JPH02236299A - Production of inorganic thin film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing an inorganic thin film, and more specifically, by using a specific micellar agent and using an electrochemical method, it is possible to produce electronic materials, coating materials, etc. This invention relates to a method for efficiently producing inorganic thin films that can be used for.

[Prior art and problems to be solved by the invention] Conventionally, methods for manufacturing various inorganic thin films include vacuum evaporation, two-thermal CVD, plasma CVD, ultra-high vacuum (ion beam, molecular beam epitaxy), LB membrane method. Casting methods are known.

However, these methods, especially vacuum evaporation and CVD
The method requires large-scale equipment and requires a vacuum system, among other problems. In addition, the casting method has problems in that it is difficult to select a solvent and the inorganic materials that can be formed into a thin film are limited.

The present inventor has conducted extensive research in order to overcome the drawbacks of the above-mentioned conventional techniques and to develop a method that can easily form thin films of various inorganic substances using a simple device.

[Means to solve the problem]

As a result, they discovered that when a ferrocene derivative is used as a micelle agent, various inorganic substances can be incorporated into micelles in water, and by electrolytically treating this, a desired inorganic thin film can be formed on an electrode. The present invention was completed based on this knowledge.

That is, the present invention solubilizes or disperses an inorganic substance in an aqueous medium with a micellizing agent made of a fekucene derivative, and electrolyzes the resulting micelle solution or dispersion to form a thin film of the inorganic substance on an electrode. The present invention provides a method for producing an inorganic thin film, which is characterized by forming an inorganic thin film.

The method of the present invention proceeds according to the following principle, and an inorganic thin film is formed on an electrode (anode).

Generally, inorganic substances such as titanium oxide have hydroxyl groups on their surfaces. Therefore, the surface exhibits strong hydrophilicity. Particles of such inorganic substances are placed in an aqueous medium in which electrical conductivity is adjusted by adding a supporting electrolyte to water as necessary.
When added together with a micellizing agent (surfactant) made of a ferrocene derivative, the hydrophilic groups of the micellizing agent are first adsorbed onto the inorganic particles. As a result, the hydrophobic group of the micelle-forming agent (located at the opposite position to the hydrophilic group of the micelle-forming agent) covers the surface of the inorganic material particles, making the surface hydrophobic (further adsorption).
. Next, the hydrophobic group of the micelle agent is further adsorbed on the hydrophobicized surface, making the surface hydrophilic and dispersing it (double-layer adsorption).
. Therefore, it is preferable that the amount of the micellizing agent added is 1.5 times or more the amount adsorbed on the surface of the inorganic substance.

In this way, after dispersing the inorganic particles, electrolysis (
When electricity is applied), the micelles are attracted to the anode, and the ferrocene derivative in the micelles loses electron e1 on the anode (Fe2+ in ferrocene is oxidized to Fe''), and at the same time, the micelles collapse and the inorganic inside The substance is deposited on the anode to form a thin film, while the oxidized ferrocene derivative is attracted to the cathode, receives electrons e, and forms micelles again.

In the process of repeating the formation and collapse of micelles, inorganic particles are deposited on the anode and become a thin film.
The desired inorganic thin film is formed.

The micellar agent used in the method of the present invention consists of a ferrocene derivative. There are various types of ferrocene derivatives, but they can be roughly divided into the following (1) to (6).
) can list six types.

First, (1) a ferrocene compound (
Examples include ferrocene or ferrocene to which an appropriate substituent (alkyl group, acetyl group, etc.) is bonded. If the number of carbon atoms in the main chain is too small, it will not form micelles, and if the number of carbon atoms is too large, it will not dissolve in water.

There are various ways in which the ferrocene compound is bonded to this surfactant, and can be roughly divided into those bonded to the end of the main chain of the surfactant, those bonded directly or through an alkyl group in the middle of the main chain, and those bonded within the main chain. Examples include those incorporated into.

Such ammonium-type ferrocene derivatives have the general formula (wherein R' and R'' each represent hydrogen or a carbon number of 1 to 4
(However, it does not exceed the integer m described below) represents an alkyl group, z and z' each represent hydrogen or a substituent (methyl group, ethyl group, methoxy group, carbomethoxy group, etc.), and X represents a halogen. . Also, m and n are m≧O
, n≧0 and represents an integer that satisfies 4≦m×n≦16. ), general formula Fe (wherein R', RZ, j and k are integers that satisfy h≧0, j≧0, k≧1 and 3≦h+j+−k≦15, and p
indicates an integer satisfying 0≦p≦k−1. ), and those expressed by general formulas.

Next, (2) other types of ferrocene derivatives include:
General formula (wherein R', R", X, Y, Z, Z" are the same as above (
However, the number of carbon atoms in R 1 and R 2 does not exceed the integer r described below. ). Also, r, s, t are r≧Q, s
Indicates an integer that satisfies ≧0, t≧1, and 4≦r+s+t≦16. ) Alternatively, an ether type ferrocene derivative represented by the general formula (wherein R', R!, X, Y, Z, Z', r, s, and t are the same as above) can be mentioned. Here, a represents an integer from 2 to 18, and b represents 2.
It is a real number between 0 and 100.0. a is 2~ as mentioned above
Since it is an integer of 18, an alkylene group having 2 to 1 carbon atoms, such as an ethylene group or a brobylene group, is interposed between the ring member carbon atom and Y. Also, b is 2.0 to 10
It means not only an integer between 0.0 but also a real number including these, and indicates the average number of repeating oxyethylene groups (-CH2CI420-) constituting the ferrocene gR form. Furthermore, Y in the above general formula is oxygen (
-0-) or an oxycarbonyl group (-0-C-), and z and z' each represent hydrogen or a substituent as described above.

These ether-type ferrocene derivatives have been published in the International Publication W
It can be produced by the method described in O89/01939.

Furthermore, (3) other types of ferrocene derivatives include pyridinium-type ferrocene derivatives represented by the general formula. In this formula, z, z', and x are the same as above, and R3 is an alkyl group having 1 to 4 carbon atoms. Carbon number 1-4
an alkoxy group, a carbalkoxy group having 1 to 5 carbon atoms.
It represents a hydroxyl group, a carpoxyl group, a sulfonic acid group, and C. Hoe represents a straight chain or branched alkylene group having 1 to 16 carbon atoms. This C. H2. Specifically, it is a tetramethylene group, a pentamethylene group. Polymethylene groups (cr-rz) such as octamethylene group, undecamethylene group, dodecamethylene group, and hexademethylene group. and branched alkylene groups such as 2-methylundecamethylene group and 4-ethylundecamethylene group.

These viridinium type ferrocene derivatives are disclosed in Japanese Unexamined Patent Publication No.
It can be manufactured by the method described in JP-226894.

(4) Another type of ferrocene derivative is
General Formula [In the formula, R4 and R5 each represent a linear or branched alkylene group having 1 to 14 carbon atoms, and X1 and X2 each represent -01 or 1010-. Further, A1 and A2 are each +CH2CHO}-qH (R' is R' hydrogen or a methyl group, and q is a real number from 2 to 70.

), Zl and Z2 each represent hydrogen. Methyl group, methoxy group, amino group, dimethylamino group, hydroxyl group, acetylamino group. Carboxyl group 7 Indicates methoxycarbonyl group, acetoxy group, aldehyde group or halogen.

c and d each represent an integer of 1 to 4. ] Examples include ferrocene derivatives represented by the following. These ferrocene derivatives can be produced by the method described in Japanese Patent Application No. 63-233798.

(5) Another type of ferrocene derivative is
General formula (in the above formula, X represents 1G H z 0C 1 methyl group or ethyl group.
) z , C H s , C H y OOH or halogen, and R3 represents hydrogen or a methyl group. n is an integer from 0 to 10, and r is a real number from 2 to 70. Moreover, a and b are each integers of 1 to 4. ] Examples include ferrocene derivatives represented by the following. These ferrocene derivatives can be produced by the method described in JP-A-1-45370.

(6) Another type of ferrocene derivative is
General formula [wherein Z1 and Z2 are each H. C}{3, CH.
0, NHCOCH. ．． N(CH,)t. COCH3,C
OOCH. and R represents hydrogen or a methyl group. k
represents a real number from 2 to 70, h represents an integer from 2 to 18,
m represents an integer from θ to 4, n represents 1 or 2, and a
and b each represent an integer from 1 to 4. ] Examples include ferrocene derivatives represented by These ferrocene derivatives can be produced by the method described in Japanese Patent Application No. 63-248601.

In the method of the present invention, first, a micellar agent made of the above ferrocene derivative, a supporting salt, and an inorganic substance are added to an aqueous medium.
Preferably, an inorganic substance having an average particle size of 10 μm or less is added and subjected to ultrasonic waves. Disperse thoroughly using a homogenizer or stirrer to form micelles, then remove excess inorganic material as necessary, and apply the resulting micelle solution to the above-mentioned electrode while standing still or with slight stirring. electrolytically treated using Additionally, an inorganic 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 inorganic substance is added to the extracted micelle solution, and the inorganic substance is thoroughly mixed and stirred. A circulation circuit for returning the liquid to the vicinity of the cathode may also be provided. The concentration of the micelle forming agent at this time may be at least the critical micelle concentration, specifically at least about 1 μM. Electrolysis conditions may be selected appropriately depending on various situations, but usually the liquid temperature is 0 to 70°C.
, preferably 20~30°C, voltage 0.03~1.5■
, preferably 0.1 to 0.7V, and the current density lOts
A/ci or less, preferably 50 to 300 μA/c
Let it be rA.

When this electrolytic treatment is performed, the reaction proceeds according to the principle described above. Focusing on the behavior of Fe ions in ferrocene derivatives, at the anode, Fe'' in ferrocene becomes Fe3+, the micelles collapse, and inorganic particles (300 to 700
(about the size of a human being) is deposited on the anode.

On the other hand, at the cathode, the Fe" oxidized at the anode is reduced to Fe" and returns to the original micelles, so the film forming operation can be repeated using the same solution.

By such electrolytic treatment, a thin film of particles of a desired inorganic substance, particularly particles having a particle size of about 300 to 700 particles, is formed on the anode.

The supporting salt (supporting electrolyte) used in the method of the present invention is added as necessary to adjust the electrical conductivity of the aqueous medium. The amount of this supporting salt added may be within a range that does not interfere with the solubilization or precipitation of the dispersed inorganic substance, and is usually at a concentration of about 0 to 300 times that of the micellizing agent.
Preferably, the concentration is about 10 to 200 times. Although electrolysis can be carried out without adding this supporting salt, in this case a highly pure thin film containing no supporting salt can be obtained. Also,
When a supporting salt is used, there is no particular restriction on the type of supporting salt as long as it does not interfere with the formation of micelles or the precipitation of the inorganic substance onto the electrode and can adjust the electrical conductivity of the aqueous medium.

Specifically, sulfates (salts such as lithium, potassium, sodium rubidium, and aluminum) and acetates (lithium, potassium, and aluminum), which are generally widely used as supporting salts, are used.
Sodium, rubidium, beryllium. magnesium,
Salts of calcium, strontium, barium, aluminum, etc.), halide salts (salts of lithium, potassium, sodium, rubidium, calcium, magnesium, aluminum, etc.), water-soluble oxide salts (lithium, potassium, sodium, rubidium, calcium, etc.) salts of magnesium, aluminum, etc.) are preferred.

Further, the electrode used in the method of the present invention may be a metal or a conductor that has a higher redox potential than ferrocene (+0.15 V vs. saturated red electrode). Specifically, I
To (mixed oxide of indium oxide and tin oxide), platinum. Money. Examples include silver, glassy carbon, and conductive metal oxide diorganic polymer conductors.

In the method of the present invention, the particle size of the inorganic substance that is a raw material for producing an inorganic thin film is not particularly uniform, but fine particles having an average particle size of 10 μm or less, most preferably 1 μm or less are used. If the average particle size exceeds 10 μm, the obtained inorganic thin film may not be smooth and uniform, and it may take time to be solubilized with a micelle agent, and depending on the conditions, the inorganic thin film obtained may not be smooth and uniform. Various problems may occur, such as large amounts of inorganic substances remaining.

The inorganic substances that can be used in the method of the present invention include inorganic oxides. There are various kinds of inorganic sulfides, such as TiOz, C, CdS, FeO:+, YzO*-Z
rOz,Zl”Oz.AlzOz,CuS,ZnS,T
eOz. L iNbox. S i3Nn, SrCe
Oz. Examples include WO3PLZT and various superconducting oxides.

〔Example〕

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

Example 1 0.0% in 100cc of water. 198 g (equivalent to 2.0 times the amount adsorbed on the surface of WO:l), and to this
After adding 0.232 g of W03 and stirring with ultrasonic waves for 10 minutes, the resulting micelle solution was stirred at 2000 rpm for 10 minutes.
Centrifugation was performed for minutes. Collect 20cc of this supernatant,
0.208 g of lithium bromide was added to this to prepare an electrolytic solution.

ITO for the anode and platinum for the cathode. A saturated sweet electrode was used as a reference electrode, and an applied voltage of 0.5 V was applied at 25°C. Constant potential electrolysis with a current density of 15 μA/crA was performed for 30 min. The amount of current applied at this time was 0.027 coulombs.

As a result, a thin film of W03 was obtained. The X-ray diffraction peak of the raw material W03 (Figure 1) and the X-ray diffraction peak of the obtained thin film (
(Fig. 2), the thin film on ITO is
It turned out to be 03.

Example 2 Formula 1 as a micelle agent in 100 cc of water? Then, 0.208 g of lithium bromide was added thereto to prepare an electrolytic solution.

Using GC as the anode, platinum as the cathode, and a saturated sweet electrode as the reference electrode, the applied voltage was 0.5 V at 25°C, and the current density was 2.
Constant potential electrolysis at 7 μA/ci was performed for 30 min. The amount of current applied at this time was 0.041 coulombs.

As a result, a thin film of T i O z was obtained. Raw material TiO
When the X-ray diffraction peak (Fig. 3) and the X-ray diffraction peak (Fig. 4) of the obtained thin film coincided with each other, it was determined that the thin film on the GC was T i O Z.

Example 3 As a micelle agent in 100cc of water? The ferrocene derivative (FTMA) represented by 0. 1
0 9 g (3.0 g of the amount adsorbed on the surface of TiO)
In addition, TiO with an average particle size of 1.2 μm
After adding 0.20g of z and stirring with ultrasonic waves for 10 minutes,
The obtained micelle solution was centrifuged at 200 rpm for 10 minutes. This supernatant was added to 20ccF. The ferrocene derivative (F P Y A) represented by e is 0
．． 1.30 g (equivalent to 2.0 times the amount adsorbed on the surface of Y203 ZrOz) was added, and to this, an average particle size of 1.0 g was added.
8? 8 mol % of Y203-ZrOz of 0. 2 0
After stirring with ultrasonic waves for 10 minutes, the resulting micelle solution was centrifuged at 2000 rpm for 10 minutes. 20 cc of this supernatant was collected, and 0.208 g of lithium bromide was added thereto to prepare an electrolyte.

Using platinum as the anode and cathode, and a saturated copper electrode as the reference electrode, the applied voltage was 0.5 V at 25°C. Current density 12μ
Constant potential electrolysis at A/ci was performed for 30 minutes.

The amount of current applied at this time was 0.03 coulombs.

As a result, a thin film of Y203ZrO■ was obtained. The X-ray diffraction peak of the raw material Y20:l ZrOz (Fig. 5) matches the X-ray diffraction peak of the obtained thin film (Fig. 6), indicating that the thin film on platinum is YZO3 ZrO■. found.

Example 4 Add 0.0% FPEG as a micelle agent to 100cc of water.
198 g (1.8 of the amount adsorbed on the surface of CdS)
(equivalent to twice as much), and in addition to this, CdS with an average particle size of 0.09 μm.
After adding 0.2 g of and stirring with ultrasonic waves for 10 minutes, the resulting micelle solution was centrifuged at 2000 rpm for 10 minutes. 20 cc of this supernatant was collected, and 0.20 cc of this supernatant was collected.
8 g of lithium bromide was added to form an electrolytic solution.

Using ITO as the anode, platinum as the cathode, and a saturated copper electrode as the reference electrode, an applied voltage of 0.5 mm was applied at 25°C. Constant potential electrolysis was performed for 30 min at a current density of 19 μA/c++l.

The amount of current applied at this time was 0.03 coulombs.

As a result, a CdS thin film was obtained. The CdSOX X-ray diffraction peak of the raw material (Figure 7) and the X-ray diffraction peak of the obtained thin film (
(Fig. 8), the thin film on ITO is C
It turned out to be dS.

Example 5 Add 0.13 ferrocene derivative (FTMA) represented by the formula as a micellizing agent to 100 d of water.
0 g (equivalent to 4.0 times the amount adsorbed on the surface of α-A 1 z O 3), and to this
After adding 0.2 g of Altos and stirring with ultrasound for 10 minutes, the resulting micelle solution was stirred at 2000 rpm for 10 minutes.
Centrifugation was performed for minutes. Collect 20cc of this supernatant,
0.208 g of lithium bromide was added to this to prepare an electrolytic solution.

ITO for the anode and platinum for the cathode. Constant potential electrolysis was performed for 30 minutes at 25"C with an applied voltage of 0.5 μA and a current density of 21 μA/ci using a saturated sweet electrode as a reference electrode. The amount of current applied at this time was 0.031 coulombs. .

As a result, a thin film of α-Aha3 was obtained. Raw material α-A1
Since the X-ray diffraction peak of gOff (Figure 9) and the X-ray diffraction peak of the obtained thin film (Figure 10) match,
The thin film on ITO was found to be α-Al20:l.

Example 6 Add 0.2 of FPEG as a micelle agent to 100 cc of water.
g (equivalent to 2.4 times the amount adsorbed on the surface of SrCeO3), and to this, SrCeO with an average particle size of 0.31 μm.
After adding 0.3 g of 3 and stirring with ultrasonic waves for 10 minutes, the resulting micelle solution was centrifuged at 200 rpm for 10 minutes. Collect 20cc of this supernatant and add 0.2
08 g of lithium bromide was added to form an electrolytic solution.

Using ITO as an anode, platinum as a cathode, and a saturated amber electrode as a reference electrode, constant potential electrolysis was performed at 25°C for 30 minutes at an applied voltage of 0.5 mm and a current density of 26 μA/afl. The amount of current applied at this time was 0.04 coulombs.

As a result, a thin film of S r C e O :l was obtained. X-ray diffraction peak of raw material S r C e O x
It was found that the thin film on ITO was SrCeO= by matching the X-ray diffraction peak of the obtained thin film (Fig. 12).

[Effects of the Invention] According to the method of the present invention, extremely thin inorganic films made of various inorganic substances can be efficiently produced using simple equipment and operations.

As described above, the inorganic thin film obtained by the method of the present invention can be used for electronic materials, display materials, fluorescent display materials. LCD color filter, color filter. Plasma displays, coating materials, electrochromic materials. It is widely and effectively used as electroluminescent materials, optical memory materials, optical disk materials, luminescent materials, solar cells, etc.

[Brief explanation of drawings]

Figure 1 shows the X-ray diffraction pattern of WO3 used in Example 1.
Figure 2 shows the X-ray diffraction pattern of the thin film obtained in Example 1.
Figure 3 shows the X-ray diffraction pattern of T i O 2 used in Example 2. Figure 4 shows the X-ray diffraction pattern of the thin film obtained in Example 2, and Figure 5 shows the Yz03 ZrOz used in Example 3.
X-ray diffraction pattern. Figure 6 shows the X-ray diffraction pattern of the thin film obtained in Example 3, and Figure 7 shows the CdS used in Example 4.
8 is the X-ray diffraction pattern of the thin film obtained in Example 4, and FIG. 9 is the X-ray diffraction pattern of αAh used in Example 5.
X-ray diffraction pattern of a3. Figure 10 is the X-ray diffraction pattern of the thin film obtained in Example 5, Figure 11 is the X-ray diffraction pattern of SrCeOz used in Example 6, and Figure 12 is the X-ray diffraction pattern of the thin film obtained in Example 6. It is a diffraction pattern. Note that in the figure, θ is the plug angle.

Claims (2)

[Claims] (1) Solubilizing or dispersing an inorganic substance in an aqueous medium with a micellizing agent made of a ferrocene derivative, and electrolyzing the resulting micelle solution or dispersion to form a thin film of the inorganic substance on an electrode. Characteristic method for producing inorganic thin films. (2) The manufacturing method according to claim 1, wherein the inorganic substance has an average particle size of 10 μm or less.