense color of the single oxidation states, they appear to be candidates for electrochromic displays Ion exchange properties in the reduced state are limited to certain ions having similar ionic radii. Thus, the reversible... 

Electrolytes for Electrochromic Devices Liquids are generally used as electrolytes in electrochemical research, but they are not well suited for practical devices (such as electrochromic displays, fuel cells, etc.) because of problems with evaporation and leakage. For this reason, solid electrolytes with single-ion conductivity are commonly used (e.g., Nafion membranes with proton conductivity. In contrast to fuel cells in electrochromic devices, current densities are much lower, so for the latter application, a high conductivity value is not a necessary requirement for the electrolyte. 

The leucos 7h-o are claimed in electrolytic recording paper using a process coined electrochromic recording which is an irreversible electrooxidation of the leuco dye to regenerate Methylene Blue, not to be confused with reversible electrochromic display. The process consists of passing an electrical pulse through a substrate containing the leuco dye and... 

Kobayashi T., Yoneyama H., Tamura H. Polyaniline film-coated electrodes as electrochromic display devices J.Electroanal.Chem., 1984 161 429-23... 

Because of the stability of their reduced forms, in combination with remarkable and reversible color changes, these quinoid radialenes have been suggested as materials for electrochromic display devices18,3515. 

Electrochromic displays, 6 572t, 582—583 Electrochromic foil device, laminated polyester- based, 23 22 Electrochromic materials, 6 571-587 anodically colored inorganic films, 6 579-580... 

The development of conducting polymers is naturally related to hopes of feasible technical applications. Thus, conducting polymers are discussed as active battery electrodes [10], electrochromic displays (BCD) [11], anticorrosives [12], sensors [13], electrocatalysts [14], antistatic materials [15], or light-emitting materials (OLED) [16],... 

Figure 8.1 Beer s law-type plot of change in optical absorbance against charge density q for the cell WO3 polymer electrolyte Prussian Blue. Reprinted from Inaba, H Iwaka, M., Nakase, K., Yasukawa, H., Seo, I. and Oyama, N., Electrochromic display device of tungsten trioxide and Prussian Blue films using polymer gel electrolyte of methacrylate , Electrochim. Acta, 40, 227-232 (1995), Copyright 1995, with permission from Elsevier Science.

Since the band structure which develops upon doping induces changes not only in the conductivity but also in the optical absorption (see Fig. 9.8), conducting polymers may be exploited for electrochromic displays, which are optical devices with marked colour transitions. An example is illustrated diagramatically in Fig. 9.18. 

For instance, inclusion of l,T-dimethyl-4,4 -dipyridyl cation-radical (the cation-radical of methyl viologen) into a cavity of sulfocalixarenes prevents the disadvantageous n dimerization. This is important for more effective use of viologens as components of electrochromic displays and electric condnctors (Gno et al. 2007, references therein). 

Fast ion conduction has been made use for developing electrochromic displays. WO3 is a pale yellow solid that becomes deep blue when a small amount of Na is incorporated, owing to formation of Na (W03. Since the change occurs reversibly and very fast, the material has been used in displays. 

Fuel cell polymer battery photoelectric cell capacitor Storage element liquid crystal display device electrochromic display device electrochemiluminescence device photoelectric transducer Biosensor ion sensor detector in HPLC and FIA gas sensor voltam-metric indicator electrode reference electrode... 

There is growing evidence of developing high-technology uses of pyridines, particularly as quaternary salts, as components of electrolytic capacitors, photocondnctors. rechargeable batteries, complex-coated electrodes for photosensors, electrochromic display elements and photoresist matrix resins. 

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