JPH0551793A - Method for electrodeposition of electroconductive polymer or the like - Google Patents

Abstract

PURPOSE:To electrodeposit a film of an electroconductive polymer or the like in uniform thickness on a transparent electroconductive film having relatively large area by electrodepositing to make the transparent electroconductive film to be electrodeposited to be a functional pole and to face an electroconductive plate like body shaped in similar to the transparent electroconductive film and having a specific similarity ratio. CONSTITUTION:The substrate 5 (glass plate), on which the transparent conductive film 3 (such as ITO film) having >=800cm<2> area, is formed and the conductive plate like body 6 (such as platinum plate) are dipped to face each other into the electrolyte 1 (such as saturated calomel electrolyte). The conductive polymer, metallic complexing material and metallic oxide are electrodeposited on the transparent conductive film to make the substrate 5 and the conductive plate like body respectively to be the functional pole and the counter electrode. In this case, the conductive belt 4 lower in resistance than the conductive film 3 is provided on the peripheral part of the transparent conductive film 3. The conductive plate like body is shaped similar to the transparent conductive film 3 and similarity ratio to the transparent conductive film 3 excepting the low resistant conductive belt 4 is 0.55-0.80. As the result, electrodeposition uniform in thickness is executed on the transparent conductive film 3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to conductive polymers such as polyaniline, polypyrrole, polythiophene and polytriphenylamine, which are useful as color-forming electrodes for electrochromic display devices, metal complexes such as Prussian blue or pentoxide. The present invention relates to a method of electrodepositing a metal oxide such as vanadium on a transparent conductive film.

[0002]

2. Description of the Related Art It is relatively easy to obtain a uniform film when electrodepositing polyaniline or the like on a metal electrode such as platinum or gold, but it is possible to obtain a transparent conductive film such as an ITO film or a NESA film. When polyaniline is electrodeposited on the film, the concentration of the aniline monomer and the acidic aqueous solution are each 1
Adhesion is possible at about mol / l, but it is difficult to synthesize polyaniline with a sufficient film thickness, and polyaniline is finely pulverized on the transparent conductive film when polymerized for a long time at a low concentration. It was difficult to obtain a uniform film. Further, if the concentration is further increased, there is a problem that the polymerized polyaniline is dissolved in the electrolytic solution and peeled off.

Therefore, the present inventors have filed Japanese Patent Application No. 1-31129.
As No. 0, a method of twice electrodeposition under specific conditions was proposed. However, when electrodeposition is performed on a transparent conductive film having a relatively large area on which a transparent conductive film having an area of 800 cm ² or more is formed, it is impossible to perform electrodeposition with a uniform film thickness due to a voltage drop. It was

The present invention has been made in view of the above circumstances, and a conductive polymer such as polyaniline, a metal complex such as Prussian blue or vanadium pentoxide is formed on a transparent conductive film having a relatively large area. It is an object of the present invention to provide a method for electrodepositing the metal oxide of 1 to a uniform thickness.

[0005]

[Means for Solving the Problems] A substrate on which a transparent conductive film having an area of 800 cm ² or more and a conductive plate-like body are immersed in an electrolytic solution so as to face each other, and the substrate is worked or conductive plate. In a method of electrodepositing a conductive polymer, a metal complex or a metal oxide on a transparent conductive film with a sheet as a counter electrode, a conductive band having a resistance lower than that of the conductive film is provided in the peripheral portion of the transparent conductive film. The conductive plate-shaped body has a shape similar to that of the transparent conductive film, and the similarity ratio is 0.55 to 0.80 with respect to the transparent conductive film excluding the low resistance conductive band. To do.

[0006]

[Function] Since the substrate on which the transparent conductive film having an area of 800 cm ² or more is formed is large, even if a low resistance conductive band is provided in the peripheral portion of the transparent conductive film, it can be electrodeposited by Prussian blue or the like. Current density of about 5 μA / cm ² and a relatively small voltage drop and a transparent conductive film of about 45 cm square can deposit Prussian blue to a uniform thickness, but polyaniline, polypyrrole The current density when electrodepositing a conductive polymer such as 30 to 200 μA /
Since it becomes as large as cm ² , the voltage drop increases from the peripheral part to the central part, and when the transparent conductive film as the working electrode and the conductive plate as the counter electrode are electrodeposited with the same size and shape, the direction of the electric field is changed. Is parallel to the surface of the conductive plate from the surface of the transparent conductive film, the amount of electrodeposition is small in the central portion as compared with the peripheral portion, and it is unavoidable that the film thickness becomes uneven. Therefore, in the present invention, the shape of the conductive plate-shaped body as the counter electrode is made similar to the transparent conductive film to be electrodeposited, and the similarity ratio is 0.55 to 0.80 with respect to the transparent conductive film.
Since the counter electrode is made smaller than the transparent conductive film, the diffusion of ions to the peripheral part of the transparent conductive film is delayed, and the strength of the electric field is weaker than that in the central part, so electrodeposition is better than when the size and shape of the counter electrode are the same. As a result, the amount of electrodeposition on the peripheral portion and the central portion is balanced, resulting in a substantially uniform film thickness.

When the similarity ratio of the counter electrode is 0.55 or less, the film thickness in the peripheral portion of the transparent conductive film becomes thinner than that in the central portion, and 0.8
When it is 0 or more, the peripheral portion has a larger film thickness than the central portion, and a uniform film cannot be electrodeposited in any case.

Also, in the case of electrodepositing a metal complex such as Prussian blue, if the transparent conductive film has a size of up to about 45 cm square, the counter electrode may be used in the same size.
In the case of a quadrilateral transparent conductive film having a side of 50 cm or more and a diameter of 50 cm or more, the similarity ratio of the counter electrode needs to be 0.55 to 0.80 with respect to the transparent conductive film.

[0009]

EXAMPLES Examples of the present invention will be described in detail below together with comparative examples. FIG. 1 is a schematic view showing an example of an apparatus for carrying out the method of electrodeposition of a conductive polymer or the like of the present invention.

EXAMPLE 1 An electrolytic cell 2 containing a mixture of 0.1 mol / l of aniline and 0.1 mol / l of sulfuric acid as an electrolytic solution 1 was coated with an ITO film as a transparent conductive film 3 on the entire surface. Further, as a conductive band 4 having a lower resistance, a silver paste having a width of 20 mm is screen-printed over the entire circumference of the peripheral portion, and a glass plate having a thickness of 3 mm as a square substrate 5 of 45 cm square and baked, and a conductive plate-shaped body 6. The square platinum plate and the saturated calomel electrode are immersed as the working electrode, the counter electrode, and the reference electrode 7, respectively,
It was connected to a DC power supply 8.

In this state, the size of the platinum plate is 30c.
m square (similarity ratio: 0.73), 23 cm square (similarity ratio: 0.
56), in the case of 32 cm square (similarity ratio: 0.78), it was confirmed that the anode potential at the reference electrode was about 0.85 V or more initially by the voltmeter 9 by the DC power source, and the current density was 100 μA. / Cm ² (constant current) was applied for 5 minutes to polymerize the polyaniline film on the ITO film. After that, the glass plate was taken out from the electrolytic bath and washed with water. As a result, polyaniline having a weak adhesive force on the surface layer was removed, and a 200 Å-thick polyaniline film was formed on the ITO film.

Next, this glass plate was immersed together with a saturated calomel electrode and a reference electrode in an electrolytic cell containing a mixture of 0.5 mol / l of aniline and 0.5 mol / l of sulfuric acid as an electrolytic solution to obtain a current density. The polyaniline film was polymerized by energizing at 100 μA / cm ² for 10 minutes.

The film thickness of the polyaniline thus obtained is about 3500Å, and the film thickness distribution of the polyaniline is shown in visible light transmittance for a 41 cm square excluding the low resistance conductive band. Corner (similarity ratio: 0.73),
Table 1, Table 2 and Table 3 for a 23 cm square (similarity ratio: 0.56) and a 32 cm square (similarity ratio: 0.78), respectively.
The results shown in are obtained.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

[Table 3]

As is clear from this result, the difference in transmittance between adjacent regions is small, the difference between the maximum and minimum values of transmittance is small, and the uniformity is good, and no color unevenness is observed. ..

(Application to Electrochromic Element) An example in which the polyaniline obtained in Example 1 is applied to an electrochromic element will be shown.

A glass substrate having a thickness of 3 mm obtained in Example 1, a glass plate having a thickness of 3 mm, a transparent conductive film and a coloring layer WO
_After the substrates having ₃ formed thereon were opposed to each other and the peripheral portions were sealed, a propylene carbonate solution containing 1 mol of lithium perchlorate was filled as an electrolytic solution.

When a direct current voltage of 1.0 V was applied to the electrochromic device thus obtained using polyaniline as an anode and WO ₃ as a cathode, polyaniline was colored green and WO ₃ was colored blue to produce visible light. Transmittance is 1
It became 0.5%, showing a good light-shielding property, and when a DC voltage of -0.5 V was applied with WO ₃ as an anode and polyaniline as a cathode, both polyaniline and WO ₃ were decolored and the visible light transmittance was 55%. And showed good light transmittance.

Even if this coloring / decoloring is repeated about 2000 times,
It was confirmed that the polyaniline film exhibited excellent electrochromism without peeling and without causing color unevenness during coloring. Further, during this period, when a constant voltage was applied to the electrochromic device, the concentration fluctuation was extremely small and a constant concentration was obtained, and stable driving could be performed. This indicates that polyaniline is uniformly polymerized on the ITO film and its adhesive force is strong.

Comparative Example As in Example 1, an ITO film as a transparent conductive film was placed in an electrolytic bath containing a mixture of 0.1 mol / l of aniline and 0.1 mol / l of sulfuric acid as an electrolytic solution. Cover the entire surface,
A silver paste with a width of 20 m is used as a conductive band having a lower resistance.
Screen-printed and fired on the entire circumference of the surrounding area at m. 4
A 5 cm square glass plate, a square platinum plate as a conductive plate, and a saturated calomel electrode were immersed as a working electrode, a counter electrode, and a reference electrode, respectively, and connected to a DC power source.

In this state, the size of the platinum plate is 21c.
m square (similarity ratio: 0.51), 34 cm square (similarity ratio: 0.
In the case of No. 83), it was confirmed that the anode potential at the reference electrode was about 0.85 V or more at the initial stage by the DC power source, and the polyaniline film was energized at a current density of 100 μA / cm ² (constant current) for 5 minutes. Was polymerized on the ITO film. After that, the glass plate was taken out from the electrolytic bath and washed with water. As a result, polyaniline having a weak adhesive force on the surface layer was removed, and a 200 Å-thick polyaniline film was formed on the ITO film.

Next, this glass plate was immersed together with a saturated calomel electrode and a reference electrode in an electrolytic cell containing a mixture of 0.5 mol / l of aniline and 0.5 mol / l of sulfuric acid as an electrolytic solution to obtain a current density. The polyaniline film was polymerized by energizing at 100 μA / cm ² for 10 minutes.

The film thickness distribution of the polyaniline thus obtained is shown in visible light transmittance with respect to 41 cm square excluding the low resistance conductive band. The dimension of the platinum plate is 21 cm square (similarity ratio: 0.51), When 34 cm square (similarity ratio: 0.83), the results shown in Table 4 and Table 5 were obtained.

[0026]

[Table 4]

[0027]

[Table 5]

As is clear from this result, there are some areas where the difference in transmittance between adjacent regions is large, and there is also a large difference between the maximum value and the minimum value of the transmittance, which is inferior in uniformity and uneven in color, making it practical. It was not something I could offer.

When the size of the platinum plate is 41 cm square (similarity ratio: 1.00), which is the same as that of the transparent conductive film excluding the low resistance conductive band, it is 34 cm square (similarity ratio: 0.83).
Since the film thickness becomes more uneven than in the case of No. 1 and cannot be put to practical use, the film thickness distribution is omitted. A 45 cm square glass plate coated with an ITO film, a platinum plate, and a saturated calomel electrode were placed in an electrolytic cell containing a mixture of 0.5 mol / l and sulfuric acid 0.5 mol / l as an electrolytic solution.
Immersion as a reference electrode, current density 100 μA / cm
^When the polyaniline film is polymerized by being energized at ² (constant current) for 30 minutes and washed with water, the polyaniline film flows out, the film thickness falls below 100Å, and the uniformity is impaired, which can be put to practical use. Was not.

Example 2 to Example 4 Example 2 is an example in which polypyrrole is electrodeposited.
As an electrolyte solution 1, an acetonitrile solution containing mol / l of pyrrole (C ₄ H ₄ N) and 0.1 mol / l of silver perchlorate (AgClO ₄ ) was used as a transparent working electrode, as in Example 1. A glass substrate 5 on which a conductive film 3 and a low resistance conductive band 4 are formed,
Along with the reference electrode 7, a platinum plate as a counter electrode (conductive plate-shaped body 6) having a similarity ratio of 0.55 to 0.80 to the transparent conductive film excluding the low-resistance conductive band was immersed, and 160
3200Å when electrodeposition is performed for 800 seconds at a constant current of μA / cm ^2.
Of polypyrrole was polymerized. The film thickness distribution of the polypyrrole thus obtained was also good in uniformity.

Example 3 is an example in which Prussian blue is electrodeposited. A 0.01 mol / l potassium ferricyanide (K ₃ Fe (CN) ₆ ) solution and 0.01 mol / l ferric chloride ( FeC
l ₃ ) is mixed as an electrolyte solution 1 and the entire surface is covered with an ITO film as a transparent conductive film 3, and a silver paste with a width of 20 mm is screen-printed as a conductive band 4 having a lower resistance over the entire periphery. , Fired 100 cm square glass substrate 5, 70 c as conductive plate-like body 6.
A square m-square platinum plate and a saturated calomel electrode were dipped as the working electrode, counter electrode, and reference electrode 7, respectively, and connected to a DC power source 8 and electrodeposited at a constant current of 5 μA / cm ² for 50 minutes to obtain a uniform surface of 4000 Å A thick Prussian blue could be electrodeposited.

Example 4 is an example in which vanadium pentoxide was electrodeposited, and 1 mol / l was added to a 31% hydrogen peroxide (H ₂ O ₂ ) solution.
Vanadium pentoxide (V ₂ O ₅ ) was dissolved, and water was added to this to synthesize 0.1 mol / l vanadium pentoxide (V ₂ O ₅ ).
Using the solution as the electrolytic solution 1, a working electrode having the same configuration as in Example 1,
Immerse the counter electrode and the reference electrode and set the scan speed to 50 mV /
Sweep from -1.2V to + 1.5V in 200 sec
By repeating this process, a uniform vanadium oxide film having a thickness of 2500 Å could be electrodeposited.

As described above, the preferred embodiment has been described.
The invention is not limited to this, and various applications are possible.
Is. The transparent conductive film is not only ITO film but also NESA film etc.
Can also be used and its shape depends on the shape of the substrate.
It is formed, but it may be formed regardless of the shape of the substrate.
However, the shape is not limited to square, but rectangular, trapezoidal, etc.
Quadrangular or triangular shape, pentagonal or more polygonal shape
A shape consisting of any straight line, a curve such as a circle or an ellipse
Composed of a straight line and a curved line
The area is 800 cm ²The transparent conductive film with various shapes
You can wear it.

In addition to the platinum plate, the conductive plate-like body as the counter electrode may be a metal plate such as stainless steel or aluminum having acid resistance, and of course, a plate-like body such as carbon may be used. The shape may be similar to the shape of the transparent conductive film, and the similarity ratio may be appropriately selected within the range of 0.55 to 0.80.

[0035]

According to the present invention, a transparent conductive film to be electrodeposited is used as a working electrode, and conductive plate-like bodies having a similar shape and a similarity ratio of 0.55 to 0.80 are opposed to each other. By electro-deposition, it is possible to electro-deposit a film of a conductive polymer or metal complex on a transparent conductive film having a relatively large area of 800 cm ² or more to a uniform thickness. It can be suitably applied to optical bodies and display bodies.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus for carrying out a method for electrodepositing a conductive polymer or the like of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrolyte 2 Electrolyzer 3 Transparent conductive film 4 Conductive band 5 Substrate 6 Conductive plate 8 DC power supply

Claims (1)

[Claims] 1. A substrate on which a transparent conductive film having an area of 800 cm ² or more and a conductive plate-shaped body are immersed in an electrolytic solution so as to face each other, and the substrate is used as a working electrode and the conductive plate-shaped body as a counter electrode. In the method of electrodepositing a conductive polymer, a metal complex or a metal oxide on a transparent conductive film, a conductive band having a resistance lower than that of the conductive film is provided in the peripheral portion of the transparent conductive film, and the conductive plate is provided. A conductive polymer having a shape substantially similar to that of the transparent conductive film and having a similarity ratio of 0.55 to 0.80 with respect to the transparent conductive film excluding the low resistance conductive band. Electrodeposition method such as.