JPH02101199A - Method for washing electrode - Google Patents

Abstract

PURPOSE:To efficiently and effectively wash an electrode especially used as a counter electrode in a micelle electrolysis method by electrifying the electrode in an aq. medium or an org. solvent. CONSTITUTION:A hydrophobic substance is solubilized in an aq. medium with a ferrocene deriv. as a micelle forming agent and the resulting micelle soln. is electrolyzed to form a thin film of the hydrophobic substance on an electrode. After the film formation, an electrode used as a counter electrode and contaminated is put in an aq. medium such as water or an org. solvent and electrified to remove the contaminant. Only the counter electrode can be efficiently washed and the thin film is not adversely affected. By combining the washing method with the micelle electrolysis method or other electrical treatment, a high quality photoelectric conversion material contg. no impurities, a high quality color filter, etc., can be produced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for cleaning an electrode, and more specifically, a method for cleaning an electrode, particularly an electrode used as a counter electrode in a so-called micelle electrolysis method, efficiently and effectively. Regarding the method.

[Prior Art and Problems to be Solved by the Invention] Color filters, liquid crystal display materials, image pickup devices, etc. are generally subjected to electrical processing using electrodes, and contamination of the electrodes is a problem. In particular, the micelle electrolysis method (patent application 1986-1975)
When thin films are formed one after another on multiple electrodes using a method (see specification of No. 930, etc.), dirt on the electrodes (those used as counter electrodes and those not yet energized) may cause another thin film to be formed on this electrode next. It is necessary to completely remove it as it becomes an obstacle when doing so. In particular, when forming thin films on electrodes for applications such as photosensitive material color filters and photoelectric exchange materials, if the electrodes are dirty, the resulting thin film will contain impurities, and even if the impurities are in trace amounts, the thin film will be damaged. Since the performance of the film is significantly reduced, it is an important condition to remove as much of the above-mentioned dirt as possible in order to obtain a high-performance thin film.

However, in the usual cleaning using water or a hot melt medium, a large amount of cleaning liquid is required. ■Since the cleaning process involves flowing liquid, there is a risk that the thin film that has already been formed may be damaged. ■There are various problems such as the possibility that parts that do not need to be cleaned may be washed.

Therefore, the inventor of the present invention has conducted extensive research in order to solve the problems of the conventional cleaning methods described above and to develop a method that can effectively clean only the target electrode without affecting others. Ta.

[Means to solve the problem]

As a result, it has been found that the above problems can be solved at once by subjecting the electrodes to be cleaned to electrical current treatment in a cleaning solution. The present invention was completed based on this knowledge.

That is, the present invention provides an electrode cleaning method characterized by subjecting the electrode to electrical current treatment in an aqueous medium or an organic solvent.

In the method of the present invention, electricity may be applied to the electrode to be cleaned while it is immersed in a cleaning solution, that is, an aqueous medium or an organic solvent.

This cleaning method is effective for cleaning electrodes that have become contaminated due to various uses, but is particularly effective for cleaning electrodes that have become contaminated when used as a counter electrode when producing thin films by micellar electrolysis. be.

This micelle electrolysis method is described in detail in the specification of Japanese Patent Application No. 62-75930, etc., but the outline thereof will be explained as follows.

First, a hydrophobic substance, which is a constituent material of the thin film, is solubilized in an aqueous medium with a micelle agent made of a ferrocene derivative.
The resulting micellar solution is then electrolyzed to form a thin film on the electrode (ie, the conductive substrate). Specifically, this operation involves placing a micelle agent (the concentration is based on the limit micelle concentration), a supporting salt, and a hydrophobic substance in an electrolytic cell, and thoroughly dispersing the mixture using ultrasonic waves, a homogenizer, a stirrer, etc. After that, excess hydrophobic substances are removed if necessary, and the resulting micelle solution is subjected to electrolytic treatment using the above-mentioned electrode while standing still or with slight stirring. Additionally, a hydrophobic substance may be supplemented and added to the micelle solution during the electrolytic treatment, or the micelle solution near the anode is extracted from the system, the hydrophobic substance is added to the extracted micelle solution, and the mixture is thoroughly mixed and stirred. A circulation circuit for returning this liquid to the vicinity of the cathode later may also be provided. The electrolysis conditions at this time may be selected appropriately depending on various situations, but usually the liquid temperature is 0 to 70°C, preferably 20 to 30°C, and the voltage is 0.03 to 1.5cm, preferably 0.1 ~0.5■, current density 10mA/cm2 or less, preferably 50~3
00 μA/crn 2.

When this electrolytic treatment is performed, the redox reaction of the ferrocene derivative proceeds. Focusing on the behavior of Fe ions in ferrocene derivatives, we can see that at the anode, the Fe'' of ferrocene is
becomes e3+, the micelles collapse, and hydrophobic particles (
about 600 to 900 people) are deposited on the anode. On the other hand, at the cathode, the Fe" oxidized at the anode is reduced to Fe24 and returned to the original micelles, so the film forming operation can be repeated using the same solution.

Here, the hydrophobic substance that is the material of the thin film is not limited to organic substances, and may be inorganic substances, and there are various types.

Examples of organic substances include phthalocyanine, metal complexes of phthalocyanine and derivatives thereof, naphthalocyanine, metal complexes of naphthalocyanine and derivatives thereof, and porphyrins.

In addition to photomemory dyes and organic dyes such as porphyrin metal complexes and their derivatives, 1,1 diheptyl-
Electrochromic materials such as 4,4″-bipyridinium dibromide, 1,1″-didodecyl-4,4″-bipyridinium dibromide, 6-nitro-1,3,3
- Photosensitive materials (photochromic materials) such as -1-limethyl spiro (2'H-1'-benzobilane-2,2'-indoline) (commonly known as spiropyran) and optical sensor materials,
Liquid crystal display dyes such as P-azoxyanisole, and
Electronics dyes, recording dyes, environmental chromism dyes, and photographic dyes listed in "Color Chemical Encyclopedia", CMC Co., Ltd., published March 28, 1988, pages 542-717.

Examples include energy dyes, biomedical dyes, food/cosmetic dyes, dyes, pigments, and hydrophobic compounds among special coloring dyes. In addition, organic conductive materials such as a 1:1 complex of 7788-tetracyanoquinone dimethane (TCNQ) and tetrathiafulvalene (TTF), gas sensor materials, photocurable paints such as pentaerythritol diacrylate, stearic acid Examples include insulating materials such as diazo type photosensitive materials such as 1-phenylazo-2-naphthol, paints, and the like.

Furthermore, water-insoluble polymers such as polycarbonate polystyrene, polyethylene, polypropylene, polyamide, polyphenylene sulfide (PPS)
, polyphenylene oxide (PPO), polyacrylonitrile (PAN), and various other polymers (such as polyvinylpyridine), polyphenylene, polypyrrole, polyaniline, polythiophene, acetylcellulose, polyvinyl acetate, polyvinyl phthyral, etc. Copolymers (such as copolymers of methyl methacrylate and methacrylic acid) can be mentioned.

Furthermore, examples of inorganic substances include Ti0z, C, and CdS.

W O31F e z 03+ Y 203 Z r
02, A I z O3, Cu S .

There are various materials such as ZnS, Te0z, LiNb0z, Si3N4, and various superconducting oxides.

In addition, as a micellar agent used in this micelle electrolysis method, ferrocene derivatives include, for example, Japanese Patent Application No. 63-1479.
Various compounds can be used, including the known compounds and novel compounds listed in the specification of No. 59, and may be appropriately selected depending on the type of thin film forming material.

By such electrolytic treatment, a thin film of about 600 to 900 particles of the desired hydrophobic substance is formed on the anode.

Further, the electrode used in this micelle electrolysis method may be any metal or conductor that has a higher oxidation potential than ferrocene (+0.15 V vs. saturated electrode). Specifically, ITO (
Examples include mixed oxides of indium oxide and tin oxide), platinum, gold, silver, grady carbon, conductive metal oxides, and organic polymer conductors.

For example, when forming thin films of various colors on an ITO pattern as shown in Fig. 1, first, a red dye is applied to a thin film using part A as an anode and part B as a cathode (counter electrode) (see Fig. 1 (a)). If a micelle electrolysis method is performed using the material, a red thin film (R) will be formed in the portion A. On the other hand, this red dye adheres to portion B, which is the cathode (counter electrode), and stain 1 is generated.

Note that if this ITO pattern has a portion C (not shown) that is not energized during the thin film formation of the portion A,
Dirt also occurs in this portion C as well.

According to the cleaning method of the present invention, by placing the ITO pattern in an aqueous medium such as water or an organic solvent and applying electricity using the portion B as an electrode, the stain 1 is cleaned, and the red color of the portion A is removed. The thin film is not damaged in any way (see FIG. 1(b)).

Furthermore, if the above-mentioned portion C is also cleaned by applying the cleaning method of the present invention before forming the thin film,
A clean thin film can be obtained.

At this time, usable aqueous media and organic solvents include propylene carbonate, acetonitrile, tetrahydrofuran (
Examples include TI (F), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), methanol, ethanol, water, and mixtures thereof, but are not limited to these and can be used in various situations. It may be selected as appropriate. In addition, this aqueous medium and organic solvent may include LiBr, TM, etc. as necessary.
A-BF, (TMA represents tetramethylamine)T
MA-CI! , O,, TBA-BF4 (TBA represents tetrabutylamine -), LiB F4+ LiC42
0a.

It is also effective to add a supporting salt such as KBF.

Furthermore, the voltage applied to the part B, which is the electrode to be cleaned, is not particularly limited, but a negative voltage or a voltage waveform including a negative voltage is preferable, and in particular, if it is appropriately selected in the range of 0 to -2.0 good. Note that there are various voltage waveforms that can be used, and examples include direct current, triangular wave, pulse, and sine wave. Furthermore, in the energization process of the portion B, the portion A in which a thin film is formed as a counter electrode may be used, or another electrode may be used.

After the above-mentioned cleaning treatment of part B, use this part B as an anode,
If the micelle electrolysis method is repeated using a thin film material such as a green dye, a green thin film (G) will be formed in part B (Fig. 1(c)
,)reference).

By repeating the thin film formation by the micelle electrolysis method and the cleaning method of the present invention in this way, high purity and high quality thin films of different types can be sequentially formed on the portions CD, E, . . . . Specifically, when performing micelle electrolysis with part B as an anode, part C or another part is used as a cathode (counter electrode), and when performing micelle electrolysis with part C as an anode, part The other part is the cathode (
By repeating the procedure of using the electrode as a counter electrode, high-purity thin films containing no desired impurities can be successively formed. In this case, a platinum electrode or the like may be used independently and always used as a counter electrode in the repeated micelle electrolysis method.

[Examples] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Production Example 1 190 μm was added and stirred to prepare a uniform micelle solution. Add 0.2g of phthalocyanine to 50cc of this micelle solution.
In addition, after stirring with ultrasonic waves for 1 minute, stir with a stirrer for 3 minutes.
The mixture was stirred for several days. This solubilized micelle solution was allowed to settle naturally for one day, and the supernatant liquid was collected.

To this supernatant, 0.104 g of LiBr was added and 0.104 g of LiBr was added.
2M LiBr/2mM F PEG/4. ImM
A phthalocyanine solution was obtained. Using this as an electrolyte, the second
Using part A of the ITO pattern as shown in the figure as an anode, part B as a cathode, and a saturated red electrode as a reference electrode, constant potential electrolysis was carried out for 30 minutes at 25°C with an applied voltage of 0.5 V and a current density of 17.2 μA/cA. went. As a result, it was confirmed using a stereoscopic microscope that a phthalocyanine thin film was formed in part A, and a 1η leak 1 due to phthalocyanine was generated in part B (cathode).

Example 1 The ITO pattern in which the phthalocyanine thin film was formed on the part A produced in Production Example 1 above was placed in a 0.1 MIjBr aqueous solution, and the pattern was repeatedly swept at a rate of 100 mV/sec in the range of +o and av. As a result, it was confirmed with a stereoscopic microscope that no phthalocyanine was present in portion B, and it was found that the adhering stain 1 due to phthalocyanine had been washed and removed.

Example 2 The procedure of Example 1 was repeated, except that the ITO pattern in which the phthalocyanine thin film was formed on part A produced in Production Example 1 above was placed in a propylene carbonate solution of 0.1 M tetrabutylammonium-boron tetrafluoride. A similar operation was performed.

As a result, it was confirmed with a stereoscopic microscope that no phthalocyanine was present in portion B, and it was found that the adhering stain 1 due to phthalocyanine had been washed and removed.

Further, the current potential curve at this time is shown in FIG.

Thus, it can be seen that phthalocyanine is dissolved and removed at a negative potential.

Example 3 The ITO pattern with a phthalocyanine thin film formed on part A manufactured in Production Example 1 above was placed in the same solution as in Example 2, part B was used as the actuating rod, part A was used as the counter electrode, and the saturated sweet electrode was used as the reference electrode. As such, a potential was applied so that the actuating rod of part B was -0.8V.

As a result, it was confirmed by stereoscopic microscope observation that only the phthalocyanine attached to part B was dissolved and that there was no change in the phthalocyanine thin film on the part.

Example 4 The same operation as in Example 3 was performed except that the solution was changed to a 0.1 M tetramethylammonium-boron tetrafluoride acetonitrile solution.

As a result, it was confirmed by observation using a stereoscopic microscope that the phthalocyanine in part B could be washed without damaging the phthalocyanine thin film in part A.

Comparative Example 1 The IT◯ pattern in which a phthalocyanine thin film was formed on part A produced in Production Example 1 above was washed for 10 minutes in a water tank containing 1000 cc of water while stirring with Starcy, and then washed in a water tank containing 500 cc of methanol. Washing was carried out for 10 minutes in a tank with stirring using Starcy.

However, the phthalocyanine stain on portion B observed in Production Example 1 remained as it was, and was hardly cleaned.

〔Effect of the invention〕

According to the method of the present invention, only the target electrode can be efficiently cleaned without adversely affecting the thin films formed on other electrodes.

Therefore, if the cleaning method of the present invention is combined with various electrical treatments including micelle electrolysis, high-quality photoelectric conversion materials, color filters (RGB), photosensitive materials, solar cells, etc. that do not contain impurities can be produced. can be manufactured.

[Brief explanation of the drawing]

FIGS. 1(a), 1(b), and 1(C) are explanatory diagrams showing a procedure for forming a thin film on an ITO pattern and cleaning it. Further, FIG. 2 is a schematic diagram of the ITO pattern used in Manufacturing Example 1. FIG. 3 is a current potential curve used in Example 2.

Claims (3)

[Claims] (1) A method for cleaning an electrode, which comprises subjecting the electrode to electrical current treatment in an aqueous medium or an organic solvent. (2) A hydrophobic substance was solubilized in an aqueous medium with a micelle agent made of a ferrocene derivative, and the resulting micelle solution was electrolyzed to form a thin film of the hydrophobic substance on an electrode, which was used as a counter electrode. 2. The cleaning method according to claim 1, wherein the electrode is subjected to an electric current treatment. (3) The cleaning method according to claim 1 or 2, characterized in that during the energization process of the electrode, a negative voltage or a voltage waveform including a negative voltage is applied to the electrode.