JPH079523B2 - Method for manufacturing substrate with EC film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a substrate with an EC film (electrochromic film), and particularly to amorphous hexacyano which is suitable for use in the production of a transmissive EC device. The present invention relates to a method for producing a substrate with an EC film in which an iron salt of ferric acid film is coated on an electrode substrate.

[Conventional technology]

Hexacyanoferric acid iron salt is known as a substance having EC characteristics, and a transmissive EC element using a thin film of the hexacyanoferric acid iron salt is known.

For the production of the hexacyanoferrate iron salt film used for the transmission type EC element, the film 0.6 V vs SCE {Fe (III), [Fe (III) (CN)
₆ ] The electroless plating method that can be performed only on a substrate of a metal (for example, Ni, Fe, Cu, etc.) having a reduction potential lower than the potential at which a ^3- ionic species or complex is reduced} In terms of properties, it cannot be used, and the electrolytic plating method has been exclusively used.

In the electrolytic deposition method, the electrode substrate and the counter electrode are immersed in a mixed aqueous solution of a trivalent iron salt such as ferric chloride or ferric sulfate and a ferricyanide salt such as potassium ferricyanide to form the electrode substrate. This is a method of performing electric field reduction as a cathode.

[Problems to be solved by the invention]

The electric field deposition method has a merit of being able to deposit hexacyanoferric acid iron salt having EC characteristics on a glass substrate with a transparent conductive film which can be used for a transmission type EC device, but hexacyano prepared by the electrolytic deposition method. The iron ferrate salt film has a problem in that it has poor adhesion to the substrate and causes peeling and the like.

[Means for solving problems]

The present invention has been made to solve the above problems, and provides a method for producing a substrate with an EC film in which an amorphous iron hexacyanoferrate salt film is coated on an electrode substrate.

The substrate with the EC film is Fe (III) ions and [Fe (III) (C
N) ₆ ] ^3- Ions are contacted with an aqueous solution containing an ion substrate to form an iron hexacyanoferrate salt on the surface of the electrode substrate.
In a method for producing a substrate with an EC film for depositing an EC film, hypophosphite is added to the aqueous solution in advance, and then the aqueous solution containing the hypophosphite is brought into contact with the electrode substrate, An amorphous EC film is deposited on the surface of the electrode substrate by an electrolytic method.

As the above-mentioned electrode substrate, a transparent electrode substrate suitable for manufacturing a transmissive EC device is preferably used, and a glass plate coated with a transparent electrode film is preferable because of high productivity.

It is preferable that the amorphous iron hexacyanoferrate film is provided with a thickness of 10 nm to 1 μm, which has a color developability as an EC device and is highly productive, and particularly has good contrast and does not cause film distortion such as cracks. A film thickness of 100 nm to 500 nm is desirable.

Further, the hypophosphite added in the present invention has a lower reduction potential than the iron ion in the mixed aqueous solution,
As a result, it is possible to deposit an EC film by a chemical reduction reaction (that is, an electroless method). The hypophosphite is preferably one that does not cause harm even if the cations constituting the salt are taken into the hexacyanoferrate iron salt film, for example, H ₃ PO ₂ , NaH ₂ PO ₂ , KH ₂ PO ₂ etc. is preferable.

The amount of the hypophosphite added is Fe (III) ions and [Fe
It is preferable to adjust the concentration of (III) (CN) ₆ ] ³⁻ ions, etc.
II) (CN) ₆ ] ^{3-When the} ion concentration is 0.01 mol / min.
Concentration of 001 mol / -0.1 mol / Desirably 0.01 mol /
It is preferable to add it at a concentration of about 0.04 mol /. If the concentration of hypophosphite is less than 0.001 mol /, it is difficult to obtain the effect of adding hypophosphite, and it is difficult to obtain an amorphous iron hexacyanoferrate film. Further, when the concentration of the hypophosphite is higher than 0.1 mol / l, precipitation or the like is likely to occur in the mixed solution of Fe (III) ions and [Fe (III) (CN) ₆ ] ^3- ions.

[Operation] Since the iron hexacyanoferrate film produced by the conventional manufacturing method is crystalline, the adhesion to the substrate is poor and peeling is likely to occur.

On the other hand, the substrate with an EC film manufactured according to the present invention is an amorphous hexacyanoferrate iron salt film on the substrate surface, and therefore the adhesion strength of the hexacyanoferrate iron salt film to the substrate is improved. However, there is no risk of problems such as the conventional one.

Further, in the present invention, Fe (III) ions and [Fe (II
By adding hypophosphite to a mixed solution of I) (CN) ₆ ] ^3- ion, an amorphous iron hexacyanoferrate salt film can be obtained. The reason for this is not clear, but due to the chemical reduction effect of the addition of hypophosphite, Fe
The (III) ion is reduced to coordinate phosphoric acid, and [Fe (II
I) (CN) ₆ ] ^3- It is thought that this is because of the binding.

〔Example〕

Example 1 (electroless method) 0.02 mol / potassium ferricyanide aqueous solution and 0.02 mol /
100 ml of each ferric chloride aqueous solution was prepared. After mixing these two solutions, 0.02 mol / hypophosphorous acid (0.2 ml) was added, the glass substrate with the indium tin oxide film (about 120 nm thickness) was immediately immersed, and 10 hours later, the indium tin oxide film was pulled up. An iron hexacyanoferrate film with a thickness of about 200 nm was formed on top.

As a result of measuring the X-ray diffraction characteristics of the obtained film, the result as shown in FIG. 1 was obtained. (CuKα: 0.154nm) 3 seen in Fig. 1
Two diffraction peaks are diffraction lines of indium tin oxide, and no diffraction peak of iron hexacyanoferrate is observed. Therefore, the crystal state of the iron hexacyanoferrate film obtained by the above operation was examined by the X-ray diffraction method. as a result,
It was confirmed that the iron hexacyanoferrate film was amorphous.

Further, both ends of the obtained glass substrate were fixed, and a fixing jig having a bottom surface of about 0.3 cm ² was fixed on the iron hexacyanoferrate film at the center position of the glass substrate by using an epoxy resin adhesive to fix the fixing jig in the vertical direction ( The tensile strength was 40 Kg / cm ² or more as a result of pulling in the direction opposite to gravity and peeling the coating and separating the jig.

Further, the cyclic voltammogram of the amorphous iron hexacyanoferrate film in a 0.5 mol / concentration aqueous potassium chloride solution (pH = 4.0) was measured. Figure 4 shows the results of cyclic voltammograms with a sweep rate of 10 mV / sec. The amorphous iron hexacyanoferrate salt film showed a transparent blue coloration / decoloration at ± 0.5V.

Comparative Example-1 100 ml each of 0.02 mol / potassium ferrocyanide and 0.02 mol / ferric chloride aqueous solution were prepared, and after mixing both solutions, a glass plate with an indium tin oxide film similar to Examples 1 and 2 and The counter electrode was immersed, and electrolytic reduction was performed at a constant current with a current density of 10 μA / cm ² to form a hexacyanoferrate iron salt film with a thickness of about 200 nm on the indium tin oxide film.

The tensile strength of the thus-prepared iron hexacyanoferrate salt film was measured in the same manner as in the example. As a result, the tensile strength was 17.0 Kg / cm ² , which indicates that the film obtained in Example 1 had a high tensile strength. Also, the X-ray diffraction characteristics and cyclic voltammogram were measured as in the examples. The results are shown in FIGS. 2 and 3. From FIG. 2, the hexacyanoferrate iron salt film obtained by the conventional method has diffraction peaks (marks) due to crystals of hexacyanoferrate iron salt in addition to the diffraction peaks of three indium tin oxides (marked by ↓). It was found to be a crystalline film. Further, the cyclic voltammograms show that the coating films obtained in the examples showed the same coloration / decoloration as the conventional crystalline film.

〔The invention's effect〕

As described above in detail, according to the production method of the present invention, a substrate with an EC film having improved adhesion strength to the substrate can be obtained as compared with a crystalline iron hexacyanoferrate film obtained by a conventional method. It is a thing. Further, the amorphous hexacyanoferrate iron salt film obtained by the present invention has the same electrochromic property as the crystalline hexacyanoferrate iron salt film obtained by the conventional method, so that a high-quality transmissive EC element is obtained. It can be used for manufacturing.

[Brief description of drawings]

FIG. 1 is a diagram showing an X-ray diffraction characteristic of a hexacyanoferrate iron salt film on an indium tin oxide film obtained in Example 1 of the present invention, and FIG. 2 is a graph showing a conventional X-ray diffraction property obtained in Comparative Example 1. FIG. 4 is a diagram showing an X-ray diffraction characteristic of a hexacyanoferrate iron salt film on an indium tin oxide film, and FIG. 3 shows a cyclic voltammogram of the hexacyanoferrate iron salt film obtained in Example 1 and Comparative Example 1. It is a figure.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Hideo Kawahara, Inventor Hideo Kawahara, 4-8 Doshomachi, Higashi-ku, Osaka-shi, Osaka, Japan Nihon Sheet Glass Co., Ltd. (56) Reference JP-A-57-195182 (JP, A)

Claims (2)

[Claims] 1. Fe (III) ions and [Fe (III) (CN) ₆ ]
^{In a} method for producing a substrate with an EC film, which comprises contacting an aqueous solution containing ^3- ions with an electrode substrate, and depositing an EC film made of iron hexacyanoferrate on the surface of the electrode substrate, the hypophosphorous acid is previously added to the aqueous solution. A salt is added in advance, and thereafter, the aqueous solution containing the hypophosphite is brought into contact with the electrode substrate to deposit an amorphous EC film on the surface of the electrode substrate by an electroless method. Manufacturing method of substrate with EC film. 2. The hypophosphite is added in an amount of 0.001 mol / 1 to 0.1 mol / 1.
The method for producing a substrate with an EC film according to claim 1, which is added as an aqueous solution having a concentration of.