JPS62124534A - Electrochromic element - Google Patents

Abstract

PURPOSE:To obtain a solid electrochromic display element having superior durability without causing coloration of solution nor diffusion of colored matters by adopting phthalocyanine film causing no absorption of light in the visible ray region in the stage of impression of electric field to a spacer layer. CONSTITUTION:An electrochromic element comprises a substrate A, transparent electroconductive film B, nonsubstituted phthalocyanine film C formed by the Langmuir-Blodgett's technique, electrolyte D, a spacer layer E, and electrode film F. Film of indium oxide, tin oxide, indium-tin oxide, etc., is used preferably for the transparent electroconductive film B. A display electrode is formed by forming Langmuir-Blodgett's film of nonsubstituted phthalocyanine on the display electrode comprising the substrate A and the transparent electroconductive film B. Usually, solid electrolyte such as lithium fluoride, calcium chloride, etc., is used pref. for the electrolyte D. Suitable spacer layer E comprises vapor-deposited film of copper phthalocyanine, nonsubstituted phthalocyanine, or their mixture, or heat-treated film of nonsubstituted phthalocyanine formed to film by the Langmuir-Blodgett's technique.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a display element using an electrochromic material. More specifically, the present invention relates to an electrophthalmic display element with improved durability.

(b) Prior Art A display element is known that utilizes an electrochromic phenomenon in which light absorption (1) increases when an electric field is applied to a light-transmitting body and recovers reversibly when the electric field is removed.

This display element basically has an electrochromic material layer interposed between a counter electrode and a display electrode. Conventionally, known inorganic materials of this type include tungsten oxide, molybdenum oxide, iridium hydroxide, and titanium oxide.

On the other hand, known organic substances include viologen compounds, lutetinium phthalocyanine, and anthraquinone compounds. An electrolyte is essential for the electrochromic phenomenon to occur, and depending on the method of bringing this electrolyte into contact with the electrochromic layer, there are two types of devices: solution-type devices that use an electrolyte solution, and solid-state devices that use a solid electrolyte. . In the case of a solution type, there may be practical problems such as coloration of the solution itself and diffusion of colored species, but it is superior in terms of responsiveness and number of repetitions. On the other hand, although the above-mentioned drawbacks are avoided in solid-state devices, irreversible reactions often occur between the counter electrode and the electrochromic coloring layer, and for this reason, the sharpness of the coloring becomes difficult with repeated operation. There are problems such as a decrease in performance and a decrease in response time. As a result of intensive studies to overcome the drawbacks of such electrochromic elements, the present inventors have arrived at the present invention, which eliminates the coloring of solutions, the diffusion of colored substances, and the excellent durability. A solid electrochromic display element could be obtained.

(C) Disclosure of the Invention Substrate (A), transparent conductive film (8), and unsubstituted phthalocyanine film (C) formed by Langmuir-Blodgett method.

An electrochromic device consisting of an electrolyte (D), a spacer layer (E), and an electrode film (F), and a phthalocyanine film that does not absorb light in the visible light region when an electric field is applied to the spacer layer (E). It is an electrochromic element characterized by a spacer-Fl (E
The phthalocyanine film used in ) is copper phthalocyanine,
An unsubstituted phthalocyanine film formed by vapor deposition of an unsubstituted phthalocyanine or a mixture thereof, or an unsubstituted phthalocyanine film formed by the Langmuir-Blodgett method at 200 to 400'C.
This is an electrochromic device that has been heat-treated at a temperature range of .

As the substrate (A) used in the present invention, a transparent material such as a glass plate or polyethylene terephthalate,
Organic polymer films such as polyethylene and polyester sulfone can be used.

The transparent conductive film (B) contains indium oxide and tin oxide.

A film of indium tin oxide or the like is preferably used.

A display electrode is obtained by forming a Langmuir-Blodgett film of unsubstituted phthalocyanine on a display electrode made of such a substrate (A) and a transparent conductive film (B). The great advantage of wood materials compared to ordinary electrochromic abrasive materials is that the Langmuir-Blodgett method spreads a monomolecular film on the water surface.
Since this is a method of forming a thin film by accumulation, there is no need to apply heat compared to the vacuum evaporation method, and it is highly oriented. Because it has a structure, the vividness of the coloring is further improved. Moreover, since the display element is fixed on the electrode, there is no coloring of the solution or diffusion of colored substances, which is a preferable aspect.

The electrolyte (D) used in the present invention may be any electrolyte as long as it can easily inject ions and electrons essential for the coloring reaction of the phthalocyanine film. Suitable for solid electrolyte trading such as KUMU. Also KBr, LIC, Q O4
,L! BF+, NH+ C, 1104,
AQC, I)04, NaCf1. NaBr.

KCρ, K1. Solvents in which ions such as KNO3 are dissolved, such as water, alcohols such as methanol, ethanol, propatool, butanol, aprotic polar solvents such as chloroform, acetonitrile, nitrobenzene, ethyl acetate, dioxane, dimethylformamide, dimethyl sulfoxide, etc. alone. Alternatively, a liquid electrolyte from a mixed solution is used, or a solid electrolyte is preferably used from the viewpoint of solidifying the inside element. As the facing type tIiU(F), metals such as gold, platinum, silver, aluminum, nickel, copper, palladium, etc. may be used, or the above-mentioned display electrode materials may be obtained as is.

The spacer 11 (E) referred to in the present invention refers to a layer between this counter electrode and the solid electrolyte. The spacer layer (E) is a vapor-deposited film of copper phthalcyanine, unsubstituted phthalocyanine, or a mixture thereof, or unsubstituted Notaro formed by the Langmuir-Blodgett method.

It is essential to use a film in which cyanine has been heat-treated. Normally, phthalocyanine-based materials exhibit electrochromic changes upon application of an electric field, but no color change is observed in films formed from the above-mentioned materials.

The main feature of the present invention is that it focuses on this point. Although no color change occurs in an electric field, movement of ions or electrons is observed, so by forming the spacer, the opposing electrode is normally reversible between Undesirable electrode reactions, such as the formation of an oxide-forming film, that occur during the process are greatly suppressed, and it becomes possible to prevent a decrease in the activity of the counter electrode for a long period of time.

In particular, considering that the display electrode is an unsubstituted phthalocyanine formed by the Langmuir-Blodgett method, the fact that this effect can be achieved simply by heat-treating it is of great significance from an industrial standpoint. This heat treatment is 200
It is carried out at a temperature of ~400°C.

The present invention will be explained in more detail by referring to Examples below.

[Example 1 and Comparative Example 1] A U display electrode was obtained by forming 20 layers of a Z-type cumulative film of unsubstituted phthalocyanine on NESΔ glass by the Langmuir-Blodgett method. On top of this, liF:Ca CN 2 =2
A solid electrolyte layer was formed by vapor deposition using an evaporation material consisting of 0:1, and a spacer layer formed by vapor-depositing unsubstituted phthalocyanine was further vapor-deposited to form a counter electrode layer. On the other hand, as a comparative example, a counter electrode was prepared by depositing silver without forming the spacer layer.

2.0 with the NESA glass side as an electrode on this green element.
When V was applied, the color turned red, and when an electric field of -2.0V was applied, the color changed to purple. This application of the electric field was repeated 50 times, but no change was observed in the brightness, sharpness, or response speed of the device of the present invention.

On the other hand, when the comparison was repeated 30 times, bubbles were observed on the surface of the counter electrode, and no change in the coloring state was observed.

[Example 2] NESA glass with a Langmuir Blodgett film of unsubstituted phthalocyanine used in Example 1 was heated at 300°C for 6
Heat treated for hours. The NESA glass heat-treated in this manner was used as a counter electrode, the unsubstituted phthalocyanine cumulative NESA glass without heat treatment was used as a display electrode, and an electric field was repeatedly applied in the same manner as in Example 1 using a 1.3M KCρ aqueous solution as a liquid electrolyte. However, even after 30 cycles, no bubbles were generated on the opposing electrode side and stable color development was observed.

Claims (1)

[Claims] 1. Substrate (A), transparent conductive film (B), unsubstituted phthalocyanine film (C) formed by Langmuir-Blodgett method
, electrolyte (D), spacer layer (E) and electrode film (F)
An electrochromic device characterized in that the spacer layer (E) is a phthalocyanine film that does not absorb light in the visible light region when an electric field is applied. 2. The electrochromic device according to claim 1, wherein the spacer layer (E) comprises a deposited film of copper phthalocyanine, unsubstituted phthalocyanine, or a mixture thereof. 3. The spacer layer (E) is an unsubstituted phthalocyanine film formed by the Langmuir-Blodgett method.
The electrochromic device according to claim 1, which is a film heat-treated in a temperature range of ~400°C.