JPH0281032A - Electrochromic electrode and production thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is an electronic device that can be used in various dimming devices and display devices, and in which an organic conductive polymer film does not peel off from an inorganic substrate electrode. The present invention relates to a chromink electrode and a method for manufacturing the same.

(Prior art and its problems) An electrochromic device (hereinafter abbreviated as ECD), in which an electrochemical reaction is induced in the device by external voltage application, and its color and absorption rate change reversibly,
It has many features not found in solid-state light emitting devices (LEDs) and liquid crystal devices (LCDs). Therefore, in various industrial fields including the electronics industry, practical use is progressing as light control elements and display elements. The ECD is composed of an electrochromic electrode (hereinafter abbreviated as EC electrode), an electrolyte, and a counter electrode. The materials constituting the EC electric scraper can be broadly classified into inorganic materials and organic materials, and the former are known to include various transition metal oxides. Also,
Viologen-based compounds and styryl acid-based compounds are known as the latter, but recently, conductive polymers obtained by electrolytic polymerization have also been developed and researched. Conductive polymers are attracting attention because of their characteristics such as being easy to form into thin films and having excellent responsiveness.

The basic composition of the organic EC electrode made of the conductive polymer is [TO (11203 containing about 5% by weight of SnO□)]
) A conductive polymer film is laminated on a transparent electrode such as glass or SnO□ glass, or a metal electrode such as a platinum plate.

The method for laminating the conductive polymer film mentioned above includes electrolytic polymerization method,
The dip method and spin code method are known, but when using either method, if an inorganic material is used as the substrate electrode, a problem has been observed where the conductive polymer film peels off from the substrate electrode after lamination. . This is because the bonding force between the inorganic material of the substrate electrode and the organic material of the conductive polymer film is weak, and the reason for this weak bonding force is explained as follows.

In the process of laminating conductive polymers, the conductive polymers generally have strong bonding strength with each other. This is because the straight chain parts of the polymer are connected by covalent bonds, and the straight chain parts are entangled with other parts. However, no coexisting bond is formed between the inorganic substrate electrode and the conductive polymer, and it is thought that a hydrogen bond is probably formed between the oxide or hydroxide at the inorganic interface and the polymer. Hydrogen bonds are weaker than covalent bonds, and the adhesion of polymers to substrate electrodes is not sufficient.

For these reasons, there has been a problem in which the yield rate is reduced when manufacturing EC electrodes. In addition, during operation as an EC electrode, the electrolytic solution intervenes in hydrogen bonds at the substrate-conductive polymer interface, causing the conductive polymer to peel off from the substrate electrode, which may cause uneven coloring and decoloring or an inoperable state. Ta. As a result, there was a problem that the driving life of the EC electrode was reduced.

(Description of the first invention) The first invention (invention set forth in claim (1))
In view of the above-mentioned problems of the conventional technology, we provide an electrochromic electrode that improves the adhesion between an inorganic substrate electrode and an organic conductive polymer, and has excellent yields during the production of electrochromic electrodes and a long driving life. This is what I am trying to do.

That is, the present invention relates to an electrochromink electrode composed of an electrode substrate and a conductive polymer, characterized in that the electrode substrate and the conductive polymer are bonded via a covalent bond.

The substrate electrode constituting the electrocomic electrode according to the present invention is made of an inorganic material such as ITO, and the conductive polymer is an organic material. Therefore, even if the two substances are combined by, for example, electrolytic polymerization, the oxide or hydroxide on the inorganic surface and the polymer are simply combined by hydrogen bonds, which prevents the polymer from adhering to the substrate electrode. Sex is not enough. The electrochromic electrode according to the present invention is characterized in that an inorganic electrode substrate is bonded to an organic conductive polymer via a covalent bond. Covalent bonds have significantly greater bond strength than hydrogen bonds. Therefore, the adhesion between the substrate electrode and the conductive polymer film becomes strong, and the conventional problem of separation between the inorganic substrate electrode and the organic conductive polymer is completely prevented. As a result, the yield in manufacturing electrochromic electrodes is improved, and the operating life of electrochromic electrodes is improved.

Further, since the electrochromic electrode according to the present invention does not peel off during use, it is widely used as display devices for various industrial equipment, light control glass for automobiles and building materials, and anti-glare mirrors for automobiles.

(Description of the second invention) The second invention (invention set forth in claim (2))
relates to a method for producing an electrochromic electrode characterized by comprising the steps of treating an electrode substrate with a silane coupling agent solution and forming a conductive polymer film on the electrode substrate.

The silane coupling agents used in the silane coupling treatment include T-chloropropyl trimethoxysilane, vinyl trimethoxysilane, β(3,4-epoxycyclohexyl)trimethoxysilane, and γ-glycidoxypropyl trimethoxysilane. Methoxysilane, γ-mercaptopropyl trimethoxysilane, N-β-(aminoethyl)-γ
There are aminopropyl trimethoxysilane, T-aminopropyl trimethoxysilane, etc., and one or more of these may be used. A silane camping agent is usually used after being dissolved in water or alcohol. The concentration of the silane coupling agent is preferably in the range of 1 to 30% by volume (vol). If the concentration is less than 1% lvO, the silane coupling agent film will be thin and it will be difficult to obtain sufficient adhesion. However, 30
Even if the value is ν01% or more, no improvement in adhesion can be expected, and on the contrary, cleaning after silane camping treatment becomes time consuming.

The treatment with a silane camping agent solution is carried out by degreasing the substrate electrode with a solvent such as acetone, and then immersing the electrode in a solution in which the silane camping agent is dissolved. Soaking is 1
Do this for ~15 minutes. If the time is less than 1 minute, a conductive polymer film with good adhesion cannot be formed on the electrode surface even if a treatment with a silane camping agent solution is performed. However, even if immersed for more than 15 minutes, no improvement in adhesion can be expected.

As the substrate electrode, ITO (InzO:+ containing about 5% by weight of SnO2) film, glass coated with SnO□ film,
Alternatively, a conductive material such as a transparent plastic film or a metal such as stainless steel, platinum, or nickel may be used.

As the conductive polymer formed on the surface of the substrate electrode, one or more selected from the group consisting of polyaniline, polypyrrole, and polythiophene are used.

The thickness of the conductive polymer film is preferably within the range of 500 to 2 μm. If the film thickness is less than 500 μm, the color change during coloring and decoloring will be small when used as an electrochromic device, and if it is thicker than 2 μm, decoloring will be difficult. Good electrochromic properties have a film thickness of 1,000 to 1
Obtained when μm. The conductive polymer film is formed on the substrate electrode by electrolytic polymerization. As the electrolytic polymerization electrodepositing solution, when forming polyaniline as a conductive polymer, an acidic aqueous solution in which an aniline monomer and a water-soluble polyanion salt are dissolved is used. In the case of polypyrrole, a solution in which virol monomer and lithium perchlorate are dissolved in acetonitrile, and in the case of polythiophene, a thiophene monomer and lithium perchlorate are dissolved in acetonitrile. A pair of substrate electrodes is immersed in the electrolytic polymerization electrodepositing solution, and a DC voltage is applied between the electrodes to form a film on the positive substrate electrode. The current density during electrolytic polymerization is 10 μA/cd
The range is preferably 1 m/Ac+M. 10μA/ct
If it is smaller than this, the film formation rate will be slow, and if it is larger than 1 mA/c111, the formed film may become pulverized and its performance may deteriorate. Further, the conductive polymer film can also be formed by a dip method or a spin code method.

By the method according to the second aspect of the present invention, it is possible to produce an electrochromic electrode in which an inorganic substrate bridge and an organic conductive polymer film are bonded by covalent bonds and the conductive polymer film has excellent bonding strength so that the conductive polymer film does not peel off.

(Examples) Example 1 The effect of improving adhesion by silane coupling treatment when polyaniline was formed on a 1T◯ electrode substrate was investigated by a tape peel test.

A methanol solution containing a silane coupling agent at a volume ratio of 10% was prepared as a silane coupling treatment solution.

As a silane coupling agent, γ-chloropropyl,
Trimethoxysilane, vinyl trimethoxysilane, β
-(3,4-epoxycyclohexyl) trimethoxysilane, T glycidoxypropyl trimethoxysilane, T mercaptopropyl trimethoxysilane, Nβ-
(Aminoethyl)-γ-aminopropyl trimethoxysilane and T-aminopropyl trimethoxysilane were used.

An ITO electrode (5 cm long and 2 cm wide) that had been degreased and washed with acetone was immersed in the silane coupling treatment solution for 10 minutes. Next, the electrode was taken out from the treatment solution, washed thoroughly with methanol, and dried for 10 minutes at i o o ''c.

A polyaniline film was electrolytically polymerized on this electrode under the following conditions. Aniline monomer, as an electrodepositing solution for electrolytic polymerization,
An aqueous solution containing perchloric acid and potassium polyvinyl sulfate was prepared. The respective concentrations were 0.1 m o I/1 for aniline monomer and 0.2 m o I/1 for perchloric acid.
o l/l, polyvinyl potassium sulfate is 0.01
It was set as mol/I. Next, the picture electrode was immersed in the above electrodeposition solution using the ITO electrode subjected to silane coupling treatment by the above method as an anode and the carbon plate as a cathode, and the current density was 50 μA/ct per unit area of the electrode at room temperature. A green to dark blue polyaniline layer was formed on the anode (TO) electrode by an electrolytic polymerization method in which electricity was applied for 30 minutes.

The obtained electrode was washed with distilled water and vacuum dried at room temperature for 1 hour.

A cellophane tape was attached to the surface of the polyaniline EC electrode prepared in this way, and the extent to which the polyaniline film was peeled off from the ITO substrate when it was strongly peeled off was examined. The results are shown in Table 1.

As shown in Table 1, the polyaniline film formed on ITO electroplating without silane coupling treatment peeled off in the tape test. On the other hand, no peeling was observed in any of the polyaniline films formed on the I'rO electrodes subjected to the silane coupling treatment according to the present invention, and a remarkable improvement in adhesion was observed.

Example 2 In this example, the effect of improving adhesion by silane coupling treatment when polyaniline was formed on SnO and electrode substrates was investigated by tape peeling test. The results are shown in Table 2. Example 1 except that a SnO□ electrode was used as the electrode.
The test was conducted under the same silane cambling treatment conditions, polyaniline film formation conditions, and tape peeling test conditions.

Similar to the effect seen with the ITO substrate electrode, adhesion was significantly improved with each silane coupling treatment.

Example 3 In this example, an electrode subjected to silane coupling treatment and polyaniline film formation under the conditions of Example 1 was immersed in a propylene carbonate solution for 1 hour, and then immersed in a nonwoven paper (Kimwipe, manufactured by Jujo Kimberly). The degree of peeling when the polyaniline film surface was wiped was examined. The results are shown in Table 3.

Example 4 In this example, in order to examine the peel strength under even harsher conditions, the electrodes subjected to silane coupling treatment and polyaniline film formation under the conditions of Example 1 were treated with O, O 1 mol/
The degree of peeling of potassium hydroxide (I) was examined when it was immersed in 80°C hot water. The results are shown in Table 4.

It is thought that the hydrogen bond between the polyaniline film and the ITO substrate is easily broken by the alkali treatment.

Therefore, it is thought that the stronger the covalent bonding ratio between the two, the less likely peeling will occur, but as shown in Table 4, T-mercaptopropyl trimethoxysilane showed the best adhesion. Further, improvement in adhesion was also observed in electrodes subjected to other silane coupling treatments.

Claims (3)

[Claims] (1) An electrochromic electrode composed of an electrode substrate and a conductive polymer, characterized in that the electrode substrate and the conductive polymer are bonded via a covalent bond. (2) A method for producing an electrochromic electrode, comprising the steps of treating an electrode substrate with a silane coupling agent solution and forming a conductive polymer film on the electrode substrate. (3) The electrochromic electrode according to claim (1) or claim (2), wherein the conductive polymer film is one or more of the group consisting of polyaniline, polypyrrole, and polythiophene. A method for manufacturing an electrochromic electrode.