JPH068515B2 - Organic thin film manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing an organic thin film, specifically using a specific micelle-forming agent, and using a mixed solution of a non-aqueous solvent and an aqueous medium, The present invention relates to a method for efficiently producing an organic thin film that can be used as an optical memory material, a photosensitive material, an electronic material, a coating material and the like by taking an electrochemical method.

[Problems to be Solved by Conventional Techniques and Inventions] In recent years, various techniques have been developed for forming organic thin films, and for hydrophobic organic substances including dyes such as phthalocyanine or derivatives, Generally, it is thinned by a vacuum vapor deposition method, a thermal CVD method, a plasma CVD method, an ultrahigh vacuum (ion beam, molecular beam epitaxy) method, an LB method, a casting method, or the like. Furthermore, recently, a thin film forming technique called a so-called micelle electrolysis method has been developed (see Japanese Patent Application Laid-Open No. 63-243298), which facilitates thinning of the above-mentioned hydrophobic organic substance and at the same time homogenizes the thin film. ， Thinning has been further improved, making it possible to form high quality thin films. This micellar electrolysis method is characterized in that a film can be formed while maintaining the shape of primary particles or secondary particles of a hydrophobic organic substance.

However, although the above-mentioned micelle electrolysis method can form a film while maintaining the shapes of primary particles and secondary particles, it was not possible to form a thin film in a molecularly dispersed state.

Therefore, the present inventor has conducted earnest studies to develop a method for forming a molecularly dispersed thin film, which cannot be achieved by the micelle electrolysis method.

As a result, the hydrophobic organic substance is dispersed in the conventional micelle solution,
It has been found that the intended purpose can be achieved by dissolving a hydrophobic organic substance in a non-aqueous solvent instead of solubilizing the mixture, and subjecting the solution to a mixture of a micelle-forming agent and an aqueous medium with an electric current. The present invention has been completed based on such findings.

[Means for Solving the Problems]

That is, the present invention is a mixture of (a) a solution in which a hydrophobic organic substance is dissolved in a non-aqueous solvent, (b) an aqueous medium and (c) a micelle-forming agent consisting of a ferrocene derivative, and the resulting mixed solution is subjected to electrical treatment. And a thin film of the hydrophobic organic substance is formed on the electrode.

Examples of the hydrophobic organic substance used in the method of the present invention include various ones. For example, perylene, metal complexes of perylene and their derivatives, lake pigments, phthalocyanines, metal complexes of phthalocyanines and their derivatives (phthalocyanine blue). , Phthalocyanine green), naphthalocyanine, metal complex of naphthalocyanine and their derivatives, porphyrin, metal complex of porphyrin and their derivatives, anthraquinone, azo dyes, quinacridone, viologen, and organic dyes for optical memory such as sudan. Introduction 1,1'-diheptyl-4,4'-bipyridinium dibromide, 1,1'-
Electrochromic materials such as didodecyl-4,4'-bipyridinium dibromide, 6-nitro-1,3
A photosensitive material (photochromic material) such as 3-trimethylspiro- (2'H-1'-benzopyran-2,2'-indoline) (commonly known as spiropyran) or an optical sensor material,
Liquid crystal display dyes such as p-azoxyanisole, and "Color Chemical Encyclopedia" CMC, 198.
Electronic dyes, recording dyes, environmental chromism dyes, photographic dyes, energy dyes, biomedical dyes, food and cosmetic dyes, listed on pages 542 to 717 issued on March 28, 1996, Examples include dyes, pigments, and hydrophobic compounds among special coloring pigments.
Further, organic conductive materials such as 1: 1 complex of 7,7,8,8-tetracyanoquinone dimethane (TCNQ) and tetrathiafulvalene (TTF), gas sensor materials, and photocurable materials such as pentaerythritol diacrylate. Insulating material such as paint, stearic acid, 1-phenylazo-
Examples thereof include diazo type photosensitive materials such as 2-naphthol and paints.

Next, there are various non-aqueous solvents that dissolve the above-mentioned hydrophobic organic substances. For example, aliphatic hydrocarbons such as hexane and heptane, cyclic ethers such as tetrahydrofuran (THF), methanol, ethanol, propanol, etc. Suitable alcohols, acetone, ketones such as methyl ethyl ketone, ethers such as ethyl acetate, aromatic hydrocarbons such as benzene, toluene, xylene, etc., as well as dimethylformamide (DMF), dimethyl sulfoxide, acetonitrile, methylene chloride, chloronaphthalene, etc. Can be given as In any case, as long as it dissolves the above-mentioned hydrophobic organic substance, various organic solvents can be used regardless of whether or not they have compatibility with the aqueous medium (b).

In the method of the present invention, a solution prepared by dissolving the above hydrophobic organic substance in a non-aqueous solvent is used as the component (a), and (b) an aqueous medium and
(c) Mixing the micellizing agent. Here, (b) the aqueous medium includes various water-based media such as water, a mixed solution of water and alcohol, a mixed solution of water and acetone. You can

On the other hand, the micellizing agent used as the component (c) is a ferrocene derivative. Here, there are various ferrocene derivatives that can be used. For example, JP-A-63-
Ammonium-type ferrocene derivative disclosed in JP-A-243298, ether-type ferrocene derivative disclosed in Japanese Patent Application No. 62-212718, and Japanese Patent Application No. 63-52
696, a pyridinium-type ferrocene derivative, and Japanese Patent Application No. 63-233798.
63-248600, 63-248601.
There are various types of ferrocene derivatives shown in the specification and the like.

In the method of the present invention, a mixed solution obtained by mixing the components (a), (b) and (c) is used. This mixed solution, when the non-aqueous solvent in the component (a) and the aqueous medium (b) are insoluble, a solution of a hydrophobic organic substance dissolved in the non-aqueous solvent ((a)
It is considered that the component) is emulsified in an aqueous medium containing a micelle forming agent to form an emulsion, and that the hydrophobic organic substance is partially dissolved (dispersed) in the aqueous medium by the micelle forming agent. When the non-aqueous solvent and the aqueous medium are compatible with each other, the hydrophobic organic substance is dispersed throughout the system by the micellizing agent without forming an emulsion,
It is considered to be incorporated into the micellizing agent. In either case, since the hydrophobic organic substance is dispersed or solubilized in a molecular form, it becomes a thin film formed by being dispersed in a molecular form by the subsequent energization treatment.

The energization treatment performed by the method of the present invention is the above (a), (b) and
A mixed solution containing the component (c) is used, and as a result, a thin film of a hydrophobic organic substance is formed on the electrode.

The operating procedure of the method of the present invention can be variously modified, and one example thereof is as follows.

That is, first, a micelle agent composed of a ferrocene derivative is put into an aqueous medium to prepare a micelle solution. The concentration of the micellizing agent at this time is not particularly limited, but it is usually selected in the range of not less than the limit micelle concentration, specifically 10 μM to 1 M, preferably 0.5 to 5 mM. It is also effective to add a supporting salt to the micelle solution, if desired. When a supporting salt is added, the type of the supporting salt is not particularly limited as long as it can control the electric conductivity of the aqueous medium without hindering the progress of solubilization of the hydrophobic organic substance or the deposition on the electrode. . Specifically, various sulfates, acetates, halogenated salts,
Examples include water-soluble oxide salts. The amount of the supporting salt added is usually about 0 to 300 times, preferably about 10 to 200 times that of the above micellizing agent.

On the other hand, a hydrophobic organic substance is dissolved in the non-aqueous solvent at an appropriate concentration, usually at a concentration equal to or higher than the saturated amount, and the solution of the hydrophobic organic substance is mixed with the above-mentioned micelle solution. At the time of this mixing, ultrasonic waves, a homogenizer, a stirrer, or the like is used for thorough mixing and stirring, after which excess hydrophobic organic substances are removed as necessary, and the resulting mixed solution is allowed to stand or is slightly stirred. Meanwhile, energization is performed using the electrodes. In addition, during the energization treatment, a solution of a hydrophobic organic substance dissolved in a non-aqueous solvent may be replenished and added to the mixed solution, or the mixed solution in the vicinity of the anode may be drawn out of the system and the extracted mixed solution may be A solution (a solution in which a hydrophobic organic substance is dissolved in a non-aqueous solvent) is added and sufficiently mixed and stirred, and then a circulation circuit for returning the solution to the vicinity of the cathode may be additionally provided.
The energization conditions at this time may be appropriately selected according to various situations, but usually the liquid temperature is 0 to 70 ° C., preferably 20 to 30.
C., voltage is set to 0.03 to 1.5V, preferably 0.1 to 0.5V. The energization time varies depending on the situation, but generally 30 minutes to 2 hours is sufficient.

The electrode used in this case may be a metal or a conductor that is more noble than the oxidation potential of the ferrocene derivative that is a micellizing agent (+0.10 to 0.30 V vs. saturated sweet kou electrode). Specific examples include 1TO (a mixed oxide of indium oxide and tin oxide), platinum, gold, silver, glassy carbon, a conductive metal oxide, and an organic polymer conductor.

In this way, the thin film in which the hydrophobic organic substance is molecularly dispersed is formed by subjecting the mixed liquid comprising the components (a), (b) and (c) to the electric current treatment. This thin film has a remarkably different microstructure from the thin film formed by dispersing the hydrophobic organic substance particles obtained by the conventional micelle electrolysis method.

〔Example〕

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

Example 1 Tetraphenylporphyrin was dissolved in ethanol,
A saturated dye solution was prepared. The visible absorption spectrum of this saturated dye solution is shown in FIG. 1 (mark A).

On the other hand, the formula for 100m of water The micelle-forming agent (FPEG) represented by the formula (1) was added to make a 2 mM micelle solution. To this micelle solution (25 cc) was added the saturated dye solution (3 cc), and the mixture was stirred with a stirrer for 1 hour to prepare a mixed solution (micelle mixed solution). Further, lithium bromide as a supporting salt was added to this mixed solution of micelles to a concentration of 0.1 M to prepare a micelle electrolyte solution. The visible absorption spectrum of this micelle electrolyte is shown in FIG. 1 (mark B).

ITO transparent glass electrode as an anode in this micelle electrolyte,
Using platinum as the cathode and a saturated sweet koh electrode as the reference electrode, 2
Constant-potential electrolysis was performed at 5 ° C and an applied voltage of 0.5V. At this time, the current density was 6.8 μA / cm ² , the energization time was 30 minutes, and the energization amount was 0.01 coulomb (C).

As a result, a dye thin film was obtained on the ITO transparent glass electrode.
The visible spectrum of this thin film is shown in FIG. 1 (mark C). Compared with the visible absorption spectrum (Fig. 1 (mark D)) of the thin film produced in Comparative Example 1 described later, it shows a spectrum similar to that of a saturated dye solution and has a structure close to dissolution (monomolecular dispersion). .

From the above, in Example 1, it was possible to obtain a molecularly dispersed thin film.

Comparative Example 1 A thin film was produced in the same manner as in Example 1 except that tetraphenylporphyrin was not dissolved in ethanol and 0.1 g thereof was dispersed and solubilized in the micelle solution as it was.

As a result, a dye thin film was obtained on the ITO transparent electrode. The visible absorption spectrum of this thin film is shown in FIG. 1 (mark D).

Example 2 Tetraphenylporphyrin was dissolved in treene to prepare a saturated dye solution. The visible absorption spectrum of this saturated dye solution is shown in FIG. 2 (mark A).

On the other hand, the formula for 100m of water 2 mM by adding the micelle agent (FEST9) represented by
The above micelle solution (25 cc) was mixed with the saturated dye solution (3 cc) and stirred with a stirrer for 1 hour to give a micelle mixed solution. Further, lithium bromide as a supporting salt was added to this mixed solution of micelles to a concentration of 0.1 M to prepare a micelle electrolyte solution. The visible absorption spectrum of this micelle electrolyte is shown in FIG. 2 (mark B).

This ITO cell was subjected to constant potential electrolysis at 25 ° C. and an applied voltage of 0.5 V using an ITO transparent glass electrode as an anode, platinum as a cathode, and a saturated sweet koh electrode as a reference electrode. The current density at this time was 11.5 μA / cm ² , and the energization time was 30
Minutes, the amount of electricity was 0.02C.

As a result, a dye thin film was obtained on the ITO transparent glass electrode.
The visible absorption spectrum of this thin film is shown in FIG. 2 (mark C). As compared with the visible absorption spectrum (Fig. 1 (mark D)) of the thin film produced in Comparative Example 1, it is found that the thin film has a spectrum close to that of a saturated dye solution and has a structure close to dissolution (monomolecular dispersion).

From the above, in Example 2, it was possible to obtain a molecularly dispersed thin film.

Example 3 A tetraphenylporphyrin zinc complex was dissolved in ethanol to prepare a saturated dye solution. The visible absorption spectrum of this saturated dye solution is shown in FIG. 3 (mark A).

On the other hand, the formula for 100m of water 2 mM by adding the micellizing agent represented by (FEST8)
The above micelle solution (25 cc) was mixed with the saturated dye solution (3 cc) and stirred with a stirrer for 1 hour to give a micelle mixed solution. Further, lithium bromide as a supporting salt was added to this mixed solution of micelles to a concentration of 0.1 M to prepare a micelle electrolyte solution. The visible absorption spectrum of this micelle electrolyte is shown in FIG. 3 (mark B).

This ITO cell was subjected to constant potential electrolysis at 25 ° C. and an applied voltage of 0.5 V using an ITO transparent glass electrode as an anode, platinum as a cathode, and a saturated sweet koh electrode as a reference electrode. The current density at this time was 15.6 μA / cm ² , and the energization time was 30
Minutes, the energization amount was 0.025C.

As a result, a dye thin film was obtained on the ITO transparent glass electrode.
The visible absorption spectrum of this thin film is shown in FIG. 3 (mark C). Compared with the visible absorption spectrum (Fig. 3 (mark D)) of the thin film produced in Comparative Example 2 described later, it shows a spectrum similar to that of a saturated dye solution and has a structure close to dissolution (monomolecular dispersion). .

From the above, in Example 3, it was possible to obtain a molecularly dispersed thin film.

Comparative Example 2 The tetraphenylporphyrin zinc complex was not dissolved in ethanol, and 0.1 g thereof was dispersed in the micelle solution as it was.
A thin film was produced in the same manner as in Example 3 except that it was solubilized.

As a result, a dye thin film was obtained on the ITO transparent electrode. The visible absorption spectrum of this thin film is shown in FIG. 3 (mark D).

Example 4 Phthalocyanine was dissolved in chloronaphthalene to prepare a saturated dye solution. The visible absorption spectrum of this saturated dye solution is shown in FIG. 4 (mark A).

On the other hand, FPEG was added to 100 m of water to make a 2 mM micelle solution, and 25 cc of this micelle solution was added with 3 cc of the saturated dye solution and stirred for 1 hour with a stirrer to give a micelle mixed solution. Further, lithium bromide as a supporting salt was added to this mixed solution of micelles to a concentration of 0.1 M to prepare a micelle electrolyte solution. The visible absorption spectrum of this micelle electrolyte is shown in FIG. 4 (mark B).

This ITO cell was subjected to constant potential electrolysis at 25 ° C. and an applied voltage of 0.5 V using an ITO transparent glass electrode as an anode, platinum as a cathode, and a saturated sweet koh electrode as a reference electrode. At this time, the current density is 8.6 μA / cm ² , and the energization time is 30
Minutes, the amount of electricity was 0.015C.

As a result, a dye thin film was obtained on the ITO transparent glass electrode.
The visible absorption spectrum of this thin film is shown in FIG. 4 (mark C). It can be seen that, as compared with the visible absorption spectrum (Fig. 4 (mark D)) of the thin film produced in Comparative Example 3 described later, it has a spectrum close to that of a saturated dye solution and has a structure close to dissolution (monomolecular dispersion).

As described above, in Example 4, it was possible to obtain a molecularly dispersed thin film.

Comparative Example 3 Phthalocyanine was not dissolved in chloronaphthalene,
A thin film was produced in the same manner as in Example 4, except that 0.1 g was dispersed and solubilized in the micelle solution as it was.

As a result, a dye thin film was obtained on the ITO transparent electrode. The visible absorption spectrum of this thin film is shown in FIG. 4 (mark D).

Example 5 Magnesium phthalocyanine is dissolved in ethanol,
A saturated dye solution was prepared. The visible absorption spectrum of this saturated dye solution is shown in FIG. 5 (mark A).

On the other hand, FPEG was added to 100 m of water to make a 2 mM micelle solution, and 25 cc of this micelle solution was added with 3 cc of the saturated dye solution and stirred for 1 hour with a stirrer to give a micelle mixed solution. Further, lithium bromide as a supporting salt was added to the mixed solution of micelles so as to have a concentration of 0.1 M to prepare a micelle electrolyte solution. The visible absorption spectrum of this micelle electrolyte is shown in FIG. 5 (mark B).

This ITO cell was subjected to constant potential electrolysis at 25 ° C. and an applied voltage of 0.5 V using an ITO transparent glass electrode as an anode, platinum as a cathode, and a saturated sweet koh electrode as a reference electrode. The current density at this time was 9.1 μA / cm ² , and the energization time was 30
Minutes, the amount of electricity was 0.015C.

As a result, a dye thin film was obtained on the ITO transparent glass electrode.
The visible absorption spectrum of this thin film is shown in FIG. 5 (mark C). It can be seen that, as compared with the visible absorption spectrum (Fig. 5 (mark D)) of the thin film produced in Comparative Example 4 described later, it has a spectrum close to that of a saturated dye solution and has a structure close to dissolution (monomolecular dispersion).

As described above, in Example 5, it was possible to obtain a molecularly dispersed thin film.

Comparative Example 4 A thin film was produced in the same manner as in Example 5 except that magnesium phthalocyanine was not dissolved in ethanol, and 0.1 g thereof was dispersed and solubilized in the micelle solution as it was.

As a result, a dye thin film was obtained on the ITO transparent electrode. The visible absorption spectrum of this thin film is shown in FIG. 5 (mark D).

〔The invention's effect〕

As described above, according to the method of the present invention, it is possible to form a thin film made of various kinds of hydrophobic organic substances in a state in which the film thickness is extremely thin and is dispersed in a molecular state (that is, monomolecular dispersion). .

Therefore, the organic thin film produced by the method of the present invention has a high optical response, and is an optical disc material, an optical memory material, a photo hole burning (PHB) memory material, a photosensitive material, a photochromic material, a color filter, a solar cell, an electronic material, It is expected to be effectively used as a coating material.

[Brief description of drawings]

1 to 5 show Examples 1 to 5 and Comparative Examples 1 to 4, respectively.
The visible absorption spectra of the saturated dye solution, the micelle electrolyte solution, and the thin film obtained in step 2 are shown.

Claims (1)

[Claims] 1. A mixture of (a) a solution in which a hydrophobic organic substance is dissolved in a non-aqueous solvent, (b) an aqueous medium, and (c) a micelle-forming agent comprising a ferrocene derivative, and the resulting mixed solution is electrically treated. Forming a thin film of the hydrophobic organic substance on the electrode.