JP7104919B2 - A method for producing a transparent conductive substrate by thermocompression bonding a graphene bonded body composed of graphene aggregates in which the graphene flat surfaces are overlapped and bonded to a synthetic resin transparent film. - Google Patents

Description

The present invention provides a manufacturing method for producing a transparent conductive substrate by thermocompression bonding a graphene bonded body, which is a collection of graphenes obtained by bonding the flat surfaces of graphene that overlap each other, to a transparent film of a synthetic resin. involved. That is, a graphene bonded body having transparent conductive properties is extremely thin and difficult to handle. However, by thermocompression bonding a graphene bonded body to a transparent synthetic resin film, a transparent conductive substrate that is easy to handle can be obtained.
In other words, graphene is a single-crystal material composed of a collection of carbon atoms that two-dimensionally form a network structure composed of hexagonal carbon atoms. Therefore, it has a thickness of 0.332 nm, which is three orders of magnitude smaller than the wavelength of visible light, so it has transparency to transmit visible light. Also, its thermal conductivity is 19.5 W/Cm, which is 4.5 times higher than that of silver, which has the highest thermal conductivity among metals. Furthermore, the electrical conductivity is 7.5×10 ⁷ S/m, which is 1.2 times the electrical conductivity of silver. Therefore, a graphene bonded body in which the flat surfaces of graphene are overlapped and bonded together becomes a transparent conductive film having a certain area and having transparency, thermal conductivity, and electrical conductivity similar to graphene.
Therefore, the transparent conductive substrate obtained by thermocompression bonding the graphene conjugate, which has excellent transparency, thermal conductivity, and electrical conductivity, to a transparent synthetic resin film has a certain thickness, making it easy to handle. become. As a result, this transparent conductive base material can be used as a transparent conductive base material for touch panels, a flexible circuit board, a transparent conductive base material for organic EL, a transparent conductive base material for organic thin-film solar cells, a flexible LED conductive film, and the like. Widely adaptable.

Conventional methods for producing a transparent conductive film include a method of coating a transparent substrate with a conductive ink or conductive paste, and a method of forming a transparent conductive film on a transparent substrate by physical vapor deposition or chemical vapor deposition. be.
For example, in Patent Document 1, a transparent conductive film is formed by coating or printing a conductive paste comprising conductive oxide fine particles made of tin oxide, antimony-doped tin oxide, or phosphorus-doped tin oxide and a binder resin on a substrate. Techniques for forming are described.
Patent Document 2 describes a technique for forming a transparent conductive thin film by laminating a metal oxide layer, a silicon oxide layer, and an indium/tin oxide layer on a transparent plastic substrate by magnetron sputtering.

However, conventional methods for forming a transparent conductive film on a transparent substrate have the following problems.
First, the problem of forming a transparent conductive film by applying conductive ink or conductive paste will be described. Conductive ink or conductive paste is prepared by dispersing metal fine particles, metal powder or conductive metal oxide fine particles as a conductive filler in a vehicle composed of a synthetic resin binder and a solvent. Therefore, there are problems caused by using the conductive filler and problems caused by dispersing the conductive filler in the vehicle.
The first problem is due to the use of conductive fillers. That is, the applied or printed ink or paste is heat-treated to cure the resin, and the cured resin binds the conductive filler to form a transparent conductive film. However, the cured resin prevents the conductive fillers from being directly bonded to each other, increasing the electrical resistance of the transparent conductive film. Therefore, when a current is passed through the transparent conductive film, heat is generated, which promotes deterioration and peeling of the transparent conductive film.
The second problem is due to the dispersibility of the conductive filler. In other words, if the dispersibility of the conductive filler in the vehicle is poor, the conductive filler will be unevenly distributed after the heat treatment. As a result, the electrical resistance of the transparent conductive film increases as described above. On the other hand, if the amount of the organic compound adsorbed on the conductive filler is increased in order to improve the dispersibility of the conductive filler, the electrical resistance of the transparent conductive film after heat treatment increases because the organic compound is an insulator.
A third problem is caused by aggregation of the conductive filler particles. The finer the conductive filler, the easier it is to agglomerate. As a result, the dispersibility of the filler in the vehicle deteriorates and the electric resistance of the transparent conductive film increases.
The above-described problems are fundamental problems caused by using the conductive filler and dispersing the conductive filler, and are difficult to solve. Therefore, there is a strong demand for a technique for forming a transparent conductive film by a method other than using conductive ink or conductive paste.

Next, the problem of forming a transparent conductive film by physical vapor deposition or chemical vapor deposition will be described. Here, the problems will be explained by focusing on the most widely used sputtering method, but the formation of a transparent conductive film by chemical vapor deposition also has similar problems.
First, the principle of forming a transparent conductive film by the sputtering method is to collide ions with a target at high speed, knock out atoms constituting the target, and the knocked-out atoms rush into the transparent substrate, whereupon the atoms deposited to form a transparent conductive film. Since the atoms ejected from the target travel straight toward the transparent substrate, defects such as protrusions called nodules are likely to occur depending on the surface condition of the transparent substrate. Therefore, it is necessary to correct structural defects by annealing. This annealing treatment increases the cost of forming the transparent conductive film.
Second, recoil particles are generated in the target when the atoms are ejected from the target, and if the recoil particles rush into the transparent substrate, they damage the transparent conductive film. For this reason, a magnetron sputtering apparatus is used to lower the magnetron impedance, thereby lowering the discharge voltage and mitigating the damage caused by recoiled particles. However, it is necessary to raise the temperature of the transparent substrate and leave it for a long time. becomes difficult to do.
Third, the vacuum chamber is once evacuated, and then sputtering is performed. At the time of evacuation, moisture and foreign matter are gasified from the transparent base material and released into the atmosphere of the transparent conductive film, which hinders the formation of a low-resistance transparent conductive film. Therefore, it is necessary to sufficiently vacuum the transparent substrate in advance and vacuum clean the surface of the transparent substrate. This vacuum cleaning increases the cost of forming the transparent conductive film.
Fourthly, when forming an electrode pattern on a transparent substrate, the transparent conductive film is patterned by etching after forming the transparent conductive film. Therefore, the transparent substrate and the transparent conductive film must have chemical resistance to the etchant. Also, the cost of forming the electrode pattern increases with the etching process.
Fifth, since the transparent conductive film formed by the sputtering method does not have sufficient electrical conductivity, an annealing treatment involving heat treatment is required. For this reason, the transparent conductive film once formed is left to stand for a long period of time in an atmosphere in which oxygen gas does not exist for annealing. This annealing treatment limits the material of the transparent substrate.
Sixthly, in the sputtering method, the resistivity of the transparent conductive film increases with increasing distance from directly below the center of the target. Therefore, it is unsuitable for forming a large-area transparent conductive film.
Since all of the above-described problems depend on the principle of forming a transparent conductive film by sputtering, it is difficult to solve them. Therefore, there is a strong demand for a technique for forming a transparent conductive film by a method other than the sputtering method.

On the other hand, graphene is produced by various methods, but when used as a transparent conductive film, a certain area is required, and the larger the area of graphene produced, the higher the production cost.
For example, Patent Document 3 describes a method of producing graphene by thermally decomposing a single crystal of silicon carbide. That is, silicon carbide is heated in an inert atmosphere to pyrolyze the surface. At this time, silicon, which has a relatively low sublimation temperature, preferentially sublimes, and graphene is generated from the remaining carbon. However, single crystal silicon carbide is a very expensive material, and the larger the area, the more expensive it is to grow the single crystal. Furthermore, silicon is sublimated at a high temperature exceeding 1600 ° C. and in a high vacuum atmosphere, but if even a small amount of silicon remains or impurities other than carbon are present, graphene will be formed as a residue after pyrolysis. Not generated. As a result, the costs involved in producing single crystals of silicon carbide and pyrolyzing the single crystals are high.
Furthermore, Patent Literature 4 describes a method of producing graphene by bringing a carbon-based material into contact with a sheet-like single-crystal graphitized metal catalyst and heat-treating in a reducing atmosphere. First, the production cost of producing a single crystal graphitized metal catalyst is much higher than that of a silicon carbide single crystal, and the larger the area, the higher the production cost of the single crystal. Second, if impurities other than carbon remain or are produced when the single crystal graphitized metal catalyst is brought into contact with the carbonaceous material, graphene is not produced. Third, the method of reducing the graphitized metal catalyst at a high temperature exceeding 1000° C. in an atmosphere rich in nitrogen gas containing hydrogen gas results in high heat treatment costs.

Graphene production methods to date are not cheap. Furthermore, graphene used as a transparent conductive film must have a certain area. However, the larger the area, the higher the production cost of graphene, and it cannot be used as a general-purpose transparent conductive film. Second, the graphene produced is not necessarily graphene. In other words, graphene is a single crystal material composed of a collection of carbon atoms that form a two-dimensional network structure composed of hexagons. Graphene cannot be produced without crystal growth of only carbon atoms. Furthermore, since the produced graphene is extremely thin and extremely light, it is troublesome to confirm that the produced product is graphene.
For this reason, the present inventors have found a method for producing a large amount of graphene instantaneously, in which all of the produced graphene is complete graphene, and by an extremely simple method (Patent Document 5). In other words, it is a technology for instantaneously producing a large amount of graphene from graphite particles, which consist only of graphite single crystals, the crystallization of graphite is advanced by 100%, and which is the cheapest carbon material. That is, a mass of graphite particles obtained by crushing a mass of natural graphite crystals and selecting scale-like graphite particles or agglomerated graphite particles from the crushed graphite crystals is pulled into the gap between two parallel plate electrodes, In this method, an electric field is applied to parallel plate electrodes, and the interlayer bonding of all the basal planes of graphite crystals forming graphite particles is simultaneously destroyed by the application of the electric field to produce a large amount of graphene consisting of basal planes. According to this method, 1.62×10 ¹³ graphene aggregates can be instantaneously obtained from only 1 g of flake graphite particles or massive graphite particles.
However, the area of graphene made from graphite particles is too small to be used as a transparent conductive film. Therefore, if flat surfaces of graphene can be bonded together by an inexpensive method, a graphene bonded body having a large area can be used as an inexpensive transparent conductive film. Furthermore, since the graphene bonded body is thin, if it can be integrated with a transparent base material made of another material, the graphene bonded body can be easily handled. Therefore, there is a demand for a technique for bonding flat surfaces of graphene and a technique for integrating a graphene bonded body with a transparent base material made of another material.

JP 2015-220192 A JP 2011-065937 A JP 2015-110485 A JP 2009-143799 A Patent No. 6166860

Nair RR, et al. , Science 320, 1308 (2008)

Although a large amount of graphene can be produced instantaneously by the method according to Patent Document 5, no method has yet been found for producing a graphene bonded body in which the flat surfaces of graphene are bonded together using this collection of graphene. Graphene is an extremely thin substance composed of a single crystallite in which carbon atoms form a two-dimensional network structure composed of hexagons, and is extremely lightweight and has almost no mass. Therefore, in the method for producing a graphene cluster in Patent Document 5, when a large amount of graphene is deposited, the graphene scatters. In addition, graphene is easily scattered when the manufactured graphene is handled. Thus, graphene is a material that is difficult to handle.
On the other hand, regarding the transparency of graphene, according to Non-Patent Document 1, the transmittance of visible light is 97.7%, and the absorbance per graphene layer is 2.3%. For this reason, the graphene bonded body in which the flat surfaces of graphene are bonded to each other decreases in transparency as the number of bonded graphenes increases. On the other hand, tin oxide-doped indium oxide (In ₂ O ₃ —SnO ₂ , commonly known as ITO) is the most commonly used transparent conductive film at present. ITO has a visible light transmittance of 84%. Therefore, in order to obtain transparency superior to that of ITO, it is necessary to suppress the number of bonded graphene sheets to 7 or less in the graphene bonded body. However, the thickness of the graphene bonded body in which the number of bonded graphene sheets is suppressed to 7 or less is as thin as 2.3 nm or less, and is transparent, so that it is difficult to handle. Therefore, if a transparent conductive graphene bonded body can be integrated with a transparent base material made of another material, the graphene bonded body becomes a transparent conductive base material that is easy to handle.
Therefore, in order to use graphene as a general-purpose transparent conductive substrate, there are the following five problems to be solved.
First, a mass of graphene is produced in a liquid-filled container. As a result, the graphene precipitated in the liquid does not scatter during and after the graphene production.
Secondly, flat surfaces of graphene are superimposed on the bottom surface of the container with the liquid interposed therebetween. After that, when the liquid is vaporized, a group of graphenes with overlapping flat surfaces is formed on the bottom surface of the container. This prepares the graphene conjugate to be formed in the container. That is, the thickness of graphene is extremely thin, and the aspect ratio, which is the ratio of the surface area to the thickness, is extremely large. Also, graphene is extremely thin and has almost no mass. Therefore, by utilizing these two characteristics, it is possible to form a group of graphenes in which the flat surfaces overlap with each other on the bottom surface of the container.
Thirdly, the portions where the flat surfaces of the graphene overlap each other are bonded to form a graphene bonded body in which the flat surfaces overlap each other and are bonded to each other on the bottom surface of the container in the shape of the bottom surface. That is, the breaking strength of graphene is 42 N/m, which is a tough material having a strength exceeding 100 times that of steel. Therefore, by using a method that utilizes this feature, it is possible to join the portions where the flat surfaces overlap each other. As a result, restrictions on the area and shape of the graphene bonded body are eliminated, and the graphene bonded body can be used as a transparent conductive substrate.
Fourth, the graphene bonded body described above is integrated with a transparent substrate made of another material. That is, in order to obtain transparency superior to that of ITO, it is necessary to suppress the number of graphene flat surfaces to be bonded to each other within seven sheets. However, the thickness of the graphene bonded body is as thin as 2.3 nm or less, and it is not easy to handle. Therefore, if a transparent conductive graphene bonded body can be integrated with a transparent substrate made of another material, the graphene bonded body can be easily handled, and the graphene bonded body can be used as a general-purpose transparent conductive substrate. Available.
Fifth, the treatments in the four steps described above are all extremely simple, and the materials used are inexpensive. As a result, an inexpensive group of graphite particles is used to produce a graphene group by an inexpensive method, a graphene bonded body is produced by an inexpensive method, and the graphene bonded body is used as an inexpensive transparent base material by an inexpensive method. It is possible to manufacture an integrated, inexpensive transparent conductive substrate.
The problems to be solved by the present invention are the above five problems.

A method for producing a transparent conductive substrate comprising a structure in which a graphene bonded body composed of a collection of graphenes in which the flat surfaces of the graphene are overlapped with each other is bonded to a transparent film of a synthetic resin by thermocompression,
A group of scale-like graphite particles or a group of massive graphite particles is flattened on the surface of one of the two parallel-plate electrodes, and the parallel-plate electrode is immersed in methanol filled in a container. Further, the other parallel plate electrode is superimposed on the one parallel plate electrode, and the two parallel plate electrodes are separated via the collection of the scale-like graphite particles or the collection of the massive graphite particles. , the two spaced apart parallel plate electrodes are immersed in the methanol;
After that, a DC potential difference is applied across the gap between the two parallel plate electrodes, whereby an electric field corresponding to the value obtained by dividing the potential difference by the gap between the two parallel plate electrodes is generated. , a coulomb sufficient to break the interlayer bonding of the basal planes of graphite crystals for all of the graphite particles by the application of the electric field applied to the cluster of flake graphite particles or the cluster of massive graphite particles. A force is simultaneously applied to all the π electrons responsible for the interlaminar bonds of the basal planes forming the graphite particles, thereby causing all the interlaminar bonds of the basal planes forming the flake graphite particles or the massive graphite particles. are destroyed at the same time, and a group of graphene corresponding to the basal plane is produced in the gap between the two parallel plate electrodes.
After that, the gap between the two parallel plate electrodes is widened, the two parallel plate electrodes are tilted in the methanol, and further vibration acceleration is repeatedly applied to the container in three directions: left and right, front and back, and up and down. , the graphene mass is transferred from the gap between the two parallel plate electrodes into the methanol, and then the two parallel plate electrodes are removed from the container, whereby the graphene in the container a suspension is produced in which aggregates precipitate in said methanol;
Next, a transparent film of synthetic resin having the shape of the bottom surface of the container is placed on the bottom surface of the container for producing the transparent conductive base material, and the suspension produced by the above method is added to the transparent conductive base material. The container is filled in an amount necessary for manufacturing the base material, and then the container is repeatedly subjected to vibration acceleration in three directions: back and forth, left and right, and up and down, whereby the graphene constituting the suspension moves in the methanol constituting the suspension with the flat surface of the graphene facing upward, the graphene diffuses throughout the container, and the flat surfaces of the graphene overlap with each other through the methanol. The graphene aggregates are formed on the synthetic resin transparent film in the shape of the bottom surface of the container.
After that, a plate material having the size of the graphene cluster is placed on the graphene cluster, the container is heated to the boiling point of methanol to vaporize the methanol, and then the plate member is compressed. , the container is heated to the Vicat softening temperature of the synthetic resin constituting the transparent film, whereby after the methanol is vaporized, the graphene aggregates in which the flat surfaces of the graphene overlap with each other form the synthetic resin is formed on the transparent film as the shape of the bottom surface of the container, and then the collection of graphene is compressed, frictional heat is generated at the portion where the flat surfaces of the graphene overlap each other, and the graphene is generated by the frictional heat The flat surfaces of the graphene are bonded to each other, and a graphene bonded body composed of a collection of graphenes in which the flat surfaces of the graphene are bonded to each other is formed, and the transparent film of the synthetic resin is softened. The graphene bonded body is pressure-bonded to the surface of the softened synthetic resin transparent film, and the transparent conductive substrate obtained by thermocompression bonding the graphene bonded body to the synthetic resin transparent film is attached to the bottom surface of the container from the shape of the bottom surface. is formed as a transparent conductive substrate,
After that, vibration acceleration is repeatedly applied to the container in three directions: back and forth, left and right, and up and down, and the transparent conductive substrate is removed from the container, thereby bonding the flat surfaces of graphene that overlap each other. A method for producing a transparent conductive base material, wherein the transparent conductive base material is produced by thermocompression bonding a graphene bonded body consisting of an aggregate of the graphenes obtained by bonding to a transparent film of a synthetic resin.

That is, the method for producing a transparent conductive substrate in the present invention consists of the following three steps.
First, a collection of graphene is produced from a collection of graphite particles in methanol, and a suspension of the collection of graphene precipitated in methanol is produced. For this reason, a group of scale-like graphite particles or a group of massive graphite particles squeezed into the gap between two parallel plate electrodes is immersed in methanol, which is an insulator, and a direct current is applied between the two parallel plate electrodes. A potential difference is applied. As a result, an electric field corresponding to a value obtained by dividing the potential difference by the size of the gap between the two parallel plate electrodes is generated in the electrode gap where the group of flake graphite particles or the group of massive graphite particles exists. This electric field simultaneously imparts a Coulomb force sufficient to break the interlayer bonding of the basal planes of graphite crystals to all the π electrons responsible for the interlayer bonding of the basal planes of all the graphite particles. As a result, the π electrons are released from the constraint on the π orbital, and all the π electrons leave the π orbital and become free electrons. In other words, when the Coulomb force acting on the π-electrons is given to the π-electrons as a force greater than the interaction of the π-orbitals, the π-electrons are released from the π-orbital constraints and become free electrons. As a result, all the π electrons responsible for the interlayer bonds of the basal plane cease to exist on the π orbital, and all the interlayer bonds of the basal plane forming the graphite particles are simultaneously destroyed for all the graphite particles. As a result, a collection of basal planes, that is, a collection of graphene is instantly produced in the gap between the two parallel plate electrodes. The manufactured graphene is an intrinsic substance consisting only of graphite crystals without impurities, and a suspension of the graphene aggregates precipitated in methanol is manufactured in a container. Since the two parallel plate electrodes are immersed in methanol, the aggregate of graphene deposited in the gap between the two parallel plate electrodes does not scatter. This solved the first of the five problems described in paragraph 9.
When a potential difference is applied between two parallel plate electrodes immersed in methanol, which is an insulator, an electric field is generated in the gap between the two parallel plate electrodes. That is, methanol is an insulator with a specific resistance of 3 MΩ·cm or more and a dielectric constant of 33. Ethanol is also an insulator with a dielectric constant of 24, and the electric conductivity of ethanol is 7.5×10 ⁻⁶ S/m. On the other hand, the electric conductivity of the flake graphite particles is 43.9 S/m. Therefore, ethanol is an insulator whose electric conductivity is 1.7×10 ⁷ times lower than that of flake graphite particles, which are conductors. In the present invention, methanol, which is the lowest viscosity, lowest boiling point, and cheapest industrial alcohol, is used as the alcohol.
Second, a transparent film made of synthetic resin having the shape of the bottom surface is placed on the bottom surface of a container for manufacturing a transparent conductive base material, and the flat surfaces of graphene are placed on the transparent film via methanol. As the number of sheets is less than the number of sheets, the overlapping graphene clusters are formed. For this reason, a transparent film having the shape of the bottom surface of the container is placed on the bottom surface of the container, and the suspension produced by the above-described production method is added to the container in an amount necessary for producing the transparent conductive substrate. After that, the container is repeatedly subjected to vibration acceleration in three directions: back and forth, left and right, and up and down, and a group of graphene in which the flat surfaces of the graphene are overlapped with each other via methanol is formed on the transparent film. That is, since the thickness of graphene is extremely thin, the aspect ratio, which is the ratio of the surface area to the thickness, is extremely large. Also, graphene is extremely thin and has almost no mass. When vibration acceleration in three directions is applied to a suspension in which graphene aggregates with these characteristics are precipitated in methanol, the graphene moves in methanol with the flat surface facing up, and the graphene diffuses throughout the container. , flat planes overlap each other through methanol. When the application of vibration to the container is stopped, a group of graphene in which the flat surfaces are overlapped with each other via methanol is formed on the transparent film. Note that the vibration acceleration applied to the container is approximately 0.2 G because graphene is extremely lightweight. Further, when forming a transparent conductive substrate having the shape of the bottom surface on the bottom surface of the container, the number of graphene sheets is set to less than 7 so that the transparent conductive substrate has transparency superior to that of ITO. are superimposed on each other. Therefore, in forming the transparent conductive substrate, the amount of the suspension to be filled in the container is determined in advance. This solved the second problem among the five problems described in paragraph 9.
Thirdly, flat surfaces of graphene are bonded to each other to form a graphene bonded body, and the graphene bonded body is thermocompression bonded to a synthetic resin transparent film. For this reason, after evaporating methanol from the container, a plate material having the size of a cluster of graphene is placed on the cluster of graphene, the cluster of graphene is evenly compressed, and the container is placed at the Vicat softening temperature of the synthetic resin. The temperature rises to At this time, when the methanol evaporates from the suspension, a group of graphenes in which the flat surfaces overlap each other is formed on the transparent film. Next, frictional heat is generated at the portion where the flat surfaces of graphene overlap each other, and the flat surfaces of graphene are bonded by the frictional heat, and the graphene bonded body in which the flat surfaces of graphene overlap and are bonded is softened and transparent. Crimp to film. After that, the container is repeatedly subjected to vibration acceleration in three directions: back and forth, left and right, and up and down, so that the transparent conductive substrate in which the graphene bonded body is thermocompression bonded to the synthetic resin transparent film is separated from the container, and the transparent conductive substrate is separated . is removed from the container. The vibration acceleration applied to the container is about 0.2G.
In other words, the breaking strength of graphene is 42 N/m, which is a tough material having a strength exceeding 100 times that of steel. Therefore, even if excessive compressive stress is applied to the upper planes of graphene clusters, the flat planes of graphene will not deform or break. In contrast, the synthetic resin that forms the transparent film has a high compressive strength. For example, it is 19-25 MPa for high-density polyethylene resin. 1 MPa corresponds to 9.8 kg force/mm ² , which corresponds to the compressive strength when a 9.8 kg load is placed on a small area of 1 mm ² . Therefore, even a high-density polyethylene resin having a relatively low compressive strength among synthetic resins constituting a transparent film has a compressive strength close to at least 186 kg weight/mm ² . The compressive strength of other synthetic resins that form transparent films is 55-89 MPa for polyvinyl chloride resin, 140-190 MPa for polyvinylidene chloride resin, 38-55 MPa for polypropylene resin, 76-103 MPa for polyethylene terephthalate resin, and polycarbonate. 69-86 MPa for resin, 82-89 MPa for polystyrene resin, 73-125 MPa for polymethylmethacrylate resin, 276 MPa for polysulfone resin, 81-108 MPa for polyethersulfone resin, and 140 MPa for polyetherimide resin, all of which are high-density polyethylene resins. Higher compressive strength. Therefore, even with a high-density polyethylene resin having a low compressive strength, the transparent film will not break if the load is 186 kg or less with respect to an area of 1 mm ² . Therefore, even if a large compressive stress is applied when flat surfaces of graphene are bonded together, the transparent film of synthetic resin is not destroyed.
On the other hand, when the temperature of a thermoplastic resin is raised, the Vicat softening temperature is a measure of the temperature at which the thermoplastic resin begins to soften rapidly. The Vicat softening temperature is 70-80° C. for high-density polyethylene resin, 80-100° C. for polypropylene resin, 70-85° C. for polyvinyl chloride resin, 85-100° C. for polystyrene resin, and 90° C. for polymethyl methacrylate resin. -110°C and 142-146°C for polycarbonate resin. Both are higher than 65°C, which is the boiling point of methanol. Therefore, when the temperature is raised to the Vicat softening temperature, the transparent film begins to soften, and the softened transparent film is pressed against the graphene conjugate due to compressive stress.
This solved the 3rd and 4th problems out of the 5 problems described in paragraph 9. The vaporized methanol is collected by a collector and reused.
By the way, methanol used for producing graphene conjugates is an inexpensive industrial chemical. Graphite particles are also an inexpensive industrial material. Also, the above three steps consist of extremely simple processes. Therefore, according to the present method, when inexpensive graphite particles and methanol are used and extremely simple three steps are continuously performed, the graphene bonded body is thermocompression bonded to the transparent film. This solved the 5th problem out of the 5 problems described in paragraph 9, and solved all the problems.
The graphene conjugate produced by the method described above has the following effects.
First, since the transparent conductive substrate is manufactured to have the shape of the bottom surface of the container, the shape and area of the transparent conductive substrate can be freely changed according to the shape of the bottom surface of the container. Therefore, there are no restrictions on the area and shape of the transparent conductive substrate, and it can be used as a general-purpose transparent conductive substrate.
Second, the graphene bonded body forming one surface of the transparent conductive substrate is composed only of graphene. Therefore, it has transparency, thermal conductivity, and electrical conductivity equivalent to those of graphene, and also has an antistatic function, an electromagnetic wave shielding function, and a heat dissipation function.
Third, the roughness of the surface of the graphene conjugate is only 0.332 nm of the thickness of graphene, which is close to a perfect plane. Therefore, one surface of the transparent conductive substrate exhibits super water repellency with a contact angle close to 180 degrees, and this surface has both water repellency, oil repellency, and antifouling properties.
Fourth, since the graphene conjugate has a thickness of only 2.3 nm or less and is transparent, it is difficult to identify the presence of the graphene conjugate with the naked eye. However, a transparent conductive substrate obtained by thermocompression bonding a transparent film to a graphene conjugate can be handled manually.
Here, in the first treatment, the interlayer bonding of the basal plane composed of graphite crystals forming graphite particles that are squeezed into the gap between the two parallel plate electrodes by an electric field applied across the gap between the two parallel plate electrodes. explain the phenomenon of destruction at the same time.
A carbon atom forming a graphite crystal in a graphite particle has four valence electrons. Three of these valence electrons are the σ electrons that form the basal plane, ie graphene. The σ electrons are covalently bonded to the σ electrons of three adjacent carbon atoms on the basal plane at an angle of 120 degrees to form a two-dimensional strong hexagonal network structure. The remaining one valence electron is a π electron and exists on a π orbital extending in a direction perpendicular to the basal plane. These π electrons bond with π electrons of carbon atoms adjacent in the vertical direction perpendicular to the basal plane with weak bonding force, and the basal plane is layered on the basis of this weak bonding force. That is, the basal planes, that is, graphene, are bonded to each other in layers by the interaction of π orbitals, which are weak bonding forces. For this reason, the graphite particles have the property of being easily peeled off at the base surface composed of graphite crystals, that is, they have mechanical anisotropy. This mechanical anisotropy is well known as the lubricity of graphite particles.
When an electric field is applied to such graphite particles, a Coulomb force due to the electric field acts on all π electrons. When the Coulomb force acting on the π-electrons acts on the π-electrons as a larger force than the π-orbital interaction acting on the π-electrons, the π-electrons are released from the π-orbital restraint. As a result, all π electrons leave the π orbit and become free electrons. As a result, all the .pi.-electrons responsible for the interlayer bonds on the basal plane are no longer on the .pi.-orbitals, so that all the interlayer bonds on the basal plane are destroyed at the same time. That is, when the π electrons move by the Coulomb force F over the interlayer distance b on the basal plane, the π electrons perform work W (W=b·F). This work W is 35 milli-electron volts, which is the magnitude of the interaction of the π-orbital per atom acting on the π-electron (electron-volt is a unit that expresses the magnitude of the energy possessed by an electron, and 1 electron-volt is 1. (corresponding to 62×10 ⁻¹⁹ joules), the π-electrons are released from the constraints of the π-orbital interactions and become free electrons. For example, when the gap between two parallel plate electrodes is 100 μm and a DC potential difference of 10.6 kilovolts or more is applied to the gap between the electrodes, the interlayer bond on the basal plane is destroyed instantly. In this way, a large amount of graphene can be produced inexpensively by a very simple means of applying an electric field to a group of inexpensive graphite particles. Also, since all of the interlayer bonds on the basal plane are broken at the same time, the resulting fine material is reliably graphene, the basal plane made of graphite crystals.
The term "aggregate of graphite particles" as used herein refers to an aggregate of relatively small amounts of graphite particles of about 1 g to 100 g. That is, flake graphite particles or massive graphite particles are fine particles having a bulk density of 0.2-0.5 g/cm ³ and a particle size distribution of 1-300 microns. Therefore, it is easy to draw a group of graphite particles into the gap between the two parallel plate electrodes, and it is also easy to apply a potential difference between the two parallel plate electrodes. When a potential difference is applied across the gap between the two parallel plate electrodes, an electric field is generated in all areas where the graphite particles are pulled together. This electric field acts on the π-electrons as a Coulomb force greater than the π-orbital interaction, and the π-electrons are released from the π-orbital restraints and become free electrons. As a result, all of the basal plane interlayer bonds in the graphite particles are broken simultaneously, producing clusters of graphene in the gap between the two parallel plate electrodes.
Now, arithmetically determine the number of graphenes dispersed in the suspension. Here, we assume that all graphite particles consist of spheres with a diameter of 25 microns, and since the true density of graphite is 2.25×10 ³ kg/m ³ , the weight of one graphite particle is is only 1.84×10 ⁻⁸ g. In addition, assuming that the average thickness of graphite particles is 10 microns, the interlayer distance is 3.354 angstroms, so 297,265 graphenes are stacked in a scale-like graphite particle having a thickness of 10 microns. . Therefore, by breaking all the basal plane interlayer bonds, 297,265 graphene clusters can be obtained from just one spherical graphite particle. For this reason, when all the interlayer bonds on the basal plane are broken for a mass of only 1 g of spherical graphite particles, a mass of graphene consisting of 1.62×10 ¹³ particles is obtained. Therefore, according to this production method, a huge number of graphene aggregates can be obtained from a small amount of aggregates of graphite particles.

The method of forming a transparent electrode on the surface of the transparent conductive substrate produced by the method described in paragraph 10 includes:
A metal compound that deposits a metal having a refractive index of 0.4 or more and 2.4 or less in the wavelength region of visible light by thermal decomposition is dispersed in methanol, and the metal compound is dispersed in the methanol in a molecular state. create a dispersion,
A first property of being soluble or miscible with the methanol, a second property having a viscosity higher than that of the methanol, a third property having a melting point lower than 20°C, and a boiling point lower than the thermal decomposition temperature of the metal compound. mixing an organic compound having the fourth property with the methanol dispersion to prepare a mixture in which the organic compound is uniformly mixed with the methanol dispersion;
The mixed solution is applied or printed on the surface of the graphene bonded body constituting the transparent conductive substrate produced by the method described in paragraph 10, and the transparent conductive substrate is heat-treated to thermally decompose the metal compound. Then, by this, the first feature consisting of a metal having a refractive index in the wavelength region of visible light of 0.4 or more and 2.4 or less, and the granular particle size of which is one order of magnitude smaller than the wavelength of visible light A group of fine metal particles made of fine particles and having the second characteristic are deposited all at once on the surface of the graphene bonded body to which the mixed solution is applied or printed, and the metal fine particles are metallically bonded at the sites where they are in contact with each other, The aggregate of the metal fine particles that are metal-bonded is formed on the surface of the graphene bonded body to which the mixed solution is applied or printed.
After that, the surface of the graphene bonded body on which the collection of the metal fine particles is formed is uniformly compressed to plastically deform the collection of the metallically bonded fine metal particles, and the collection of the plastically deformed metal fine particles transforms into the graphene Frictional heat is generated at a portion in contact with the surface of the joined body, and by the frictional heat, the aggregation of the plastically deformed metal fine particles is joined to the surface of the graphene joined body, whereby the transparent conductive substrate is formed. A method of forming a transparent electrode on the surface of a transparent conductive substrate produced by the method described in paragraph 10, wherein a transparent electrode composed of a collection of the metal fine particles is formed on the surface of the graphene bonded body.

That is, the method of forming a transparent electrode composed of a collection of metallically bonded fine metal particles on a graphene bonded body, which is one surface of a transparent conductive substrate, comprises the following five steps.
First, a metal compound having a refractive index in the wavelength range of visible light of 0.4 or more and 2.4 or less is dispersed in methanol, and the metal compound is dispersed in methanol in a molecular state. and liquefy the raw material of the metal fine particles.
Second, an organic compound having the four properties is mixed with a methanol dispersion to prepare a mixture in which the organic compound and the methanol dispersion are uniformly mixed.
Thirdly, the mixed liquid is applied or printed on the portion where the transparent electrode is to be formed on the graphene bonded body, which is one surface of the transparent conductive substrate, to form a coating or printed film with a thickness corresponding to the viscosity of the mixed liquid. to form The viscosity of the mixed liquid can be freely changed according to the viscosity of the organic compound and the concentration of the organic compound in the mixed liquid, and the thickness of the coating film or the printed film can be freely changed. Furthermore, if the viscosity of the mixed liquid is reduced, there is no restriction on the shape and line width of the printed film during screen printing. In addition, there is no restriction on the shape and size of the coating film or the printed film, and there is no restriction on the shape and size of the collection of metal fine particles bonded to the graphene bonded body, that is, the transparent electrode.
Fourth, the coating or printed film is heat-treated to thermally decompose the metal compound. At this time, the following phenomenon occurs as the temperature rises. First, when the boiling point of methanol is reached, methanol evaporates from the coating or print film. At this time, since the metal compound is dispersed in methanol but not in the organic compound, the fine crystals of the metal compound are precipitated all at once in the organic compound, and the fine crystals are uniformly precipitated in the organic compound in the coating or printing film. become turbid. Next, when the boiling point of the organic compound is reached, the organic compound is vaporized from the coating or printed film. The vaporized organic compound is recovered and reused. As a result, the coating film or printing film becomes a collection of fine crystals of the metal compound. The size of fine crystals is close to the size of fine metal particles of 40 to 60 nm deposited by thermal decomposition of metal compounds. Furthermore, when the metal compound reaches a temperature at which it thermally decomposes, the fine crystals are thermally decomposed, and the fine crystals of the metal compound are decomposed into an inorganic substance or an organic substance and a metal. A collection of fine metal particles having a first feature of being granular fine particles and a second feature of being made of a metal having a property that the refractive index in the wavelength region of visible light is 0.4 or more and 2.4 or less , precipitate all at once on the graphene bonded body on which the coating film or the printed film is formed. The metal fine particles are precipitated in an active state without impurities, and are metallically bonded at the sites where the metal fine particles are in contact with each other, forming a group of metallically bonded metal fine particles in the graphene conjugate. As a result, the collection of metal fine particles has transparency and conductivity.
Fifth, evenly compressing the upper plane of the graphene bonded body on which a collection of metal fine particles is formed, plastically deforming the collection of metal fine particles, and the plastic deformation of the collection of metal fine particles is Frictional heat is generated at the portion that contacts the graphene bonded body, and the frictional heat bonds the plastically deformed metal fine particle assembly to the graphene bonded body. As a result, a collection of metallically bonded metal fine particles is bonded to the graphene bonded body, and a transparent electrode made of the collection of metal fine particles is bonded to the surface of the graphene bonded body. Note that the fine metal particles are made of an intrinsic metal with no impurities, and the graphene bonded body is also an intrinsic substance with no impurities, so the fine metal particles are firmly bonded to the graphene bonded body.
All of the above-described processes for bonding the collection of metal fine particles to the graphene bonded body are extremely simple, and the materials used are inexpensive industrial chemicals. As a result, an inexpensive transparent conductive base material can be joined to a group of fine metal particles by an inexpensive method, an inexpensive transparent electrode can be formed on the transparent conductive base material, and the transparent conductive base material can be used for various purposes. can be used for
If the synthetic resin transparent film does not thermally decompose at the temperature at which the metal compound thermally decomposes, the transparent film will not irreversibly change and will maintain its original physical properties. A transparent electrode consisting of a collection of metallically bonded fine metal particles can be formed on the joined body. For this reason, a transparent film made of a synthetic resin having a higher thermal decomposition temperature than the thermal decomposition temperature of the metal compound is used.
The transparent electrode formed on the transparent conductive substrate described above provides the following effects.
First, since the raw material of the metal fine particles deposited by thermal decomposition is made into a paint, there is no restriction on the size and shape of the collection of metal fine particles to be bonded to the graphene bonded body, that is, the transparent electrode. In addition, the viscosity of the paint can be freely adjusted, and there are no restrictions in applying or printing the paint.
Second, the fine metal particles are precipitated as true metal with no impurities. On the other hand, from the time the graphene conjugate is taken out of the container until the liquid mixture is applied to the surface of the graphene conjugate, low-boiling-point impurities such as water molecules, hydroxyl groups, and organic substances may adhere to the surface of the graphene conjugate. . However, during the vaporization of methanol from the coating or printing film, followed by the vaporization of the thermal decomposition product of the metal compound, these impurities vaporize in the order of their boiling points, and the graphene conjugate is produced in the container as it was. , reverts to a pure substance without impurities. In addition, when the methanol and the thermal decomposition product of the metal compound are vaporized, the part where the coating film or the printed film is formed has a relatively positive pressure from the outside, so the coating film or the printed film is not formed. Impurities do not enter and re-adsorb to the surface of the graphene conjugate. Therefore, the collection of metal fine particles made of intrinsic metal is strongly bonded to the graphene bonded body made of intrinsic material.
Third, in the visible light wavelength region, the refractive index of metal is 0.4 or more and 2.4 or less, which is close to the refractive index of air 1, so that 70% or more of visible light is metal-bonded fine metal particles. incident on a collection of In addition, since the size of the fine metal particles is one order of magnitude smaller than the wavelength of the visible light, the visible light is not scattered in the collection of the fine metal particles and passes through the collection of the fine metal particles with high transparency. As a result, a collection of metallically bonded fine metal particles constitutes a transparent electrode.
Fourth, by using inexpensive materials and an inexpensive method, a collection of metal-bonded fine metal particles can be bonded to the graphene conjugate, and an inexpensive transparent electrode can be formed on the surface of the graphene conjugate.
As described above, according to this method, a transparent electrode can be formed on the surface of a transparent conductive substrate. As a result, transparent conductive films that can be applied to various applications such as transparent conductive films for touch panels, flexible circuit boards, transparent conductive films for organic EL, transparent conductive films for organic thin-film solar cells, and flexible LED conductive films are inexpensive. can be manufactured to
The surface reflectance and total light transmittance of visible light in a collection of metal-bonded fine metal particles will be described in paragraph 14 below, and the scattering of light in a collection of metal fine particles will be described in paragraph 15 below. .

Here, surface reflectance and total light transmittance will be explained. When light enters the base material, surface reflection occurs depending on the difference in refractive index between air and the base material. Therefore, even transparent glass causes loss due to surface reflection, and the total light transmittance does not reach 100%. Incidentally, a float glass with a thickness of 2 mm has a total light transmittance of about 90% in the visible light wavelength region. The surface reflectance R on the surface of light incident perpendicularly to the base material is calculated by Equation 1, which consists of the refractive index n of the base material and the refractive index m of air. Further, the total light transmittance T is calculated by Equation 2 consisting of the surface reflectance R. Therefore, when the refractive index of the metal is 0.4, the total light transmittance incident on the transparent electrode is 67%, and when the metal refractive index is 2.4, the total light transmittance is 69%, and 70% or more of the visible light enters the conductive layer.
Number 1
R=(nm) ² /(n+m) ²
Number 2
T = (1-R) ²

Next, light scattering will be described. The Rayleigh scattering formula shown in Numerical formula 3 can be applied to the scattering of light when a group of particles is irradiated with visible light. In Expression 3, S is a scattering coefficient that means a scattering ratio, λ is the wavelength of visible light, D is the particle diameter, m is the refractive index of the particle, and π is the circular constant. Therefore, the magnitude of the scattering coefficient S depends on the fourth power of the ratio D/λ of the particle diameter D to the wavelength λ of visible light, and also depends on the square of the particle diameter D and the refractive index m. Since the size D of the fine metal particles is one order of magnitude smaller than the wavelength λ of visible light, the ratio D/λ is small and the particle diameter D is also sufficiently small. Furthermore, the refractive index m of the metal is 0.4 or more and 2.4 or less. Therefore, the scattering coefficient S is extremely small, visible light is not scattered by the collection of metal fine particles, and the transparent electrode composed of the collection of metal fine particles exhibits high transparency.
Number 3
S=4/3·π ⁵ /λ ⁴ ·D ⁶ {(m ² −1)/(m ² +1)} ²

The method of forming a transparent electrode on the surface of the transparent conductive substrate described in paragraph 12 includes:
The metal compound described in paragraph 12 is a metal compound that deposits nickel or aluminum by thermal decomposition, and the metal compound is used as the metal compound described in paragraph 12, and according to the method described in paragraph 12, transparent conductive The method of forming a transparent electrode on the surface of a transparent conductive substrate according to paragraph 12, wherein the transparent electrode is formed on the surface of the substrate.

In other words, nickel or aluminum has a refractive index of 0.4 or more and 2.4 or less in the visible light wavelength region (380 to 750 nm), and 70% or more of the visible light is a collection of the above metal-bonded metal fine particles. incident on. In addition, the size of the fine particles made of nickel or aluminum is one order of magnitude smaller than the wavelength of visible light, and the scattering coefficient S of the visible light in the group of metal-bonded metal fine particles is extremely small. , does not scatter visible light and exhibits high transparency. As a result, a collection of metallically bonded fine metal particles forms a transparent electrode.
That is, the refractive index of nickel is 1.61 at 380 nm and increases with increasing wavelength to 1.75 at 539 nm, 2.21 at 709 nm, 2.28 at 729 nm and 2.34 at 750 nm. On the other hand, light rays are reflected on the surface of the aggregate of nickel fine particles due to the difference in refractive index between air and nickel. At this time, the light transmittance is 89% at 380 nm, 86% at 539 nm, 74% at 709 nm, 72% at 729 nm, and 70% at 750 nm. Also, the size of the nickel fine particles is one order of magnitude smaller than the wavelength of visible light. Therefore, part of the red visible light component is reflected by the surface of the nickel fine particle cluster, but the light ray entering the nickel fine particle cluster passes through the nickel fine particle cluster without being scattered. Therefore, the aggregate of nickel fine particles exhibits transparency.
Also, the refractive index of aluminum has a maximum of 2.80 at 800 nm and decreases sharply with decreasing wavelength to 2.40 at 750 nm, 1.91 at 708 nm, closest to the refractive index of air at 560 nm and 1 at 450 nm. 0.620 and 0.45 at 380 nm. On the other hand, light rays are reflected by the difference in refractive index between air and aluminum on the surface of the cluster of aluminum fine particles. At this time, the light transmittance is 69% at 750 nm, 81% at 708 nm, 100% at 560 nm, 89% at 450 nm, and 73% at 380 nm. Also, the size of the aluminum fine particles is one order of magnitude smaller than the wavelength of visible light. For this reason, part of the red and violet visible light rays is reflected on the surface of the cluster of aluminum fine particles, but the light that has entered the cluster of aluminum fine particles passes through the cluster of aluminum fine particles without being scattered. Therefore, the aggregate of aluminum fine particles exhibits transparency.
As explained above, when the metal is aluminum, part of the light rays that constitute the red and violet visible light rays are reflected by the surface of the aluminum fine particles, and when the metal is nickel, red light rays are reflected. A part of the visible light is reflected on the surface of the nickel fine particles and emits a color corresponding to these light rays, but the metal fine particles do not scatter visible light and are transparent.
Furthermore, the collection of fine particles of nickel or aluminum provides the following effects based on the size and material of the fine particles.
First, irregularities are formed on the surface based on the size of the metal fine particles. Since the number of fine metal particles forming the surface is enormous, the total surface area of the irregularities on the surface has an enormous surface area and becomes a surface close to a so-called fractal surface. When a droplet comes into contact with such a surface, the surface tension of the droplet prevents the liquid from entering the irregularities of the size of the metal microparticles, and the liquid surface of the droplet comes into point contact with an enormous number of protrusions of the microparticles. . As a result, the surface of the transparent electrode exhibits superhydrophobicity with a contact angle close to 180 degrees, and the surface is provided with water repellency, oil repellency, and antifouling properties.
Second, it has electrical and thermal conductivity similar to that of nickel or aluminum. Therefore, the transparent electrode has an antistatic function, an electromagnetic wave shielding function, and a heat dissipation function.

The method of forming a transparent electrode on the surface of the transparent conductive substrate described in paragraph 12,
The metal compound described in the 12th paragraph is a complex composed of an inorganic metal compound having a metal complex ion in which a ligand composed of an inorganic molecule or an inorganic ion is coordinated to a metal ion, and in the 12th paragraph The organic compound described is any one organic compound belonging to carboxylic acid esters, glycols or glycol ethers, and using these two substances, according to the method described in paragraph 12, transparent conductive Forming a transparent electrode on the surface of a base material is the method of forming a transparent electrode on the surface of a transparent conductive base material described in paragraph 12.

That is, a complex composed of an inorganic metal compound is thermally decomposed at a relatively low temperature of 180° C. to 220° C. in a reducing atmosphere to deposit a metal. Moreover, it is dispersed in methanol, which is the most commonly used alcohol, at a ratio close to 10% by weight. Therefore, the complex composed of the inorganic metal compound becomes a raw material for producing the liquid mixture described in the 12th paragraph.
That is, when a complex composed of an inorganic metal compound having a metal complex ion in which a ligand composed of an inorganic molecule or an inorganic ion is coordinated to a metal ion is heat-treated in a reducing atmosphere, the coordinate bond is first broken. and decomposes into inorganic substances and metals. When the temperature is further increased, the inorganic matter takes the heat of vaporization and vaporizes, and after the vaporization of all the inorganic matter is completed, the metal precipitates. In other words, among the ions forming the complex, the metal ion located in the center of the molecule is the largest. Therefore, the distance between the metal ion and the ligand is the longest. Therefore, when the complex is heat-treated in a reducing atmosphere, the coordinate bond site where the metal ion bonds with the ligand is first cleaved and decomposed into the metal and the inorganic material. When the temperature rises further, the inorganic material takes the heat of vaporization and vaporizes, and after the vaporization is completed, the metal precipitates. At this time, since the inorganic material has a low molecular weight, the vaporization of the inorganic material is completed at a low temperature of 180-220° C. according to the molecular weight of the inorganic material. Examples of such a complex include a complex composed of an inorganic metal compound having an ammine metal complex ion coordinately bonded to a metal ion with ammonia NH ₃ as a ligand, a chloride ion Cl ⁻ , or a chloride ion Cl ⁻ and ammonia NH 3 − . A complex composed of an inorganic metal compound having a chlorometal complex ion in which ₃ becomes a ligand and coordinates to a metal ion, and a cyano metal in which a cyano group CN- becomes a ligand ion ^and coordinates to a metal ion. A complex composed of an inorganic metal compound having a complex ion, a complex composed of an inorganic metal compound having a bromo metal complex ion in which the bromine ion Br- serves as a ligand ion ^and is coordinated to the metal ion, ^and an iodide ion I- is coordinated. There is a complex made of an inorganic metal compound having an iodine metal complex ion that becomes a child ion and coordinates with a metal ion. Moreover, such a complex composed of an inorganic metal compound having a small molecular weight is a metal complex having a metal complex ion that is easy to synthesize and is the cheapest.
In addition, the carboxylic acid esters, glycols or glycol ethers have a first property of dissolving or being miscible with methanol, a second property of having a viscosity higher than that of methanol, and a melting point lower than 20°C. There are organic compounds that have the third property and the fourth property that the boiling point is lower than the thermal decomposition temperature of the complex of the inorganic metal compound. All such organic compounds are general-purpose industrial chemicals. Therefore, such an organic compound is an inexpensive raw material for producing the mixed liquid described in the 12th paragraph.
Therefore, when any one of the above organic compounds is mixed with a methanol dispersion of a complex composed of an inorganic metal compound, the complex and the organic compound are uniformly mixed in a molecular state to produce a large amount of mixed liquid. As a result, a complex consisting of an inorganic metal compound, which is an inexpensive industrial chemical, methanol, which is the most commonly used alcohol, and an organic compound, which is a commonly used industrial chemical, are used as raw materials, and the 12 paragraphs are obtained at a low cost. is prepared.
It should be noted that many of the synthetic resins forming the transparent film do not thermally decompose at a temperature of 180° C.-220° C. in a reducing atmosphere. For this reason, a ligand composed of inorganic molecules or ions thermally decomposes a complex composed of an inorganic metal compound having a metal complex ion coordinately bonded to a metal ion composed of nickel or aluminum, thereby irreversibly changing the transparent film. A transparent electrode is formed on the surface of the transparent conductive base material without causing the formation of the transparent electrode. In other words, once the synthetic resin begins to thermally decompose, the molecular structure of the polymer undergoes an irreversible change, and the physical properties of the synthetic resin cannot be restored. Therefore, unless thermal decomposition of the synthetic resin is initiated by the thermal decomposition of the complex composed of the inorganic metal compound, a transparent electrode is formed on the surface of the transparent conductive substrate without irreversibly changing the transparent film.

The method of forming a transparent electrode on the surface of the transparent conductive substrate described in paragraph 12 includes:
The metal compound described in paragraph 12 has the first feature that the oxygen ion that constitutes the carboxyl group in the carboxylic acid is covalently bonded to the metal ion, and the second feature that the carboxylic acid is composed of a saturated fatty acid. The organic compound described in paragraph 12 is any one of carboxylic acid esters, glycols, or glycol ethers, and these two kinds of substances are used to obtain 12 The method of forming a transparent electrode on the surface of a transparent conductive substrate according to paragraph 12, wherein the transparent electrode is formed on the surface of the transparent conductive substrate according to the method described in paragraph 12.

That is, the carboxylic acid metal compound having two characteristics completes thermal decomposition at 290 to 430° C. in the air atmosphere and deposits the metal. Moreover, it disperses at a concentration close to 10% by weight in methanol, which is the most commonly used alcohol. Therefore, the metal carboxylate compound is used as a raw material for producing the mixed liquid described in the 12th paragraph. The thermal decomposition temperature of the metal octylate compound is 290° C. in the atmosphere, which is the lowest thermal decomposition temperature among the metal carboxylate compounds. That is, since the boiling point of octylic acid is the lowest among carboxylic acids, the thermal decomposition temperature of metal octylate compounds is the lowest. On the other hand, the thermal decomposition temperature of the metal octylate compound in a nitrogen atmosphere is 340° C., which is 50° C. higher than in the atmosphere.
That is, in a carboxylic acid metal compound having both the first feature that the oxygen ion constituting the carboxyl group of the carboxylic acid is covalently bonded to the metal ion and the second feature that the carboxylic acid is a saturated fatty acid, the metal ion is The distance between the oxygen ion, which is the largest ion and constitutes the carboxyl group, and the metal ion is longer than the distance between other ions. When a metal carboxylate compound with such molecular structural features is heat-treated in an air atmosphere, when the boiling point of the carboxylic acid is exceeded, the bond between the oxygen ion and the metal ion constituting the carboxyl group is first cleaved, and the carboxylic acid and separate from the metal. Furthermore, when the carboxylic acid is composed of a saturated fatty acid, it does not have an unsaturated structure in which carbon atoms are in excess of hydrogen atoms. It takes away and vaporizes, and when the vaporization is complete, the metal deposits. Such metal carboxylate compounds include metal octylate compounds, metal laurate compounds, metal stearate compounds, and the like. The boiling point of octylic acid is 228°C, the boiling point of lauric acid is 296°C, and the boiling point of stearic acid is 361°C. Therefore, these carboxylic acid metal compounds are completely thermally decomposed in an air atmosphere at 290-430°C. It also disperses in methanol at a rate close to 10% by weight. The thermal decomposition of the metal carboxylate compound in the nitrogen atmosphere shifts to the high temperature side of about 50°C.
Furthermore, carboxylic acid metal compounds are inexpensive industrial chemicals that can be easily synthesized. That is, when a carboxylic acid, which is the most commonly used organic acid, is reacted with a strong alkali, an alkali metal carboxylate compound is produced, and when an alkali metal carboxylate is reacted with an inorganic metal compound, a metal carboxylate is synthesized. be. Therefore, it is the most inexpensive organometallic compound among organometallic compounds. Therefore, although the heat treatment temperature is higher than that of the complex made of the inorganic metal compound described in the 16th paragraph, the metal compound is cheaper than the complex.
In addition, carboxylic acid esters, glycols or glycol ethers have a first property of dissolving or being miscible with methanol, a second property of having a viscosity higher than that of methanol, and a third property of having a melting point lower than 20°C. and a fourth property whose boiling point is lower than the thermal decomposition temperature of the carboxylic acid metal compound. Such organic compounds are common industrial chemicals. Therefore, such an organic compound is an inexpensive raw material for producing the mixed liquid described in the 12th paragraph.
Therefore, when any one of the organic compounds is mixed with the methanol dispersion of the metal carboxylate compound, the metal carboxylate compound and the organic compound are uniformly mixed in a molecular state to produce a large amount of mixed liquid. As a result, the carboxylic acid metal compound, which is an inexpensive industrial chemical, methanol, which is the most general alcohol, and the organic compound, which is a general industrial chemical, are used as raw materials, and at a low cost, A mixed liquid is produced.
There is a synthetic resin that does not thermally decompose at 340° C. in a nitrogen atmosphere among the synthetic resins that constitute the transparent film. In other words, the thermal decomposition reaction of the polymer that constitutes the synthetic resin is greatly different between the atmosphere in which oxygen gas is present and the atmosphere in which nitrogen gas is present. Thermal decomposition of a polymer in an atmosphere in which oxygen gas is present is accompanied by heat generation because it is thermal decomposition due to an oxidation reaction. This exothermic phenomenon accelerates the thermal decomposition of polymers composed of easily oxidizable organic substances. On the other hand, thermal decomposition in a nitrogen atmosphere does not cause an oxidation reaction, but an endothermic thermal decomposition and no exothermic phenomenon. Therefore, the temperature at which the polymer starts to thermally decompose shifts to the high temperature side with a significant delay compared to the atmosphere in which oxygen gas exists. For example, thermal decomposition of high-density polyethylene resin starts at around 250° C. in an air atmosphere, whereas it starts around 400° C. in a nitrogen atmosphere and shifts to the high temperature side by 150° C. as well. As for the thermal decomposition of other polymers in a nitrogen atmosphere, the thermal decomposition of polystyrene resin begins at 350°C and ends at around 460°C. Thermal decomposition of polyethylene terephthalate resin begins at 425°C and ends at around 480°C. Thermal decomposition of polypropylene resin begins at 370°C and ends at around 500°C. Thermal decomposition of high-density polyethylene resin begins at 400°C and ends at around 520°C. Therefore, if the transparent film is made of a synthetic resin that does not thermally decompose at 340° C. in a nitrogen atmosphere, the transparent electrode can be formed by the thermal decomposition of the metal octylate compound. Therefore, transparent films such as unstretched polypropylene films, stretched polystyrene films, PET films, PES films, PTFE films, and polycarbonate films can be used.

FIG. 2 is a diagram schematically showing an enlarged part of a side surface of a graphene bonded body in which flat planes of graphene overlap each other.

Embodiment 1
This embodiment firstly dissolves or mixes with methanol, secondly has a higher viscosity than methanol, thirdly has a melting point lower than 20° C., and fourthly is either a complex composed of an inorganic metal compound or a metal octylate compound. This embodiment relates to an organic compound having these four properties, the boiling point of which is lower than the temperature at which one of them thermally decomposes.
In other words, if the boiling point of the organic compound is lower than around 180-220° C. at which the inorganic metal compound complex thermally decomposes, the organic compound forms a mixture with the methanol dispersion of the inorganic metal compound complex. If the boiling point of the organic compound is lower than 290° C. at which the metal octylate compound thermally decomposes, it forms a mixture with the methanol dispersion of the metal octylate compound. Therefore, the organic compound becomes a modifier for adjusting the viscosity of the mixed liquid. Many organic compounds having these four properties are organic compounds belonging to carboxylic acid esters, glycols, or glycol ethers.

Carboxylic acid esters are composed of three types: esters with saturated carboxylic acids, esters with unsaturated carboxylic acids, and esters with aromatic carboxylic acids.
Among the acetate esters with low molecular weight among the saturated carboxylic acids is methylcyclohexyl acetate, which has a melting point lower than 20°C, is soluble in methanol, has a viscosity four times that of methanol, and has a boiling point of 182°C. Thus, among acetates with a molecular weight lower than that of methylcyclohexyl acetate, there are acetates with a melting point lower than 20°C, are soluble in methanol, have a higher viscosity than methanol, and have a boiling point lower than 180°C.
Methyl laurate is an ester of methanol and lauric acid, which has a large molecular weight among saturated fatty acids. Methyl laurate has a melting point below 20°C, is soluble in methanol, has a viscosity 4.4 times that of methanol, and has a boiling point of 262°C. Therefore, among the saturated fatty acid esters having a molecular weight greater than that of methylcyclohexyl acetate and less than that of methyl laurate, there are esters that are soluble in methanol, have a higher viscosity than methanol, and have a boiling point of less than 290°C.
On the other hand, butyl acrylate, which has twice the viscosity of methanol and a boiling point of 148°C, and 2-ethylhexyl acrylate, which has a boiling point of 214°C and twice the viscosity of methanol, are added to acrylic esters, which are unsaturated carboxylic acids with a small molecular weight. and so on. All of them have a melting point lower than 20°C and dissolve in methanol.

Glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol and tripropylene glycol.
Ethylene glycol is a liquid monomer that has a melting point lower than 20°C, is soluble in methanol, has a viscosity as high as 36 times that of methanol, and has a boiling point of 197°C. Diethylene glycol is a liquid monomer that has a melting point lower than 20°C, is soluble in methanol, has a viscosity as high as 61 times that of methanol, and has a boiling point of 244°C. Propylene glycol is a liquid monomer that has a melting point lower than 20°C, is miscible with methanol, has a viscosity 82 times higher than that of methanol, and has a boiling point of 188°C. Dipropylene glycol is a liquid monomer that is miscible with methanol, has a viscosity as high as 127 times that of methanol, and has a boiling point of 232°C. Tripropylene glycol is a liquid monomer that is miscible with methanol, has a viscosity as high as 97 times that of methanol, and has a boiling point of 265°C. In addition, since a polymerization inhibitor or a polymerization inhibitor is added to such a liquid monomer to prevent the polymerization reaction from being caused by light or heat, the polymerization reaction does not occur even when the temperature is raised.

Glycol ethers include ethylene glycol-based ethers, propylene glycol-based ethers, and dialkyl glycol ethers obtained by substituting terminal hydrogens of ethylene glycol, diethylene glycol, and triethylene glycol with alkyl groups.
Among ethylene glycol-based ethers, glycol ethers with a melting point lower than 20°C, soluble in methanol, and a boiling point lower than the thermal decomposition temperature of a complex composed of an inorganic metal compound, have a viscosity three times that of methanol and a boiling point of 125°C. isopropyl glycol, which is five times more viscous than methanol and has a boiling point of 142°C; butyl glycol, which is six times more viscous than methanol and has a boiling point of 171°C; isobutyl glycol, which is five times more viscous than methanol and has a boiling point of 161°C; is four times that of methanol and has a boiling point of 159°C, methyldiglycol is 6.6 times that of methanol and has a boiling point of 194°C, and hexyl glycol is 8.8 times that of methanol and has a boiling point of 208°C. do.
Among ethylene glycol-based ethers, glycol ethers having a melting point lower than 20°C, being soluble in methanol, and having a boiling point lower than the thermal decomposition temperature of the metal octylate compound have a viscosity 12.7 times that of methanol and a boiling point. Methyl triglycol with a viscosity of 249° C., isopropyl diglycol with a viscosity 8.3 times that of methanol and a boiling point of 207° C., butyl diglycol with a viscosity 11 times that of methanol and a boiling point of 231° C., viscosity 13.7 times that of methanol. Butyl triglycol with a boiling point of 271° C., isobutyl diglycol with a viscosity of 8.8 times that of methanol and a boiling point of 220° C., hexyl diglycol with a viscosity of 14.6 times that of methanol and a boiling point of 259° C., viscosity of 12.0° C. of methanol. 2-ethylhexyl glycol with a boiling point of 229° C. 9 times that of methanol; 2-ethylhexyl diglycol with a viscosity of 17.6 times that of methanol and a boiling point of 272° C.; There is benzyl glycol which is 20 times more than methanol and has a boiling point of 256°C. Benzyldiglycol, which has a viscosity 33 times that of methanol and a boiling point of 302° C., dissolves in methanol and has a boiling point higher than the thermal decomposition temperature of the metal octylate compound.
Next, among propylene glycol ethers, glycol ethers with a melting point lower than 20°C, soluble in methanol, and a boiling point lower than the thermal decomposition temperature of a complex composed of an inorganic metal compound have a viscosity 3.2 times that of methanol. Methylpropylene glycol with a boiling point of 121°C at , Methylpropylene glycol acetate with a viscosity 2.2 times that of methanol and a boiling point of 146°C, Propylpropylene glycol with a viscosity 4.7 times that of methanol and a boiling point of 150°C, Viscosity of methanol There is butylpropylene diglycol which is 5.8 times the viscosity of methanol and has a boiling point of 170°C, and methylpropylene diglycol which is 6.9 times the viscosity of methanol and has a boiling point of 187°C.
Among propylene glycol-based ethers, glycol ethers having a melting point lower than 20°C, being soluble in methanol, and having a boiling point lower than the thermal decomposition temperature of the metal octylate compound have a viscosity 18.3 times that of methanol and a boiling point. Propylpropylene diglycol with a viscosity of 212° C., Butylpropylene diglycol with a viscosity of 12.5 times that of methanol and a boiling point of 231° C., Phenylpropylene glycol with a viscosity of 39.3 times that of methanol and a boiling point of 243° C., A viscosity of 13 that of methanol. There is butyl propylene triglycol with a boiling point of 274°C at 0.9 times.
Finally, among the dialkyl glycol ethers, glycol ethers having a melting point lower than 20°C, being soluble in methanol and having a boiling point lower than the thermal decomposition temperature of the complex composed of inorganic metal compounds, and having a viscosity 1.9 times that of methanol. , dimethyl glycol with a boiling point of 85° C., dimethyl diglycol with a viscosity of 3.4 times that of methanol and a boiling point of 162° C., dimethyl propylene diglycol with a viscosity of 1.9 times that of methanol and a boiling point of 171° C., viscosity is 21 times that of methanol and has a boiling point of 176°C, and diethyldiglycol has a viscosity of 2.4 times that of methanol and a boiling point of 189°C.
Among the dialkyl glycol ethers, glycol ethers with a melting point lower than 20°C, soluble in methanol, and a boiling point lower than the thermal decomposition temperature of the metal octylate compound have a viscosity 6.4 times that of methanol and a boiling point of 216. C. and dibutyl diglycol with a viscosity 4.1 times that of methanol and a boiling point of 255.degree.
As described above, among carboxylic acid esters, glycols, and glycol ethers, there are many organic compounds having the four properties described in paragraph 20.

Embodiment 2
This embodiment is an embodiment of the complex composed of the inorganic metal compound described in paragraph 16. As the metal compound that is thermally decomposed at a low temperature to deposit a metal, a ligand composed of inorganic molecules or ions is a metal ion It is explained that a metal complex having a metal complex ion coordinated to is suitable. That is, since the metal complex has a small inorganic molecular weight, it is thermally decomposed at a relatively low heat treatment temperature in a reducing atmosphere. Here, nickel is used as the metal, and a nickel compound that deposits nickel by thermal decomposition will be described.
First, the nickel compound dispersed in methanol will be described. Nickel sulfate and nickel chloride are soluble in water, nickel ions are dissolved, and many nickel ions cannot participate in nickel deposition. Also, nickel hydroxide and nickel oxide do not disperse in methanol. Therefore, such an inorganic nickel compound having a low molecular weight is not suitable as a raw material for depositing nickel.
Next, a nickel compound that deposits nickel by thermal decomposition will be described. Among the chemical reactions in which nickel is produced from nickel compounds, thermal decomposition is the simplest chemical reaction. In other words, simply by raising the temperature of the nickel compound, the nickel compound is thermally decomposed to deposit nickel. Furthermore, if the thermal decomposition temperature of the nickel compound is low, the heat treatment temperature is low, so that the transparent electrode can be formed at low cost. Inorganic nickel complexes having nickel complex ions coordinately bonded to nickel ions located in the center of the molecular structure with molecules or ions made of inorganic substances as ligands can be thermally decomposed in a reducing atmosphere if the molecular weight of the inorganic substance is small. The temperature at which the reaction is carried out is lower than the temperature at which the organonickel complex in which the organic substance having the higher molecular weight forms the ligand thermally decomposes in the air atmosphere. For this reason, although the inorganic nickel complex is a substance relatively more expensive than the organic nickel complex, it deposits nickel at a lower temperature, so that a transparent electrode can be formed at a low cost.
That is, the nickel ion is the largest among the molecules that constitute the inorganic nickel complex. Incidentally, the covalent radius of nickel atoms is 101 pm, while the covalent radius of nitrogen atoms is 71 pm, and the covalent radius of oxygen atoms is 66 pm. Therefore, in the molecular structure of the inorganic nickel complex, the length of the coordinate bond portion where the ligand bonds to the nickel ion is the longest. Therefore, in the heat treatment in a reducing atmosphere, the coordination bonds are first broken, decomposed into nickel and inorganic substances, and after the inorganic substances are completely vaporized, nickel is precipitated.
Among such inorganic nickel complexes, an ammine complex in which ammonia NH ₃ serves as a ligand and is coordinated to nickel ions, a chloride ion Cl ⁻ , or a chloride ion Cl ⁻ and ammonia NH ₃ are coordinated. A chloro complex that forms a child and coordinates with a nickel ion is relatively easy to synthesize as compared to other nickel complexes, and thus can be produced at a relatively low production cost. In addition, when such an inorganic nickel complex is heat-treated in a reducing atmosphere such as ammonia gas or hydrogen gas, since the molecular weight of the ligand is small, the coordination bond site is first cleaved at a temperature lower than 200 ° C., and then, Nickel deposits at temperatures around 200°C. Furthermore, it is dispersed in methanol to nearly 10% by weight. Such nickel complex ions include, for example, hexaamminenickel ion [Ni(NH ₃ ) ₆ ] ²⁺ , and nickel complexes include, for example, hexaamminenickel chloride [Ni(NH ₃ ) ₆ ]Cl ₂ and hexaammine There is nickel nitrate [Ni( _NH3 ) ₆ ]( _NO3 ) ₂ .

Embodiment 3
In this embodiment, as a second raw material for depositing a metal by thermal decomposition, oxygen ions constituting the carboxyl group of a carboxylic acid are used as a material whose thermal decomposition temperature is higher than that of the complex composed of the inorganic metal compound described above, but which is cheaper than the complex. is suitable for metal carboxylate compounds that combine the first characteristic that is covalently bonded to the metal ion and the second characteristic that the carboxylic acid is a saturated fatty acid. Among metal carboxylate compounds, the metal octylate compound has the lowest thermal decomposition temperature of 290° C. in the atmosphere. On the other hand, the thermal decomposition temperature of the metal octylate compound in a nitrogen atmosphere is 340° C., which is 50° C. higher than in the atmosphere. Here, aluminum is used as the metal, and an aluminum carboxylate compound will be described.
As with the nickel complex described above, an aluminum compound that deposits aluminum by thermal decomposition must firstly disperse in methanol and secondly deposit aluminum by thermal decomposition.
First, an aluminum compound dispersed in methanol will be described. Aluminum chloride is soluble in water and hydrolyzes to aluminum hydroxide and hydrochloric acid. Also, aluminum hydroxide does not disperse in methanol. Furthermore, aluminum sulfate dissolves in methanol and aluminum ions are eluted. Also, aluminum oxide does not disperse in methanol. Therefore, these inorganic aluminum compounds with low molecular weights do not disperse in methanol.
Next, organoaluminum compounds have the property of precipitating aluminum upon thermal decomposition. Among chemical reactions in which aluminum is produced from organoaluminum compounds, thermal decomposition is the simplest chemical reaction. In other words, aluminum is precipitated simply by raising the temperature of the organoaluminum compound. Furthermore, if the organoaluminum compound is easy to synthesize, it can be produced at low cost. An example of an organoaluminum compound having these properties is an aluminum carboxylate compound.
That is, the compositional formula of the aluminum carboxylate compound is represented by Al(COOR) ₃ . R is a hydrocarbon and has a compositional formula of C _m H _n (where m and n are integers). Among the ions that make up the aluminum carboxylate compound, the aluminum ion Al ³⁺ located in the center of the molecule is the largest. Therefore, when aluminum ions Al ³⁺ and oxygen ions O 2 ⁻ that form a carboxyl group are covalently bonded, the distance between aluminum ions Al ³⁺ and oxygen ions O 2 ⁻ becomes maximum. This is because the covalent radius of aluminum ion atoms is 121 pm, the covalent radius of oxygen ion atoms is 66 pm, and the covalent radius of carbon atoms is 73 pm. Therefore, in the aluminum carboxylate compound in which an aluminum ion and an oxygen ion forming a carboxyl group are covalently bonded, at the boiling point of the carboxylic acid, the bond between the aluminum ion having the longest bond distance and the oxygen ion forming the carboxyl group is It is first cleaved and separated into aluminum and carboxylic acid. When the temperature is further increased, if the carboxylic acid is a saturated fatty acid, the carboxylic acid absorbs the heat of vaporization and vaporizes, and aluminum precipitates after the vaporization of the carboxylic acid is completed. Such aluminum carboxylate compounds include aluminum octoate, aluminum laurate, aluminum stearate, and the like. Many of such aluminum carboxylate compounds are inexpensive industrial chemicals marketed as metal soaps.
Furthermore, if the boiling point of the saturated fatty acid is low, the aluminum carboxylate compound will be thermally decomposed at a low temperature, and the heat treatment cost for depositing aluminum will be inexpensive. When the hydrocarbon constituting the saturated fatty acid has a long-chain structure, the longer the chain, that is, the larger the molecular weight of the saturated fatty acid, the higher the boiling point of the saturated fatty acid. Incidentally, the boiling point of lauric acid having a molecular weight of 200.3 at atmospheric pressure is 296°C, and the boiling point of stearic acid having a molecular weight of 284.5 at atmospheric pressure is 361°C.
Furthermore, when the saturated fatty acid is a saturated fatty acid having a branched chain structure, the chain length is shorter and the boiling point is lower than that of the saturated fatty acid having a linear structure. As a result, the aluminum carboxylate compound composed of saturated fatty acid having a branched chain structure is thermally decomposed at a relatively low temperature. Furthermore, since saturated fatty acids with a branched chain structure are polar, aluminum carboxylate compounds composed of saturated fatty acids with a branched chain structure are also polar and disperse in relatively high proportions in polar organic solvents such as methanol. . Octylic acid is a saturated fatty acid with such a branched structure. The boiling point of octylic acid at atmospheric pressure is 228°C, which is 68°C lower than that of lauric acid. Therefore, aluminum octylate, which has a low thermal decomposition temperature, is desirable as a raw material for depositing aluminum. Thermal decomposition of aluminum octylate is completed at 290° C. in an air atmosphere to deposit aluminum, which is dispersed in methanol up to 10% by weight.
In addition, the aluminum carboxylate compound is an organic aluminum compound that is easy to synthesize and inexpensive. That is, when a carboxylic acid is reacted in a strong alkaline solution such as sodium hydroxide, an alkali metal carboxylate compound is produced. When the alkali metal carboxylate compound is reacted with an inorganic aluminum compound such as aluminum sulfate, an aluminum carboxylate compound is produced.
As explained above, since aluminum octylate Al(C ₇ H ₁₅ COO) ₃ has a low thermal decomposition temperature, it is suitable as a raw material for depositing aluminum by thermal decomposition.

Example 1
The present example is an example in which a graphene bonded body in which graphene flat surfaces are overlapped and bonded is formed on the bottom surface of a container.
First, 2 liters of methanol was filled into a shallow container with a base of 1.2 m x 1.2 m.
Next, parallel plate electrodes having an effective area of 1 m × 1 m for generating an electric field in the gap between the two parallel plate electrodes are prepared, and the two parallel plate electrodes are superimposed with a gap of 100 µm. Graphite particles are evenly packed in. Assuming that the graphite particles are spheres with a particle size of 25 μm and the average thickness of the graphite particles is 10 μm, the graphite particles are evenly packed into the 100 μm gap formed by the two parallel plate electrodes. , there are 6.4×10 ⁷ graphite particles. When a DC voltage of 10.6 kilovolts or more is applied to this group of graphite particles, the interlaminar bonds of the basal planes of all the graphite particles are broken at the same time. At this time, a group of 1.9×10 ¹³ graphene particles is obtained, and the group of graphite particles used is only 1.18 g.
For this reason, 5 g of flake graphite particles (eg, XD100 manufactured by Ito Graphite Industry Co., Ltd.) was piled up on the surface of a parallel plate electrode having an effective area of 1 m×1 m to generate an electric field and was tightened. This parallel plate electrode is immersed in a container filled with methanol, the other parallel plate electrode is superimposed on the parallel plate electrode, and the two parallel plate electrodes are separated by a gap of 100 μm, A DC voltage of 12 kilovolts was applied across the electrodes. Next, the gap between the two parallel plate electrodes is widened, the two parallel plate electrodes are tilted in methanol, and a vibration acceleration of 0.2 G in three directions is repeatedly applied to the container. Two parallel plate electrodes were taken out from the . This produced a suspension of graphene clusters deposited in methanol in the vessel.
Furthermore, the container was again repeatedly subjected to three-way vibration acceleration of 0.2 G. The container was then heated to 65° C. to evaporate the methanol. Furthermore, an aluminum plate of 1.2 m × 1.2 m is placed on the upper plane of the sample formed on the bottom of the container, and then a 60 kg weight is placed on the aluminum plate to evenly spread the upper plane of the sample. compressed to After removing the weight and the aluminum plate, the container was subjected to a three-way vibration acceleration of 0.2 G and the sample was removed from the container. An aluminum plate was placed again on the removed sample, and a weight of 20 kg was further placed thereon, but the state of the sample did not change.
Next, the two planes and sides of the sample were observed and analyzed using an electron microscope. As an electron microscope, an ultra-low accelerating voltage SEM manufactured by JFE Techno-Research Corporation was used. This device is capable of surface observation with an extremely low acceleration voltage from 100 volts, and has the feature that the surface of a sample can be observed directly without forming a conductive film on the sample. First, a secondary electron beam between 900-1000 volts of the reflected electron beam from the plane of the sample was extracted and imaged. An extremely thin step was confirmed on the plane of the sample. Next, a secondary electron beam between 900 and 1000 volts of the reflected electron beam from the side surface of the sample was picked up and subjected to image processing. Five layers of extremely thin material were superimposed. Furthermore, as a result of image processing of the energy and intensity of the characteristic X-rays, it was confirmed that only carbon atoms were present, and that the sample was a graphene conjugate in which flat planes of graphene overlapped with each other. Even when the graphene bonded body was taken out of the container and a weight of 20 kg was placed on the graphene bonded body, the graphene bonded body was not destroyed, so the graphene flat surfaces were bonded to each other with a constant bonding force. FIG. 1 schematically shows an enlarged part of the side surface of the graphene bonded body in which the flat planes of graphene overlap each other.
Next, the optical performance related to multiple sites on the plane of the graphene conjugate was examined from light transmittance and haze value. The light transmittance in the visible light wavelength region (380-750 nm) measured by a spectrophotometer (product UV-1280 manufactured by Shimadzu Corporation) was as high as 88-90%. The haze value measured by a haze meter (Haze meter HZ-V3 manufactured by Suga Test Co., Ltd.) was less than 1%. As a result, the graphene conjugate had high transparency.

Example 2
In this example, according to the production method described in paragraph 10, a transparent conductive substrate having a configuration in which a graphene bonded body in which graphene flat surfaces are overlapped and bonded is bonded to a transparent film of a synthetic resin by thermocompression, is attached to a container. It is an embodiment formed on the bottom surface of the .
As a transparent film, an acrylic resin transparent film having a film thickness of 50 μm (for example, a product of Mitsubishi Rayon Co., Ltd., product number HBS006) was cut into a size of 1.2 m × 1.2 m and placed on the bottom of the container. . After this, a suspension was prepared according to the method of Example 1, 10 g of this suspension was filled in a container, and a vibration acceleration of 0.2 G in three directions was repeatedly applied to the container. The container was then heated to 65° C. to vaporize the methanol. Furthermore, an aluminum plate of 1.2 m × 1.2 m is placed on the upper plane of the sample formed on the bottom of the container, and then a 60 kg weight is placed on the aluminum plate to evenly spread the upper plane of the sample. compressed to After removing the weight and the aluminum plate, the container was subjected to a three-way vibration acceleration of 0.2 G and the sample was removed from the container. An aluminum plate was placed again on the removed sample, and a weight of 20 kg was further placed thereon, but the state of the sample did not change.
Next, the optical performance related to a plurality of parts of the sample was examined from the light transmittance and haze value in the same manner as in Example 1. The light transmittance in the visible light wavelength region (380-750 nm) measured by a spectrophotometer was as high as 86-88%. Also, the haze value measured by a haze meter was less than 2%. As a result, the graphene conjugate had high transparency.

Example 3
This example is an example of forming a transparent electrode composed of a collection of nickel microparticles on the transparent conductive substrate prepared in Example 2. FIG. As a raw material for the nickel fine particles, hexaamminenickel nitrate [Ni(NH ₃ ) ₆ ](NO ₃ ) ₂ described in paragraph 27 (for example, a product of Mitsuwa Chemicals Co., Ltd.) was used. The organic compound used was ethylene glycol (for example, a product of Nippon Shokubai Co., Ltd.) having a boiling point of 197°C, a melting point of -12.6°C, and a viscosity of 21 mPa sec at 20°C, as described in paragraph 25. .
First, 29 g of hexaamminenickel nitrate (corresponding to 0.1 mol) was dispersed in methanol to a concentration of 10% by weight, and ethylene glycol was mixed into the dispersion to a concentration of 10% by weight. created a liquid. This mixed solution was printed on the surface of the transparent conductive substrate prepared in Example 2 to form a coating film with a width of 3 mm at intervals of 2 mm, placed in a heat treatment furnace in an ammonia atmosphere, and heated at 20 ° C./min. Heat treatment was performed by increasing the temperature to 210° C. at a temperature rate. After that, an aluminum plate of 1.2 m × 1.2 m was placed on the upper plane of the transparent conductive substrate, and a weight of 20 kg was further placed on the aluminum plate, and the upper plane of the transparent conductive substrate was It was evenly compressed to prepare a sample. After removing the weight and the aluminum plate, the container was subjected to a three-way vibration acceleration of 0.2 G and the sample was removed from the container.
First, as in Example 1, the optical performance of a plurality of portions of the sample on which the coating film was formed was examined from the light transmittance and the haze value. The light transmittance in the visible light wavelength range measured by a spectrophotometer was as high as 88-90%. Also, the haze value measured by a haze meter was less than 2%. As a result, the part where the coating film was formed had high transparency.
Next, the bonding strength between the portion of the sample on which the coating film was formed and the transparent conductive substrate was measured based on the test method for adhesive strength specified in JIS Z0237. Therefore, the coating film was bonded to the graphene conjugate with a certain bonding force.
Further, the surface resistance of a plurality of portions of the sample on which the coating film was formed was measured by a surface resistance meter (for example, a surface resistance meter ST-4 manufactured by Simco Japan Co., Ltd.). Since the surface resistance value was 1×10 ³ Ω/□, the surface resistance was close to that of metal.
Furthermore, the surface of the sample on which the coating film was formed was observed with an electron microscope in the same manner as in Example 1. First, image processing was performed by extracting a secondary electron beam between 900 and 1000 volts for the reflected electron beam from the surface of the portion where the coating film was formed. The surface was covered with clusters of granular fine particles with a size of 40-60 nm.
Next, an energy between 900 and 1000 volts was extracted from the reflected electron beam from the surface, image processing was performed, and the material of the fine particles was analyzed based on the density of the image. No shading was observed in any of the granular fine particles, indicating that the fine particles were composed of a single atom.
Furthermore, the energy and intensity of the characteristic X-rays from the surface were image-processed, and the types of elements composing the fine particles were analyzed. Since the granular fine particles were composed only of nickel atoms, the granular fine particles are nickel granular fine particles.
From the above results, as a result of heat-treating the coating film of the mixed solution, a collection of granular nickel particles precipitated on the transparent conductive substrate, and when the upper plane of this transparent conductive substrate was evenly compressed, the nickel particles were formed. The mass bonded to the transparent conductive substrate with constant strength. In addition, this collection of nickel fine particles exhibited transparency.

Example 4
The present example is an example of forming a transparent electrode composed of a collection of fine aluminum particles on the transparent conductive substrate prepared in Example 2. FIG. Aluminum octylate Al(C ₇ H ₁₅ COO) ₃ (for example, a product of Hope Pharmaceutical Co., Ltd.) described in paragraph 28 was used as the raw material of the aluminum fine particles. 46 g (corresponding to 0.1 mol) of aluminum octylate was dispersed in methanol to a concentration of 10% by weight, and the ethylene glycol used in Example 3 was mixed to the dispersion to a concentration of 10% by weight. to prepare a mixture. This mixed liquid was printed on the surface of the transparent conductive substrate prepared in Example 2 to form a coating film having a width of 3 mm at intervals of 2 mm, heated to 290° C. in the atmosphere, and allowed to stand for 1 minute. After that, a 1.2 m × 1.2 m aluminum plate was placed on the upper plane of the transparent conductive substrate, and a 15 kg weight was placed on the aluminum plate, and the upper plane of the transparent conductive substrate was It was evenly compressed to prepare a sample. After removing the weight and the aluminum plate, the container was subjected to a three-way vibration acceleration of 0.2 G and the sample was removed from the container.
First, in the same manner as in Example 3, the optical performance of the portion of the sample on which the coating film was formed was examined from the light transmittance and haze value. The light transmittance in the visible light wavelength range measured by a spectrophotometer was as high as 88-90%. Also, the haze value measured by a haze meter was less than 2%. As a result, the part where the coating film was formed had high transparency.
Next, the bonding strength between the portion of the sample on which the coating film was formed and the transparent conductive substrate was measured based on the test method for adhesive strength in the same manner as in Example 3. As a result, the sample was able to withstand a load of 200 g. Therefore, the coating film was bonded to the graphene conjugate with a certain bonding force.
In addition, the surface resistance was measured by a surface resistance meter in the same manner as in Example 3 at a plurality of portions of the sample on which the coating film was formed. Since the surface resistance value was 1×10 ³ Ω/□, the surface resistance was close to that of metal.
Furthermore, the surface of the sample on which the coating film was formed was observed with an electron microscope in the same manner as in Example 3. The surface was covered with fine aluminum particles of 40-60 nm.
From the above results, as a result of heat-treating the coating film of the mixed solution, a group of granular aluminum fine particles precipitated on the transparent conductive substrate, and when the upper plane of this transparent conductive substrate was evenly compressed, the aluminum fine particles were formed. The mass bonded to the transparent conductive substrate with constant strength. In addition, this collection of aluminum fine particles exhibited transparency.

Claims (5)

A method for producing a transparent conductive substrate comprising a structure in which a graphene bonded body, which is a collection of graphenes in which flat surfaces of graphene that overlap each other are bonded to each other, is thermocompressed to a transparent film of a synthetic resin,
A group of scale-like graphite particles or a group of massive graphite particles is flattened on the surface of one of the two parallel-plate electrodes, and the parallel-plate electrode is immersed in methanol filled in a container. Further, the other parallel plate electrode is superimposed on the one parallel plate electrode, and the two parallel plate electrodes are separated via the collection of the scale-like graphite particles or the collection of the massive graphite particles. , the two spaced apart parallel plate electrodes are immersed in the methanol;
After that, a DC potential difference is applied across the gap between the two parallel plate electrodes, whereby an electric field corresponding to the value obtained by dividing the potential difference by the gap between the two parallel plate electrodes is generated. , a coulomb sufficient to break the interlayer bonding of the basal planes of graphite crystals for all of the graphite particles by applying the electric field to the cluster of flake graphite particles or the cluster of massive graphite particles. A force is simultaneously applied to all the π electrons responsible for the interlaminar bonds of the basal planes forming the graphite particles, thereby causing all the interlaminar bonds of the basal planes forming the flake graphite particles or the massive graphite particles. are destroyed at the same time, and a group of graphene corresponding to the basal plane is produced in the gap between the two parallel plate electrodes.
After that, the gap between the two parallel plate electrodes is widened, the two parallel plate electrodes are tilted in the methanol, and further vibration acceleration is repeatedly applied to the container in three directions: left and right, front and back, and up and down. , the graphene mass is transferred from the gap between the two parallel plate electrodes into the methanol, and then the two parallel plate electrodes are removed from the container , whereby the graphene in the container is A suspension is produced in which a collection of precipitated in the methanol,
Next, a transparent film of synthetic resin having the shape of the bottom surface of the container is placed on the bottom surface of the container for producing the transparent conductive base material, and the suspension produced by the above method is added to the transparent conductive base material. The container is filled in an amount necessary for manufacturing the base material, and then the container is repeatedly subjected to vibration acceleration in three directions: back and forth, left and right, and up and down, whereby the graphene constituting the suspension moves in the methanol constituting the suspension with the flat surface of the graphene facing upward, the graphene diffuses throughout the container, and the flat surfaces of the graphene overlap with each other through the methanol. The graphene aggregates are formed on the synthetic resin transparent film in the shape of the bottom surface of the container.
After that, a plate having the size of the graphene cluster is placed on the graphene cluster, the container is heated to the boiling point of methanol to vaporize the methanol, and then the plate is compressed. At the same time, the container is heated to the Vicat softening temperature of the synthetic resin constituting the transparent film, whereby after the methanol is vaporized, the graphene aggregates in which the flat surfaces of the graphene overlap each other are transformed into the It is formed on a transparent film of synthetic resin in the shape of the bottom surface of the container, then the collection of graphene is compressed, and frictional heat is generated at the portion where the flat surfaces of the graphene overlap each other, and the frictional heat The flat surfaces of the graphene are bonded to each other, and a graphene bonded body is formed by a collection of the graphenes in which the flat surfaces of the graphene overlap each other and the flat surfaces are bonded to each other, and the transparent film of the synthetic resin is softened. , the graphene conjugate is pressure-bonded to the surface of the softened synthetic resin transparent film, and the transparent conductive substrate obtained by thermocompression bonding the graphene conjugate to the synthetic resin transparent film is attached to the bottom surface of the container. formed as a transparent conductive substrate comprising a shape,
After that, vibration acceleration is repeatedly applied to the container in three directions: back and forth, left and right, and up and down, and the transparent conductive substrate is removed from the container, thereby bonding the flat surfaces of graphene that overlap each other. A method for producing a transparent conductive base material, wherein the transparent conductive base material is produced by thermocompression bonding a graphene bonded body consisting of an aggregate of the graphenes obtained by bonding to a transparent film of a synthetic resin. A method for forming a transparent electrode on the surface of a transparent conductive substrate produced by the method according to claim 1,
A metal compound that deposits a metal having a refractive index of 0.4 or more and 2.4 or less in the wavelength region of visible light by thermal decomposition is dispersed in methanol, and the metal compound is dispersed in the methanol in a molecular state. create a dispersion,
A first property of being soluble or miscible with the methanol, a second property having a viscosity higher than that of the methanol, a third property having a melting point lower than 20°C, and a boiling point lower than the thermal decomposition temperature of the metal compound. mixing an organic compound having the fourth property with the methanol dispersion to prepare a mixture in which the organic compound is uniformly mixed with the methanol dispersion;
The mixed liquid is applied or printed on the surface of the graphene bonded body constituting the transparent conductive substrate produced by the method according to claim 1, and the transparent conductive substrate is heat-treated to heat the metal compound. By decomposing, the first feature consisting of a metal having a refractive index of 0.4 or more and 2.4 or less in the wavelength region of visible light, and a granular shape whose particle size is one order of magnitude smaller than the wavelength of visible light are deposited all at once on the surface of the graphene bonded body to which the mixed solution is applied or printed, and the metal fine particles are metallically bonded at the sites where they come into contact with each other. , the collection of metal fine particles that are metal-bonded is formed on the surface of the graphene bonded body to which the mixed solution is applied or printed;
After that, the surface of the graphene bonded body on which the collection of the metal fine particles is formed is uniformly compressed to plastically deform the collection of the metallically bonded fine metal particles, and the collection of the plastically deformed metal fine particles transforms into the graphene Frictional heat is generated at a portion in contact with the surface of the joined body, and by the frictional heat, the aggregation of the plastically deformed metal fine particles is joined to the surface of the graphene joined body, whereby the transparent conductive substrate is formed. 2. A method for forming a transparent electrode on the surface of a transparent conductive substrate produced by the method according to claim 1, wherein a transparent electrode composed of a collection of the metal fine particles is formed on the surface of the graphene bonded body. The method for forming a transparent electrode on the surface of the transparent conductive substrate according to claim 2,
The metal compound described in claim 2 is a metal compound that deposits nickel or aluminum by thermal decomposition, and the metal compound is used as the metal compound described in claim 2, and according to the method described in claim 2, 3. The method of forming a transparent electrode on the surface of a transparent conductive substrate according to claim 2, wherein the transparent electrode is formed on the surface of the transparent conductive substrate. The method for forming a transparent electrode on the surface of the transparent conductive substrate according to claim 2,
The metal compound according to claim 2 is a complex composed of an inorganic metal compound having a metal complex ion in which a ligand composed of an inorganic molecule or an inorganic ion is coordinately bonded to a metal ion. The organic compound described is any one organic compound belonging to carboxylic acid esters, glycols or glycol ethers . 3. A method for forming a transparent electrode on the surface of a transparent conductive substrate according to claim 2, wherein the transparent electrode is formed on the surface of the substrate. The method for forming a transparent electrode on the surface of the transparent conductive substrate according to claim 2,
In the metal compound according to claim 2, the first feature is that the oxygen ion that constitutes the carboxyl group in the carboxylic acid is covalently bonded to the metal ion, and the second feature is that the carboxylic acid is composed of a saturated fatty acid. and the organic compound described in claim 2 is any one kind of organic compound belonging to carboxylic acid esters, glycols or glycol ethers, and these two kinds of substances are used 3. The method of forming a transparent electrode on the surface of a transparent conductive substrate according to claim 2, wherein the transparent electrode is formed on the surface of the transparent conductive substrate according to the method of claim 2.

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