JPH05114314A - Transparent conductive membrane moulding method - Google Patents

Abstract

PURPOSE:To obtain a transparent conductive membrane of a low resistance and a high transmissivity by heat treating an organic solution which consists of an organic compound which can be coordinated with either indium or tin, an inorganic indium compound, and an organic tin compound. CONSTITUTION:An organic compound consisting of an organic compound which can be coordinated with either indium or tin, an inorganic indium compound, and an organic tin compound, is heat treated. And the organic tin compound is hydrolyzed partially to form an intermediate complex compound between the indium and the tin, and a pyrolytic catalyst is mixed. As a result, an uneven membrane owing to the evaporation of the tin is suppressed, and since a low resistance and a high transmissivity can be given to the resultant membrane, a transparent conductive membrane with an excellent conductivity and an excellent transmissivity in the visible area can be obtained easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a transparent conductive film on a substrate such as glass or ceramics.

[0002]

2. Description of the Related Art Visible in electrodes of display elements such as liquid crystal display elements and electroluminescence (EL) display elements and in heating resistors for defrosting or preventing freezing of window glass of automobiles, aircraft, buildings, etc. An electrode material having high transparency to light is used.

As such transparent conductive material, tin oxide / antimony oxide (ATO) and indium oxide / tin oxide (ITO) are known, and these metal oxides are deposited on a glass or ceramic substrate. A film can be easily formed to form a transparent conductive film.

As a method for forming the transparent conductive film, a vacuum vapor deposition method, a sputtering method, a CVD method and a coating method are known.

[0005]

However, in the methods other than the CVD method, the apparatus is complicated and expensive, and there are problems in cost and mass productivity. Further, although the CVD method has a possibility of solving the problems of other methods, it is difficult to form a film that can be practically used.

For example, when an organic solution of an inorganic compound such as indium nitrate, indium chloride, and stannic chloride is used, white turbidity occurs in the formed film, and the mechanical strength of the obtained film is insufficient, which is easy. There are drawbacks such as scratches. In addition, in the method of using an organic acid indium having a strong ionic bond such as indium octylate, the organic acid indium is easily hydrolyzed and undergoes a chemical change relatively easily. There is. further,
A method using an organic complex of indium or tin has also been proposed, but in this method, evaporation of the tin compound, etc., impedes uniformization of the film during thermal decomposition of the coating film after coating on the substrate. In addition, there is a defect that a low resistance homogeneous film cannot be obtained.

An object of the present invention is to provide a method for forming a composition for forming a transparent conductive film which solves the above problems.

[0008]

In order to achieve the above object, the present invention provides an organic solution containing an inorganic indium compound, an organic tin compound, and an organic compound capable of coordinating indium and tin. A composition for forming a transparent conductive film and a method for forming a transparent conductive film, which are obtained by heating and partially hydrolyzing the mixture and mixing the organic solution with a thermal decomposition catalyst.

[0009]

[Function] An inorganic indium compound in which an organic compound is partly coordinated, an organic tin compound, and water of crystallization contained in the inorganic indium compound react to partially hydrolyze the organic tin compound to form an intermediate composite compound of indium and tin. To suppress the non-uniformity of the film due to the evaporation of tin, which has been a problem in the past, and to provide the resulting film with a low resistivity and a high transmittance. Further, the addition of a thermal decomposition catalyst also improves the thermal decomposition property, and imparts a low resistivity and a high transmittance of the film obtained by coating and baking the composition on a substrate.

[0010]

EXAMPLES Examples of the present invention will be described in detail below.
The composition for forming a transparent conductive film of the present invention is synthesized as follows. First, an inorganic indium compound is mixed with an organic compound capable of coordinating both indium and tin. Here, the inorganic indium compound may have an organic compound capable of coordinating with indium or tin and a ligand capable of substituting. Examples thereof include indium nitrate and indium chloride, and those having crystal water are preferable. Further, an organic compound capable of coordinating both indium and tin is necessary for coordinating in part with indium and tin to assist formation of an intermediate compound thereof and to have solubility in an organic solvent. ,
Examples thereof include β-diketones, α- or β-ketone acids, esters of the above ketone acids, and α- or β-amino alcohols.

Next, an organic solvent and an organic tin compound are added to the solution, and the organic solution is heat-treated. here,
The organotin compound may be any compound as long as it is relatively stable in the air but easily hydrolyzed by heat treatment. Examples thereof include tin carboxylate and tin dicarboxylate, and tin formate, tin acetate, and tin oxalate having a small carbon number are preferable. Further, as the organic solvent,
Any material capable of dissolving the organic compound or the inorganic compound used in the present invention may be used. For example, aromatic hydrocarbons such as toluene and xylene, alcohols such as ethanol and isopropanol, acetic acid esters such as ethyl acetate and butyl acetate,
Examples thereof include ketones such as acetone and diethyl ketone, ethers such as methoxyethanol and ethoxyethanol, and tetrahydrofuran. Further, the temperature of the heat treatment is preferably at or near the reflux temperature of the organic solution containing the inorganic indium compound, the organic tin compound, and the organic compound capable of coordinating with them.

Then, the organic solution after the heat treatment is cooled to around room temperature, a thermal decomposition catalyst is added, and the mixed organic solution is used as a composition for forming a transparent conductive film. Here, the thermal decomposition catalyst improves the thermal decomposition property and gives low resistivity and high transmittance of a film obtained by applying the composition to a substrate and baking the composition. For example, a peroxide or a nitro compound is used. Can be mentioned,
Hydrogen peroxide, trinitrotoluene, and picric acid, which have a small number of carbon atoms and are less likely to cause carbon residue during thermal decomposition, are preferable.

The transparent conductive film-forming composition thus obtained is applied to a substrate, dried and then baked to form a transparent conductive film. Here, for the coating of the composition for forming a transparent conductive film, a screen printing method, a roll coating method, a dip coating method, a spin coating method or the like can be used.
The dip coating method and the spin coating method are preferable. Also,
The baking temperature may be higher than or equal to the temperature at which the composition for forming a transparent conductive film is decomposed and lower than the deformation temperature of the substrate, 40
0-700 degreeC is preferable.

Hereinafter, the present invention will be described with reference to more detailed examples, but the present invention is not limited to these examples.

(Example 1) In an Erlenmeyer flask of 1 liter, 45 g
Of indium nitrate (Chemical Formula 1) was weighed, 50 g of acetylacetone was added, and they were mixed and dissolved at room temperature. To the solution was added 5.4 g [(numerical formula 1) of 10 wt%] stannous oxalate (Chemical Formula 2) and acetone, and the mixture was refluxed. The solution after the reflux was cooled to around room temperature, 0.1 g of hydrogen peroxide was added, and the mixture was stirred and mixed to synthesize a composition for forming a transparent conductive film. The transparent conductive film-forming composition was dip-coated with a silica (Chemical 4) -coated glass substrate at a pulling rate of 60 cm / min. The substrate was left at room temperature for 5 minutes, dried at 100 ° C. for 5 minutes, and then baked at 500 ° C. for 1 hour. The thickness of the obtained film is 0.05 μm.

[0016]

[Chemical 1]

[0017]

[Equation 1]

[0018]

[Chemical 2]

[0019]

[Chemical 3]

Example 2 Indium chloride (Chemical Formula 3) was used as the inorganic indium compound, and stannous oxalate was used as the organotin compound, and the content was set to 10 wt% in (Equation 1). Others are the same as in Example 1.

[0021]

[Chemical 4]

(Example 3) Stannous acetate was used as the organotin compound, and the content was adjusted to 10 wt% in (Equation 1).
Others are the same as in Example 1.

Example 4 2-Amino alcohol was used as an organic compound capable of coordinating both indium and tin. Others are the same as in Example 1.

Example 5 1 g of trinitrotoluene was used as a thermal decomposition catalyst. Others are the same as in Example 1.

(Comparative Example 1) In a 1 l Erlenmeyer flask, 45 g
10 wt% of indium nitrate (Chemical formula 1) and 5.4 g [(Equation 1)]
%] Stannous chloride (Chemical Formula 5) and acetone were added, and the mixture was stirred and mixed to synthesize a composition for forming a transparent conductive film. The transparent conductive film-forming composition was dip-coated with a silica (Chemical Formula 3) -coated glass substrate at a pulling rate of 60 cm / min. The substrate was left at room temperature for 5 minutes, dried at 100 ° C. for 5 minutes, and then baked at 500 ° C. for 1 hour.

[0026]

[Chemical 5]

Table 1 shows the results of Examples 1 to 5 and Comparative Example 1.

[0028]

[Table 1]

[0029]

As described above, according to the present invention, it is possible to easily and inexpensively obtain a transparent conductive film having excellent conductivity and transparency in the visible region, and it is possible to obtain a transparent conductive film such as a display element or a heating resistor. It is suitable for applications such as transparent electrodes.

Claims (5)

[Claims] 1. An organic solution comprising an organic compound capable of coordinating with indium and tin, an inorganic indium compound, and an organic tin compound is heat-treated to partially hydrolyze, and the organic solution is heated. A method for forming a transparent conductive film, which comprises forming a decomposition catalyst by mixing. 2. The inorganic indium compound is indium nitrate or indium chloride.
The method for forming a transparent conductive film as described above. 3. The method for forming a transparent conductive film according to claim 1, wherein the organic tin compound is a carboxylate or a dicarboxylate. 4. The coordinating organic compound is selected from the group consisting of β-diketones, α- or β-ketone acids, esters of the ketone acids, and α- or β-amino alcohols. The method for forming a transparent conductive film according to claim 1, wherein 5. The method for forming a transparent conductive film according to claim 1, wherein the thermal decomposition catalyst is either a peroxide or a nitro compound.