JP2935917B2 - Electrodeposition method for conductive polymer etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive polymer such as polyaniline, polypyrrol, polythiophene or polytriphenylamine, a metal complex such as Prussian blue or a pentoxide useful as a coloring electrode of an electrochromic display device. The present invention relates to a method for 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 polyaniline or the like is electrodeposited on a metal electrode such as platinum or gold, but it is relatively easy to obtain a transparent conductive film such as an ITO film or a NESA film. When polyaniline is electrodeposited on the film, the concentrations 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 of sufficient film thickness, and when the concentration is lowered and polymerized for a long time, polyaniline is pulverized on the transparent conductive film. And it was difficult to obtain a uniform film. Further, when the concentration is further increased, there is a problem that the polymerized polyaniline dissolves in the electrolytic solution and peels off.

[0003] The inventors of the present invention have proposed Japanese Patent Application No. Hei.
No. 0 proposed a method of electrodeposition twice under specific conditions. However, when electrodeposition is performed on a relatively large-area transparent conductive film 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. Was.

[0004] The present invention has been made in view of such a point, and a conductive polymer such as polyaniline, a metal complex such as Prussian blue or vanadium pentoxide is formed on a relatively large-area transparent conductive film. It is an object of the present invention to provide a method for electrodepositing a metal oxide having 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 is formed is immersed in an electrolytic solution so as to face the conductive plate-like body. In the method of electrodepositing a conductive polymer, a metal complex, or a metal oxide on a transparent conductive film with the solid as a counter electrode, a conductive band having a lower resistance than the conductive film is provided around the transparent conductive film. The conductive plate-like member is substantially similar in shape to the transparent conductive film, and has a similarity ratio of 0.55 to 0.80 with respect to the transparent conductive film excluding the low-resistance conductive band. I do.

[0006]

The substrate on which the transparent conductive film having an area of 800 cm ² or more is formed is large. Therefore, even if a low-resistance conductive band is provided around the transparent conductive film, it is difficult to perform electrodeposition with Prussian blue. Since the current density of the transparent conductive film is about 5 μA / cm ² and the voltage drop is relatively small, the Prussian blue can be electrodeposited to a uniform thickness with a transparent conductive film of about 45 cm square. Current density when electrodepositing a conductive polymer such as 30 to 200 μA /
becomes larger cm ^2, and the voltage drop from the peripheral portion toward the central portion is increased, the same dimensions conductive plate body as a transparent conductive film and the counter electrode as a working electrode, the electrodeposition by a shape, an electric field orientation of Becomes parallel to the surface of the conductive plate from the surface of the transparent conductive film, the amount of electrodeposition is smaller at the central portion than at the peripheral portion, and it is inevitable that the film thickness becomes uneven. Therefore, the present invention is to make the shape of the conductive plate-like body as the counter electrode similar to the transparent conductive film to be electrodeposited, and by setting the similarity ratio to 0.55 to 0.80 with respect to the transparent conductive film,
Since the counter electrode is smaller than the transparent conductive film, the diffusion of ions to the periphery of the transparent conductive film is delayed, and the strength of the electric field is weaker than that of the central part. As a result, the amount of electrodeposition in the peripheral portion and the central portion is balanced, and a substantially uniform film thickness can be obtained.

If the similarity ratio of the counter electrode is set to 0.55 or less, the thickness of the peripheral portion of the transparent conductive film becomes smaller than that of the central portion, and 0.8
If it is set to 0 or more, the peripheral portion becomes thicker than the central portion, and in any case, a uniform film cannot be electrodeposited.

When a metal complex such as Prussian blue is electrodeposited, the same size of the counter electrode may be used if the size of the transparent conductive film is up to about 45 cm square.
In the case of a rectangular 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 below in detail along with comparative examples. FIG. 1 is a schematic view showing an example of an apparatus for performing the method for electrodepositing a conductive polymer or the like according to the present invention.

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

In this state, the size of the platinum plate is reduced to 30c.
m square (similarity ratio: 0.73), 23 cm square (similarity ratio: 0.4 mm)
56), in the case of a 32 cm square (similarity ratio: 0.78), it was confirmed by a DC power supply that the anode potential at the reference electrode was initially about 0.85 V or more by a voltmeter 9 and the current density was 100 μA. / Cm ² (constant current) for 5 minutes to polymerize the polyaniline film on the ITO film. After that, the glass plate was taken out of the electrolytic cell and washed with water. As a result, polyaniline having a low adhesive force on the surface layer was dropped, and a polyaniline film having a thickness of 200 mm 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 bath containing an electrolytic solution containing a mixture of 0.5 mol / l of aniline and 0.5 mol / l of sulfuric acid. Electric current was applied at 100 μA / cm ² for 10 minutes to polymerize the polyaniline film.

The thickness of the polyaniline thus obtained is about 3500 °, and the distribution of the thickness of the polyaniline in terms of visible light transmittance for a 41 cm square excluding the low-resistance conductive band shows that the size of the platinum plate is 30 cm. Angle (similarity ratio: 0.73),
Table 1, Table 2, and Table 3 when 23 cm square (similarity ratio: 0.56) and 32 cm square (similarity ratio: 0.78), respectively.
The result as shown in FIG.

[0014]

[Table 1]

[0015]

[Table 2]

[0016]

[Table 3]

As is apparent from the results, the difference in transmittance between adjacent areas is small, the difference between the maximum value and the minimum value of transmittance is small, 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 described.

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

When a DC voltage of 1.0 V was applied to the thus obtained electrochromic device using polyaniline as an anode and WO ₃ as a cathode, the polyaniline developed a green color, the WO ₃ developed a blue color, and a visible light Transmittance is 1
Becomes 0.5%, showed good light-shielding property, was of WO ₃ is applied anode, a DC voltage of -0.5V polyaniline as the cathode, polyaniline, WO ₃ together decoloring, visible light transmittance of 55% And showed good light transmittance.

Even if this color change is repeated about 2000 times,
It was confirmed that the polyaniline film exhibited excellent electrochromism without peeling and without causing color unevenness during coloring. Also, during this period, when a constant voltage was applied to the electrochromic element, the fluctuation of the density was extremely small and a constant density was obtained, so that stable driving could be performed. This indicates that polyaniline is uniformly polymerized on the ITO film and that the adhesion is strong.

COMPARATIVE EXAMPLE In the same manner as in Example 1, an ITO film as a transparent conductive film was placed in an electrolytic tank containing, as an electrolytic solution, a mixture of aniline 0.1 mol / l and sulfuric acid 0.1 mol / l. Cover the entire surface,
Further, a silver paste of 20 m in width is used as a lower resistance conductive band.
m, screen-printed and fired over the entire periphery 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 supply.

In this state, the size of the platinum plate is reduced to 21c.
m square (similarity ratio: 0.51), 34 cm square (similarity ratio: 0.51).
83), a DC power supply was used to confirm that the anode potential at the reference electrode was about 0.85 V or more at the beginning, and a current was passed for 5 minutes at a current density of 100 μA / cm ² (constant current). Was polymerized on the ITO film. After that, the glass plate was taken out of the electrolytic cell and washed with water. As a result, polyaniline having a low adhesive force on the surface layer was dropped, and a polyaniline film having a thickness of 200 mm 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 bath containing an electrolytic solution containing a mixture of 0.5 mol / l of aniline and 0.5 mol / l of sulfuric acid. Electric current was applied at 100 μA / cm ² for 10 minutes to polymerize the polyaniline film.

When the film thickness distribution of the polyaniline thus obtained is shown in terms of visible light transmittance for a 41 cm square excluding the low-resistance conductive band, the dimensions of the platinum plate are 21 cm square (similarity ratio: 0.51). In the case of a 34 cm square (similarity ratio: 0.83), results as shown in Tables 4 and 5 were obtained.

[0026]

[Table 4]

[0027]

[Table 5]

As is apparent from these results, there is a large difference in transmittance between adjacent areas, and a difference between the maximum value and the minimum value of the transmittance is large, the uniformity is poor, and there is uneven color. It was not an 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, 34 cm square (similarity ratio: 0.83)
The film thickness distribution is omitted because the film thickness becomes more non-uniform than in the case of (1) and cannot be put to practical use. A 45 cm square glass plate, a platinum plate, and a saturated calomel electrode each coated with an ITO film were placed in an electrolytic tank containing an electrolyte containing a mixture of 0.5 mol / l and 0.5 mol / l sulfuric acid.
Dipped as a reference electrode, current density 100 μA / cm
^{2 When} the polyaniline film is polymerized by applying a current at (constant current) for 30 minutes and washed with water, the polyaniline film flows out, and the film thickness is less than 100 mm, and the uniformity is impaired. Was not.

Examples 2 to 4 Example 2 is an example in which polypyrrole is electrodeposited.
An acetonitrile solution containing mol / l pyrrole (C ₄ H ₄ N) and 0.1 mol / l silver perchlorate (AgClO ₄ ) was used as the electrolyte solution 1 and the transparent electrode as the working electrode was used in the same manner 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 6) having a similarity ratio of 0.55 to 0.80 with respect to the transparent conductive film excluding the low-resistance conductive band was immersed, and 160
Electrodeposition at a constant current of μA / cm ² for 800 seconds results in 3200Å
Of polypyrrole was polymerized. The film thickness distribution of the polypyrrole thus obtained was also excellent 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 (K) are used. FeC
l ₃ ) as an electrolytic solution 1, covering the entire surface with an ITO film as a transparent conductive film 3, and further as a lower resistance conductive band 4, a silver paste having a width of 20 mm and a screen printing over the entire peripheral portion. Baked 100 cm square glass substrate 5, 70 c as conductive plate 6
An m-square square platinum plate and a saturated calomel electrode were immersed as a working electrode, a counter electrode and a reference electrode 7, respectively, connected to a DC power supply 8 and electrodeposited at a constant current of 5 μA / cm ² for 50 minutes. A thick Prussian blue could be electrodeposited.

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

As described above, the preferred embodiment has been described.
The invention is not limited to this, and various applications are possible.
It is. Transparent conductive film other than ITO film, such as NESA film
Can also be used, and the shape also depends on the shape of the substrate
Formed, but may be formed irrespective of the shape of the substrate.
The shape is not limited to a square, but a rectangle, trapezoid, etc.
Square or triangular, pentagon or more polygonal
Which line is composed of straight lines, curves such as circles and ellipses
, Composed of straight and curved lines
Throat area is 800cm ^TwoElectrodes are applied to the above transparent conductive films of various shapes.
You can wear it.

As the conductive plate as the counter electrode, a plate such as carbon as well as a metal plate such as stainless steel and aluminum can be used as well as a metal plate having acid resistance in addition to the platinum plate. The shape may be similar to the shape of the transparent conductive film, and the similarity ratio may be appropriately selected in 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 a conductive plate-like member having a similarity ratio and a similarity ratio of 0.55 to 0.80 is opposed to each other. Electrodeposition, a film of a conductive polymer or a metal complex can be electrodeposited 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 light bodies, display bodies, and the like.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an apparatus for performing 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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-290896 (JP, A) JP-A-55-152200 (JP, A) JP-A-60-23805 (JP, A) 173787 (JP, A) Japanese Utility Model Application Hei 3-41856 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) C25D 9/00 C25D 13/06

Claims (1)

(57) [Claims] 1. A substrate on which a transparent conductive film having an area of 800 cm ² or more is formed is immersed in an electrolytic solution so as to face the substrate, and the substrate is used as a working electrode and the conductive plate as a counter electrode. A method for electrodepositing a conductive polymer, a metal complex or a metal oxide on a transparent conductive film, wherein a conductive band having a lower resistance than the conductive film is provided around the transparent conductive film, The conductive polymer is substantially similar in shape to the transparent conductive film, and has a similarity ratio of 0.55 to 0.80 with respect to the transparent conductive film excluding the low-resistance conductive band. Electrodeposition method.