WO2005081265A1

WO2005081265A1 - Dispersion liquid for forming transparent conductive film, method for forming transparent conductive film and transparent electrode

Info

Publication number: WO2005081265A1
Application number: PCT/JP2005/003009
Authority: WO
Inventors: Sadayuki Ukishima; Hideo Takei; Satoru Ishibashi; Tsutomu Atsuki; Masaaki Oda; Hiroshi Yamaguchi; Toshiharu Hayashi; Reiko Kiyoshima; Shinya Shiraishi
Original assignee: Ulvac, Inc.; Jemco Inc.
Priority date: 2004-02-24
Filing date: 2005-02-24
Publication date: 2005-09-01
Also published as: TWI364402B; JP4814491B2; JP2005243249A; TW200535090A

Abstract

Disclosed is a dispersion liquid for forming a transparent conductive film wherein metal particles of In, Sn, Sb, Al or Zn, particles of an alloy of such metals or a mixture of these particles, and particles of ITO, IZO, ATO or AZO are dispersed in an organic solvent. A transparent conductive film having low resistance and high transmittance is formed by applying this dispersion liquid to a base and then firing it at a low temperature in a vacuum atmosphere, inert gas atmosphere, reducing gas atmosphere, oxidizing gas atmosphere, air atmosphere. The inert gas atmosphere is a gaseous atmosphere of a rare gas, carbon dioxide or nitrogen; the reducing gas atmosphere is a gaseous atmosphere of hydrogen, carbon monoxide or a lower alcohol; and the oxidizing gas atmosphere is an oxygen-containing gaseous atmosphere. Also disclosed is a transparent electrode composed of such a transparent conductive film.

Description

Specification

Dispersion for forming transparent conductive film, method for forming transparent conductive film, and transparent electrode

The present invention relates to a dispersion for forming a transparent conductive film, a method for forming a transparent conductive film, and a transparent electrode, and particularly relates to a field such as an electric and electronic industry including metal fine particles or alloy fine particles and oxide fine particles. The present invention relates to a dispersion for forming a transparent conductive film that can be used in the above, a method for forming a transparent conductive film using the dispersion, and a transparent electrode made of the transparent conductive film.

Background art

In general, a transparent electrode made of an oxide such as ITO or ATO is used for an electrode of a flat panel display represented by a liquid crystal display. The manufacturing method in this case includes an evaporation method, an ion plating method, a sputtering method, and the like, and a transparent electrode is formed by depositing a metal oxide film on a glass substrate by these methods. More generally, at present, an ITO film, which is an oxide film, is formed by a sputtering method.

[0003] Further, as a method of forming a transparent conductive film used as an antistatic film and an electrode 'circuit forming film, a dispersion of tin-doped indium oxide powder is prepared, the dispersion is applied on a substrate, and after drying, A method of obtaining a transparent conductive film by firing is known (for example, see Patent Document 1). In the method disclosed in Patent Document 1, an oxide film is formed directly on a transparent substrate such as a glass substrate, and the obtained transparent conductive film is used for a flat panel display represented by a liquid crystal or a plasma display. For this purpose, it is necessary to bake at 200 to 900 ° C. (in this embodiment, at 400 ° C.) after film formation on the transparent substrate. However, in the display manufacturing on acrylic substrates, which are becoming mainstream along with the increase in size, there is a problem that the substrate is damaged by the film forming technology at such a high temperature of 400 ° C due to the thermal restrictions on the substrates. There is.

[0004] As a solution to these problems, in the case of a transparent electrode for a display, for example, by using metal nanoparticles, coating, drying, and baking to produce an ITO film and an ATO film, the cost is low and the cost is large. It is known to form a transparent conductive film having an area (for example, see Patent Document 2).

[0005] In addition, metal ultrafine particles such as Ag ultrafine particles are used to form transparent plastic films and the like. It is also known to form a transparent conductive film on a substrate at a relatively low temperature to obtain a low-resistance film.

(See, for example, Patent Document 3). As shown in Patent Document 3, it is possible to reduce the resistance by using Ag, but the ultrafine particles of Ag are colored by plasmon absorption, and if sufficient transmittance cannot be obtained, it is difficult. There is a problem.

[0006] Further, a transparent conductive metal film and a metal oxide film for forming a transparent conductive film are alternately laminated on a substrate in a plurality of layers in this order, and the laminated film is fired for each layer or collectively. Low-resistance transparent conductive films are also known (for example, see Patent Document 4). In this case, there is a problem that the manufacturing process becomes complicated.

[0007] Further, as another method for producing an antistatic film, there is a technique in which transparent oxide particles having low resistance are used, and conductivity is ensured by contacting the particles. In this case, to form a more dense packing, a transparent conductive film is formed on the substrate, and then a second layer of film is applied thereon, and the adhesion between the particles is improved by utilizing the heat shrinkage. The method of increasing the contact resistance to lower the contact resistance and consequently the surface resistance is reduced. Also in this case, there is a problem that the manufacturing process becomes complicated.

Patent Document 1: JP-A-07-242842 (Claims, Examples)

Patent Document 2: Japanese Patent Application Laid-Open No. 2003-249131 (Claims)

Patent Document 3: Japanese Patent Application Laid-Open No. 2001-176339 (Claims)

Patent Document 4: Japanese Patent Application Laid-Open No. 2003-249126 (Claims)

Disclosure of the invention

Problems to be solved by the invention

[0008] However, in the above-mentioned conventional method, the transmittance is high but the resistance is high when only the oxide fine particles are used, and the resistance is low when only the metal fine particles are used. Phenomenon. Furthermore, when oxide fine particles and metal fine particles are used, there is a problem that the manufacturing process becomes complicated.

[0009] An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a dispersion containing metal fine particles, alloy fine particles or a mixture thereof and a metal-doped oxide, An object of the present invention is to provide a method for forming a transparent conductive film having low resistance and high transmittance by low-temperature sintering and a transparent electrode comprising the transparent conductive film. Means for solving the problem

[0010] The dispersion for forming a transparent conductive film of the present invention comprises fine particles of at least one metal selected from indium, tin, antimony, aluminum and zinc, and two or more metals selected from the metals. At least one kind of alloy fine particles, or a mixture of the metal fine particles and alloy fine particles, with Sn-doped In O, Sb-doped Sn〇, Zn-doped In O, and A1-doped Zn〇

2 3 2 2 3

At least one kind of oxide fine particles is mixed and dispersed in an organic solvent. By using this dispersion, a transparent conductive film having low resistance and high transmittance can be formed by low-temperature baking.

[0011] The method for forming a transparent conductive film of the present invention is characterized in that the dispersion for forming a transparent conductive film is applied to a substrate and then fired.

The calcination is performed in an atmosphere selected from a vacuum atmosphere, an inert gas atmosphere, a reducing gas atmosphere, and an oxidizing gas atmosphere.

[0013] The calcination is performed in an atmosphere in which a metal or alloy selected from a vacuum atmosphere, an inert gas atmosphere, and a reducing gas atmosphere is not oxidized, and then in an oxidizing gas atmosphere.

After firing in the oxidizing gas atmosphere, firing is further performed in an atmosphere selected from a vacuum atmosphere, an inert atmosphere, and a reducing gas atmosphere.

[0015] By employing the above-described firing process using the above-described dispersion, a transparent conductive film having low resistance and high transmittance can be formed by low-temperature firing.

[0016] The inert gas atmosphere is an atmosphere composed of at least one inert gas selected from a rare gas, carbon dioxide, and nitrogen, and the reducing gas atmosphere is hydrogen, carbon monoxide, and a lower alcohol. Wherein the oxidizing gas atmosphere is an atmosphere comprising at least one oxidizing gas selected from oxygen-containing gases.

[0017] The vacuum atmosphere includes at least one inert gas selected from a rare gas, carbon dioxide, and nitrogen, at least one oxidizing gas selected from an oxygen element-containing gas, hydrogen, carbon monoxide, At least one reducing gas selected from lower alcohols, or a mixed gas comprising the inert gas and an oxidizing gas or a reducing gas. To do.

[0018] It is characterized in that the oxidizing gas atmosphere contains oxygen, an oxygen-containing gas, water vapor or a water vapor-containing gas.

[0019] The metal fine particles and the alloy fine particles are characterized in that organic compounds are attached around the fine particles. By using such fine particles, the dispersibility of each fine particle is improved, and a uniform conductive film can be obtained.

[0020] Further, the transparent electrode of the present invention is characterized in that the transparent electrode is formed by the transparent conductive film forming method.

The invention's effect

According to the present invention, a transparent conductive film is prepared by using a dispersion liquid for forming a transparent conductive film containing specific metal fine particles, alloy fine particles, or a mixture thereof, and specific metal-doped oxide fine particles, at a low temperature. The film can be formed by firing, and the obtained film has an effect of having a low resistance and a high transmittance, and can provide a transparent electrode or the like made of this conductive film and which can be used for various applications. To play. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described. In the case of “metal fine particles”, these fine particles include alloy fine particles unless otherwise specified.

As described above, fine particles of at least one metal of each of the component metals (indium, tin, antimony, aluminum, and zinc) of the metal oxide for forming the transparent conductive film, and a metal component of the component Dispersions containing fine particles of at least one alloy composed of at least one kind of metal, mixed fine particles of these metal fine particles and alloy fine particles, and an oxide doped with tin, antimony, aluminum or zinc are: It is a useful dispersion for forming a transparent conductive film.

[0024] The metal oxide used in the present invention includes, for example, IT〇 (In-Sn-〇) (

twenty three

Sn range is usually 0≤311≤20 ^^%, preferably 3≤Sn≤10wt%), Sb-doped SnO

2 as ATO (Sn-Sb-〇) (Sb range is usually 0≤Sb≤20wt%, preferably 5≤Sb≤l 5wt%), Zn-doped In O as IZ〇 (In-Zn-〇) ( The range of Zn is usually 0≤Zn≤20wt

twenty three

%, Preferably 5≤Zn≤15wt%), A1 doped Zn〇 as ΑΖ〇 (Ζη_Α1-0) (range of A1 Is usually 0≤Al≤20wt%, preferably 5≤Al≤15wt%). These ITO, ΑΤΟ, ΙΖ〇, ΑΖΟ are useful for forming a target transparent conductive film.

[0025] The substrate that can be used in the method for forming a transparent conductive film of the present invention is not particularly limited as long as it is a transparent substrate. For example, a low-temperature baking such as an acrylic substrate, a polyimide substrate, or a polyethylene terephthalate (PET) film can be used. Or a glass electrode with an organic film such as an organic filter. As the organic resin material, in addition to the above, for example, cellulose acetates, polystyrene, polystyrenes, polyethers, polyimide, epoxy resin, phenoxy resin, polycarbonate, polyvinylidene fluoride, Teflon (registered trademark), etc. It can also be used. These can be used alone or bonded together as a substrate. The shape of the substrate is not particularly limited, and may be, for example, a flat plate, a three-dimensional object, a film, or the like. Note that it is preferable that the substrate to be processed be cleaned using pure water, ultrasonic waves, or the like before applying the dispersion liquid.

In the present invention, the method of coating the substrate is not particularly limited, and examples thereof include a spin coating method, a spray method, an ink jet method, an immersion method, a roll coating method, a screen printing method, a non-contour printing method and the like. Can be used. The coating may be performed once or repeatedly, as long as a desired film thickness can be obtained.

[0027] In the method for forming a transparent conductive film according to the present invention, the dispersion liquid is applied on a substrate to be treated by a known application method, and then a vacuum atmosphere, an inert gas atmosphere, a reducing gas atmosphere, and an oxidizing atmosphere are used. The baking treatment (annealing) is performed in at least two stages in at least two kinds of atmospheres selected from a neutral gas atmosphere. In this case, if firing is first performed in an oxidizing gas atmosphere, the surface resistance of the obtained film increases, which is not preferable. However, in firing in a vacuum atmosphere, it is preferable to introduce an oxidizing gas.In this case, the effect is that only the organic substances adhering to the particle surface are burned without oxidizing the metal or alloy. There is. In the present invention, preferably, in the second step, firing is performed in an oxidizing gas atmosphere to oxidize the metal fine particles. Before the first baking, the base material to which the dispersion is applied may be dried at a predetermined temperature to remove the dispersion medium and the like. This removal of the dispersion medium may be performed by a firing process.

According to the present invention, the sintering temperature in the above-described sintering process is controlled by setting the fine metal particles or fine alloy particles It is preferable that the heat-resistant allowable temperature be in a range from the melting point of the core to a temperature lower than the softening point of the substrate to be treated. The firing temperature is more preferably, for example, 300 ° C. or lower. Within this temperature range, the substrate will not be damaged.

As described above, in the present invention, since a dense film is formed at a lower temperature than in the conventional case, a transparent conductive film having a small electric resistance can be manufactured at a low temperature, and an oxidizing gas atmosphere can be produced. In the sintering, the permeability of the obtained membrane can be improved. In the sintering process, irradiation with a UV lamp during sintering is more effective in reducing time and lowering the temperature. Furthermore, in the firing in the present invention, a method using a known atmospheric pressure plasma is also effective.

According to the present invention, when the coating film is baked in a vacuum atmosphere, the vacuum state may be determined by simply pulling with a pump or after drawing with an inert gas, a reducing gas, or an oxidizing gas. A neutral gas may be introduced. Firing in a vacuum atmosphere can usually line Ukoto at 10- ⁵ 10 ³ Pa about.

As described above, in the firing atmosphere, the inert gas atmosphere is, for example, an atmosphere composed of at least one inert gas selected from a rare gas, carbon dioxide, and nitrogen. Contains argon, neon, etc., and the reducing gas atmosphere is an atmosphere composed of at least one reducing gas selected from hydrogen, carbon monoxide and lower alcohol, and the oxidizing gas atmosphere is And an atmosphere containing at least one oxidizing gas selected from oxygen element-containing gas, for example, oxygen, oxygen-containing gas, water vapor, and water vapor-containing gas. Etc. are included.

[0032] Furthermore, the vacuum atmosphere may contain an inert gas, an oxidizing gas, a reducing gas, or a mixed gas of an inert gas and an oxidizing gas or a reducing gas.

[0033] The lower alcohol in the reducing gas atmosphere is a lower alcohol having 16 to 16 carbon atoms, for example, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, hexyl alcohol and the like. This reducing gas atmosphere is a firing atmosphere for removing only oxygen from the surface of the metal fine particles, and is not an atmosphere for reducing so-called oxides to metal.

[0034] The particle size of the metal fine particles and alloy fine particles used in the present invention is 0.5 nm to 50 nm. Is preferred. When the thickness is less than 0.5 nm, the substantial surface area of the particles increases, and as a result, the amount of organic substances attached around the particles increases. . If it exceeds 50 nm, sedimentation is likely to occur when dispersed in an organic solvent. The primary particle diameter of the metal oxide fine particles is preferably about 20 to 30 nm.

[0035] The method for producing the metal fine particles and alloy fine particles used in the present invention is not particularly limited. For example, even in the case of the gas evaporation method, the wet reduction method or the heat treatment by spraying the organometallic compound to a high-temperature atmosphere is used. A reduction method or the like may be used. The surfaces of the obtained metal fine particles and alloy fine particles are preferably in a metal state, but may be in a state where at least a part thereof is oxidized.

[0036] In the gas evaporation method among the above-mentioned production methods, a metal is evaporated in a gas atmosphere and in a gas phase in which a vapor of a solvent coexists, and the evaporated metal is condensed into uniform fine particles and separated into a solvent. And a dispersion is obtained (for example, Japanese Patent No. 2561537). By this gas evaporation method, metal fine particles having a uniform particle size of 50 nm or less can be produced. In order to use such metal fine particles as a raw material and make them suitable for various uses, it is necessary to perform substitution in an organic solvent in the final step. What is necessary is just to add a dispersing agent. As a result, the metal fine particles are independently and uniformly dispersed, and a fluid state is maintained.

[0037] The organic solvent may be appropriately selected depending on the type of metal fine particles to be used, and examples thereof include the following. That is, alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, hexanol, heptanol, octanol, decanol, cyclohexanol and terpineol, glycols such as ethylene glycol and propylene glycol, acetone , Methylethyl ketone, and ketones such as getyl ketone; esters such as ethyl acetate, butyl acetate, and benzyl acetate; ether alcohols such as methoxyethanol and ethoxyethanol; ethers such as dioxane and tetrahydrofuran. Acid amides such as, Ν-dimethylformamide; aromatic hydrocarbons such as benzene, toluene, xylene, trimethylbenzene and dodecylbenzene; hexane, heptane, octane, Down, decane, Undekan, Liquid at room temperature, such as long-chain alkanes such as dodecane, tridecane, tetradecane, pentadecane, hexadecane, octadecane, nonadecane, eicosane, and trimethylpentane; cycloalkanes; What is necessary is just to select and use them appropriately. It is assumed that water is also contained in this organic solvent.

[0038] As the organic solvent in which the metal fine particles prepared by the gas evaporation method are dispersed, a solvent such as the above can be used. Preferably, a nonpolar solvent such as toluene, xylene, benzene, or tetradecane; acetone; Ketones such as ethyl ketone, alcohols such as methanol, ethanol, propanol, and butanol can be used. When preparing an ink solution for ink-jet printing, the ink must be compatible with the head material (including the surface coating material) (for example, it must have the property of not corroding, dissolving, etc.), and the aggregation of metal fine particles in the head. It is necessary to select an appropriate solvent in consideration of particle clogging.

[0039] The organic solvent may be used alone or in the form of a mixed solvent. For example, it may be a mineral spirit that is a mixture of long-chain alkane.

[0040] The amount of the solvent to be used may be appropriately set according to the type and use of the metal fine particles to be used so that the solvent can be easily applied and a desired film thickness can be obtained. For example, if a solvent is used, the concentration of the metal fine particles can be adjusted as needed by heating in a vacuum or the like even after the dispersion liquid is manufactured so that the concentration of the metal fine particles is about 70% by weight.

Further, as described above, the fine metal particles and fine alloy particles used in the present invention may be fine particles having an organic compound attached around the fine particles. The metal fine particle dispersion prepared by the gas evaporation method is an organic metal fine particle having a particle diameter of 50 nm or less in an isolated state using at least one selected from alkynoleamine, carboxylic acid amide, and amino carboxylate as a dispersant. It is dispersed in a solvent. These metal fine particles are particles having an organic compound as a dispersant adhered to the periphery thereof, and the use of these fine particles facilitates dispersion.

[0042] The alkylamine of the above dispersant may be a primary or tertiary amine, or may be a monoamine, a diamine, or a triamine. Alkylamines having main chain carbon atoms of 412 to 20 are preferable, and alkylamines having main chain carbon atoms of 8 to 18 are more preferable in terms of stability and handling. If the carbon number of the main chain of the alkylamine is shorter, the basicity of the amine It is too strong and tends to corrode the metal fine particles, and eventually there is a problem that the metal fine particles are dissolved. Also, if the carbon number of the main chain of the alkylamine is longer than 20, when the concentration of the metal fine particle dispersion is increased, the viscosity of the dispersion increases and the handling property becomes slightly inferior. There is a problem that the carbon tends to remain in the film, and the specific resistance increases. In addition, the ability of all series of alkylamines to work effectively as a dispersant. Primary alkylamines are preferably used in terms of stability and handling.

Specific examples of alkylamines include, for example, butylamine, octylamine, dodecinoleamine, hexadodecylamine, octadecylamine, cocoamine, taroamine, hydrogenated talamine, oleylamine, laurylamine, and stearylamine. Secondary amines such as primary amines, dicocoamine, dihydrogenated tallowamine, and distearylamine, and dodecyldimethylamine, didodecylmonomethylamine, tetradecyldimethinoleamine, octadecyldimethyl. Tertiary amines such as dimethylamine, cocodimethylamine, dodecyltetradecyldimethinoleamine, and trioctylamine; and, in addition, naphthalenediamine, stearylpropylenediamine, otatamethylenediamine, and Nonandiamine There is a Jiamin like.

[0044] Specific examples of the carboxylic acid amide diaminocarboxylate include, for example, stearic acid amide, normitic acid amide, lauric acid lauric amide, oleic acid amide, oleic acid diethanolanolamide, oleic acid laurylamide, stearanilide, Oleylaminoethyldaricin and the like.

The metal fine particles used in the present invention may be a dispersion obtained by a chemical reduction method such as a wet reduction (liquid phase reduction) method. As such, a reducing raw material that is a metal-containing organic compound may be used.

The chemical reduction method is a method for preparing a metal fine particle dispersion by a chemical reaction using a reducing agent. In the case of fine particles produced by this reduction method, the particle diameter can be arbitrarily adjusted to 50 nm or less. This reduction method is performed, for example, as follows. In a state where the dispersant is added to the raw material, metal fine particles are generated by using a power or a reducing agent such as hydrogen or sodium borohydride which thermally decomposes the raw material at a predetermined temperature. Almost all the generated metal fine particles are recovered in an independent dispersion state. The particle size of these metal particles is about 50 nm or less. Below. By substituting the metal fine particle dispersion with the organic solvent as described above, a desired metal fine particle dispersion can be obtained. The obtained dispersion maintains a stable dispersion state even when concentrated by heating in vacuum.

The transparent conductive film formed by the method for forming a transparent conductive film of the present invention as described above includes, for example, a transparent electrode for a flat display, a transparent antistatic film, a transparent electromagnetic wave shielding film, a surface heating element, a transparent electrode antenna, It can be used for solar cells, electronic paper electrodes, transparent electrode gas sensors, etc.

Next, an example of a method for producing metal fine particles used in the present invention will be described.

(Production Example 1)

[0049] When producing In-Sn alloy fine particles containing 6wt% of Sn by a gas evaporation method using high-frequency induction heating under a helium gas pressure of 0.5 torr, the In-Sn alloy fine particles in the generation process are produced. In contact with a 20: 1 (volume ratio) vapor of terpineol and dodecylamine, it is cooled and collected to collect the In-Sn alloy fine particles, which are dispersed independently in a-terbineol solvent. A dispersion liquid containing 20% by weight of In-Sn alloy fine particles having an average particle diameter of lOnm was prepared. Five volumes of acetone were added to one volume of this dispersion (colloidal solution) and stirred. Fine particles in the dispersion liquid settled out due to the action of polar acetone. After allowing to stand for 2 hours, the supernatant was removed, and the same amount of acetone as the first was added again, followed by stirring. After allowing to stand for 2 hours, the supernatant was removed. The residual solvent was completely removed from the sediment, and In—Sn alloy fine particles having an average particle size of l Onm were produced.

[0050] Fine particles of each metal of In, Sn, Sb, Al, and Zn, and alloy fine particles other than In_Sn, which is a metal force of these metals, can be obtained in the same manner according to the above-described production method.

Hereinafter, examples and comparative examples of the present invention will be described.

Example 1

[0052] As the metal fine particles, In-Sn alloy fine particles produced by evaporation in gas in Production Example 1 were used. These particles had an average particle size of lOnm, and were confirmed to be non-oxidized alloy fine particles by X-ray diffraction. X-ray fluorescence analysis confirmed that the Sn content in the fine particles was 6 wt%. As the oxide fine particles to be combined with the alloy fine particles, ITO fine particles having a primary particle of 20 nm were used. These alloy fine particles and ITO fine particles Are mixed and dispersed in an organic solvent (toluene) at a ratio of 5:95 (wt%) to a total solid content of 30 wt% to obtain a dispersion for forming a transparent conductive film. Was.

[0053] The dispersion obtained by the force was applied onto a glass substrate by spin coating to form a film. The resulting coating film baked at a ^{1 X 10- 3 Pa 230 ° C} , 30 minutes condition under a reduced pressure of (1st Aniru) was performed. Next, the atmosphere was returned to the atmosphere, and calcination (2nd anneal) at 230 ° C and 10 min was performed in air. The obtained transparent conductive film (thickness: 200 nm) was sufficiently densified, and its surface resistance was as low as 60 Ω / mouth, and the transmittance at 550 nm was as high as 99.4%. In this case, after firing in an air atmosphere, firing in a reducing gas atmosphere (hydrogen gas atmosphere and carbon monoxide atmosphere) (3rd anneal) further resulted in a further increase in the surface resistance of the obtained transparent conductive film. Got low.

[0054] The transparent conductive film obtained in Example 1 was useful as a transparent electrode of a display device.

(Comparative Example 1)

[0055] In-Sn alloy fine particles were removed from the dispersion obtained in Example 1, and a dispersion of only ITO fine particles was applied on a glass substrate in the same manner as in Example 1 to form a dispersion. The membrane was made. Next, the obtained coating film was fired at 230 ° C. for 30 minutes under the same conditions as in Example 1. The resulting transparent conductive film, the transmittance was as high as 98% power its surface resistance 7 Χ 10 ³ Ω / mouth and very Kokaka ivy.

From the results of Example 1 and Comparative Example 1, the following points are presumed.

[0057] (4) When only the fine particles are used, since the raw material already in the oxidized state is used, the obtained film shows a sufficient transmittance, but is not satisfactory in terms of surface resistance. This is thought to be because in the case of low-temperature sintering, (1) the sintering of the fine particles does not proceed, and (2) the contact resistance of the fine particles increases, resulting in a high-resistance film. As described above, when low-temperature baking was performed using a dispersion liquid containing only fine particles, it was not useful as a transparent electrode.

On the other hand, when the fine particles and the metal fine particles are used in combination, the metal fine particles having a small particle size fill gaps between the ITO fine particles, and the metal fine particles serve as an adhesive to densify the film. It is presumed that the contact resistance of the fine particles was reduced, resulting in a low-resistance film. Regarding the mixing ratio of the metal fine particles and the ITO fine particles, since the metal fine particles only need to act as a binder, the concentration of the metal fine particles in all the fine particles is generally about 110 to 30 wt%, preferably about 3 to 30 wt%. It is convenient to From the viewpoint of the cost of the dispersion, the concentration of the metal fine particles is lower, and the more preferable.

Next, calcination was performed according to the method described in Example 1 by changing the types and composition ratios of the metal fine particles and oxide fine particles of each component metal of the metal oxide for forming a transparent conductive film and the calcination conditions. The surface resistance and transmittance of the obtained film were measured. The results are shown in Table 1. Table 1 also shows comparative examples.

[Table 1]

In-Zn

28 Zn6wt% IZO 20wt% 80wt% 230 1.00E-03 Decompression only 30 230 Atmospheric pressure Atmosphere 15 230 Atmospheric pressure — Carbon oxide 10 60 99

In-Zn

29 Zn6wt% 120 20wl% 80wt% 230 Atmospheric pressure N ₂ 15 230 Atmospheric pressure Oxygen 15 230 Atmospheric pressure Methanol 10 65 98

In-Zn

30 Zn6wt% IZO 20wt% 80wt% 230 Atmospheric pressure ₂ 30 230 Atmospheric pressure Atmospheric 15 230 1.00E-03 Atmospheric 10 62 96

In-Zn

31 Zn6wt JZO 20 t% 80wt% 230 8.2 Atmospheric pressure only 15 230 Atmospheric pressure Oxygen 15 230 1.00E-03 Atmosphere 10 60 97

In-Zn

32 Zn6wt% IZO 20wt% 80wt% 230 8.2 Decompression only 30 230 Atmospheric pressure Atmosphere 15 230 1.00E-03 —Carbon oxide 10 50 96

Sn-Sb

33 Sb5wt% ATO 3wt 97wt 230 1.00E-03 Atmospheric pressure only 30 230 Atmospheric pressure Oxygen 15 4500 98

Sn-Sb

34 Sb5wt% ATO 3wt% 97wt% 230 1.00E-03 Carbon monoxide 30 230 Atmospheric pressure Atmosphere 15 4000 97

Sn-Sb

35 Sb5wt ATO 3wt% 97wt% 250 8.2 Decompression only 30 230 Atmospheric pressure Oxygen 15 230 Atmospheric pressure N ₂ , Hydrogen 10 2000 97

Sn-Sb

36 Sb5wt% ATO 3wt% 97wt% 250 8.2 Atmospheric pressure only 30 230 Atmospheric pressure Atmosphere 15 230 Atmospheric pressure Carbon monoxide 10 2500 97

Sn-Sb

37 Sb5wt% ATO 10wt% 90wt% 250 8.2 Decompression only 30 230 Atmospheric pressure Oxygen 15 230 Atmospheric pressure Methanol / 10 2800 98

Sn-Sb

38 Sb5wt% ATO 10wt% 90wt% 250 Atmospheric pressure 30 230 Atmospheric pressure Atmospheric 15 230 1.00E-03 Atmospheric 10 7000 99

Sn-Sb

39 Sb5wt% ATO 10wt 90wt 250 Atmospheric pressure 30 230 Atmospheric pressure Oxygen 15 230 1.00E-03 Atmospheric 10 6500 99

Zn-Al

40 Al 5wt AZO 3wt 97wt% 250 1.00E-03 Decompression only 30 230 Atmospheric pressure Atmosphere 15 360 97

Zn-Al

41 Al 5wt% AZO 3wt 97wt 250 1.00E-03 Carbon monoxide 30 230 Atmospheric pressure Oxygen 15 420 96

Zn-Al

42 Al 5wt% AZO 3wt% 97wt% 250 8.2 Decompression only 30 230 Atmospheric pressure Atmosphere 15 444 97

Zn-Al

43 Al 5wt% AZO 10 t% 90wt% 250 8.2 Decompression only 30 230 Atmospheric pressure Oxygen 15 504 98

Zn-Al

44 Ai 5wt% AZO 10wt% 90wt% 250 8.2 Decompression only 30 230 Atmospheric pressure Atmosphere 15 576 99

Zn-Al

45 Al 5wt% AZO I0wt 90wt% 250 Atmospheric pressure 30 230 Atmospheric pressure Oxygen 15 230 1.00E-03 Atmosphere 10 456 97

Zn-Al

46 Al 5wt% AZO 10wt 90wt% 250 Atmospheric pressure a 30 230 Atmospheric pressure Atmospheric 15 230 1.00E-03 Atmospheric 10 492 98

47 In ATO 5wt% 95wt% 250 1.00E-03 Decompression only 15 250 Atmospheric pressure Atmosphere 15 4800 98

In-Zn

48 Zn6wt% ITO 5wt% 95wt% 230 1.00E-03 Atmospheric pressure only 15 230 Atmospheric pressure Oxygen 15 90 98

Sn-Sb

49 Sb5wt AZO 3wt% 97wt% 230 1.00E-03 Decompression only 30 230 Atmospheric pressure Oxygen 15 1000 98

Zn-Al

50 Al 5wt% ITO 3wt 97wt% 250 1.00E-03 Decompression only 30 230 Atmospheric pressure Atmosphere 15 120 97 ratio!

1 ITO 100wt% 230 1.00E-03 Decompression only 30 7000 98

2 In ITO 20wt% 80wt% 230 1.00E-03 Decompression only 30 60 70

3 In ITO 20 t 80wt% 230 Atmospheric pressure Oxygen 30 230 1.00E-03 Atmospheric pressure only 15 900 98

In-Sn

4 Sn6wt ITO 20wt 80wt% 230 1.00E-03 Decompression only 30 54 68

In-Sn

5 Sn6wt% ITO 20wt% 80wt% 230 Atmospheric pressure Air 30 230 1.00E-03 Decompression only 15 1200 9

6 ATO 100wt% 250 l.OOE-03 Decompression only 30 48000 9

Sn-Sb

7 Sb5wt% ATO 10wt% 90wt% 250 l.OOE-03 减 sho only 30 3240 7

Sn-Sb

8 Sb5wt% ATO 10wt% 90wt% 250 Atmospheric pressure Atmosphere 30 250 1.00E-03 Decompression only 15 36 600 9

9 AZO 100wt 250 l.OOE-03 Decompression only 30 4570 9

Zn-Al

10 Al 5wt% AZO 10wt% 90wt 250 Atmospheric pressure Atmosphere 30 250 1.00E-03 Decompression only 15 2568 9

Analysis of the data of the examples and comparative examples described in 1 shows the following.

In Examples 2 to 4, In fine particles and I T〇 fine particles were used, and in Examples 5 to 18, In_Sn alloy fine particles.

Replacement form (Rule 26) (Sn: 6 wt%) and ITO fine particles were used. In the obtained films, those without the addition of Sn exhibited a higher resistance value than those with the addition of Sn, and the force transmittance was almost the same.

In Examples 19-32, In—Zn alloy fine particles (Zn: 6 wt%) and IZO fine particles were used. In the obtained film, the resistance value was almost the same as that in the case of using the In—Sn alloy fine particles and the ZITO fine particles, and the value was slightly higher, and the transmittance was almost the same as in these cases.

In Examples 33-39, 311_31) alloy fine particles (3

And ΑΤ〇 fine particles.

In the obtained film, the resistance value is higher than when using In fine particles or In-Sn alloy fine particles ΖΙΤΟ fine particles, or when using In-Zn alloy fine particles ΖΙΖΟ fine particles. However, the transmittance was almost the same as in these cases. This film was excellent in thermal stability and chemical stability. No change in resistance was observed even after baking this film at 600 ° C.

In Examples 40-46, Zn—A1 alloy fine particles (A1: 5 wt%) and AZ〇 fine particles were used. In the obtained film, the resistance value is lower than when using Sn—Sb fine particles / ATO fine particles, and higher than when using In—Sn fine particles / ITO fine particles or In—Zn fine particles / IZO fine particles. The force S and the transmittance were almost the same as in these cases.

[0066] In the above example, the metal constituting the metal fine particles and the metal constituting the metal oxide as the base particles were considered. An example is shown in Examples 47-50.

[0067] In Example 47, In fine particles and ATO fine particles were used. In the obtained film, the resistance value and the transmittance were almost the same as those when the Sn—Sb fine particles / ATO fine particles were used.

In Example 48, In—Zn fine particles (Zn: 6 wt%) and ITO fine particles were used. In the obtained film, the resistance value and the transmittance were almost the same as those of the In—Sn fine particles and the ZITO fine particles.

In Example 49, Sn—Sb fine particles (Sb: 5 wt%) and AZ〇 fine particles were used. In the obtained film, the resistance value was higher than that when the Zn-A1 fine particles and the ZAZO fine particles were used, and the transmittance was almost the same.

In Example 50, Zn—A1 fine particles (A1: 5 wt%) and ITO fine particles were used. In the obtained film, the resistance value was slightly lower than that in the case of using the In—Sn fine particles / ITO fine particles, but the transmittance was almost the same. [0071] All of the above films had excellent etching characteristics. In particular, films obtained using In-Zn fine particles and oxide fine particles were composed of In fine particles, In-Sn fine particles or Sn-Sb fine particles and oxides. The etching characteristics were superior to the film obtained using the fine particles. From these facts, it can be seen that the film obtained using the system composed of the In-Zn fine particles and the oxide fine particles is a film excellent in workability.

As is clear from the above examples, as a result of examining the firing method using a mixed material of various metal fine particles and metal oxide base particles as a starting material, it was found that various transparent materials having a predetermined surface resistance and transmittance were obtained. It was found that a conductive film could be formed.

[0073] In Comparative Examples 1-110, when only oxide (IT〇, ΑΤ〇, and ΑΖΟ) fine particles were used, when metal fine particles and oxide (ΙΤΟ, ΑΤΟ, and ΑΖ〇) fine particles were used, The surface resistance and transmittance of the obtained film were evaluated when firing only in a vacuum atmosphere and first firing in an oxidizing gas atmosphere. When only ΙΤ〇 fine particles, ΑΤ〇 fine particles or ΑΖ〇 fine particles were used, there was a problem as a conductive film having a high resistance value. In the case of using metal fine particles and oxide fine particles, when fired only in a vacuum atmosphere, the transmittance is too low, which is a problem as a transparent conductive film. In addition, first, in an oxidizing gas atmosphere (1st annealing), Then, when it was fired in a vacuum atmosphere (2 d-anneal), it had a problem as a conductive film having a high resistance value. Also, from these comparative examples, the transmission characteristics are improved by increasing the baking time in an oxidizing gas atmosphere, but at the same time, the resistance value is significantly degraded due to the progress of oxidation in the film. I understand.

Industrial applicability

According to the present invention, a transparent conductive film having low resistance and high transmittance can be formed by firing at a low temperature using a specific dispersion liquid. The film can be applied to the field of a transparent conductive film (for example, a transparent electrode) used for a display device such as a flat panel display, a charging of a display surface, and an electromagnetic wave shielding film in a field of, for example, an electric and electronic industry. .

Claims

The scope of the claims

[1] Fine particles of at least one metal selected from indium, tin, antimony, aluminum and zinc, at least one fine particle of an alloy composed of two or more metals selected from the metals, or the metal A mixture of fine particles and alloy fine particles, Sn-doped In O, Sb-doped S

twenty three

Fine particles of at least one oxide selected from n〇, Zn-doped In〇 and A1-doped Zn〇

2 2 3

A dispersion for forming a transparent conductive film, wherein the dispersion is mixed and dispersed in an organic solvent.

[2] A method for forming a transparent conductive film, which comprises applying the dispersion for forming a transparent conductive film according to claim 1 to a substrate, followed by baking.

3. The method for forming a transparent conductive film according to claim 2, wherein the firing is performed in an atmosphere selected from a vacuum atmosphere, an inert gas atmosphere, a reducing gas atmosphere, and an oxidizing gas atmosphere.

[4] The calcination is performed first in an atmosphere in which a metal or alloy selected from a vacuum atmosphere, an inert gas atmosphere, and a reducing gas atmosphere is not oxidized, and then in an oxidizing gas atmosphere. Item 4. The method for forming a transparent conductive film according to Item 2 or 3.

5. The transparent conductive material according to claim 3, wherein after firing in the oxidizing gas atmosphere, firing is further performed in an atmosphere selected from a vacuum atmosphere, an inert atmosphere, and a reducing gas atmosphere. Method of forming a film.

[6] The inert gas atmosphere is an atmosphere composed of at least one inert gas selected from a rare gas, carbon dioxide and nitrogen, and the reducing gas atmosphere is hydrogen, carbon monoxide and lower alcohol. Wherein the oxidizing gas atmosphere is an atmosphere comprising at least one oxidizing gas selected from oxygen-containing gases. Item 36. The method for forming a transparent conductive film according to any one of Items 35 to 35.

[7] The vacuum atmosphere includes at least one inert gas selected from a rare gas, carbon dioxide and nitrogen, at least one oxidizing gas selected from a gas containing an oxygen element, hydrogen, carbon monoxide and At least one reducing gas selected from lower alcohols, or a mixed gas comprising the inert gas and an oxidizing gas or a reducing gas. The method for forming a transparent conductive film according to any one of claims 3-5.

8. The method for forming a transparent conductive film according to claim 3, wherein the oxidizing gas atmosphere contains oxygen, an oxygen-containing gas, water vapor, or a water vapor-containing gas.

9. The method for forming a transparent conductive film according to claim 28, wherein the metal fine particles and the alloy fine particles are fine particles obtained by adhering an organic compound around the fine particles.

[10] A transparent electrode comprising a transparent conductive film formed by the method according to any one of claims 2 to 9.