WO2015129781A1 - Metal nanowire-forming composition, metal nanowire, and method for producing same - Google Patents

Metal nanowire-forming composition, metal nanowire, and method for producing same Download PDF

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WO2015129781A1
WO2015129781A1 PCT/JP2015/055514 JP2015055514W WO2015129781A1 WO 2015129781 A1 WO2015129781 A1 WO 2015129781A1 JP 2015055514 W JP2015055514 W JP 2015055514W WO 2015129781 A1 WO2015129781 A1 WO 2015129781A1
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metal
nanowire
nanowires
primary amine
range
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PCT/JP2015/055514
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French (fr)
Japanese (ja)
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井上　修治
義成 山本
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新日鉄住金化学株式会社
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/05—Metallic powder characterised by the size or surface area of the particles
    • B22F1/054—Nanosized particles
    • B22F1/0547—Nanofibres or nanotubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
    • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
    • B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic System
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/52—Alloys
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/60—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape characterised by shape
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B7/00—Single-crystal growth from solutions using solvents which are liquid at normal temperature, e.g. aqueous solutions
    • C30B7/005—Epitaxial layer growth

Definitions

  • the present invention relates to a composition for forming metal nanowires that can be suitably used as a material such as a transparent electrode, a metal nanowire, and a method for producing the same.
  • metal nanowires have attracted attention as a next-generation transparent electrode material replacing indium tin oxide (ITO).
  • the metal nanowire is a fibrous material having a diameter of several nm to several tens of nm and a length of several ⁇ m to several tens of ⁇ m.
  • a transparent conductive film using metal nanowires as a conductor exhibits conductivity by forming an electrical network between fibrous metal nanowires.
  • Metal nanowires have a high light transmission because the diameter is smaller than the visible light wavelength (400 to 800 nm), and since they are fibrous, a large number of entanglement points can be secured by applying them to the substrate. It is possible to achieve both transparency.
  • metal nanowires can be produced by various methods such as a liquid phase method and a gas phase method.
  • Silver, gold, copper, cobalt, etc. are known as the material of the metal nanowire.
  • silver nanowire has high electroconductivity and can be easily manufactured by a liquid phase method, it is anticipated as an excellent conductive material.
  • Patent Document 1 proposes a metal nanowire made of silver and gold or platinum in order to improve the heat resistance of the silver nanowire.
  • Patent Document 2 proposes a method for producing copper nanowires by a liquid phase method under a mild temperature condition.
  • metal nanowires made of materials such as silver and copper and methods for producing the same have been proposed.
  • a technique for producing metal nanowires having a specific function is required depending on the purpose of use.
  • An object of the present invention is to efficiently and easily produce metal nanowires having physical properties and functionality according to the purpose of use from two or more metals.
  • composition for forming metal nanowires of the present invention includes the following components A to C; (A) a carboxylate containing a first metal having a standard electrode potential in the range of ⁇ 0.5 V to +0.4 V; (B) a metal halide containing a second metal that is higher than the standard electrode potential of the first metal and has a standard electrode potential in the range of +0.3 V to +1.0 V; as well as, (C) primary amine, Containing.
  • the manufacturing method of the metal nanowire of the present invention includes the following steps I and II; I) a carboxylate containing a first metal having a standard electrode potential in the range of ⁇ 0.5 V to +0.4 V, higher than the standard electrode potential of the first metal, and the standard electrode potential from +0.3 V Dissolving a metal halide containing a second metal in a range of +1.0 V in a primary amine to obtain a mixed solution of metal precursors; as well as, II) After the step I, the mixed liquid of the metal precursor is heated to reduce the first metal ions to precipitate the first metal, and the deposited first metal and second metal ions. A step of reducing ions of the second metal by a metal substitution reaction to precipitate the second metal and growing the metal nanowires; Is provided.
  • the first metal may be one or more selected from the group consisting of Fe, Co, Ni, Sn, Pb, and Cu.
  • the first metal is preferably Co or Ni.
  • the second metal may be one or more selected from the group consisting of Cu, Ru, Rh, Ag, and Pd.
  • the second metal is preferably Cu.
  • the carboxylate of the component A may be a formate or an acetate.
  • the halide of the component B may be a chloride.
  • the primary amine may have a carbon number in the range of 14 to 20, and the primary amine is oleylamine. Is preferred.
  • the content of the nitrate containing the second metal may be 0.1 mol% or less with respect to the B component.
  • the metal nanowire of the present invention is produced by any one of the methods described above.
  • a metal nanowire containing a first metal and a second metal having different standard electrode potentials can be efficiently and easily produced by a liquid phase method.
  • desired physical property and functionality can be provided to metal nanowire by selection of the 1st metal and the 2nd metal. Therefore, the metal nanowire obtained by the method of the present invention can be widely used as a material for various electronic parts and industrial products.
  • composition for forming metal nanowires of the present invention can be preferably used in the method for producing metal nanowires.
  • FIG. 2 is a SEM (scanning electron microscope) photograph of the metal nanowire obtained in Example 1. It is drawing which shows the result of the XRD measurement of the metal nanowire obtained in Example 1.
  • FIG. 4 is a SEM (scanning electron microscope) photograph of metal nanowires obtained in Example 2. It is drawing which shows the result of the XRD measurement of the metal nanowire obtained in Example 2.
  • FIG. 4 is a SEM (scanning electron microscope) photograph of metal nanowires obtained in Example 3. It is drawing which shows the result of the XRD measurement of the metal nanowire obtained in Example 3.
  • composition for forming metal nanowires of the present embodiment includes the following components A to C; (A) a carboxylate containing a first metal having a standard electrode potential in the range of ⁇ 0.5 V to +0.4 V (hereinafter sometimes referred to as “first metal-containing carboxylate”), (B) a metal halide containing a second metal that is higher than the standard electrode potential of the first metal and has a standard electrode potential in the range of +0.3 V to +1.0 V (hereinafter referred to as “second metal-containing halide”). ”), as well as, (C) primary amine, Containing.
  • first metal-containing carboxylate a carboxylate containing a first metal having a standard electrode potential in the range of ⁇ 0.5 V to +0.4 V
  • second metal-containing halide a metal halide containing a second metal that is higher than the standard electrode potential of the first metal and has a standard electrode potential in the range of +0.3 V to +1.0 V
  • the first metal is a metal whose standard electrode potential is in the range of ⁇ 0.5V to + 0.4V.
  • the first metal include Fe ( ⁇ 0.44 V), Co ( ⁇ 0.277 V), Ni ( ⁇ 0.228 V), Sn ( ⁇ 0.1375 V), Pb ( ⁇ 0.126 V), Cu (0 .337V). You may use these in combination of 2 or more type.
  • the carboxylate of the first metal is not limited to the type of carboxylic acid.
  • the carboxyl group may be a monocarboxylic acid having one carboxyl group, or a carboxylic acid having two or more carboxyl groups. Also good.
  • the carboxylic acid constituting the carboxylate may be an acyclic carboxylic acid or a cyclic carboxylic acid.
  • an acyclic monocarboxylic acid salt can be suitably used from the viewpoint that the thermal decomposition temperature is low and the cost is low and the cost can be reduced.
  • Examples of the acyclic monocarboxylate include formate, acetate, propionate, oxalate, benzoate, etc. Among these, it is more preferable to use formate or acetate.
  • the carboxylate may be an anhydride or a hydrate.
  • examples of the carboxylate include nickel formate, nickel acetate, nickel propionate, nickel oxalate and the like.
  • examples of the carboxylate include cobalt formate, cobalt acetate, cobalt propionate, and cobalt oxalate. These may be hydrates.
  • inorganic salts such as chlorides, nitrates, sulfates, carbonates, hydroxides, etc.
  • dissociation decomposition
  • heating at a higher temperature is required, which is not preferable.
  • the first metal-containing carboxylate may contain a metal other than the first metal as long as the effects of the invention are not impaired.
  • the metal other than the first metal include titanium, chromium, manganese, aluminum, sodium, potassium, magnesium, zirconium, tungsten, molybdenum, vanadium, barium, calcium, strontium, silicon, aluminum, phosphorus, and other base metals, gold, Examples include noble metals such as platinum, iridium, osmium, rhenium, neodymium, niobium, holonium, dysproium, yttrium, and rare earth metals. These may be contained alone or in combination of two or more, and may be alloys thereof.
  • the first metal-containing carboxylate may contain an element other than a metal element such as hydrogen, oxygen, carbon, nitrogen, sulfur, boron.
  • the second metal is a metal that is higher than the standard electrode potential of the first metal and has a standard electrode potential in the range of + 0.3V to + 1.0V.
  • the second metal include Cu (0.337 V), Ru (0.46 V), Rh (0.758 V), Ag (0.7991 V), Pd (0.915 V), and the like. You may use these in combination of 2 or more type.
  • one or more selected from Fe, Co, Ni, Sn, Pb and Cu as the first metal and Cu, Ru, Rh, Ag and Pd as the second metal are selected. All combinations excluding the combination of Cu and Cu can be selected from combinations of one or more. This combination can also include the case where the first metal and / or the second metal are two or more.
  • the second metal contains halide ions in the mixed solution of the above components (A) to (C).
  • Halides such as chlorides and bromides that are easily formed are used.
  • the halide is adsorbed as a capping agent on a specific crystal plane with respect to the nucleus of the first metal generated by reduction, and the growth rate of the crystal plane is promoted or suppressed. It is thought to promote the generation of.
  • chloride is preferably used from the viewpoint of increasing the decomposition temperature as compared with the complex of the first metal.
  • examples of the chloride thereof include cuprous chloride CuCl and cupric chloride CuCl 2 . These may be hydrates.
  • the second metal is, for example, an oxide, hydroxide, nitrate, sulfate, or carbonate
  • the content of the nitrate containing the second metal is preferably 0.1 mol% or less with respect to the B component, and does not contain the nitrate. Is more preferable.
  • the nitrate containing the second metal is contained in an amount exceeding 0.1 mol% with respect to the component B, the function of the halide as a capping agent is inhibited, and thus the formation reaction of the metal nanowire may not proceed.
  • the second metal-containing halide may contain a metal other than the second metal as long as the effects of the invention are not impaired.
  • the metal other than the second metal include titanium, chromium, manganese, aluminum, sodium, potassium, magnesium, zirconium, tungsten, molybdenum, vanadium, barium, calcium, strontium, silicon, aluminum, phosphorus, and other base metals, gold, Examples include noble metals such as platinum, iridium, osmium, rhenium, neodymium, niobium, holonium, dysproium, yttrium, and rare earth metals. These may be contained alone or in combination of two or more, and may be alloys thereof.
  • the second metal-containing halide may contain an element other than a metal element such as hydrogen, oxygen, carbon, nitrogen, sulfur, boron.
  • the primary amine can form a complex with the first metal ion, and effectively exhibits a reducing ability for the first metal complex (or the first metal ion).
  • secondary amines have great steric hindrance, which may hinder the good formation of complexes of the first metal, and tertiary amines do not have the ability to reduce ions of the first metal, so both are used alone
  • primary amines when primary amines are used, they can be used in combination as long as the effects of the invention are not impaired.
  • the primary amine is not particularly limited as long as it can form a complex with ions of the first metal, and can be solid or liquid at room temperature.
  • room temperature means 20 ° C. ⁇ 15 ° C.
  • the primary amine that is liquid at room temperature also functions as an organic solvent in forming the complex of the first metal.
  • it is a primary amine solid at normal temperature, there is no particular problem as long as it is liquid by heating at 100 ° C. or higher, or can be dissolved using an organic solvent.
  • the primary amine may be an aromatic primary amine, but an aliphatic primary amine is preferable from the viewpoint of easy formation of a complex of the first metal in the reaction solution.
  • the aliphatic primary amine include octylamine, trioctylamine, dioctylamine, hexadecylamine, dodecylamine, tetradecylamine, stearylamine, oleylamine, myristylamine, laurylamine and the like.
  • these aliphatic primary amines those having a carbon number in the range of 14 to 20 are preferable and oleylamine having a double bond in the molecule is more preferable from the viewpoint of increasing the formation efficiency of metal nanowires.
  • Oleylamine also has an advantage that the reaction can proceed efficiently in a homogeneous solution because it exists in a liquid state under temperature conditions in the process of producing metal nanowires.
  • the primary amine functions as a surface modifier when the metal nanowire is produced, secondary aggregation can be suppressed even after removal of the primary amine.
  • the primary amine is liquid at room temperature from the viewpoint of ease of processing operation in the washing process for separating the solid component of the metal nanowires generated after the reduction reaction and the solvent or the unreacted primary amine.
  • the primary amine preferably has a boiling point higher than the reduction temperature from the viewpoint of ease of reaction control when the metal nanowire is obtained by reducing the complex of the first metal. That is, the aliphatic primary amine preferably has a boiling point of 200 ° C. or higher, more preferably 250 ° C. or higher, and preferably has 14 or more carbon atoms. For example, the boiling point of oleylamine having 18 carbon atoms is 348 ° C.
  • the metal nanowire-forming composition of the present embodiment can be prepared by mixing the components (A) to (C). By mixing the above components (A) to (C), the first metal-containing carboxylate of component (A) and the second metal-containing halide of component (B) are converted into primary amines of component (C). Can be dissolved. Thus, the composition for metal nanowire formation which is a liquid mixture of the metal precursor for forming metal nanowire can be obtained.
  • the blending amount of the first metal-containing carboxylate as the component (A) is within a range of, for example, 0.05 to 2.0 moles with respect to 1 mole of the blending amount of the second metal-containing halide of the component (B). In the range of 0.1 to 1.0 mol is more preferable. If the blending amount of the component (A) is less than the above lower limit value, the formation of metal nanowires may be insufficient, and if it exceeds the above upper limit value, wire and particulate matter may be mixed. Therefore, it is not preferable.
  • the blending amount of the second metal-containing halide which is the component (B) is, for example, based on the total amount of metal ions of the second metal, and as the blending amount of halide ions, The range is preferably from 0.1 to 5.0 mol, more preferably from 1.0 to 3.0 mol. If the blending amount of the component (B) is less than the above lower limit value, the formation of metal nanowires may be insufficient, and if the above upper limit value is exceeded, the reduction of the second metal is inhibited, and a non-uniform metal May become nanowire.
  • the blending ratio of the first metal-containing carboxylate as the component (A) and the second metal-containing halide as the component (B) affects the shape, physical properties, and functionality of the metal nanowire.
  • the aspect ratio (average major axis / average minor axis) of the metal nanowire is desired to be within a range of 30 to 1000
  • the mixing ratio of the component (A) and the component (B) is 0.05 to 1.
  • a range of 0 is preferable.
  • the blending ratio of Ni in the component (A) and Cu in the component (B) is 0.5 to 5 in terms of the molar ratio of the metal element. It is preferable to be within the range of 1.2.
  • the shape and aspect ratio of the metal nanowire can be controlled by adjusting, for example, the type of carboxylate, the type of aliphatic amine, the concentration of the reaction solution, and the like.
  • the amount of the primary amine as component (C) is preferably in the range of 1.0 to 100 mol, for example, when the total sum of the first metal-containing carboxylic salt and the second metal-containing halide is 1 mol. A range of 0 to 20.0 mol is more preferable.
  • the blending amount of the component (C) is less than the above lower limit value, the amount as a reducing agent is insufficient, unreacted amount increases, and formation of metal nanowires may be insufficient. If it exceeds, productivity is lowered, which is not preferable.
  • the primary amine of component (C) needs to be present in excess in the reaction solution.
  • At least 2 mol per 1 mol of the first metal ion in the component (A) is present, more preferably 2.2 mol or more, and more preferably 4 mol or more.
  • the amount of the primary amine is less than 2 mol with respect to 1 mol of the first metal ion, the reduction of the first metal ion may be insufficient.
  • the upper limit of the amount of primary amine is not particularly limited, but is preferably 20 mol or less with respect to 1 mol of ions of the first metal from the viewpoint of productivity, for example.
  • the composition for forming metal nanowires of the present embodiment includes, as optional components, for example, an organic solvent, a surfactant, a dispersant, a reducing agent, metal nanoparticles, and the like. Can be contained.
  • the composition for forming metal nanowires of the present embodiment obtained as described above can be preferably used for producing metal nanowires.
  • the first metal is deposited by heat reduction, hydrothermal synthesis, reduction with a reducing agent, and the like, and by metal substitution reaction between the deposited first metal and second metal ions.
  • the metal nanowire containing a 1st metal and a 2nd metal can be manufactured by reduce
  • the method for producing metal nanowires of the present embodiment includes the following steps I and II; I) a carboxylate containing a first metal whose standard electrode potential is in the range of ⁇ 0.5 V to +0.4 V, higher than the standard electrode potential of the first metal, and the standard electrode potential is +0.3 V to +1 Dissolving a metal halide containing a second metal in the range of 0.0 V in a primary amine to obtain a mixed solution of metal precursors; as well as, II) After Step I, the mixed liquid of the metal precursor is heated to reduce the first metal ions to precipitate the first metal and to replace the deposited first metal and second metal ions with each other. A step of reducing ions of the second metal by reaction to precipitate the second metal and growing the metal nanowires; It has.
  • Step I Step of obtaining mixed liquid of metal precursor>
  • Step I by mixing the components (A) to (C), the first metal-containing carboxylate of component (A) and the second metal-containing halide of component (B) are converted into the component (C).
  • the second metal-containing halide is preferably a second metal chloride.
  • the metal nanowire-forming composition can be used as it is as the mixed liquid of the metal precursor used in Step I.
  • step I it is preferable that the components (A) to (C) are mixed and then heated, for example, within a range of 30 to 170 ° C.
  • the complexing reaction between the primary metal ion and the primary amine can proceed even at room temperature, but in the range of 100 ° C. to 165 ° C. in order to perform a sufficient and more efficient complexing reaction. It is preferable to carry out the reaction by heating to a temperature of. This heating is particularly advantageous when a hydrate such as nickel formate dihydrate or nickel acetate tetrahydrate is used as the first metal-containing carboxylate.
  • the heating temperature is preferably a temperature exceeding 100 ° C., more preferably a temperature of 105 ° C.
  • nickel formate dihydrate has a complex structure in which two coordination waters and two formate ions as bidentate ligands exist at room temperature.
  • the heat treatment in the complex formation reaction between nickel carboxylate and primary amine is reliably separated from the subsequent heat reduction process in Step II, and the complex formation reaction is completed in order to complete the complex formation reaction.
  • the complex formation reaction is completed in order to complete the complex formation reaction.
  • 160 ° C. or lower more preferably 150 ° C. or lower.
  • the heating time can be appropriately determined according to the heating temperature and the content of each raw material, but is preferably 10 minutes or more from the viewpoint of completing the complex formation reaction. There is no upper limit on the heating time, but heat treatment for a long time is useless from the viewpoint of saving energy consumption and process time.
  • the heating method is not particularly limited, and a microwave, an oil bath, a hot plate, an infrared heater, or the like can be used.
  • an organic solvent other than the primary amine may be newly added to allow the reaction in the homogeneous solution to proceed more efficiently.
  • the organic solvent may be mixed at the same time as the above components (A) to (C).
  • the organic solvent is added after first mixing the above components (A) to (C), the primary amine is added. Is more preferable because it efficiently coordinates to a nickel atom.
  • the organic solvent that can be used is not particularly limited as long as it does not inhibit the complex formation between the primary amine and the nickel ion. For example, the organic solvent having 4 to 30 carbon atoms, the organic solvent having 7 to 30 carbon atoms, and the like.
  • a saturated or unsaturated hydrocarbon organic solvent, an alcohol organic solvent having 8 to 18 carbon atoms, or the like can be used. Further, from the viewpoint of enabling use even under heating conditions, it is preferable to select an organic solvent having a boiling point of 170 ° C. or more, more preferably a solvent having a temperature in the range of 200 to 300 ° C. Good. Specific examples of such an organic solvent include tetraethylene glycol and n-octyl ether.
  • Step II the mixed metal of the metal precursor obtained in Step I is heated to reduce the first metal ions to precipitate the first metal.
  • the second metal ion is reduced by the metal substitution reaction between the deposited first metal ion and the second metal ion to precipitate the second metal.
  • metal nanowire is manufactured by the wet reduction method in a liquid phase.
  • the mixed liquid of the metal precursor obtained in step I is heated to a temperature of 170 ° C. or higher.
  • the temperature at which the mixed liquid of the metal precursor is heated is preferably 180 ° C. or higher, more preferably 190 ° C. or higher, from the viewpoint of suppressing variation in the shape of the obtained metal nanowires.
  • the upper limit of the heating temperature is not particularly limited, but is preferably set to 270 ° C. or less, for example, from the viewpoint of efficiently performing the treatment.
  • the heating temperature can be appropriately adjusted depending on, for example, the types of the first metal and the second metal and the use of an additive for promoting the generation of metal fine particles serving as a nucleus.
  • the method for heating the mixed liquid of the metal precursor is not particularly limited.
  • a heating method for example, a microwave, an oil bath, a hot plate, an infrared heater, or the like can be used.
  • microwave heating it is preferable to use microwave heating. Since the microwave penetrates into the mixed liquid of the metal precursor, uniform heating is performed and energy can be directly applied to the medium, so that rapid heating can be performed.
  • the whole liquid mixture of the metal precursor can be made uniform at a desired temperature, and the reduction of the first metal ions, the nucleation, the generation of the second metal by the metal substitution reaction with the second metal ions, Processes such as growth into metal nanowires can occur simultaneously in the entire solution, and as a result, metal nanowires having a uniform shape can be easily produced in a short time.
  • the use wavelength of a microwave is not specifically limited, For example, it is 2.45 GHz.
  • the metal nanowire slurry obtained by heating by microwave irradiation is, for example, statically separated, and after removing the supernatant liquid, the metal nanowire is obtained by washing with an appropriate solvent and drying. .
  • the above-described organic solvent may be added as necessary, but it is preferable to use a primary amine as it is as an organic solvent.
  • the metal nanowire can be prepared as described above.
  • the metal nanowires thus produced have, for example, an average minor axis (thickness) in the range of 10 to 300 nm, an average major axis (length) in the range of 1.0 to 30.0 ⁇ m, and an aspect ratio
  • the fiber has a fibrous form (average major axis / average minor axis) of 30 to 1,000.
  • metal nanowires in which the first metal is uniformly distributed in the second metal are obtained.
  • the content ratio of the first metal and the second metal in the metal nanowire obtained in the present embodiment is, for example, 0.01 to 30 for the first metal from the viewpoint of improving oxidation resistance, catalytic properties, and imparting magnetic properties.
  • the second metal is preferably in the range of 70 to 99.9% by mass
  • the first metal is in the range of 0.1 to 5.0% by mass
  • the second metal Is more preferably in the range of 95.0 to 99.9% by mass.
  • the metal nanowire obtained in the present embodiment has a fibrous shape as an aggregate of a large number of long metal particles, and a large number of entanglement points can be secured.
  • a simple coating method, a printing method, etc. Depending on the application method, a metal layer having excellent conductivity can be formed. Therefore, the metal nanowires obtained in the present embodiment can be used in various applications such as displays, touch panels, electronic circuits, various sensors, solar cells, etc. as electrode materials, electromagnetic wave shielding materials, heat conduction materials, bonding materials, catalysts, etc. It can be suitably used for electronic parts and industrial products.
  • metal nanowires are formed by a two-step reduction reaction. That is, first, the reduction reaction of the first metal ions proceeds by heating the mixed liquid of the metal precursor, and the first metal is deposited. Next, the second metal ion is reduced by the metal substitution reaction between the deposited first metal and the second metal ion, and the second metal is deposited.
  • the mechanism of the reduction reaction will be described by taking as an example the case where the first metal is nickel and the second metal is copper.
  • nickel and copper have different standard electrode potentials, reduction and particle formation occur at different temperatures (eg, Ni 2+ 463K, Cu 2+ 433K).
  • metallic copper is first produced, and metallic nickel is produced with metallic copper as a nucleus as the temperature rises.
  • the nickel carboxylate and copper halide used in the present embodiment are heated in the presence of excess primary amine (for example, oleylamine), so that the nickel carboxylate is at a lower temperature than the copper halide.
  • the released nickel ions are reduced by the reducing action of the primary amine to produce metallic nickel.
  • metallic copper is formed by a metal substitution reaction between metallic nickel and copper ions.
  • the metal substitution reaction is a reaction in which a zero-valent metal is oxidized and ionized and a metal that is an ion is reduced by a difference in standard electrode potential between the metals.
  • a complex of nickel carboxylate and primary amine (nickel complex) is heated in the mixed solution of metal precursors, and the nickel ions of the nickel complex are reduced and distributed to the nickel ions.
  • nickel complex a complex of nickel carboxylate and primary amine
  • the nickel ions of the nickel complex are reduced and distributed to the nickel ions.
  • a large number of fine nickel metal particles having an oxidation number of 0 are generated.
  • the large number of metal nickel fine particles function as the core of the metal nanowire.
  • the metal substitution reaction between the metal nickel and the copper ions proceeds on each surface of the many metal nickel fine particles by heating, and the copper ions are reduced to produce metal copper.
  • the produced copper metal grows with anisotropy by adsorbing chloride ions to specific crystal planes, and forms long metal nanowires.
  • the metal nanowire obtained by this Embodiment can provide a desired physical property and functionality to a metal nanowire by selection of a 1st metal and a 2nd metal.
  • oxidation resistance can be imparted to the metal nanowire by combining Ni having excellent oxidation resistance as the first metal and Cu as the second metal.
  • fusing point of metal nanowire can be adjusted by combining Sn with low melting
  • catalytic performance can be imparted to the metal nanowires by a combination of Ni as the first metal and Pd as the second metal.
  • Example 1 ⁇ Preparation of mixed liquid of metal precursor> To 690 g of oleylamine, 27.2 g of copper chloride dihydrate and 14.5 g of nickel formate dihydrate were added and heated at 120 ° C. for 20 minutes under a nitrogen flow to obtain a metal precursor mixture 1 Got.
  • the mixed liquid 1 was irradiated with microwaves and heated in the range of 190 to 250 ° C. for 5 minutes to obtain a metal nanowire slurry 1.
  • ⁇ Washing and drying process> The obtained slurry 1 was allowed to stand and separated, and the supernatant was removed. Then, the slurry 1 was washed twice with toluene and methanol, and then dried for 6 hours in a vacuum dryer maintained at 60 ° C. Got.
  • FIG. 1 An SEM (scanning electron microscope) photograph of the metal nanowire 1 is shown in FIG. Referring to FIG. 1, it was confirmed to be a fibrous metal having a thickness of 30 to 100 nm and a length of 5 ⁇ m or more. As a result of elemental analysis, it was Cu; 85.8, Ni; 0.18, O; 6.0 (unit: mass%). The results of XRD measurement are shown in FIG. From FIG. 2, it was confirmed that the obtained metal nanowire 1 has an fcc structure.
  • the metal nanowire having a large aspect ratio as in this example can be expected to be applied to a transparent conductive film.
  • Example 2 ⁇ Preparation of mixed liquid of metal precursor> To 690 g of oleylamine, 27.2 g of copper chloride dihydrate and 20.0 g of nickel acetate tetrahydrate were added and heated at 120 ° C. for 20 minutes under a nitrogen flow to obtain a metal precursor mixture 2 Got.
  • the mixed liquid 2 was irradiated with microwaves and heated in the range of 235 to 250 ° C. for 5 minutes to obtain a slurry 2 of metal nanowires.
  • FIG. 3 An SEM (scanning electron microscope) photograph of the metal nanowire 2 is shown in FIG. Referring to FIG. 3, it was confirmed to be a fibrous metal having a thickness of 100 to 200 nm and a length of 5 ⁇ m or more. As a result of elemental analysis, it was Cu; 94.7, Ni; 0.28, O; 3.0 (unit: mass%). The results of XRD measurement are shown in FIG. From FIG. 4, it was confirmed that the obtained metal nanowire 2 has an fcc structure.
  • the thickness of the metal nanowire can be adjusted and the amount of oxidation can be controlled by changing the type of the first metal carboxylate.
  • Example 3 ⁇ Preparation of mixed liquid of metal precursor> To 690 g of oleylamine, 54.4 g of copper chloride dihydrate and 29.0 g of nickel formate tetrahydrate were added and heated at 120 ° C. for 20 minutes under a nitrogen flow to obtain a metal precursor mixture 3 Got.
  • the mixed solution 3 was irradiated with microwaves and heated in the range of 190 to 235 ° C. for 5 minutes to obtain a slurry 3 of metal nanowires.
  • FIG. 5 An SEM (scanning electron microscope) photograph of the metal nanowire 3 is shown in FIG. Referring to FIG. 5, it was confirmed to be a fibrous metal having a thickness of around 100 nm and a length of 5 ⁇ m or more. As a result of elemental analysis, Cu was 92.5, Ni was 0.45, and O was 4.5 (unit: mass%). The results of XRD measurement are shown in FIG. From FIG. 6, it was confirmed that the obtained metal nanowire 3 has an fcc structure.
  • the thickness of the metal nanowire can be adjusted and the amount of oxidation can be controlled by changing the concentration of the mixed liquid of the metal precursor.
  • the mixed solution was irradiated with microwaves and heated in the range of 190 to 250 ° C. for 5 minutes to obtain a metal nanoparticle slurry.

Abstract

In the present invention, a method for producing a metal nanowire is provided with I) a step of obtaining a mixed metal precursor liquid by dissolving, in a primary amine, a carboxylic acid salt that contains a first metal having a standard electrode potential of -0.5 V to +0.4 V and a metal halide that contains a second metal, which has a higher standard electrode potential than the first metal and has a standard electrode potential of +0.3 V to +1.0 V and, following step I), II) a step of growing a metal nanowire by heating the mixed metal precursor liquid so as to reduce ions of the first metal and precipitate the first metal, and subjecting the precipitated first metal and ions of the second metal to a metal substitution reaction so as to reduce ions of the second metal and precipitate the second metal.

Description

金属ナノワイヤー形成用組成物、金属ナノワイヤー及びその製造方法Composition for forming metal nanowire, metal nanowire and method for producing the same
　本発明は、例えば透明電極等の材料として好適に利用できる金属ナノワイヤー形成用組成物、金属ナノワイヤー及びその製造方法に関する。 The present invention relates to a composition for forming metal nanowires that can be suitably used as a material such as a transparent electrode, a metal nanowire, and a method for producing the same.
　インジウム・スズ・オキサイド（ＩＴＯ）に替わる次世代の透明電極材料として、近年、金属ナノワイヤーが注目されている。金属ナノワイヤーは、その径が数ｎｍ～数十ｎｍ、長さが数μｍ～数十μｍの繊維状材料である。金属ナノワイヤーを導体として用いる透明導電膜は、繊維状の金属ナノワイヤー間の電気的なネットワーク形成によって導電性が発現する。金属ナノワイヤーは、径が可視光波長（４００～８００ｎｍ）より小さいため光透過性が高く、しかも繊維状であるため、基材に塗布することにより多数の交絡点が確保できることから、導電性と透明性の両立が可能となる。 In recent years, metal nanowires have attracted attention as a next-generation transparent electrode material replacing indium tin oxide (ITO). The metal nanowire is a fibrous material having a diameter of several nm to several tens of nm and a length of several μm to several tens of μm. A transparent conductive film using metal nanowires as a conductor exhibits conductivity by forming an electrical network between fibrous metal nanowires. Metal nanowires have a high light transmission because the diameter is smaller than the visible light wavelength (400 to 800 nm), and since they are fibrous, a large number of entanglement points can be secured by applying them to the substrate. It is possible to achieve both transparency.
　金属ナノワイヤーは、例えば、液相法、気相法など種々の方法で作製できることが報告されている。金属ナノワイヤーの材質としては、銀、金、銅、コバルトなどが知られている。これらの中でも、銀ナノワイヤーは、高い導電性を有し、液相法で簡便に製造することができるため、優れた導電材料として期待されている。しかし、銀ナノワイヤーは、酸化安定性や硫化物安定性に対して一定の性能が認められるものの、耐熱性に対する課題があることが知られている。そこで、特許文献１では、銀ナノワイヤーの耐熱性を改善するため、銀と、金又は白金とからなる金属ナノワイヤーが提案されている。 It has been reported that metal nanowires can be produced by various methods such as a liquid phase method and a gas phase method. Silver, gold, copper, cobalt, etc. are known as the material of the metal nanowire. Among these, since silver nanowire has high electroconductivity and can be easily manufactured by a liquid phase method, it is anticipated as an excellent conductive material. However, it is known that silver nanowires have a problem with respect to heat resistance, although certain performance is recognized with respect to oxidation stability and sulfide stability. Therefore, Patent Document 1 proposes a metal nanowire made of silver and gold or platinum in order to improve the heat resistance of the silver nanowire.
　また、銀や金などの貴金属に代えて、安価な材料を利用するものとして、特許文献２では、温和な温度条件における液相法による銅ナノワイヤーの製造方法が提案されている。 Further, as a method of using an inexpensive material instead of a noble metal such as silver or gold, Patent Document 2 proposes a method for producing copper nanowires by a liquid phase method under a mild temperature condition.
国際公開ＷＯ２０１１／０７７８９６号（特許請求の範囲など）International Publication WO2011 / 077786 (Claims etc.) 日本国特開２０１３－１９４２９０号公報（特許請求の範囲など）Japanese Unexamined Patent Publication No. 2013-194290 (Claims etc.)
　上記のとおり、銀、銅などの材質による金属ナノワイヤーとその製造方法が多数提案されている。しかし、金属ナノワイヤーの工業的な利用範囲は多岐にわたるため、その使用目的に応じて、特定の機能を有する金属ナノワイヤーを製造する手法が求められている。 As described above, a number of metal nanowires made of materials such as silver and copper and methods for producing the same have been proposed. However, since the industrial use range of metal nanowires is diverse, a technique for producing metal nanowires having a specific function is required depending on the purpose of use.
　本発明の目的は、２種以上の金属から、使用目的に応じた物性や機能性が付与された金属ナノワイヤーを効率良く、簡易に製造することである。 An object of the present invention is to efficiently and easily produce metal nanowires having physical properties and functionality according to the purpose of use from two or more metals.
　本発明の金属ナノワイヤー形成用組成物は、次の成分Ａ～Ｃ；
　（Ａ）標準電極電位が－０．５Ｖから＋０．４Ｖの範囲内である第１金属を含むカルボン酸塩、
　（Ｂ）前記第１金属の標準電極電位よりも高く、且つ標準電極電位が＋０．３Ｖから＋１．０Ｖの範囲内である第２金属を含む金属ハロゲン化物、
及び、
　（Ｃ）１級アミン、
を含有する。 The composition for forming metal nanowires of the present invention includes the following components A to C;
(A) a carboxylate containing a first metal having a standard electrode potential in the range of −0.5 V to +0.4 V;
(B) a metal halide containing a second metal that is higher than the standard electrode potential of the first metal and has a standard electrode potential in the range of +0.3 V to +1.0 V;
as well as,
(C) primary amine,
Containing.
　また、本発明の金属ナノワイヤーの製造方法は、次の工程I及びII；
　I）標準電極電位が－０．５Ｖから＋０．４Ｖの範囲内である第１金属を含むカルボン酸塩と、前記第１金属の標準電極電位よりも高く、且つ標準電極電位が＋０．３Ｖから＋１．０Ｖの範囲内である第２金属を含む金属ハロゲン化物とを１級アミンに溶解して、金属前駆体の混合液を得る工程、
及び、
　II）前記工程Iの後に、前記金属前駆体の混合液を加熱して、第１金属のイオンを還元し、第１金属を析出させるとともに、析出した第１金属と第２金属のイオンとの金属置換反応によって、第２金属のイオンを還元して第２金属を析出させて金属ナノワイヤーに成長させる工程、
を備える。 Moreover, the manufacturing method of the metal nanowire of the present invention includes the following steps I and II;
I) a carboxylate containing a first metal having a standard electrode potential in the range of −0.5 V to +0.4 V, higher than the standard electrode potential of the first metal, and the standard electrode potential from +0.3 V Dissolving a metal halide containing a second metal in a range of +1.0 V in a primary amine to obtain a mixed solution of metal precursors;
as well as,
II) After the step I, the mixed liquid of the metal precursor is heated to reduce the first metal ions to precipitate the first metal, and the deposited first metal and second metal ions. A step of reducing ions of the second metal by a metal substitution reaction to precipitate the second metal and growing the metal nanowires;
Is provided.
　本発明の金属ナノワイヤー形成用組成物及び金属ナノワイヤーの製造方法は、前記第１金属が、Ｆｅ、Ｃｏ、Ｎｉ、Ｓｎ、Ｐｂ及びＣｕからなる群から選ばれる１種以上であってもよく、前記第１金属が、Ｃｏ又はＮｉであることが好ましい。 In the composition for forming metal nanowires and the method for producing metal nanowires of the present invention, the first metal may be one or more selected from the group consisting of Fe, Co, Ni, Sn, Pb, and Cu. The first metal is preferably Co or Ni.
　本発明の金属ナノワイヤー形成用組成物及び金属ナノワイヤーの製造方法は、前記第２金属が、Ｃｕ、Ｒｕ、Ｒｈ、Ａｇ及びＰｄからなる群から選ばれる１種以上であってもよく、前記第２金属が、Ｃｕであることが好ましい。 In the composition for forming metal nanowires and the method for producing metal nanowires of the present invention, the second metal may be one or more selected from the group consisting of Cu, Ru, Rh, Ag, and Pd. The second metal is preferably Cu.
　本発明の金属ナノワイヤー形成用組成物及び金属ナノワイヤーの製造方法は、前記Ａ成分のカルボン酸塩が、ギ酸塩又は酢酸塩であってもよい。 In the composition for forming metal nanowires and the method for producing metal nanowires of the present invention, the carboxylate of the component A may be a formate or an acetate.
　本発明の金属ナノワイヤー形成用組成物及び金属ナノワイヤーの製造方法は、前記Ｂ成分のハロゲン化物が、塩化物であってもよい。 In the composition for forming metal nanowires and the method for producing metal nanowires of the present invention, the halide of the component B may be a chloride.
　本発明の金属ナノワイヤー形成用組成物及び金属ナノワイヤーの製造方法は、前記１級アミンの炭素数が、１４～２０の範囲内であってもよく、前記１級アミンが、オレイルアミンであることが好ましい。 In the composition for forming metal nanowires and the method for producing metal nanowires of the present invention, the primary amine may have a carbon number in the range of 14 to 20, and the primary amine is oleylamine. Is preferred.
　本発明の金属ナノワイヤー形成用組成物及び金属ナノワイヤーの製造方法は、前記第２金属を含む硝酸塩の含有量が、Ｂ成分に対して、０．１モル％以下であってもよい。 In the composition for forming metal nanowires and the method for producing metal nanowires of the present invention, the content of the nitrate containing the second metal may be 0.1 mol% or less with respect to the B component.
　本発明の金属ナノワイヤーは、上記いずれかに記載の方法により製造されたものである。 The metal nanowire of the present invention is produced by any one of the methods described above.
　本発明の金属ナノワイヤーの製造方法によれば、標準電極電位が異なる第１金属と第２金属を含む金属ナノワイヤーを、液相法によって効率良く、簡易に製造することができる。そして、本発明方法によれば、第１金属と第２金属との選択によって、金属ナノワイヤーに所望の物性や機能性を付与することができる。従って、本発明方法によって得られる金属ナノワイヤーは、各種の電子部品や工業製品の材料として広く利用できる。 According to the method for producing a metal nanowire of the present invention, a metal nanowire containing a first metal and a second metal having different standard electrode potentials can be efficiently and easily produced by a liquid phase method. And according to this invention method, desired physical property and functionality can be provided to metal nanowire by selection of the 1st metal and the 2nd metal. Therefore, the metal nanowire obtained by the method of the present invention can be widely used as a material for various electronic parts and industrial products.
　また、本発明の金属ナノワイヤー形成用組成物は、上記金属ナノワイヤーの製造方法に好ましく利用できるものである。 Moreover, the composition for forming metal nanowires of the present invention can be preferably used in the method for producing metal nanowires.
実施例１で得られた金属ナノワイヤーのＳＥＭ（走査型電子顕微鏡）写真である。2 is a SEM (scanning electron microscope) photograph of the metal nanowire obtained in Example 1. 実施例１で得られた金属ナノワイヤーのＸＲＤ測定の結果を示す図面である。It is drawing which shows the result of the XRD measurement of the metal nanowire obtained in Example 1. FIG. 実施例２で得られた金属ナノワイヤーのＳＥＭ（走査型電子顕微鏡）写真である。4 is a SEM (scanning electron microscope) photograph of metal nanowires obtained in Example 2. 実施例２で得られた金属ナノワイヤーのＸＲＤ測定の結果を示す図面である。It is drawing which shows the result of the XRD measurement of the metal nanowire obtained in Example 2. FIG. 実施例３で得られた金属ナノワイヤーのＳＥＭ（走査型電子顕微鏡）写真である。4 is a SEM (scanning electron microscope) photograph of metal nanowires obtained in Example 3. 実施例３で得られた金属ナノワイヤーのＸＲＤ測定の結果を示す図面である。It is drawing which shows the result of the XRD measurement of the metal nanowire obtained in Example 3. FIG.
［金属ナノワイヤー形成用組成物］
　本実施の形態の金属ナノワイヤー形成用組成物は、次の成分Ａ～Ｃ；
　（Ａ）標準電極電位が－０．５Ｖから＋０．４Ｖの範囲内である第１金属を含むカルボン酸塩（以下、「第１金属含有カルボン酸塩」と記すことがある）、
　（Ｂ）前記第１金属の標準電極電位よりも高く、且つ標準電極電位が＋０．３Ｖから＋１．０Ｖの範囲内である第２金属を含む金属ハロゲン化物（以下、「第２金属含有ハロゲン化物」と記すことがある）、
及び、
　（Ｃ）１級アミン、
を含有する。 [Composition for forming metal nanowires]
The composition for forming metal nanowires of the present embodiment includes the following components A to C;
(A) a carboxylate containing a first metal having a standard electrode potential in the range of −0.5 V to +0.4 V (hereinafter sometimes referred to as “first metal-containing carboxylate”),
(B) a metal halide containing a second metal that is higher than the standard electrode potential of the first metal and has a standard electrode potential in the range of +0.3 V to +1.0 V (hereinafter referred to as “second metal-containing halide”). ”),
as well as,
(C) primary amine,
Containing.
（Ａ）成分：第１金属含有カルボン酸塩
（第１金属）
　本実施の形態において、第１金属は、標準電極電位が－０．５Ｖから＋０．４Ｖの範囲内である金属である。第１金属としては、例えばＦｅ（－０．４４Ｖ）、Ｃｏ（－０．２７７Ｖ）、Ｎｉ（－０．２２８Ｖ），Ｓｎ（－０．１３７５Ｖ）、Ｐｂ（－０．１２６Ｖ）、Ｃｕ（０．３３７Ｖ）等を挙げることができる。これらは２種以上を組み合わせて使用してもよい。 (A) component: 1st metal containing carboxylate (1st metal)
In the present embodiment, the first metal is a metal whose standard electrode potential is in the range of −0.5V to + 0.4V. Examples of the first metal include Fe (−0.44 V), Co (−0.277 V), Ni (−0.228 V), Sn (−0.1375 V), Pb (−0.126 V), Cu (0 .337V). You may use these in combination of 2 or more type.
（カルボン酸塩）
　第1金属のカルボン酸塩は、カルボン酸の種類を限定するものではなく、例えば、カルボキシル基が１つのモノカルボン酸であってもよく、また、カルボキシル基が２つ以上のカルボン酸であってもよい。また、カルボン酸塩を構成するカルボン酸は、非環式カルボン酸であってもよく、環式カルボン酸であってもよい。本実施の形態では、熱分解温度が低いことや、安価でコストが低減できるという観点から、非環式モノカルボン酸塩を好適に用いることができる。非環式モノカルボン酸塩としては、例えばギ酸塩、酢酸塩、プロピオン酸塩、シュウ酸塩、安息香酸塩等を挙げることができ、これらの中でも、ギ酸塩又は酢酸塩を用いることがより好ましい。カルボン酸塩は、無水物であってもよく、また水和物であってもよい。 (Carboxylate)
The carboxylate of the first metal is not limited to the type of carboxylic acid. For example, the carboxyl group may be a monocarboxylic acid having one carboxyl group, or a carboxylic acid having two or more carboxyl groups. Also good. Further, the carboxylic acid constituting the carboxylate may be an acyclic carboxylic acid or a cyclic carboxylic acid. In the present embodiment, an acyclic monocarboxylic acid salt can be suitably used from the viewpoint that the thermal decomposition temperature is low and the cost is low and the cost can be reduced. Examples of the acyclic monocarboxylate include formate, acetate, propionate, oxalate, benzoate, etc. Among these, it is more preferable to use formate or acetate. . The carboxylate may be an anhydride or a hydrate.
　好ましい形態として、第１金属がＮｉである場合、そのカルボン酸塩としては、例えばギ酸ニッケル、酢酸ニッケル、プロピオン酸ニッケル、シュウ酸ニッケルなどを挙げることができる。また、第１金属がＣｏである場合、そのカルボン酸塩としては、例えばギ酸コバルト、酢酸コバルト、プロピオン酸コバルト、シュウ酸コバルトなどを挙げることができる。これらは水和物であってもよい。 As a preferred form, when the first metal is Ni, examples of the carboxylate include nickel formate, nickel acetate, nickel propionate, nickel oxalate and the like. When the first metal is Co, examples of the carboxylate include cobalt formate, cobalt acetate, cobalt propionate, and cobalt oxalate. These may be hydrates.
　なお、カルボン酸塩に代えて、塩化物、硝酸塩、硫酸塩、炭酸塩、水酸化物等の無機塩を用いることも考えられるが、無機塩の場合、解離(分解)が高温であるため、解離後の第１金属イオン（又は第１金属の錯体）を還元する過程で更なる高い温度での加熱が必要となるため好ましくない。 In addition, instead of carboxylates, it is also possible to use inorganic salts such as chlorides, nitrates, sulfates, carbonates, hydroxides, etc., but in the case of inorganic salts, dissociation (decomposition) is high temperature, In the process of reducing the first metal ion (or first metal complex) after dissociation, heating at a higher temperature is required, which is not preferable.
　また、第１金属含有カルボン酸塩は、発明の効果を損なわない範囲で、第１金属以外の金属を含有していてもよい。第１金属以外の金属としては、例えば、チタン、クロム、マンガン、アルミニウム、ナトリウム、カリウム、マグネシウム、ジルコニウム、タングステン、モリブデン、バナジウム、バリウム、カルシウム、ストロンチウム、シリコン、アルミニウム、リン等の卑金属、金、白金、イリジウム、オスミウム、レニウム、ネオジウム、ニオブ、ホロニウム、ディスプロヂウム、イットリウム等の貴金属、希土類金属を挙げることができる。これらは、単独で又は２種以上含有していてもよく、これらの合金であってもよい。また、第１金属含有カルボン酸塩は、水素、酸素、炭素、窒素、硫黄、ボロン等の金属元素以外の元素を含有していてもよい。 Further, the first metal-containing carboxylate may contain a metal other than the first metal as long as the effects of the invention are not impaired. Examples of the metal other than the first metal include titanium, chromium, manganese, aluminum, sodium, potassium, magnesium, zirconium, tungsten, molybdenum, vanadium, barium, calcium, strontium, silicon, aluminum, phosphorus, and other base metals, gold, Examples include noble metals such as platinum, iridium, osmium, rhenium, neodymium, niobium, holonium, dysproium, yttrium, and rare earth metals. These may be contained alone or in combination of two or more, and may be alloys thereof. The first metal-containing carboxylate may contain an element other than a metal element such as hydrogen, oxygen, carbon, nitrogen, sulfur, boron.
（Ｂ）成分：第２金属含有ハロゲン化物：
（第２金属）
　本実施の形態において、第２金属は、第１金属の標準電極電位よりも高く、且つ標準電極電位が＋０．３Ｖから＋１．０Ｖの範囲内にある金属である。第２金属としては、例えばＣｕ（０．３３７Ｖ）、Ｒｕ（０．４６Ｖ）、Ｒｈ（０．７５８Ｖ）、Ａｇ（０．７９９１Ｖ）、Ｐｄ（０．９１５Ｖ）等を挙げることができる。これらは２種以上を組み合わせて使用してもよい。 (B) Component: Second metal-containing halide:
(Second metal)
In the present embodiment, the second metal is a metal that is higher than the standard electrode potential of the first metal and has a standard electrode potential in the range of + 0.3V to + 1.0V. Examples of the second metal include Cu (0.337 V), Ru (0.46 V), Rh (0.758 V), Ag (0.7991 V), Pd (0.915 V), and the like. You may use these in combination of 2 or more type.
　本実施の形態においては、例えば、第１金属であるＦｅ、Ｃｏ、Ｎｉ、Ｓｎ、Ｐｂ及びＣｕから選ばれる１種以上と、第２金属であるＣｕ、Ｒｕ、Ｒｈ、Ａｇ及びＰｄから選ばれる１種以上との組み合わせの中から、ＣｕとＣｕとの組み合わせを除くすべての組み合わせを選択することができる。この組み合わせには、第１金属及び／又は第２金属が２種以上である場合も含むことができる。 In the present embodiment, for example, one or more selected from Fe, Co, Ni, Sn, Pb and Cu as the first metal and Cu, Ru, Rh, Ag and Pd as the second metal are selected. All combinations excluding the combination of Cu and Cu can be selected from combinations of one or more. This combination can also include the case where the first metal and / or the second metal are two or more.
（ハロゲン化物）
　第２金属は、上記（Ａ）～（Ｃ）成分の混合液にハロゲン化物イオンを存在させ、後述する金属置換反応によって生成してくる第１金属イオンとの平衡を保つ観点から、陰イオンを生成しやすい塩化物や臭化物などのハロゲン化物が用いられる。ハロゲン化物は、還元されて生成した第１金属の核に対して特定の結晶面にキャッピング剤として吸着し、その結晶面の成長速度が促進されたり、または抑制されたりするために、金属ナノワイヤーの生成を助長するものと考えられる。ハロゲン化物の中でも、第１金属の錯体よりも分解温度を高くする観点から、好ましくは塩化物が用いられる。好ましい形態として、第２金属がＣｕである場合、その塩化物としては、例えば塩化第一銅ＣｕＣｌ、塩化第二銅ＣｕＣｌ２などを挙げることができる。これらは水和物であってもよい。 (Halide)
From the viewpoint of maintaining an equilibrium with the first metal ion generated by the metal substitution reaction described later, the second metal contains halide ions in the mixed solution of the above components (A) to (C). Halides such as chlorides and bromides that are easily formed are used. The halide is adsorbed as a capping agent on a specific crystal plane with respect to the nucleus of the first metal generated by reduction, and the growth rate of the crystal plane is promoted or suppressed. It is thought to promote the generation of. Among halides, chloride is preferably used from the viewpoint of increasing the decomposition temperature as compared with the complex of the first metal. As a preferred form, when the second metal is Cu, examples of the chloride thereof include cuprous chloride CuCl and cupric chloride CuCl 2 . These may be hydrates.
　第２金属が、例えば、酸化物、水酸化物、硝酸塩、硫酸塩、又は、炭酸塩である場合、ある特定の結晶面に吸着しにくいため好ましくない。特に、本実施の形態の金属ナノワイヤー形成用組成物において、第２金属を含む硝酸塩の含有量は、Ｂ成分に対して０．１モル％以下であることが好ましく、当該硝酸塩を含有しないことがより好ましい。第２金属を含む硝酸塩をＢ成分に対して、０．１モル％を超えて含有すると、ハロゲン化物のキャッピング剤としての働きを阻害するため、金属ナノワイヤーの形成反応が進行しない場合がある。 When the second metal is, for example, an oxide, hydroxide, nitrate, sulfate, or carbonate, it is not preferable because it is difficult to adsorb on a specific crystal plane. In particular, in the composition for forming metal nanowires of the present embodiment, the content of the nitrate containing the second metal is preferably 0.1 mol% or less with respect to the B component, and does not contain the nitrate. Is more preferable. When the nitrate containing the second metal is contained in an amount exceeding 0.1 mol% with respect to the component B, the function of the halide as a capping agent is inhibited, and thus the formation reaction of the metal nanowire may not proceed.
　また、第２金属含有ハロゲン化物は、発明の効果を損なわない範囲で、第２金属以外の金属を含有していてもよい。第２金属以外の金属としては、例えば、チタン、クロム、マンガン、アルミニウム、ナトリウム、カリウム、マグネシウム、ジルコニウム、タングステン、モリブデン、バナジウム、バリウム、カルシウム、ストロンチウム、シリコン、アルミニウム、リン等の卑金属、金、白金、イリジウム、オスミウム、レニウム、ネオジウム、ニオブ、ホロニウム、ディスプロヂウム、イットリウム等の貴金属、希土類金属を挙げることができる。これらは、単独で又は２種以上含有していてもよく、これらの合金であってもよい。また、第２金属含有ハロゲン化物は、水素、酸素、炭素、窒素、硫黄、ボロン等の金属元素以外の元素を含有していてもよい。 The second metal-containing halide may contain a metal other than the second metal as long as the effects of the invention are not impaired. Examples of the metal other than the second metal include titanium, chromium, manganese, aluminum, sodium, potassium, magnesium, zirconium, tungsten, molybdenum, vanadium, barium, calcium, strontium, silicon, aluminum, phosphorus, and other base metals, gold, Examples include noble metals such as platinum, iridium, osmium, rhenium, neodymium, niobium, holonium, dysproium, yttrium, and rare earth metals. These may be contained alone or in combination of two or more, and may be alloys thereof. The second metal-containing halide may contain an element other than a metal element such as hydrogen, oxygen, carbon, nitrogen, sulfur, boron.
（Ｃ）成分：１級アミン：
　本実施の形態で使用される１級アミンは、使用温度条件で液体であり、かつ第１金属イオンに配位することで液化し、均一反応溶液を形成すると考えられる。１級アミンは、第１金属のイオンとの錯体を形成することができ、第１金属の錯体（又は第１金属のイオン）に対する還元能を効果的に発揮する。一方、２級アミンは立体障害が大きいため、第１金属の錯体の良好な形成を阻害するおそれがあり、３級アミンは第１金属のイオンの還元能を有しないため、いずれも単独では使用できないが、１級アミンを使用する上で、発明の効果を損なわない範囲でこれらを併用することは差し支えない。１級アミンは、第１金属のイオンとの錯体を形成できるものであればよく、常温で固体又は液体のものが使用できる。ここで、常温とは、２０℃±１５℃をいう。常温で液体の１級アミンは、第１金属の錯体を形成する際の有機溶媒としても機能する。なお、常温で固体の１級アミンであっても、１００℃以上の加熱によって液体であるか、又は有機溶媒を用いて溶解するものであれば、特に問題はない。 Component (C): primary amine:
It is considered that the primary amine used in the present embodiment is liquid at the use temperature condition and liquefies by coordinating with the first metal ion to form a homogeneous reaction solution. The primary amine can form a complex with the first metal ion, and effectively exhibits a reducing ability for the first metal complex (or the first metal ion). On the other hand, secondary amines have great steric hindrance, which may hinder the good formation of complexes of the first metal, and tertiary amines do not have the ability to reduce ions of the first metal, so both are used alone However, when primary amines are used, they can be used in combination as long as the effects of the invention are not impaired. The primary amine is not particularly limited as long as it can form a complex with ions of the first metal, and can be solid or liquid at room temperature. Here, room temperature means 20 ° C. ± 15 ° C. The primary amine that is liquid at room temperature also functions as an organic solvent in forming the complex of the first metal. In addition, even if it is a primary amine solid at normal temperature, there is no particular problem as long as it is liquid by heating at 100 ° C. or higher, or can be dissolved using an organic solvent.
　１級アミンは、芳香族１級アミンであってもよいが、反応液における第１金属の錯体形成の容易性の観点からは脂肪族１級アミンが好適である。脂肪族１級アミンとして、例えばオクチルアミン、トリオクチルアミン、ジオクチルアミン、ヘキサデシルアミン、ドデシルアミン、テトラデシルアミン、ステアリルアミン、オレイルアミン、ミリスチルアミン、ラウリルアミン等を挙げることができる。これらの脂肪族１級アミンの中でも、金属ナノワイヤーの形成効率を高くする観点から、その炭素数が１４～２０の範囲内のものが好ましく、分子内に２重結合を有するオレイルアミンがより好ましい。また、オレイルアミンは、金属ナノワイヤーの生成過程に於ける温度条件下において液体状態として存在するため、均一溶液で反応を効率的に進行できる、という利点も有している。 The primary amine may be an aromatic primary amine, but an aliphatic primary amine is preferable from the viewpoint of easy formation of a complex of the first metal in the reaction solution. Examples of the aliphatic primary amine include octylamine, trioctylamine, dioctylamine, hexadecylamine, dodecylamine, tetradecylamine, stearylamine, oleylamine, myristylamine, laurylamine and the like. Among these aliphatic primary amines, those having a carbon number in the range of 14 to 20 are preferable and oleylamine having a double bond in the molecule is more preferable from the viewpoint of increasing the formation efficiency of metal nanowires. Oleylamine also has an advantage that the reaction can proceed efficiently in a homogeneous solution because it exists in a liquid state under temperature conditions in the process of producing metal nanowires.
　１級アミンは、金属ナノワイヤーの生成時に表面修飾剤として機能するため、１級アミンの除去後においても二次凝集を抑制できる。また、１級アミンは、還元反応後の生成した金属ナノワイヤーの固体成分と溶剤または未反応の１級アミン等を分離する洗浄工程における処理操作の容易性の観点からは室温で液体のものが好ましい。更に、１級アミンは、第１金属の錯体を還元して金属ナノワイヤーを得るときの反応制御の容易性の観点からは還元温度より沸点が高いものが好ましい。すなわち、脂肪族１級アミンにおいては沸点が２００℃以上のものが好ましく、２５０℃以上のものがより好ましく、また、炭素数が１４以上のものが好ましい。例えば炭素数が１８であるオレイルアミンの沸点は３４８℃である。 Since the primary amine functions as a surface modifier when the metal nanowire is produced, secondary aggregation can be suppressed even after removal of the primary amine. In addition, the primary amine is liquid at room temperature from the viewpoint of ease of processing operation in the washing process for separating the solid component of the metal nanowires generated after the reduction reaction and the solvent or the unreacted primary amine. preferable. Further, the primary amine preferably has a boiling point higher than the reduction temperature from the viewpoint of ease of reaction control when the metal nanowire is obtained by reducing the complex of the first metal. That is, the aliphatic primary amine preferably has a boiling point of 200 ° C. or higher, more preferably 250 ° C. or higher, and preferably has 14 or more carbon atoms. For example, the boiling point of oleylamine having 18 carbon atoms is 348 ° C.
　本実施の形態の金属ナノワイヤー形成用組成物は、上記（Ａ）～（Ｃ）成分を混合することによって調製できる。上記（Ａ）～（Ｃ）成分を混合することにより、（Ａ）成分の第１金属含有カルボン酸塩及び（Ｂ）成分の第２金属含有ハロゲン化物を、（Ｃ）成分の１級アミンに溶解させることができる。このようにして、金属ナノワイヤーを形成するための金属前駆体の混合液である金属ナノワイヤー形成用組成物を得ることができる。 The metal nanowire-forming composition of the present embodiment can be prepared by mixing the components (A) to (C). By mixing the above components (A) to (C), the first metal-containing carboxylate of component (A) and the second metal-containing halide of component (B) are converted into primary amines of component (C). Can be dissolved. Thus, the composition for metal nanowire formation which is a liquid mixture of the metal precursor for forming metal nanowire can be obtained.
　（Ａ）成分である第１金属含有カルボン酸塩の配合量は、（Ｂ）成分の第２金属含有ハロゲン化物の配合量１モルに対して、例えば０．０５～２．０モルの範囲内が好ましく、０．１～１．０モルの範囲内がより好ましい。（Ａ）成分の配合量が上記の下限値未満では、金属ナノワイヤーの形成が不十分になることがあり、上記の上限値を超えると、ワイヤー状と粒子状のものが混在することがあるので好ましくない。 The blending amount of the first metal-containing carboxylate as the component (A) is within a range of, for example, 0.05 to 2.0 moles with respect to 1 mole of the blending amount of the second metal-containing halide of the component (B). In the range of 0.1 to 1.0 mol is more preferable. If the blending amount of the component (A) is less than the above lower limit value, the formation of metal nanowires may be insufficient, and if it exceeds the above upper limit value, wire and particulate matter may be mixed. Therefore, it is not preferable.
　（Ｂ）成分である第２金属含有ハロゲン化物の配合量は、第２金属の金属イオンの総量を考慮し、ハロゲン化物イオンの配合量として、第２金属の金属イオン１モルに対して、例えば０．１～５．０モルの範囲内が好ましく、１．０～３．０モルの範囲内がより好ましい。（Ｂ）成分の配合量が上記の下限値未満では、金属ナノワイヤーの形成が不十分になることがあり、上記の上限値を超えると、第２金属の還元を阻害し、不均一な金属ナノワイヤーになることがある。 The blending amount of the second metal-containing halide which is the component (B) is, for example, based on the total amount of metal ions of the second metal, and as the blending amount of halide ions, The range is preferably from 0.1 to 5.0 mol, more preferably from 1.0 to 3.0 mol. If the blending amount of the component (B) is less than the above lower limit value, the formation of metal nanowires may be insufficient, and if the above upper limit value is exceeded, the reduction of the second metal is inhibited, and a non-uniform metal May become nanowire.
　（Ａ）成分である第１金属含有カルボン酸塩と（Ｂ）成分である第２金属含有ハロゲン化物との配合比率は、金属ナノワイヤーの形状、物性、機能性に影響を与える。
　例えば、金属ナノワイヤーのアスペクト比（平均長径／平均短径）を３０～１０００の範囲内にしたい場合は、（Ａ）成分と（Ｂ）成分の配合比率をモル比で０．０５～１．０の範囲内とすることが好ましい。
　また、金属ナノワイヤーに十分な耐酸化性を付与したい場合は、例えば、（Ａ）成分中のＮｉと（Ｂ）成分中のＣｕとの配合比率を、金属元素のモル比で０．５～１．２の範囲内とすることが好ましい。なお、金属ナノワイヤーの形状やアスペクト比は、例えばカルボン酸塩の種類や脂肪族アミンの種類、反応液の濃度などを調整することによっても制御可能である。 The blending ratio of the first metal-containing carboxylate as the component (A) and the second metal-containing halide as the component (B) affects the shape, physical properties, and functionality of the metal nanowire.
For example, when the aspect ratio (average major axis / average minor axis) of the metal nanowire is desired to be within a range of 30 to 1000, the mixing ratio of the component (A) and the component (B) is 0.05 to 1. A range of 0 is preferable.
Further, when it is desired to provide sufficient oxidation resistance to the metal nanowire, for example, the blending ratio of Ni in the component (A) and Cu in the component (B) is 0.5 to 5 in terms of the molar ratio of the metal element. It is preferable to be within the range of 1.2. The shape and aspect ratio of the metal nanowire can be controlled by adjusting, for example, the type of carboxylate, the type of aliphatic amine, the concentration of the reaction solution, and the like.
　（Ｃ）成分である１級アミンの配合量は、第１金属含有カルボン塩と第２金属含有ハロゲン化物の総和を１モルとすると、例えば１．０～１００モルの範囲内が好ましく、２．０～２０．０モルの範囲内がより好ましい。（Ｃ）成分の配合量が上記の下限値未満では、還元剤としての量が不足し、未反応が多くなるとともに、金属ナノワイヤーの形成が不十分になることがあり、上記の上限値を超えると、生産性が低下するので好ましくない。また、金属ナノワイヤー形成用組成物を、目的とする反応温度（還元温度）に於いて均一溶液とするには、（Ｃ）成分の１級アミンが過剰に反応溶液内に存在している必要があり、少なくとも（Ａ）成分中の第１金属のイオン１ｍｏｌに対し２ｍｏｌ以上存在していることが好ましく、２．２ｍｏｌ以上存在していることがより好ましく、４ｍｏｌ以上存在していることが望ましい。１級アミンの量が第１金属のイオン１ｍｏｌに対して２ｍｏｌ未満では、第１金属のイオンの還元が不十分になる場合がある。また、１級アミンの量の上限は特にはないが、例えば生産性の観点からは第１金属のイオン１ｍｏｌに対して２０ｍｏｌ以下とすることが好ましい。 The amount of the primary amine as component (C) is preferably in the range of 1.0 to 100 mol, for example, when the total sum of the first metal-containing carboxylic salt and the second metal-containing halide is 1 mol. A range of 0 to 20.0 mol is more preferable. When the blending amount of the component (C) is less than the above lower limit value, the amount as a reducing agent is insufficient, unreacted amount increases, and formation of metal nanowires may be insufficient. If it exceeds, productivity is lowered, which is not preferable. Moreover, in order to make the composition for forming metal nanowires into a uniform solution at the intended reaction temperature (reduction temperature), the primary amine of component (C) needs to be present in excess in the reaction solution. It is preferable that at least 2 mol per 1 mol of the first metal ion in the component (A) is present, more preferably 2.2 mol or more, and more preferably 4 mol or more. . When the amount of the primary amine is less than 2 mol with respect to 1 mol of the first metal ion, the reduction of the first metal ion may be insufficient. The upper limit of the amount of primary amine is not particularly limited, but is preferably 20 mol or less with respect to 1 mol of ions of the first metal from the viewpoint of productivity, for example.
　本実施の形態の金属ナノワイヤー形成用組成物は、上記（Ａ）～（Ｃ）成分以外に、任意成分として、例えば、有機溶媒、界面活性剤、分散剤、還元剤、金属ナノ粒子などを含有することができる。 In addition to the components (A) to (C), the composition for forming metal nanowires of the present embodiment includes, as optional components, for example, an organic solvent, a surfactant, a dispersant, a reducing agent, metal nanoparticles, and the like. Can be contained.
　以上のようにして得られる本実施の形態の金属ナノワイヤー形成用組成物は、金属ナノワイヤーの製造に好ましく利用できる。例えば、金属ナノワイヤー形成用組成物において、加熱還元、水熱合成、還元剤による還元等によって、第１金属を析出させるとともに、析出した第１金属と第２金属のイオンとの金属置換反応によって第２金属のイオンを還元して第２金属を析出させ、第１金属と第２金属とを含有する金属ナノワイヤーを製造することができる。 The composition for forming metal nanowires of the present embodiment obtained as described above can be preferably used for producing metal nanowires. For example, in the composition for forming metal nanowires, the first metal is deposited by heat reduction, hydrothermal synthesis, reduction with a reducing agent, and the like, and by metal substitution reaction between the deposited first metal and second metal ions. The metal nanowire containing a 1st metal and a 2nd metal can be manufactured by reduce | restoring the ion of a 2nd metal, and depositing a 2nd metal.
［金属ナノワイヤーの製造方法］
　次に、金属ナノワイヤーの製造方法について説明する。本実施の形態の金属ナノワイヤーの製造方法は、次の工程I及びII；
　I）標準電極電位が－０．５Ｖから＋０．４Ｖの範囲内である第１金属を含むカルボン酸塩と、第１金属の標準電極電位よりも高く、且つ標準電極電位が＋０．３Ｖから＋１．０Ｖの範囲内である第２金属を含む金属ハロゲン化物とを１級アミンに溶解して、金属前駆体の混合液を得る工程、
及び、
　II）工程Iの後に、金属前駆体の混合液を加熱して、第１金属のイオンを還元し、第１金属を析出させるとともに、析出した第１金属と第２金属のイオンとの金属置換反応によって、第２金属のイオンを還元して第２金属を析出させて金属ナノワイヤーに成長させる工程、
を備えている。 [Production method of metal nanowires]
Next, the manufacturing method of metal nanowire is demonstrated. The method for producing metal nanowires of the present embodiment includes the following steps I and II;
I) a carboxylate containing a first metal whose standard electrode potential is in the range of −0.5 V to +0.4 V, higher than the standard electrode potential of the first metal, and the standard electrode potential is +0.3 V to +1 Dissolving a metal halide containing a second metal in the range of 0.0 V in a primary amine to obtain a mixed solution of metal precursors;
as well as,
II) After Step I, the mixed liquid of the metal precursor is heated to reduce the first metal ions to precipitate the first metal and to replace the deposited first metal and second metal ions with each other. A step of reducing ions of the second metal by reaction to precipitate the second metal and growing the metal nanowires;
It has.
＜工程I：金属前駆体の混合液を得る工程＞
　工程Iでは、上記（Ａ）～（Ｃ）成分を混合することによって、（Ａ）成分の第１金属含有カルボン酸塩及び（Ｂ）成分の第２金属含有ハロゲン化物を、（Ｃ）成分の１級アミンに溶解させ、金属前駆体の混合液を得る。第２金属含有ハロゲン化物としては、第２金属の塩化物が好ましい。なお、工程Iで用いる金属前駆体の混合液としては、前記金属ナノワイヤー形成用組成物をそのまま利用できる。 <Step I: Step of obtaining mixed liquid of metal precursor>
In Step I, by mixing the components (A) to (C), the first metal-containing carboxylate of component (A) and the second metal-containing halide of component (B) are converted into the component (C). Dissolve in a primary amine to obtain a mixture of metal precursors. The second metal-containing halide is preferably a second metal chloride. The metal nanowire-forming composition can be used as it is as the mixed liquid of the metal precursor used in Step I.
　工程Ｉでは、上記（Ａ）～（Ｃ）成分を混合した後、例えば３０～１７０℃の範囲内に加熱することが好ましい。第１金属のイオンと１級アミンとの錯形成反応は室温に於いても進行することができるが、十分且つ、より効率の良い錯形成反応を行うために、１００℃～１６５℃の範囲内の温度に加熱して反応を行うことが好ましい。この加熱は、第１金属含有カルボン酸塩として、例えばギ酸ニッケル２水和物や酢酸ニッケル４水和物のような水和物を用いた場合に特に有利である。加熱温度は、好ましくは１００℃を超える温度とし、より好ましくは１０５℃以上の温度とすることで、カルボン酸塩に配位した配位水と１級アミンとの配位子置換反応が効率よく行われ、この錯体配位子としての水分子を解離させることができ、さらにその水を系外に出すことができるので効率よく錯体を形成させることができる。例えば、ギ酸ニッケル２水和物は、室温では２個の配位水と２座配位子である２個のギ酸イオンが存在した錯体構造をとっているため、この２つの配位水と１級アミンの配位子置換により効率よく錯形成させるには、１００℃より高い温度で加熱することでこの錯体配位子としての水分子を解離させることが好ましい。また、カルボン酸ニッケルと１級アミンとの錯形成反応における熱処理は、後に続く工程IIの加熱還元の過程と確実に分離し、前記の錯形成反応を完結させるという観点から、上記の上限温度以下とし、好ましくは１６０℃以下、より好ましくは１５０℃以下とすることがよい。 In step I, it is preferable that the components (A) to (C) are mixed and then heated, for example, within a range of 30 to 170 ° C. The complexing reaction between the primary metal ion and the primary amine can proceed even at room temperature, but in the range of 100 ° C. to 165 ° C. in order to perform a sufficient and more efficient complexing reaction. It is preferable to carry out the reaction by heating to a temperature of. This heating is particularly advantageous when a hydrate such as nickel formate dihydrate or nickel acetate tetrahydrate is used as the first metal-containing carboxylate. The heating temperature is preferably a temperature exceeding 100 ° C., more preferably a temperature of 105 ° C. or more, so that the ligand substitution reaction between the coordinated water coordinated to the carboxylate and the primary amine is efficiently performed. The water molecule as the complex ligand can be dissociated, and the water can be discharged out of the system, so that the complex can be formed efficiently. For example, nickel formate dihydrate has a complex structure in which two coordination waters and two formate ions as bidentate ligands exist at room temperature. In order to efficiently form a complex by substituting a ligand for a primary amine, it is preferable to dissociate the water molecule as the complex ligand by heating at a temperature higher than 100 ° C. In addition, the heat treatment in the complex formation reaction between nickel carboxylate and primary amine is reliably separated from the subsequent heat reduction process in Step II, and the complex formation reaction is completed in order to complete the complex formation reaction. And preferably 160 ° C. or lower, more preferably 150 ° C. or lower.
　加熱時間は、加熱温度や、各原料の含有量に応じて適宜決定することができるが、錯形成反応を完結させるという観点から、１０分以上とすることが好ましい。加熱時間の上限は特にないが、長時間熱処理することはエネルギー消費及び工程時間を節約する観点から無駄である。なお、この加熱の方法は、特に制限されず、マイクロ波、オイルバス、ホットプレート、赤外線ヒーターなどを利用することができる。 The heating time can be appropriately determined according to the heating temperature and the content of each raw material, but is preferably 10 minutes or more from the viewpoint of completing the complex formation reaction. There is no upper limit on the heating time, but heat treatment for a long time is useless from the viewpoint of saving energy consumption and process time. The heating method is not particularly limited, and a microwave, an oil bath, a hot plate, an infrared heater, or the like can be used.
　工程Iでは、均一溶液での反応をより効率的に進行させるために、１級アミンとは別の有機溶媒を新たに添加してもよい。有機溶媒を用いる場合、有機溶媒を上記（Ａ）～（Ｃ）成分と同時に混合してもよいが、上記（Ａ）～（Ｃ）成分を先ず混合した後に有機溶媒を加えると、１級アミンが効率的にニッケル原子に配位するので、より好ましい。使用できる有機溶媒としては、１級アミンとニッケルイオンとの錯形成を阻害しないものであれば、特に限定するものではなく、例えば炭素数４～３０のエーテル系有機溶媒、炭素数７～３０の飽和又は不飽和の炭化水素系有機溶媒、炭素数８～１８のアルコール系有機溶媒等を使用することができる。また、加熱条件下でも使用を可能とする観点から、有機溶媒は、沸点が１７０℃以上のものを選択することが好ましく、より好ましくは２００～３００℃の範囲内にあるものを選択することがよい。このような有機溶媒の具体例としては、例えばテトラエチレングリコール、ｎ－オクチルエーテル等が挙げられる。 In step I, an organic solvent other than the primary amine may be newly added to allow the reaction in the homogeneous solution to proceed more efficiently. When an organic solvent is used, the organic solvent may be mixed at the same time as the above components (A) to (C). However, if the organic solvent is added after first mixing the above components (A) to (C), the primary amine is added. Is more preferable because it efficiently coordinates to a nickel atom. The organic solvent that can be used is not particularly limited as long as it does not inhibit the complex formation between the primary amine and the nickel ion. For example, the organic solvent having 4 to 30 carbon atoms, the organic solvent having 7 to 30 carbon atoms, and the like. A saturated or unsaturated hydrocarbon organic solvent, an alcohol organic solvent having 8 to 18 carbon atoms, or the like can be used. Further, from the viewpoint of enabling use even under heating conditions, it is preferable to select an organic solvent having a boiling point of 170 ° C. or more, more preferably a solvent having a temperature in the range of 200 to 300 ° C. Good. Specific examples of such an organic solvent include tetraethylene glycol and n-octyl ether.
＜工程II：還元工程＞
　工程IIでは、工程Iで得た金属前駆体の混合液を加熱することによって第１金属のイオンを還元し、第１金属を析出させる。また、工程IIでは、析出した第１金属と第２金属のイオンとの金属置換反応によって、第２金属のイオンを還元して、第２金属を析出させる。このように、工程IIでは、液相での湿式還元法により、金属ナノワイヤーを製造する。 <Process II: Reduction process>
In Step II, the mixed metal of the metal precursor obtained in Step I is heated to reduce the first metal ions to precipitate the first metal. In Step II, the second metal ion is reduced by the metal substitution reaction between the deposited first metal ion and the second metal ion to precipitate the second metal. Thus, in the process II, metal nanowire is manufactured by the wet reduction method in a liquid phase.
　本工程では、工程Iで得た金属前駆体の混合液を、１７０℃以上の温度に加熱する。金属前駆体の混合液を加熱する温度は、得られる金属ナノワイヤーの形状のばらつきを抑制するという観点から、好ましくは１８０℃以上、より好ましくは１９０℃以上とすることがよい。加熱温度の上限は特にないが、処理を能率的に行う観点からは例えば２７０℃以下とすることが好適である。なお、加熱温度は、例えば第１金属及び第２金属の種類や、核となる金属微粒子の発生を促進させるための添加剤の使用などによって、適宜調整することができる。 In this step, the mixed liquid of the metal precursor obtained in step I is heated to a temperature of 170 ° C. or higher. The temperature at which the mixed liquid of the metal precursor is heated is preferably 180 ° C. or higher, more preferably 190 ° C. or higher, from the viewpoint of suppressing variation in the shape of the obtained metal nanowires. The upper limit of the heating temperature is not particularly limited, but is preferably set to 270 ° C. or less, for example, from the viewpoint of efficiently performing the treatment. The heating temperature can be appropriately adjusted depending on, for example, the types of the first metal and the second metal and the use of an additive for promoting the generation of metal fine particles serving as a nucleus.
　本工程では、金属前駆体の混合液を加熱する方法は特に問わない。加熱方法としては、例えば、マイクロ波、オイルバス、ホットプレート、赤外線ヒーターなどを利用することができる。これらの加熱方法の中でも、マイクロ波による加熱を利用することが好ましい。マイクロ波は、金属前駆体の混合液内に浸透するため、均一加熱が行われ、かつ、エネルギーを媒体に直接与えることができるため、急速加熱を行うことができる。これにより、金属前駆体の混合液全体を所望の温度に均一にすることができ、第１金属のイオンの還元、核生成、第２金属のイオンとの金属置換反応による第２金属の生成、金属ナノワイヤーへの成長などの過程を溶液全体において同時に生じさせ、結果として形状が均一な金属ナノワイヤーを短時間で容易に製造することができる。なお、マイクロ波の使用波長は、特に限定されるものではなく、例えば２．４５ＧＨｚである。 In this step, the method for heating the mixed liquid of the metal precursor is not particularly limited. As a heating method, for example, a microwave, an oil bath, a hot plate, an infrared heater, or the like can be used. Among these heating methods, it is preferable to use microwave heating. Since the microwave penetrates into the mixed liquid of the metal precursor, uniform heating is performed and energy can be directly applied to the medium, so that rapid heating can be performed. Thereby, the whole liquid mixture of the metal precursor can be made uniform at a desired temperature, and the reduction of the first metal ions, the nucleation, the generation of the second metal by the metal substitution reaction with the second metal ions, Processes such as growth into metal nanowires can occur simultaneously in the entire solution, and as a result, metal nanowires having a uniform shape can be easily produced in a short time. In addition, the use wavelength of a microwave is not specifically limited, For example, it is 2.45 GHz.
　マイクロ波照射によって加熱して得られる金属ナノワイヤーのスラリーを、例えば、静置分離し、上澄み液を取り除いた後、適当な溶媒を用いて洗浄し、乾燥することで、金属ナノワイヤーが得られる。工程IIでは、必要に応じ、前述した有機溶媒を加えてもよいが、１級アミンを有機溶媒としてそのまま用いることが好ましい。 The metal nanowire slurry obtained by heating by microwave irradiation is, for example, statically separated, and after removing the supernatant liquid, the metal nanowire is obtained by washing with an appropriate solvent and drying. . In Step II, the above-described organic solvent may be added as necessary, but it is preferable to use a primary amine as it is as an organic solvent.
　以上のようにして、金属ナノワイヤーを調製することができる。このようにして製造された金属ナノワイヤーは、例えば平均短径（太さ）が１０～３００ｎｍの範囲内、平均長径（長さ）が１．０～３０．０μｍの範囲内であり、アスペクト比（平均長径／平均短径）が３０～１０００である繊維状の形態を有するものとなる。 The metal nanowire can be prepared as described above. The metal nanowires thus produced have, for example, an average minor axis (thickness) in the range of 10 to 300 nm, an average major axis (length) in the range of 1.0 to 30.0 μm, and an aspect ratio The fiber has a fibrous form (average major axis / average minor axis) of 30 to 1,000.
　本実施の形態の金属ナノワイヤーの製造方法では、第２金属中に第１金属が均一に分布した金属ナノワイヤーが得られる。本実施の形態で得られる金属ナノワイヤーにおける第１金属と第２金属の含有比率は、耐酸化性や触媒特性の向上、磁性特性の付与の観点から、例えば第１金属が０．０１～３０質量％の範囲内であり、第２金属が７０～９９．９質量％の範囲内であることが好ましく、第１金属が０．１～５．０質量％の範囲内であり、第２金属が９５．０～９９．９質量％の範囲内であることがより好ましい。 In the metal nanowire manufacturing method of the present embodiment, metal nanowires in which the first metal is uniformly distributed in the second metal are obtained. The content ratio of the first metal and the second metal in the metal nanowire obtained in the present embodiment is, for example, 0.01 to 30 for the first metal from the viewpoint of improving oxidation resistance, catalytic properties, and imparting magnetic properties. The second metal is preferably in the range of 70 to 99.9% by mass, the first metal is in the range of 0.1 to 5.0% by mass, and the second metal Is more preferably in the range of 95.0 to 99.9% by mass.
　本実施の形態で得られる金属ナノワイヤーは、多数の長尺な金属粒子の集合体として繊維状をなしており、多数の交絡点が確保できるため、例えば、塗布法、印刷法などの簡易な適用方法によって導電性に優れた金属層を形成できる。従って、本実施の形態で得られる金属ナノワイヤーは、例えば、電極材料、電磁波シールド材料、熱伝導材料、接合材料、触媒等として、ディスプレイ、タッチパネル、電子回路、各種センサ、太陽電池などの多様な電子部品や工業製品に好適に用いることができる。 The metal nanowire obtained in the present embodiment has a fibrous shape as an aggregate of a large number of long metal particles, and a large number of entanglement points can be secured. For example, a simple coating method, a printing method, etc. Depending on the application method, a metal layer having excellent conductivity can be formed. Therefore, the metal nanowires obtained in the present embodiment can be used in various applications such as displays, touch panels, electronic circuits, various sensors, solar cells, etc. as electrode materials, electromagnetic wave shielding materials, heat conduction materials, bonding materials, catalysts, etc. It can be suitably used for electronic parts and industrial products.
＜作用＞
　次に、本発明の作用について説明する。本発明方法では、２段階の還元反応によって、金属ナノワイヤーが形成される。すなわち、まず、金属前駆体の混合液の加熱によって、第１金属イオンの還元反応が進行し、第１金属が析出する。次に、析出した第１金属と第２金属イオンとの金属置換反応によって、第２金属イオンが還元されて、第２金属が析出する。ここで、第１金属がニッケル、第２金属が銅である場合を例に挙げて還元反応の機構を説明する。 <Action>
Next, the operation of the present invention will be described. In the method of the present invention, metal nanowires are formed by a two-step reduction reaction. That is, first, the reduction reaction of the first metal ions proceeds by heating the mixed liquid of the metal precursor, and the first metal is deposited. Next, the second metal ion is reduced by the metal substitution reaction between the deposited first metal and the second metal ion, and the second metal is deposited. Here, the mechanism of the reduction reaction will be described by taking as an example the case where the first metal is nickel and the second metal is copper.
　ニッケルと銅は標準電極電位が異なるため、異なる温度で還元および粒子生成が起きる（例えば、Ｎｉ２＋　４６３Ｋ、Ｃｕ２＋　４３３Ｋ、）。一般的条件では、先に金属銅が生成し、昇温するにつれて金属銅を核として金属ニッケルが生成するものと考えられる。しかし、本実施の形態で用いるカルボン酸ニッケルおよびハロゲン化銅は、過剰の１級アミン（例えばオレイルアミン）の存在下で加熱を行うことによって、カルボン酸ニッケルの方がハロゲン化銅よりも低い温度で先に熱分解するとともに、遊離したニッケルイオンが１級アミンの還元作用により還元されて金属ニッケルが生成する。次に、金属ニッケルと銅イオンとの金属置換反応によって、金属銅が形成されるものと考えられる。ここで、金属置換反応とは、金属間の標準電極電位の差によって、０価の金属が酸化してイオン化され、イオンである金属が還元される反応である。 Since nickel and copper have different standard electrode potentials, reduction and particle formation occur at different temperatures (eg, Ni 2+ 463K, Cu 2+ 433K). Under general conditions, it is considered that metallic copper is first produced, and metallic nickel is produced with metallic copper as a nucleus as the temperature rises. However, the nickel carboxylate and copper halide used in the present embodiment are heated in the presence of excess primary amine (for example, oleylamine), so that the nickel carboxylate is at a lower temperature than the copper halide. While being thermally decomposed first, the released nickel ions are reduced by the reducing action of the primary amine to produce metallic nickel. Next, it is considered that metallic copper is formed by a metal substitution reaction between metallic nickel and copper ions. Here, the metal substitution reaction is a reaction in which a zero-valent metal is oxidized and ionized and a metal that is an ion is reduced by a difference in standard electrode potential between the metals.
　また、第１段階の還元反応では、金属前駆体の混合液中で、カルボン酸ニッケルと１級アミンとの錯体（ニッケル錯体）が加熱され、ニッケル錯体のニッケルイオンが還元され、ニッケルイオンに配位しているカルボン酸イオンが同時に分解し、酸化数が０価の金属ニッケル微粒子が多数生成する。この多数の金属ニッケル微粒子が、金属ナノワイヤーの核として機能する。金属前駆体の混合液中では、加熱によって、多数の金属ニッケル微粒子のそれぞれの表面において、金属ニッケルと銅イオンとの金属置換反応が進行し、銅イオンが還元されて、金属銅が生成する。生成した金属銅は、塩化物イオンが特定の結晶面に吸着することで、異方性をもって成長し、長尺な金属ナノワイヤーを形成する。 In the first stage reduction reaction, a complex of nickel carboxylate and primary amine (nickel complex) is heated in the mixed solution of metal precursors, and the nickel ions of the nickel complex are reduced and distributed to the nickel ions. At the same time, a large number of fine nickel metal particles having an oxidation number of 0 are generated. The large number of metal nickel fine particles function as the core of the metal nanowire. In the mixed liquid of the metal precursor, the metal substitution reaction between the metal nickel and the copper ions proceeds on each surface of the many metal nickel fine particles by heating, and the copper ions are reduced to produce metal copper. The produced copper metal grows with anisotropy by adsorbing chloride ions to specific crystal planes, and forms long metal nanowires.
　以上のような２段階の反応機構によって、本実施の形態では、第２金属（例えば銅）中に第１金属（例えばニッケル）が均一に分布した合金による金属ナノワイヤーを製造することが可能となる。また、本実施の形態で得られる金属ナノワイヤーは、第１金属と第２金属との選択によって、金属ナノワイヤーに所望の物性や機能性を付与することができる。例えば、好ましい組み合わせとして、第１金属として耐酸化性に優れたＮｉ、第２金属としてＣｕを組み合わせることによって、金属ナノワイヤーに耐酸化性を付与することができる。また、第１金属として融点の低いＳｎ、第２金属として導電性に優れたＡｇを組み合わせることによって、金属ナノワイヤーの導電率や融点を調節できる。また、第１金属としてＮｉ、第２金属としてＰｄの組み合わせによって、金属ナノワイヤーに触媒性能を付与することができる。 With the two-stage reaction mechanism as described above, in this embodiment, it is possible to manufacture metal nanowires using an alloy in which a first metal (for example, nickel) is uniformly distributed in a second metal (for example, copper). Become. Moreover, the metal nanowire obtained by this Embodiment can provide a desired physical property and functionality to a metal nanowire by selection of a 1st metal and a 2nd metal. For example, as a preferred combination, oxidation resistance can be imparted to the metal nanowire by combining Ni having excellent oxidation resistance as the first metal and Cu as the second metal. Moreover, the electrical conductivity and melting | fusing point of metal nanowire can be adjusted by combining Sn with low melting | fusing point as a 1st metal, and Ag excellent in electroconductivity as a 2nd metal. Moreover, catalytic performance can be imparted to the metal nanowires by a combination of Ni as the first metal and Pd as the second metal.
　次に、本発明を実施例によって具体的に説明するが、本発明はこれらの実施例によって何ら限定されるものではない。なお、本発明の実施例において特にことわりのない限り、各種測定、評価は下記によるものである。 Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the examples of the present invention, various measurements and evaluations are as follows unless otherwise specified.
［実施例１］
＜金属前駆体の混合液の調製＞
　６９０ｇのオレイルアミンに、２７．２ｇの塩化銅二水和物及び１４．５ｇのギ酸ニッケル二水和物を加え、窒素フロー下で１２０℃、２０分加熱することによって、金属前駆体の混合液１を得た。 [Example 1]
<Preparation of mixed liquid of metal precursor>
To 690 g of oleylamine, 27.2 g of copper chloride dihydrate and 14.5 g of nickel formate dihydrate were added and heated at 120 ° C. for 20 minutes under a nitrogen flow to obtain a metal precursor mixture 1 Got.
＜還元工程＞
　次いで、その混合液１にマイクロ波を照射して１９０～２５０℃の範囲で５分間加熱することによって、金属ナノワイヤーのスラリー１を得た。 <Reduction process>
Next, the mixed liquid 1 was irradiated with microwaves and heated in the range of 190 to 250 ° C. for 5 minutes to obtain a metal nanowire slurry 1.
＜洗浄・乾燥工程＞
　得られたスラリー１を静置分離し、上澄み液を取り除いた後、トルエンとメタノールを用いてそれぞれ２回洗浄した後、６０℃に維持される真空乾燥機で６時間乾燥して金属ナノワイヤー１を得た。 <Washing and drying process>
The obtained slurry 1 was allowed to stand and separated, and the supernatant was removed. Then, the slurry 1 was washed twice with toluene and methanol, and then dried for 6 hours in a vacuum dryer maintained at 60 ° C. Got.
　金属ナノワイヤー１のＳＥＭ（走査型電子顕微鏡）写真を図１に示す。図１を参照すると、太さが３０～１００ｎｍ、長さが５μｍ以上の繊維状の金属であることが確認された。元素分析の結果、Ｃｕ；８５．８、Ｎｉ；０．１８、Ｏ；６．０（単位は質量％）であった。また、ＸＲＤ測定の結果を図２に示す。図２より、得られた金属ナノワイヤー１は、ｆｃｃ構造を有することが確認された。 An SEM (scanning electron microscope) photograph of the metal nanowire 1 is shown in FIG. Referring to FIG. 1, it was confirmed to be a fibrous metal having a thickness of 30 to 100 nm and a length of 5 μm or more. As a result of elemental analysis, it was Cu; 85.8, Ni; 0.18, O; 6.0 (unit: mass%). The results of XRD measurement are shown in FIG. From FIG. 2, it was confirmed that the obtained metal nanowire 1 has an fcc structure.
　本実施例のようにアスペクト比が大きい金属ナノワイヤーは、透明導電膜などへの応用が期待できる。 The metal nanowire having a large aspect ratio as in this example can be expected to be applied to a transparent conductive film.
［実施例２］
＜金属前駆体の混合液の調製＞
　６９０ｇのオレイルアミンに、２７．２ｇの塩化銅二水和物及び２０．０ｇの酢酸ニッケル四水和物を加え、窒素フロー下で１２０℃、２０分加熱することによって、金属前駆体の混合液２を得た。 [Example 2]
<Preparation of mixed liquid of metal precursor>
To 690 g of oleylamine, 27.2 g of copper chloride dihydrate and 20.0 g of nickel acetate tetrahydrate were added and heated at 120 ° C. for 20 minutes under a nitrogen flow to obtain a metal precursor mixture 2 Got.
＜還元工程＞
　次いで、その混合液２にマイクロ波を照射して２３５～２５０℃の範囲で５分間加熱することによって、金属ナノワイヤーのスラリー２を得た。 <Reduction process>
Next, the mixed liquid 2 was irradiated with microwaves and heated in the range of 235 to 250 ° C. for 5 minutes to obtain a slurry 2 of metal nanowires.
＜洗浄・乾燥工程＞
　得られたスラリー２を静置分離し、上澄み液を取り除いた後、トルエンとメタノールを用いてそれぞれ２回洗浄した後、６０℃に維持される真空乾燥機で６時間乾燥して金属ナノワイヤー２を得た。 <Washing and drying process>
The obtained slurry 2 was allowed to stand and separated, and after removing the supernatant, each was washed twice with toluene and methanol, and then dried for 6 hours in a vacuum dryer maintained at 60 ° C. Got.
　金属ナノワイヤー２のＳＥＭ（走査型電子顕微鏡）写真を図３に示す。図３を参照すると、太さが１００～２００ｎｍ、長さが５μｍ以上の繊維状の金属であることが確認された。元素分析の結果、Ｃｕ；９４．７、Ｎｉ；０．２８、Ｏ；３．０（単位は質量％）であった。また、ＸＲＤ測定の結果を図４に示す。図４より、得られた金属ナノワイヤー２は、ｆｃｃ構造を有することが確認された。 An SEM (scanning electron microscope) photograph of the metal nanowire 2 is shown in FIG. Referring to FIG. 3, it was confirmed to be a fibrous metal having a thickness of 100 to 200 nm and a length of 5 μm or more. As a result of elemental analysis, it was Cu; 94.7, Ni; 0.28, O; 3.0 (unit: mass%). The results of XRD measurement are shown in FIG. From FIG. 4, it was confirmed that the obtained metal nanowire 2 has an fcc structure.
　本実施例のように第１金属のカルボン酸塩の種類を変えることで、金属ナノワイヤーの太さを調整でき、酸化量を制御できる。 As in this example, the thickness of the metal nanowire can be adjusted and the amount of oxidation can be controlled by changing the type of the first metal carboxylate.
［実施例３］
＜金属前駆体の混合液の調製＞
　６９０ｇのオレイルアミンに、５４．４ｇの塩化銅二水和物及び２９．０ｇのギ酸ニッケル四水和物を加え、窒素フロー下で１２０℃、２０分加熱することによって、金属前駆体の混合液３を得た。 [Example 3]
<Preparation of mixed liquid of metal precursor>
To 690 g of oleylamine, 54.4 g of copper chloride dihydrate and 29.0 g of nickel formate tetrahydrate were added and heated at 120 ° C. for 20 minutes under a nitrogen flow to obtain a metal precursor mixture 3 Got.
＜還元工程＞
　次いで、その混合液３にマイクロ波を照射して１９０～２３５℃の範囲で５分間加熱することによって、金属ナノワイヤーのスラリー３を得た。 <Reduction process>
Next, the mixed solution 3 was irradiated with microwaves and heated in the range of 190 to 235 ° C. for 5 minutes to obtain a slurry 3 of metal nanowires.
＜洗浄・乾燥工程＞
　得られたスラリー３を静置分離し、上澄み液を取り除いた後、トルエンとメタノールを用いてそれぞれ２回洗浄した後、６０℃に維持される真空乾燥機で６時間乾燥して金属ナノワイヤー３を得た。 <Washing and drying process>
The obtained slurry 3 was allowed to stand and separated, and the supernatant liquid was removed, followed by washing twice with toluene and methanol, and then drying for 6 hours with a vacuum dryer maintained at 60 ° C. Got.
　金属ナノワイヤー３のＳＥＭ（走査型電子顕微鏡）写真を図５に示す。図５を参照すると、太さが１００ｎｍ前後、長さが５μｍ以上の繊維状の金属であることが確認された。元素分析の結果、Ｃｕ；９２．５、Ｎｉ；０．４５、Ｏ；４．５（単位は質量％）であった。また、ＸＲＤ測定の結果を図６に示す。図６より、得られた金属ナノワイヤー３は、ｆｃｃ構造を有することが確認された。 An SEM (scanning electron microscope) photograph of the metal nanowire 3 is shown in FIG. Referring to FIG. 5, it was confirmed to be a fibrous metal having a thickness of around 100 nm and a length of 5 μm or more. As a result of elemental analysis, Cu was 92.5, Ni was 0.45, and O was 4.5 (unit: mass%). The results of XRD measurement are shown in FIG. From FIG. 6, it was confirmed that the obtained metal nanowire 3 has an fcc structure.
　本実施例のように、金属前駆体の混合液の濃度を変えることで、金属ナノワイヤーの太さを調整でき、酸化量を制御できる。 As in this example, the thickness of the metal nanowire can be adjusted and the amount of oxidation can be controlled by changing the concentration of the mixed liquid of the metal precursor.
（比較例１）
＜金属前駆体の混合液の調製＞
　６９０ｇのオレイルアミンに、２７．２ｇの塩化銅二水和物を加え、窒素フロー下で１２０℃、２０分加熱することによって、金属前駆体の混合液を得た。 (Comparative Example 1)
<Preparation of mixed liquid of metal precursor>
27.2 g of copper chloride dihydrate was added to 690 g of oleylamine, and the mixture was heated at 120 ° C. for 20 minutes under a nitrogen flow to obtain a mixture of metal precursors.
＜還元工程＞
　次いで、その混合液にマイクロ波を照射して２３５～２５０℃の範囲で５分間加熱したが、未反応であった。 <Reduction process>
Next, the mixture was irradiated with microwaves and heated in the range of 235 to 250 ° C. for 5 minutes, but was not reacted.
　本比較例１と実施例１と比較により、第１金属のカルボン酸塩が存在しない場合は金属ナノワイヤーが形成されておらず、第１金属のとの金属置換反応によって塩化銅の還元反応が進行していることが確認された。 In comparison with Comparative Example 1 and Example 1, when no carboxylate of the first metal is present, metal nanowires are not formed, and the reduction reaction of copper chloride is caused by a metal substitution reaction with the first metal. It was confirmed that it was progressing.
（比較例２）
＜金属前駆体の混合液の調製＞
　６９０ｇのオレイルアミンに、２７．２ｇの塩化銅二水和物及び０．１６ｇの硝酸銀を加え、窒素フロー下で１２０℃、２０分加熱することによって、金属前駆体の混合液を得た。 (Comparative Example 2)
<Preparation of mixed liquid of metal precursor>
27.2 g of copper chloride dihydrate and 0.16 g of silver nitrate were added to 690 g of oleylamine, and heated at 120 ° C. for 20 minutes under a nitrogen flow to obtain a metal precursor mixture.
＜還元工程＞
　次いで、その混合液にマイクロ波を照射して２３５～２５０℃の範囲で５分間加熱したが、未反応であった。 <Reduction process>
Next, the mixture was irradiated with microwaves and heated in the range of 235 to 250 ° C. for 5 minutes, but was not reacted.
　本比較例と実施例１との比較により、第２金属である銅の標準電極電位よりも高い銀の硝酸塩との組み合わせでは、第２金属イオンは還元されないことが確認された。 Comparison between this comparative example and Example 1 confirmed that the second metal ions were not reduced in combination with silver nitrate higher than the standard electrode potential of copper as the second metal.
（比較例３）
＜金属前駆体の混合液の調製＞
　６９０ｇのオレイルアミンに、２９．８ｇのギ酸銅二水和物および１４．５ｇのギ酸ニッケル二水和物を加え、窒素フロー下で１２０℃、２０分加熱することによって、金属前駆体の混合液を得た。 (Comparative Example 3)
<Preparation of mixed liquid of metal precursor>
To 690 g of oleylamine, 29.8 g of copper formate dihydrate and 14.5 g of nickel formate dihydrate were added, and heated at 120 ° C. for 20 minutes under a nitrogen flow to thereby mix the metal precursor mixture. Obtained.
　＜還元工程＞
　次いで、その混合液にマイクロ波を照射して１９０～２５０℃の範囲で５分間加熱することによって、金属ナノ粒子スラリーを得た。 <Reduction process>
Next, the mixed solution was irradiated with microwaves and heated in the range of 190 to 250 ° C. for 5 minutes to obtain a metal nanoparticle slurry.
＜洗浄・乾燥工程＞
　得られた金属ナノ粒子スラリーを静置分離し、上澄み液を取り除いた後、トルエンとメタノールを用いてそれぞれ２回洗浄した後、６０℃に維持される真空乾燥機で６時間乾燥して金属ナノ粒子を得た。 <Washing and drying process>
The obtained metal nanoparticle slurry was allowed to stand and separated, the supernatant was removed, washed twice with toluene and methanol, and then dried for 6 hours in a vacuum dryer maintained at 60 ° C. Particles were obtained.
　金属ナノ粒子のＳＥＭ観察により、粒子径２０ｎｍの球状のナノ粒子が生成していることが確認された。この結果、塩化物イオンの存在がナノワイヤー形成に重要であることがわかった。 SEM observation of the metal nanoparticles confirmed that spherical nanoparticles with a particle diameter of 20 nm were generated. As a result, it was found that the presence of chloride ions is important for nanowire formation.
　以上、本発明の実施の形態を例示の目的で詳細に説明したが、本発明は上記実施の形態に制約されることはなく、種々の変形が可能である。 As described above, the embodiments of the present invention have been described in detail for the purpose of illustration, but the present invention is not limited to the above-described embodiments, and various modifications are possible.
　本国際出願は、２０１４年２月２７日に出願された日本国特許出願２０１４－３６８１９号に基づく優先権を主張するものであり、当該出願の全内容をここに援用する。
  This international application claims priority based on Japanese Patent Application No. 2014-36819 filed on Feb. 27, 2014, the entire contents of which are incorporated herein by reference.

Claims (20)

  1. 　次の成分Ａ～Ｃ；
    　（Ａ）標準電極電位が－０．５Ｖから＋０．４Ｖの範囲内である第１金属を含むカルボン酸塩、
    　（Ｂ）前記第１金属の標準電極電位よりも高く、且つ標準電極電位が＋０．３Ｖから＋１．０Ｖの範囲内である第２金属を含む金属ハロゲン化物、及び
    　（Ｃ）１級アミン、
    を含有する金属ナノワイヤー形成用組成物。     The following components A to C;
    (A) a carboxylate containing a first metal having a standard electrode potential in the range of −0.5 V to +0.4 V;
    (B) a metal halide containing a second metal that is higher than the standard electrode potential of the first metal and has a standard electrode potential in the range of +0.3 V to +1.0 V, and (C) a primary amine,
    A composition for forming metal nanowires.
  2. 　前記第１金属が、Ｆｅ、Ｃｏ、Ｎｉ、Ｓｎ、Ｐｂ及びＣｕからなる群から選ばれる１種以上である請求項１に記載の金属ナノワイヤー形成用組成物。 The metal nanowire-forming composition according to claim 1, wherein the first metal is at least one selected from the group consisting of Fe, Co, Ni, Sn, Pb and Cu.
  3. 　前記第２金属が、Ｃｕ、Ｒｕ、Ｒｈ、Ａｇ及びＰｄからなる群から選ばれる１種以上である請求項１に記載の金属ナノワイヤー形成用組成物。 The composition for forming metal nanowires according to claim 1, wherein the second metal is one or more selected from the group consisting of Cu, Ru, Rh, Ag and Pd.
  4. 　前記第１金属が、Ｃｏ又はＮｉである請求項２に記載の金属ナノワイヤー形成用組成物。 The composition for forming metal nanowires according to claim 2, wherein the first metal is Co or Ni.
  5. 　前記第２金属が、Ｃｕである請求項３に記載の金属ナノワイヤー形成用組成物。 The metal nanowire-forming composition according to claim 3, wherein the second metal is Cu.
  6. 　前記Ａ成分のカルボン酸塩が、ギ酸塩又は酢酸塩である請求項１に記載の金属ナノワイヤー形成用組成物。 2. The composition for forming metal nanowires according to claim 1, wherein the carboxylate of component A is formate or acetate.
  7. 　前記Ｂ成分のハロゲン化物が、塩化物である請求項１に記載の金属ナノワイヤー形成用組成物。 The composition for forming metal nanowires according to claim 1, wherein the halide of the component B is a chloride.
  8. 　前記１級アミンの炭素数が、１４～２０の範囲内である請求項１に記載の金属ナノワイヤー形成用組成物。 The metal nanowire-forming composition according to claim 1, wherein the primary amine has a carbon number in the range of 14-20.
  9. 　前記１級アミンが、オレイルアミンである請求項８に記載の金属ナノワイヤー形成用組成物。 The metal nanowire-forming composition according to claim 8, wherein the primary amine is oleylamine.
  10. 　前記第２金属を含む硝酸塩の含有量が、Ｂ成分に対して、０．１モル％以下である請求項１に記載の金属ナノワイヤー形成用組成物。 The metal nanowire-forming composition according to claim 1, wherein the content of the nitrate containing the second metal is 0.1 mol% or less with respect to the component B.
  11. 　次の工程I及びII；
    　I）標準電極電位が－０．５Ｖから＋０．４Ｖの範囲内である第１金属を含むカルボン酸塩と、前記第１金属の標準電極電位よりも高く、且つ標準電極電位が＋０．３Ｖから＋１．０Ｖの範囲内である第２金属を含む金属ハロゲン化物とを１級アミンに溶解して、金属前駆体の混合液を得る工程、
    及び
    　II）前記工程Iの後に、前記金属前駆体の混合液を加熱して、第１金属のイオンを還元し、第１金属を析出させるとともに、析出した第１金属と第２金属のイオンとの金属置換反応によって、第２金属のイオンを還元して第２金属を析出させて金属ナノワイヤーに成長させる工程、
    を備える金属ナノワイヤーの製造方法。     Next steps I and II;
    I) a carboxylate containing a first metal having a standard electrode potential in the range of −0.5 V to +0.4 V, higher than the standard electrode potential of the first metal, and the standard electrode potential from +0.3 V Dissolving a metal halide containing a second metal in a range of +1.0 V in a primary amine to obtain a mixed solution of metal precursors;
    And II) After the step I, the mixed liquid of the metal precursor is heated to reduce the first metal ions to precipitate the first metal, and the deposited first metal and second metal ions A step of reducing the second metal ions to deposit the second metal by the metal substitution reaction of
    The manufacturing method of metal nanowire provided with this.
  12. 　前記金属ハロゲン化物が金属塩化物である請求項１１に記載の金属ナノワイヤーの製造方法。 The method for producing metal nanowires according to claim 11, wherein the metal halide is a metal chloride.
  13. 　前記第１金属が、Ｆｅ、Ｃｏ、Ｎｉ，Ｓｎ、Ｐｂ及びＣｕからなる群から選ばれる１種以上である請求項１１に記載の金属ナノワイヤーの製造方法。 The method for producing metal nanowires according to claim 11, wherein the first metal is at least one selected from the group consisting of Fe, Co, Ni, Sn, Pb and Cu.
  14. 　前記第２金属が、Ｃｕ、Ｒｕ、Ｒｈ、Ａｇ及びＰｄからなる群から選ばれる１種以上である請求項１１に記載の金属ナノワイヤーの製造方法。 The method for producing metal nanowires according to claim 11, wherein the second metal is at least one selected from the group consisting of Cu, Ru, Rh, Ag and Pd.
  15. 　前記第１金属が、Ｃｏ又はＮｉである請求項１３に記載の金属ナノワイヤーの製造方法。 The method for producing metal nanowires according to claim 13, wherein the first metal is Co or Ni.
  16. 　前記第２金属が、Ｃｕである請求項１４に記載の金属ナノワイヤーの製造方法。 The method for producing metal nanowires according to claim 14, wherein the second metal is Cu.
  17. 　前記Ａ成分のカルボン酸塩が、ギ酸塩又は酢酸塩である請求項１１に記載の金属ナノワイヤーの製造方法。 The method for producing metal nanowires according to claim 11, wherein the carboxylate of component A is formate or acetate.
  18. 　前記１級アミンの炭素数が、１４～２０の範囲内である請求項１１に記載の金属ナノワイヤーの製造方法。 The method for producing metal nanowires according to claim 11, wherein the carbon number of the primary amine is in the range of 14-20.
  19. 　前記１級アミンが、オレイルアミンである請求項１８に記載の金属ナノワイヤーの製造方法。 The method for producing metal nanowires according to claim 18, wherein the primary amine is oleylamine.
  20. 　請求項１１に記載の方法により製造された金属ナノワイヤー。 Metal nanowires produced by the method according to claim 11.
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