Showing papers on "Electrochromism published in 1988"

Electrochromic nickel-oxide-based coatings made by reactive dc magnetron sputtering: preparation and optical properties

Abstract: NiOx films were made by dc magnetron sputtering of Ni in O2 at a rate of 100 color‐bleach cycles to establish a fully bleached state. When removed from the KOH electrolyte, a colored NiOxHy film increased its transmittance by <1% per h. The luminous and solar transmittance could be varied between 80% and 20% and between 74% and 29%, respectively.

Electrochromic layer-set

Abstract: An electrochromic layer-set, operating with hydrogen, comprises a transparent substrate front face plate, at least two electrodes, at least one electrochromic layer, a hydrogen ion-storing layer, a hydrogen ion-conducting layer, a rear face in sealing relationship with the layer-set, directly following one of the two electrodes, there being a metallic layer between the rear face and the layer lying in front of the rear face (the electrode) or the rear face itself is formed by this metallic layer. The side of the metallic layer turned away from the substrate plate is optionally transformed into the oxide of the metal. For the application of such a metallic layer, the layer-set and a counter-electrode are immersed in an electrolyte containing the metal ions, with the electrode lying at the rear face of the layer-set being made the negative electrode.

Electrochemical Behaviors of Polypyrrole, Poly‐3‐methylthiophene, and Polyaniline Deposited on Nafion‐Coated Electrodes

Abstract: Anodic polymerization of pyrrole, 3‐methylthiophene, and aniline at Nafion‐coated electrodes gives conducting polymer‐Nafion composite films The composite films show better reversibility in the film redox process than conducting polymer films alone, owing to different charge compensation mechanisms in the redox reaction; electrolyte cations are involved in the redox process of the composite films, whereas electrolyte anions are in the ordinary conducting polymers The fast kinetics of the redox process of the composite films are effectively demonstrated by an improvement of the polypyrrole electrochromic response and by the efficient utilization of stored charge by the composite film electrodes

Electrochromic properties of sputtered nickel-oxide films

Abstract: Electrochromic properties of nickel‐oxide films have been investigated. Films were prepared by rf sputtering from a compressed powder NiO target in an atmosphere of an Ar‐O2 mixture. The deposition rate of the nickel oxide decreased when the total pressure of the sputtering atmosphere was increased, but was independent of the oxygen content. The films obtained can be electrochemically colored and bleached in a 1‐N NaOH electrolyte solution, and are colored anodically. The colored film is dark brown, and the bleached one is transparent and colorless. The maximum coloration efficiency is obtained with the films prepared at the total pressure of 0.04 Torr, and is 36 cm2/C at a wavelength of 640 nm. Coloration efficiency is independent of oxygen content in the sputtering atmosphere.

Electrochromism of a conducting polypyrrole-phosphotungstate composite electrode

Abstract: A phosphotungstate-anion (PT)-incorporated polypyrrole (PPy/PT) electrode has been prepared by electrochemical polymerization in water containing both pyrrole and the sodium salt of PT. The PPy/PT electrode showed two redox peaks accompanying electrochromism. The peak at higher potential corresponds to an oxidation–reduction of the incorporated PT, and the other at lower potential corresponds to that of the PPy. The incorporated PT is released from the PPy matrix in neutral aqueous solution (pH 7) and is not released in acidic aqueous solution (pH 2) when the PPy is reduced at < –400 mV vs. SCE. The PPy/PT electrode in neutral solution showed blue, red and yellow colours corresponding to the different redox states of the PPy/PT. However, the PPy/PT electrode in acidic solution showed blue, red and blue–purple. The blue and yellow were assigned to the oxidative and the reductive PPy, respectively. The red and blue–purple were assigned to the PT in the oxidation and the reductive PPy matrix, respectively. The red colour of the PT is a result of interaction between the incorporated PT and the pyrrole moiety. The PPy/PT composite electrode is multielectrochromic.

Electrochromic display device capable of display in plural colors

Abstract: In an electrochromic (EC) display device having oppositely arranged two EC electrode layers, two kinds of EC materials each of which takes on a characteristic color by electrochemical oxidation, or by electrochemical reduction, are used in the two EC electrode layers, respectively, on condition that the characteristic color of one EC material differs from the color of the other EC material For example, Prussian blue which colors in blue by oxidation and polytriphenylamine which colors in bronze by oxidation are used in combination An alternative example is using a combination of WO3 which colors in blue by reduction and V2 O5 which colors in green by reduction Since electrochemical oxidation of one EC electrode layer is usually accompanied by reduction of the opposite EC electrode layer, this EC device can be operated so as to selectively and alternately exhibit at least two different colors aside from colorless transparency

Electrochromic window with metal grid counter electrode

Abstract: An electrochromic transparency comprising an electrochromic film and an ion-conductive layer disposed between a pair of electrodes is disclosed wherein the optical properties and electrochromic efficiency are improved by means of a metal grid electrode.

New electrochromic device and method of making an electrochromic layer therefor

Abstract: This invention teaches an electrochromic device in which an electrochromic layer is positioned between two electrodes. The electrochromic layer comprises an organic based bulk material which has been polymerized and condensed supporting electrochromic particles and ion producing particles in fixed but generally distributed positions therewithin. The bulk material permits migration of ions produced by the ion producing particles to and from the electrochromic particles upon change in voltage between the first and second electrodes. The bulk material also prohibits the passage of electrons therethrough when a voltage is applied between the first electrode and the second electrode, whereby an electric field is built up between the first and second electrodes which causes migration of the ions. Also my invention is a method of making a material which can form an electrochromic layer. The method has the following steps. A gel producing organic material is dissolved in a solvent to produce a solution. The gel producing material is one which permits migration of ions therethrough but prohibits passage of electrons therethrough. A finely divided ion producing material is added to the solution. A finely divided electrochromic material is also added to the solution. The solution is thoroughly mixed. The solution is then polymerized and condensed to obtain a gelled material. The gelled material supports the finely divided ion producing material and the finely divided electrochromic material in fixed but generally distributed position therewithin.

Solid‐State Electrochromic Devices Composed of Prussian Blue, WO 3, and Poly(ethylene oxide)‐Polysiloxane Hybrid‐Type Ionic Conducting Membrane

Abstract: The preparation of a new type of poly(ethylene oxide)-polysiloxane hybrid (PEOS) with its application to the construction of solid-state electrochromic devices was studied. The PEOS was given as a colorless and elastic membrane by condensation of a bis(silylpropyl) ether of oligo(ethylene oxide) and a polyalkoxysilane in the presence of LiClO/sub 4/ (2-5 mole percent). The ionic conductivity reached 10/sup -3/ S cm/sup -1/ when PEOS was swollen with propylene carbonate by 160% in weight. A transparent-type solid-state electrochromic device composed of Prussian blue- and WO/sub 3/-coated electrodes with PEOS was prepared, switching of which was slower by a factor of 1.5-2.0 as a function of half-time of coloration and bleaching compared with the corresponding liquid-type cell.

Formation of Nickel Oxyhydroxide Thin Films by Electrodepositon and Their Electrochromic Characteristics

Abstract: Electrochromic nickel oxyhydroxide films were formed by an electrodeposition method from 0.005 M NiSO4+0.015 M (NH4)SO4 solution, and their memory characteristics, response time and operation lifetime were investigated. The films prepared were porous with a network structure. They were colorless and transparent in a lower oxidation state [Ni(OH)2], but were dark brown in a higher oxidation state [NiOOH]. By heat-treating the films at 250degC for 15 minutes, electrochromic characteristics such as the operation lifetime could be remarkable improved.

Planar electrochromic dimmer

Abstract: The present invention relates to a planar electrochromic dimmer used in dimming devices such as car sun roofs, and others having a structure comprising; a pair of bases, each comprising a transparent electrode film provided on each of a pair of bases, and arranged such that both transparent electrode films are facing each other, an electrolyte provided between the two electrode-equipped bases, a color-forming layer provided on at least one of the electrode-equipped bases, and a thin film with a visible ray transmittivity of 20-60% provided on at least one of the bases or the transaprent electrode films.

Photochromic-electrochromic intercalation compound

Abstract: A compound is disclosed which excels in thermal resistance and acidproofness, fits application on a surface and fabrication, and exhibits both photochromism and electrochromism.

Electrochromic properties of polycrystalline thin films of tungsten trioxide prepared by chemical vapour deposition

Abstract: The electrochromic properties of polycrystalline thin films of tungsten trioxide prepared by chemical vapour deposition were studied using cyclic voltametry and chronoamperometry measurements. Two kinds of films were investigated depending on the conditions of preparation. Although the composition of the layers obtained after pyrolysis of W(CO)6 is influenced by the presence of oxygen flow, the final annealing of these products leads to the same polycrystalline structure. Electrochromic properties have been investigated in acid and hydro-organic electrolytes. Cyclic voltametry shows that both colouration and bleaching of the films are associated with electrochemical reactions. The optical efficiencies and the response times were studied in both media and compared with amorphous WO3 thin films prepared by vacuum evaporation. Best results have been obtained in acid electrolyte for films prepared by pyrolysis of W(CO)6 in the presence of oxygen flow. We also observed that cycling greatly enhanced the response time. Current injection during colouration was found to depend strongly on time and to be mainly controlled by the resistance of the electrolyte at short times (f<200 ms).

Electrochromic, oxygen deficient metal oxide films provided by pyrolytic deposition

Abstract: This invention is directed to electrochromic devices wherein a layer of cathodic electrochromic material comprising non-stoichiometric, oxygen deficient metal oxides is provided by pyrolytic deposition techniques. The pyrolytic deposition is of a compound comprising a powdered metal compound and a reducing agent or a liquid composition and a reducing agent. The pyrolytic deposition can also be accomplished by a powdered composition or a liquid composition dispersed in a carrier gas.