JPS6099190A - Electrochromic display element - Google Patents

Abstract

PURPOSE:To provide an electrochromic display element containing a specific novel electrochromic material, leaving little or no color when erased, having high color density, and capable of accepting various kinds of solvents and developing the color over a wide voltage range. CONSTITUTION:The objective display element contains the electrochromic liquid obtained by dissolving (A) a quaternary ammonium salt of formula [R1, R2, R3 and R4 are H, alkyl, alcoxy, (substituted) phenyl, benzyl, naphthyl, anthryl or heterocyclic group; X<-> is anion] (e.g. phenyltrimethylammonium chloride) and optionally (B) a supporting electrolyte (e.g. LiClO4, etc.), in (C) an aprotic polar solvent such as water, alcohol, DMF, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display element used in the technical field, and more particularly to a display element using the electrochromic phenomenon.

BACKGROUND ART Display elements are said to utilize the so-called electrochromic phenomenon, in which the amount of light absorbed increases when electrolysis is applied to a light transmitting material, and it recovers reversibly when the electric field is removed. This display element basically has an electrochromic layer interposed between a counter electrode and a display electrode, and the layer contains an electrochromic material. As this type of electrochromic material, inorganic materials such as tungsten oxide, molybdenum oxide, iridium hydroxide, vanadium pentoxide, and titanium oxide are known, and organic materials such as viologen compounds, lutetinium phthalocanine, and anthraquinone compounds are known. However, these materials have a long writing time, a narrow range of applied voltage required for color development, are not colorless when erasing, have a low color density, and have a limited range of usable solvents. It has various drawbacks such as small size, and there is no material that satisfies all the requirements as an electrochromic material. In addition, there are few examples of electrochromic display elements that produce a colorless red color other than the above-mentioned materials, and there is a problem that the cost is high. It is an object of the present invention to provide a display element using a novel electrochromic material, which has excellent color density, has a wide allowable range of applied voltage necessary for color development, and has a wide selection range of usable solvents.

Structure The electrochromic display element of the present invention has the general formula (wherein R4, R2, R5 and R4 may be the same or different, and each of
It represents an alkoxy group, a substituted or unsubstituted phenyl group, a benzyl group, a naphthyl group, an anthryl group, or a heterocyclic group, and Xo represents an anion, and utilizes the quaternary ammonium salt noelectrochromic phenomenon of f). . In the above general formula, examples of the substituent for the phenyl group of R1 to R4 include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, an aryl group, and an aryloxy group. Examples of Xe anions include halogen ions, H3O4-1-BF4'', Ct04-
1PF6-1N05-, sulfonic acid ion, hydroxyl group, etc. can be opened. In the actual hydrogen element, an electrochromic liquid containing the above compound of the present invention is sealed in a display cell consisting of two electrodes, at least one of which is transparent, in the form of a sandwich, and leads from the two electrodes. Take out the wire and connect it to the power supply, circuit, etc. and power it.

FIG. 1 is a schematic cross-sectional view showing an example of an electrochromic display element of the present invention, in which a transparent substrate 2 is provided with a transparent or translucent display electrode 1, and a support 4 is provided with a counter electrode (back electrode) 3. An insulating material such as Mylar or Teflon is filled with an electrochromic liquid 6 through a sacrificial material 5, and
It is sealed with Seal 7. Is the display electrode made of indium oxide, tin oxide, or indium tin oxide? L+1r)3R
R41Fk + 10% - n3 register c & - 14 + 'p series rb
II! ra=L−tL The same as the transparent electrode material is alternatively made of a metal such as platinum, gold, or aluminum.

Further, the support is made of a material such as glass or plastic.

The electrochromic liquid in the present invention contains the compound of the above general formula as a main component, and also contains a solvent and, if necessary, a p-supporting electrolyte. Although it is of course effective to prepare a mixture of the compounds of the above general formula as a base, it is also effective to use a method in which certain other electrochromic compounds are added.

Generally, the electrochromic phenomenon is caused by the formation of radical cations and/or cations or radical anions and/or anions by oxidation at the anode or reduction at the cathode when voltage is applied, resulting in coloration or discoloration. Table-xto
Although it is not yet clear whether the p/FVn+Δ5a-hz sochromatic phenomenon occurs at the cathode or the anode, it is thought that the electrochromic phenomenon can be explained in the same way as described above.

Next, typical examples of quaternary ammonium salts represented by the general formula used in the present invention are listed below.

Compound Garden 1 Phenyltrimethylammonium chloride 2 Phenyltrimethylammonium bromide 3 Phenyltrimethylammonium iodite 4 Phenyltrimethylammonium hexafluorophosphate 5 Tetra n-propylammonium bromide 6 Tetrapentylammonium bromide 7 Distearyldimethylammonium chloride 8 Dicetyldimethylammonium bromide 9 Dicetylmethylbenzylammonium bromide 10 Simyristyldimethylammonium iodite 11 Benzyldimethylstearylammonium chloride 12 Cetyltrimethylammonium furomite 13 Benzyldimethylcetylammonium bromide 14 Benzyldimethylcetylammonium para-toluenesulfonate 15 Cetylethyldimethylammonium bromide Also, the present invention Examples of solvents used are water, alcohols such as methanol, ethanol, propatool, butanol, aprotic polar solvents such as dichloromethane, chloroform, 1,2-dichloromethane, acetonitrile, solobionitrile, benzonitrile, acetone. , propylene carbonate, nitromethane, nitrobenzene, ethyl acetate, tetrahydrofuran, dioxane, pyridine, dimethylformamide, dimethylsulfoyacto, dimethylacetamide, etc.
These may be used alone or in a mixed system. Further, although a supporting electrolyte is not particularly required, if it is used, a salt soluble in the solvent used is used. Examples include L1cto4,
LiBF4, NH4ClO4, (CH3)4NC1,'
(C2H5)4NCt.

CC2”5)4'NBr5 CC2H3)4NCN,
CC2F15)4NC1,04, (C2H5)4NBF
4, CCaHq)4Ncto4, (C4H9)aN
BFa, (C'4H9)4NHso4, AgC
6O4, AgBF4, NaC4, NaBr, KC/-
, KI, KNO3, Na 04, NaC'tO4:t=
' and CC2Hs)sN.

EXAMPLES The present invention will be further explained with examples below, but the present invention is not limited thereto.

Example 1 A solution of the previously exemplified compound fcFJ) 1 dissolved in KN,N-dimethylformamide at a concentration of 0.1 mol/l was sandwiched between NK8A glasses via a 13 μm mylar spacer. An electrochromic device was fabricated. This element was transparent. When a DC voltage of 6 V was applied to both electrodes of this element, the element was colored red. Next, increase the voltage to 1
When 5V was applied, the color was slightly darker, but the results were the same as when 6V was applied. When the voltage was set to Ov, it returned to transparency.

Next, the same result was obtained even after repeating 6■ application→Q V off.

The above results show that the device of the present invention exhibits a colorless-red change and is an electrochromic display device with a wide applied voltage range.

Example 2 LiC
A device similar to that of Example 1 was prepared using a solution in which tO4 was dissolved at α2 mol/l in dimethyl sulfokite, and when voltage was applied in the same manner, a change from colorless to red was expected.

Examples 3-4 Same as Example 1, except that the fct&11 compound used in Example 1 was replaced with the previously exemplified compounds of 11 and NQ15-, respectively, and the concentration was changed to 0.2 mol/l. When an element was prepared and a voltage was applied in the same manner as in Example 1, a colorless-red color change was obtained.

Effects The electrochromic display element of the present invention is colorless or hardly colored when decolored, has a high coloring density, has a wide range of applied voltage necessary for coloring (that is, high voltage enables fast switching), and can be used with various solvents. This has the effect that it can be used.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the electrochromic display element of the present invention. DESCRIPTION OF SYMBOLS 1... Display electrode, 2... Transparent substrate, 6 Counter electrode,
4...Support, 5...S-S, 6. Electrochromic liquid. Patent withdrawal Ricoh Co., Ltd. − −1゛

Claims (1)

[Claims] General formula (wherein R1, R2, R3 and R4 may be the same or different and each represents an aqueous base, an alkyl group,
A display element that utilizes the electrochromic phenomenon of a quaternary ammonium salt of an alkoxy group, a substituted or unsubstituted phenyl group, a benzyl group, a naphthyl group, an anthryl group, or a bicyclic group, and Xo represents an anion. .