JPS62278705A - Transparent conducting material - 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 (Field of Industrial Application) The present invention relates to a transparent conductive material comprising a crystalline tin oxide antimony sol.

Transparent +4 electric materials are solar cells! ! It is used in photoelectric conversion elements such as picture tubes, and transparent surface heating elements such as anti-fog and anti-icing glass, and is also applied to electroluminescent elements, liquid crystal display elements, electrochromic display elements, plasma displays, and electrophotography. Research and development is actively being carried out.

Among these, tin oxide and indium oxide-based transparent conductive materials f1 are widely used as heating elements and thin film resistors due to their excellent heat resistance and abrasion resistance. In recent years, taking advantage of this high rate, research has been actively conducted on the use of selectively permeable membranes for solar thermal power generation.

This ability, combined with the remarkable development of electro-optical elements,
Transparent conductive materials are materials whose demand has been increasing dramatically in recent years.

(Prior Art) Indium oxide-tin oxide-based materials and tin oxide-antimony-based materials have been known as transparent conductive materials, and materials such as powders of these metals or oxides have been used.

Such transparent conductive materials are generally put into practical use by being coated on a substrate in the form of a film using a film forming method such as chemical vapor deposition, vacuum evaporation, reactive ion blating, sputtering, or ion beam sputtering. There is.

However, all of these methods not only have the drawbacks of complicated equipment and slow film formation speeds, but also have complicated and very expensive equipment, which means that the film formation can be carried out over a small area and over a large area. There is a problem that it is not possible to obtain a film with a large area.

Furthermore, when forming a film in a complicated shape, this method has limitations in its use because the film becomes non-uniform.

Furthermore, chemical spraying allows a film to be obtained over a relatively large area, but requires larger equipment than spraying a solution while keeping the substrate at a high temperature, and furthermore, it is difficult to control the uniformity of the film.

On the other hand, the so-called coating method, in which a liquid raw material is dipped onto a substrate to form a film, has the advantage of being able to obtain a large-area film through a relatively simple process, and can also be applied to parts with complex shapes. This is an industrially promising method because it is relatively easy.

This coating method has been widely studied for tin oxide-antimony based materials, and the thermal decomposition behavior of a wide variety of liquid tin-antimony compounds has been studied.

The tin-antimony-based materials that have been studied so far are salt solutions of 71 organic or inorganic compounds containing both tin and antimony as ions. Therefore, when using a salt solution of an organic compound, careful thermal decomposition must be carried out to ensure that no organic matter remains.Tin and antimony may volatilize as organic salts, or the solution may have low polarity and may not interact with substrates such as glass. It was not possible to obtain a uniform film due to poor compatibility.

In addition, a large amount of stabilizer is required to maintain the liquid stability of the organic salt, resulting in a thin film (;), and the high organic content makes it difficult to perform multilayer dipping after drying. There were problems such as peeling during firing.

Furthermore, the tin oxide and antimony oxide produced during these thermal decompositions generally have a coarse particle size, which poses a problem especially when applied to fields where uniform fineness is required.

Furthermore, when inorganic compounds such as stannic chloride and antimony trichloride are used, the formed film becomes cloudy, resulting in a film with poor transparency and low film strength, and furthermore, corrosive gas is generated during firing. Therefore, it is necessary to select a furnace, which is not favorable in terms of the working environment, and there are also problems such as corrosion of the electrodes when coating on a substrate with electrodes attached in advance, integral molding, and firing.

(Problems to be Solved by the Invention) In view of these circumstances, the present inventors have conducted extensive research in order to obtain a transparent conductive material that is excellent in various properties desired when applied to a shade in the electro-optical field. As a result, the present invention has been completed.

(Means for Solving the Problems) That is, the present invention relates to a transparent conductive material 11 made of crystalline tin oxide/antimony sol in which Sb and Sn are dissolved in solid solution at an Sb/Sn molar ratio of 0.3 or less. The object of the present invention is to provide an excellent transparent conductive material that can be used by a coating method that is easy and can form a uniform film.

In addition, the crystalline tin oxide/antimony sol of the present invention is not a mixture of tin and antimony that becomes a conductive compound after heat treatment, but a solid solution of tin oxide in a molecularly dispersed state in a sol state.・Antimony microcrystalline colloid 'f8 liquid, which is used for transparent conductive materials.

Further features of the transparent conductive material of the present invention are that since it is a transparent conductive material made of a highly polar sol solution, it has good compatibility with glass substrates, ceramic materials f1, and fillers, and a uniform thin film can be obtained; In addition, since it is not a mixture of tin oxide and antimony oxide, but a sol consisting of ultrafine particles in which tin oxide and antimony oxide are uniformly dissolved in a molecular structure, the transparent conductive thin film has extremely excellent light transmittance. Furthermore, it has electrical conductivity even when heat treated at a relatively low temperature, and has extremely high electrical conductivity at 500 to 600'C.

(Function) To further explain the transparent conductive material of the present invention, the crystalline tin oxide antimony sol used in the present invention is Sb/Sb
Sb and Sn are dissolved in solid solution at an n molar ratio of 0.3 or less, and the method for producing it may be according to the method described in Japanese Patent Application No. 61-63657.

To give an example of the manufacturing method, first, antimony trichloride is mixed and dissolved in a stannic chloride aqueous solution at a Sb/Sn molar ratio of 0.07, and this is added to an ammonium bicarbonate aqueous solution to form a gel.

Next, after thoroughly washing this gel with water, a suitable amount of aqueous ammonia is added and hydrothermal treatment is performed at 200° C. for 10 hours in an autoclave to obtain a crystalline tin oxide antimony sol.

An example of a coating method for using the sol obtained in this manner as a transparent conductive material is to first apply the sol to a concentration of 10% in terms of SnO2 on a glass plate and dry it.

In this case, a transparent film is produced simply by air drying at room temperature, but drying may also be carried out at around 100°C.

Further, the desired film thickness can be adjusted by appropriately selecting the concentration of the crystalline tin oxide antimony sol and the coating method, and it is possible to adjust the thickness of the film JV by repeating the coating and drying operations.

The conventional use of aqueous solutions of stannic chloride, tetrabutoxytin compounds, etc. causes problems of volatilization during thermal decomposition and problems of peeling when the film is thickened due to the large number of thermal decomposition machines.

However, according to the present invention, since the sol is an aqueous solution and contains only a small amount of ammonia as a stabilizer, it is possible to obtain a film with sufficient strength only by drying, and after multilayer coating, heat treatment is not necessary. Even if you do this, the film will not peel off.

A transparent conductive glass substrate can be obtained by baking the substrate after coating and drying.

In the conventional use of stannic chloride and tetrabutoxytin compounds, conductivity is comparable due to residual chlorine and 71 compounds when fired at 300'C or below, but the crystalline tin oxide/antimony sol of the present invention When using tin oxide, since it has a crystalline form in which antimony is solid dissolved in tin oxide, and because it is an aqueous dispersion, most of the water and ammonia are volatilized during the drying operation, so the sheet resistance value remains unchanged even after heat treatment at 200°C. 10'Ω/s
It exhibits conductivity of about q, and has an excellent light transmittance of about 98%.

Regarding the heat treatment temperature, as mentioned above, conductivity can be obtained by low temperature treatment of about 200 °C, but the higher the temperature is, the higher the temperature is.
Since the sintering of n02 progresses and the conductivity improves, firing is more preferably performed at 500 to 600°C for about 30 to 60 minutes.

(Example) The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.

In addition, all percentages indicate 1 chamber % unless otherwise specified.

Example I A mixed solution was prepared by adding antimony trichloride to an aqueous stannic chloride solution so that the Sb/Sn molar ratio was 0.01.

It was gradually added to an aqueous ammonium bicarbonate solution while stirring to form a coprecipitated gel of Sb and Sn.

This gel was filtered and washed repeatedly until no chloride ions were observed in the filtrate.

Add an appropriate amount of ammonia and water to the washed gel to make 5N
After adjusting to OelO% and transferring to autoclave, 22
Hydrothermal treatment was performed at 0° C. for 4 hours to obtain a crystalline tin oxide/antimony sol.

Mari, Sb/Sn Mo) k ratio M O, 03,0,1,
A sol was manufactured in the same manner as above so that the Sb/Sn molar ratio was 0.25, and for comparison, a sol was prepared with a Sb/Sn molar ratio of 0.35.
The same thing was done for

The sol thus obtained was applied onto Pyrex glass which had been thoroughly degreased and dried at 100° C. for 1 hour. Next, this was heated to H1 temperature at 5°C/win, and
A transparent conductive thin film was obtained by baking at 00'C for 30 minutes.

This thin film was coated with an electric coating using a silver base, and the sheet resistance value of the thin film was measured.

In addition, the transmittance of the thin film to visible light at a wavelength of 600 nm and the film thickness were measured by optical interference method.

Furthermore, the strength of the membrane was examined by a pencil scratch test.
The chemical resistance of the membrane was examined using 10% sulfuric acid.

These results are shown in Table 1.

Example 2 A solution of antimony trichloride added to an aqueous solution of stannic sulfate so that the Sb/Sn molar ratio was 0.07 was gradually added to an aqueous ammonium bicarbonate solution with stirring. A co-precipitated gel of Sn and Sn was produced.

This gel was filtered and washed repeatedly until no chloride ions or sulfate groups were observed in the filtrate.

Add an appropriate amount of ammonia and water to the washed gel to make 5N
The mixture was adjusted to 10% O6, transferred to an au crepe, and then subjected to hydrothermal treatment at 180°C for 10 hours to obtain a crystalline tin oxide antimony sol.

The sol thus obtained was applied onto Pyrex glass which had been thoroughly degreased and dried at 100°C for 1 hour.

Next, this was baked for 1 hour at each temperature shown in Table 2,
A transparent conductive thin film was obtained.

The sheet resistance, light transmittance A, film thickness and film strength of this film were measured and the results are shown in Table 2.

Example 3 A crystalline tin oxide/antimony sol produced in the same manner as in Example 1 with an Sb/Sn molar ratio of 0.05 was thoroughly degreased. L
It was coated on JIN soda glass, dried at 100°C for 1 hour, and then fired at 500°C for 1 hour.

Next, this coating, drying, and baking process was repeated several times to obtain a transparent conductive thin film using a so-called multilayer coating method.

Examine the sheet resistance, light transmittance, and film condition of these, and record the results in Section 3.
Shown in the table.

Table 3 Example 4 Using the crystalline tin oxide antimony sol of the present invention obtained in Example 2 (Sb/Sn molar ratio 0.07, SnO □ 10%), coating on soda glass that had been thoroughly degreased. and
Drying was performed at 100°C for 20 minutes.

This operation was repeated three times, and then baking was performed at 200° C. for 2 hours.

For comparison, antimony trichloride was added to the stannic chloride aqueous solution so that the Sb/Sn molar ratio was 0.07.
Add suitable hydrochloric acid and water to this and dissolve it to make 5nO8lO%
A homogeneous solution containing tin and antimony was obtained.

Furthermore, tetrabutoxytin and antimony triptoxide are dissolved in butanol, and the Sb/Sn molar ratio is 0.0.
A solution containing 7.5 nOeI 0% tin and antimony was obtained.

Apply these solutions on soda glass in the same manner as above,
Drying and firing treatments were performed.

r obtained in this way? The sheet resistance, light transmittance, and film condition of the film were investigated, and the results are shown in Table 4.

Table 1I Procedural Amendment 1fF (Voluntary) Date of June 1986 2, Name of Invention Transparent Conductive Material f1 3, When Amendments Are Made! II Relationship with f↑ Patent applicant 1-, Noah 4, Specification subject to amendment δ 5, Contents of amendment (1) Clear! Insert the following sentence between lines 6 and 7 on page 9 of III Zunho.

“The transparent conductive material f of the present invention produced in this way i′)
1 has excellent properties as a conductive material,
Solar cells, EL elements, M crystal elements, transparent ξ poles such as transparent switches, prevention of charging on the surface of displays such as CRTs, prevention of electromagnetic wave interference caused by microwaves, promotion of electrical conductivity in discharge tubes, automobiles, aircraft, A devices Anti-fog windows, transparent heating elements, etc.
! Membrane resistors, surface treatment for electroless plating, glass fiber
1: [Can be used for electric protection etc.

Furthermore, it can also be used as a conductive powder coated with a non-aluminous filler such as charcoal or silica.

Claims (1)

[Claims] A transparent conductive material made of a crystalline tin oxide/antimony sol in which Sb and Sn are dissolved in solid solution at an Sb/Sn molar ratio of 0.3 or less.