Method for producing semiconductor single-walled carbon nanotube dispersion

Abstract

The present invention provides, in one embodiment, a method for producing a semiconducting single-walled carbon nanotube dispersion, which can separate semiconducting single-walled carbon nanotubes from a single-walled carbon nanotube mixture containing semiconducting single-walled carbon nanotubes and metallic single-walled carbon nanotubes in an aqueous medium by using an easily available separation agent and a simple operation. The present invention relates, in one embodiment, to a method for producing a semiconducting single-walled carbon nanotube dispersion, comprising: a step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes containing semiconducting single-walled carbon nanotubes and metallic single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and a step B of extracting a supernatant containing the semiconducting single-walled carbon nanotubes from the separated single-walled carbon nanotube dispersion after centrifugation of the separated single-walled carbon nanotube dispersion. CH2=CH-COOM(1)CH2=CR 5 -COO-(CH2CH2O) q -H (3)

Description

Technical Field

[0001] The present invention relates to a method for producing a semiconducting single-walled carbon nanotube dispersion, a method for producing semiconducting single-walled carbon nanotubes including the method as a process, and a method for separating metallic single-walled carbon nanotubes from semiconducting single-walled carbon nanotubes. Background Art

[0002] In recent years, nano-sized carbon materials are expected to be used in various fields due to their physical and chemical properties. As one of such materials, there is a carbon nanotube (hereinafter, also referred to as "CNT"). CNT has a structure in which a graphene sheet is wound into a cylindrical shape, and a CNT consisting of only one layer of the cylinder is called a single-walled carbon nanotube (hereinafter, also referred to as "SWCNT").

[0003] It is known that the electrical properties of CNTs vary depending on the winding method and diameter of the graphene sheet. In particular, the quantum effect of SWCNTs is greatly affected, so there are SWCNTs that show metallic properties (metallic CNTs) and SWCNTs that show semiconductor properties (semiconductor CNTs). As a method for manufacturing SWCNTs, known synthesis methods include high-pressure carbon monoxide disproportionation method (HiPco method), improved direct injection pyrolysis synthesis method (e-DIPS method), arc discharge method, laser ablation method, etc. However, there is currently no established technology for manufacturing only any one type of CNT. When SWCNTs are applied to various purposes, it is necessary to separate the target type of SWCNT from its mixture. Metallic CNTs are expected to be used in transparent electrodes for touch panels or solar cells, fine wiring of equipment, etc. due to their excellent conductivity; semiconductor CNTs are expected to be used in transistors or sensors, etc.

[0004] Several methods for separating metallic SWCNTs from semiconductor SWCNTs have been reported. For example, there are known methods: density gradient centrifugation, which uses a surfactant such as sodium dodecyl sulfate or sodium cholate to disperse SWCNTs, and then mixes them with a density gradient agent for centrifugal separation (Japanese Patent Publication No. 2010-1162); electric field separation, which applies an electric field to a dispersion obtained by dispersing SWCNTs using a surfactant to separate them (Japanese Patent Publication No. 2008-55375); a method of mixing with a separation agent such as porphyrin in an organic solvent to form a complex of semiconductor SWCNT and the separation agent and taking it out (Japanese Patent Publication No. 2007-519594); a method of mixing with a separation agent such as a polythiophene derivative in an organic solvent to selectively separate semiconductor SWCNTs by utilizing the interaction between the semiconductor SWCNT and the separation agent (Japanese Patent Publication No. 2014-503445); A method for separating semiconductor SWCNTs by mixing a separating agent such as a flavin derivative in an organic solvent and utilizing the adsorption effect of the separating agent on semiconductor SWCNTs (WO2014 / 136981); a method for placing a dispersion obtained by dispersing SWCNTs using a surfactant into a separation container filled with a separation material such as agar gel, and using an eluent to dissolve the semiconductor SWCNTs adsorbed on the separation material from the separation material (Japanese Patent Publication No. 2012-36041); a method for separating the SWCNT mixture into metallic SWCNTs and semiconductor SWCNTs by applying a voltage to the supernatant obtained by subjecting a dispersion containing a surfactant such as polyoxyethylene (100) stearyl ether and a SWCNT mixture to ultrasonic dispersion treatment and ultracentrifugal separation treatment (WO2019 / 064597), etc. Summary of the invention

[0005] In one aspect, the present invention relates to a method for producing a semiconductor single-walled carbon nanotube dispersion (hereinafter, also referred to as a "semiconductor SWCNT dispersion"), comprising:

[0006] A step A of preparing a dispersion liquid containing isolated single-walled carbon nanotubes (hereinafter, also referred to as "isolated SWCNT dispersion liquid"), wherein the isolated single-walled carbon nanotube dispersion liquid contains single-walled carbon nanotubes of semiconductor type single-walled carbon nanotubes (hereinafter, also referred to as "semiconductor type SWCNT") and metallic type single-walled carbon nanotubes (hereinafter, also referred to as "metallic type SWCNT"), an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and

[0007] A step B is to extract a supernatant containing the semiconductor-type SWCNT from the centrifuged SWCNT dispersion liquid after centrifuging the separated SWCNT dispersion liquid.

[0008] CH2=CH-COOM (1)

[0009] In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2).

[0010] [Chemical formula 1]

[0011]

[0012] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0013] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0014] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

[0015] In one embodiment, the present invention relates to a method for producing a semiconductor SWCNT, comprising the step of filtering a semiconductor SWCNT dispersion obtained by the method for producing a semiconductor SWCNT dispersion of the present invention to extract semiconductor SWCNTs.

[0016] The present invention relates in one embodiment to a method for producing a semiconductor SWCNT, comprising: a step of drying a semiconductor SWCNT dispersion obtained by the method for producing a semiconductor SWCNT dispersion of the present invention to obtain a mixture containing semiconductor single-layer SWCNTs and the above-mentioned polymer; and a step of removing the above-mentioned polymer from the above-mentioned mixture to extract the semiconductor SWCNT.

[0017] In one embodiment, the present invention relates to a method for producing semiconductor SWCNTs, which comprises obtaining a semiconductor SWCNT dispersion obtained by the method for producing a semiconductor SWCNT dispersion of the present invention as semiconductor SWCNTs without further performing a separation treatment.

[0018] The present invention relates in one embodiment to a method for separating semiconductor SWCNTs from metallic SWCNTs, comprising:

[0019] A step A of preparing a separated SWCNT dispersion liquid, wherein the separated SWCNT dispersion liquid contains single-walled carbon nanotubes including semiconductor SWCNTs and metallic SWCNTs, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and

[0020] A step B is to extract a supernatant containing the semiconductor-type SWCNT from the centrifuged SWCNT dispersion liquid after centrifuging the separated SWCNT dispersion liquid.

[0021] CH2=CH-COOM (1)

[0022] In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2).

[0023] [Chemical formula 2]

[0024]

[0025] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0026] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0027] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

[0028] In one embodiment, the present invention relates to a method for producing an ink containing a semiconductor SWCNT, which includes the method for producing a semiconductor SWCNT dispersion liquid of the present invention or the method for producing a semiconductor SWCNT of the present invention as one step.

[0029] The present invention relates in one embodiment to an ink containing a semiconductor SWCNT, comprising: at least one of an organic solvent and water, a semiconductor SWCNT, and a copolymer including a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3).

[0030] CH2=CH-COOM (1)

[0031] In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2).

[0032] [Chemical formula 3]

[0033]

[0034] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0035] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0036] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

[0037] In one embodiment, the present invention relates to an aqueous dispersion comprising: semiconductor SWCNTs; and a copolymer including a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3).

[0038] CH2=CH-COOM (1)

[0039] In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2).

[0040] [Chemical formula 4]

[0041]

[0042] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0043] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0044] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

[0045] In one embodiment, the present invention relates to use of a copolymer comprising a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3) for isolating semiconductor-type SWCNTs.

[0046] CH2=CH-COOM (1)

[0047] In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2).

[0048] [Chemical formula 5]

[0049]

[0050] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0051] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0052] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120. DETAILED DESCRIPTION

[0053] The separation methods disclosed in Japanese Patent Publication No. 2010-1162 and Japanese Patent Publication No. 2012-36041 require density gradient agents, agar gel, etc., and have many operating procedures. The separation method disclosed in Japanese Patent Publication No. 2008-55375 requires an electrophoresis device, and separation takes time, and the concentration of the separated SWCNT is thin. The separation methods disclosed in Japanese Patent Publication No. 2007-519594, Japanese Patent Publication No. 2014-503445, and WO2014 / 136981 have low practicality because they need to be carried out in a non-polar solvent and require expensive separation agents. The separation method disclosed in WO2019 / 064597 requires the processes of ultrasonic dispersion treatment and ultracentrifugal separation treatment and the process of applying voltage, and has many operating procedures.

[0054] The present invention provides a method for producing a semiconductor SWCNT dispersion liquid capable of separating semiconductor SWCNTs from a SWCNT mixture containing semiconductor SWCNTs and metallic SWCNTs in an aqueous medium by using an easily available separation agent and a simple operation, a method for producing semiconductor SWCNTs including the production method as a process, a method for separating semiconductor SWCNTs from metallic SWCNTs, and a method for producing an ink containing semiconductor SWCNTs.

[0055] The present invention is based on the finding that the inclusion of a specific copolymer in a SWCNT dispersion to be separated allows separation of metallic SWCNTs and semiconductor SWCNTs in the SWCNT dispersion to be separated by using a readily available separation agent and a simple operation.

[0056] According to the present invention, there can be provided a method for producing a semiconductor SWCNT dispersion liquid which can be produced in an aqueous medium by using an easily available separation agent and a simple operation and has excellent separability of semiconductor SWCNTs, a method for producing semiconductor SWCNTs including the production method as a process, a method for separating semiconductor SWCNTs from metal SWCNTs, and a method for producing an ink containing semiconductor SWCNTs.

[0057] The details of the mechanism by which the effects of the present invention are exhibited are not clear, but are presumed as follows.

[0058] In the present invention, the separated SWCNT dispersion contains a copolymer containing a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3). The structural unit A has a high affinity for aqueous media, and the copolymer tends to be easily dispersed in the dispersion. On the other hand, the magnitude of the interaction between the copolymer and SWCNT is different in semiconductor type and metal type, and it is believed that the degree of dispersion differs depending on the magnitude of the interaction. As a result, semiconductor type SWCNT is selectively dispersed in the above dispersion, while metal type SWCNT agglomerates, and it is speculated that by making it the object of centrifugal separation, good separation of metal type SWCNT and semiconductor type SWCNT becomes possible.

[0059] However, the present invention is not limited to these mechanisms for explanation.

[0060] [Method for producing semiconductor SWCNT dispersion, method for separating semiconductor SWCNT and metallic SWCNT]

[0061] The present invention relates in one embodiment to a method for producing a semiconductor SWCNT dispersion liquid comprising the following steps A and B (hereinafter also referred to as "the method for producing the dispersion liquid of the present invention"). In addition, the present invention relates in another embodiment to a method for separating semiconductor SWCNTs and metallic SWCNTs comprising the following steps A and B (hereinafter also referred to as "the separation method of the present invention").

[0062] (Step A) A SWCNT dispersion to be separated is prepared, wherein the SWCNT dispersion to be separated contains single-walled carbon nanotubes including semiconductor-type SWCNTs and metallic-type SWCNTs (hereinafter also referred to as a "SWCNT mixture"), a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) (hereinafter also referred to as "monomer A") and a structural unit B derived from a monomer represented by the following formula (3) (hereinafter also referred to as "monomer B"), and an aqueous medium.

[0063] (Step B) After centrifuging the separated SWCNT dispersion, a supernatant containing the semiconductor-type SWCNT is extracted from the centrifuged separated SWCNT dispersion.

[0064] CH2=CH-COOM (1)

[0065] In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2).

[0066] [Chemical formula 6]

[0067]

[0068] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group. + .

[0069] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0070] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

[0071] In the present invention, "extracting the supernatant containing the semiconductor SWCNT" means extracting the following supernatant: a supernatant in which the ratio of the semiconductor SWCNT is increased relative to the ratio of the semiconductor SWCNT to the metal SWCNT in the separated SWCNT dispersion obtained in step A; the supernatant is a semiconductor SWCNT dispersion. In the present invention, the case where a relatively small amount of metal SWCNT is contained in the supernatant compared to the semiconductor SWCNT is not excluded. If the separation of semiconductor SWCNT is improved, the ratio of semiconductor SWCNT in the SWCNT in the supernatant increases, and it becomes more useful as a material for semiconductor devices.

[0072] In step B, the operation of extracting the supernatant can be performed, for example, by separating the supernatant from its residue. The residue contains a precipitate containing a relatively larger amount of metallic SWCNTs than semiconductor SWCNTs.

[0073] [Process A]

[0074] In one or more embodiments, the method for producing a dispersion of the present invention and the separated SWCNT dispersion of the step A in the separation method of the present invention prepares a mixed solution containing at least a copolymer including a structural unit A derived from the monomer A and a structural unit B derived from the monomer B, the SWCNT mixture, and an aqueous medium (hereinafter also referred to as "mixed solution A"), and then the mixed solution A is subjected to a dispersion treatment. The mixed solution A can be prepared, for example, by adding the SWCNT mixture to an aqueous solution of the copolymer.

[0075] [Copolymer comprising structural unit A derived from monomer A and structural unit B derived from monomer B]

[0076] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the above copolymer is preferably water-soluble. In the present invention, "water-soluble" means that more than 1 g of the copolymer is dissolved in 100 g of water at 20° C. In one or more embodiments, the above copolymer can be used to separate semiconductor-type SWCNTs. That is, in one embodiment, the present invention relates to the use of a copolymer comprising a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3) for separating semiconductor-type SWCNTs.

[0077] The structural unit A contained in the copolymer is a structural unit derived from the monomer A represented by the above formula (1). In the above formula (1), M is a hydrogen atom, a metal atom, or a group having a structure represented by the above formula (2) from the viewpoint of improving the separability of the semiconductor-type SWCNT and improving the productivity. From the viewpoint of improving the separability of the semiconductor-type SWCNT, improving the productivity, and improving the versatility, it is preferably a hydrogen atom or a group having a structure represented by the above formula (2), and more preferably a hydrogen atom.

[0078] Examples of the monomer A include acrylic acid (AA).

[0079] The structural unit B contained in the above copolymer is a structural unit derived from the monomer B represented by the above formula (3). In the above formula (3), R 5 It may be any of a hydrogen atom and a methyl group. From the viewpoint of improving the separability of the semiconductor-type SWCNT, q is 2 or more, preferably 3 or more, and more preferably 4 or more, and, from the same aspect, is 120 or less, preferably 90 or less, more preferably 45 or less, further preferably 25 or less, and further preferably 12 or less.

[0080] Examples of the monomer B include polyethylene glycol monoacrylate and the like.

[0081] The copolymer includes, for example, at least one selected from acrylic acid / polyethylene glycol (10) monoacrylate copolymer and acrylic acid / polyethylene glycol (4.5) monoacrylate copolymer. The numerical values ​​in parentheses () represent the average number of added moles.

[0082] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the content (mass %) of the structural unit A in all the structural units of the above-mentioned copolymer is preferably 30 mass % or more, more preferably 40 mass % or more, further preferably 50 mass % or more, further preferably 60 mass % or more, further preferably 75 mass % or more, and from the viewpoint of improving the separability of semiconductor-type SWCNTs, it is preferably less than 100 mass %, more preferably 95 mass % or less, further preferably 90 mass % or less, further preferably 85 mass % or less.

[0083] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the content (mol%) of the structural unit A in all the structural units of the above-mentioned copolymer is preferably 55 mol% or more, more preferably 70 mol% or more, further preferably 85 mol% or more, further preferably 90 mol% or more, further preferably 95 mol% or more, and from the viewpoint of improving the separability of semiconductor-type SWCNTs, it is preferably less than 100 mol%, more preferably 99 mol% or less, and further preferably 98 mol% or less.

[0084] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the content (mass %) of the structural unit B in all the structural units of the above-mentioned copolymer is preferably more than 0 mass %, more preferably 5 mass % or more, further preferably 10 mass % or more, and further preferably 15 mass % or more. From the viewpoint of improving the separability of semiconductor-type SWCNTs, it is preferably 70 mass % or less, more preferably 60 mass % or less, further preferably 50 mass % or less, further preferably 40 mass % or less, and further preferably 25 mass % or less.

[0085] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the content (mol%) of the structural unit B in all the structural units of the above-mentioned copolymer is preferably more than 0 mol%, more preferably 1 mol% or more, and further preferably 2 mol% or more. From the viewpoint of improving the separability of semiconductor-type SWCNTs, it is preferably 45 mol% or less, more preferably 30 mol% or less, further preferably 15 mol% or less, further preferably 10 mol% or less, and further preferably 5 mol% or less.

[0086] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the total content (mass%) of the structural unit A and the structural unit B in all the structural units of the copolymer is preferably 80 mass% or more, more preferably 90 mass% or more, further preferably 95 mass% or more, further preferably 99 mass% or more and 100 mass% or less. From the viewpoint of improving the separability of semiconductor-type SWCNTs, it is further preferably substantially 100 mass%.

[0087] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the total content (mol%) of the structural unit A and the structural unit B in all structural units of the copolymer is preferably 80 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, further preferably 99 mol% or more and 100 mol% or less. From the viewpoint of improving the separability of semiconductor-type SWCNTs, it is further preferably substantially 100 mol%.

[0088] The above copolymer may contain a structural unit C other than the structural units A and B within a range that does not impair the effects of the present invention. As the structural unit C, for example, a structural unit derived from a carboxylic acid monomer such as methacrylic acid and maleic acid, and a nonionic monomer other than the structural unit B can be cited. From the viewpoint of improving the separability of the semiconductor-type SWCNT, the content of the structural unit C in the copolymer is preferably 20% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, further preferably 1% by mass or less, and further preferably substantially free of. Here, "substantially free of" means not intentionally contained, for example, it means contained in the raw material monomers constituting the structural units A and B, or unintentionally contained.

[0089] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the mass ratio (A / B) of the structural unit A to the structural unit B in the above-mentioned copolymer is preferably 0.45 or more, more preferably 0.7 or more, further preferably 1 or more, further preferably 1.5 or more, further preferably 3 or more, and from the viewpoint of improving the separability of semiconductor-type SWCNTs, it is preferably 19 or less, more preferably 9 or less, and further preferably 6 or less.

[0090] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the molar ratio (A / B) of the structural unit A to the structural unit B in the above copolymer is preferably 1.2 or more, more preferably 2.3 or more, further preferably 5.6 or more, further preferably 9 or more, further preferably 19 or more, and from the viewpoint of improving the separability of semiconductor-type SWCNTs, it is preferably 300 or less, more preferably 100 or less, and further preferably 50 or less.

[0091] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the weight average molecular weight of the copolymer is preferably 1,000 or more, more preferably 3,000 or more, and even more preferably 4,500 or more. From the viewpoint of improving the separability of semiconductor-type SWCNTs, the copolymer is preferably 300,000 or less, more preferably 100,000 or less, even more preferably 60,000 or less, and even more preferably 20,000. In the present invention, the weight average molecular weight of the polymer is a weight average molecular weight based on gel permeation chromatography, and specifically, can be measured by the method described in the Examples.

[0092] From the viewpoint of improving the separability of semiconductor-type SWCNTs and improving productivity, the mass ratio of the copolymer to SWCNT in the mixed solution A and in the separated SWCNT dispersion (copolymer / SWCNT) is preferably 1 or more, more preferably 2 or more, further preferably 5 or more, and further preferably 10 or more, and from the viewpoint of improving the separability of semiconductor-type SWCNTs and improving productivity, it is preferably 100 or less, more preferably 70 or less, and further preferably 50 or less.

[0093] From the viewpoint of improving the separability of semiconductor-type SWCNTs and improving productivity, the content of the above-mentioned copolymer in the above-mentioned mixed solution A and in the separated SWCNT dispersion is preferably 0.1 mass% or more, more preferably 0.2 mass% or more, further preferably 0.5 mass% or more, and further preferably 1 mass% or more, and, from the same viewpoint, is preferably 10 mass% or less, more preferably 7 mass% or less, and further preferably 5 mass% or less.

[0094] [SWCNT]

[0095] There is no particular limitation on the SWCNT used in the preparation of the mixed solution A and the separated SWCNT dispersion. The SWCNT is, for example, a SWCNT synthesized by a conventionally known synthesis method such as the HiPco method and the e-DIPS method, and may include SWCNTs of various winding methods and diameters. The metallic SWCNT and the semiconductor SWCNT may be included in any ratio, but the generally synthesized SWCNT is a SWCNT mixture containing about 1 / 3 metallic SWCNT and about 2 / 3 semiconductor SWCNT.

[0096] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the average diameter of SWCNTs is preferably 0.5 nm or more, more preferably 0.8 nm or more, and, from the same viewpoint, is preferably 3 nm or less, more preferably 2 nm or less. The average diameter of SWCNTs can be calculated by measuring the diameters of 10 or more CNTs from an image obtained using a transmission electron microscope and averaging the diameters.

[0097] From the viewpoint of electrical properties, the average length of SWCNT is preferably 0.1 μm or more, more preferably 0.3 μm or more, and further preferably 0.5 μm or more, and from the viewpoint of improving the separability of semiconductor-type SWCNT and improving productivity, it is preferably 100 μm or less, more preferably 50 μm or less, further preferably 20 μm or less, and further preferably 10 μm or less. The average length of SWCNT can be calculated, for example, by measuring the lengths of 10 or more CNTs from an image obtained using a transmission electron microscope and averaging the lengths.

[0098] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the content of SWCNTs in the mixed solution A and in the separated SWCNT dispersion is 0.001 mass % or more, more preferably 0.01 mass % or more, and further preferably 0.03 mass % or more, and from the viewpoint of improving the separability of semiconductor-type SWCNTs and improving productivity, it is preferably 5 mass % or less, more preferably 1 mass % or less, and further preferably 0.5 mass % or less.

[0099] [Aqueous medium]

[0100] The mixed solution A and the separated SWCNT dispersion solution contain an aqueous medium as a dispersion medium. As the aqueous medium, water is preferred. From the viewpoint of improving the separation of semiconductor-type SWCNTs and improving productivity, the water is preferably pure water, ion-exchanged water, purified water or distilled water, and pure water is more preferred.

[0101] The mixed solution A and the separated SWCNT dispersion solution may contain, in addition to water, a water-soluble organic solvent such as methanol, ethanol, isopropanol or the like, acetone, tetrahydrofuran, dimethylformamide or the like as an aqueous medium.

[0102] When the aqueous medium is a combination of water and a dispersion medium other than water, the proportion of water in the aqueous medium is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more, from the viewpoint of improving the separability of semiconductor-type SWCNTs.

[0103] From the viewpoint of improving the separability of semiconductor-type SWCNTs and improving productivity, the content of the aqueous medium in the mixed solution A and the separated SWCNT dispersion is preferably 85 mass % or more, more preferably 92 mass % or more, and even more preferably 96 mass % or more. From the same viewpoint, it is preferably 99.9 mass % or less, more preferably 99.8 mass % or less, even more preferably 99.5 mass % or less, and even more preferably 99.0 mass % or less.

[0104] From the viewpoint of improving the separability of semiconductor-type SWCNTs, the pH of the mixed solution A and the separated SWCNT dispersion is preferably 1 or more, more preferably 1.5 or more, and even more preferably 2 or more, and from the same viewpoint, it is preferably 5 or less, more preferably 4 or less, and even more preferably 3.5 or less. In the present invention, the pH of the mixed solution A and the separated SWCNT dispersion is a value at 25° C., and can be measured using, for example, a pH meter (manufactured by DKK Toa Co., Ltd.).

[0105] The dispersion treatment of the mixed solution A can be performed using a disperser such as a bath type ultrasonic disperser, a homomixer, a high pressure homogenizer, an ultrasonic homogenizer, a jet mill, a bead mill, or a pulverizer.

[0106] In step A, the mixed solution A may be subjected to a defoaming treatment before the dispersion treatment.

[0107] [Process B]

[0108] In step B, the separated SWCNT dispersion obtained in step A is subjected to centrifugal separation, and a supernatant containing semiconductor SWCNTs is extracted from the separated SWCNT dispersion subjected to centrifugal separation. The supernatant is a supernatant in which the ratio of semiconductor SWCNTs is increased relative to the ratio of semiconductor SWCNTs to metal SWCNTs in the separated SWCNT dispersion before being subjected to centrifugal separation. The ratio varies depending on centrifugal separation conditions, etc., but from the perspective of improving the separation of semiconductor SWCNTs and improving productivity, the rotation speed of the centrifuge is preferably 5,000 rpm or more, more preferably 10,000 rpm or more, and from the same perspective, it is preferably 100,000 rpm or less, and more preferably 70,000 rpm or less. From the perspective of improving the separation of semiconductor SWCNTs and improving productivity, the gravitational acceleration of the centrifuge is preferably 10 kG or more, more preferably 50 kG or more, and from the same perspective, it is preferably 1000 kG or less, and more preferably 500 kG or less.

[0109] From the viewpoint of semiconductor properties, the separability of the semiconductor-type SWCNT in the supernatant obtained in step B is preferably 1.1 or more, more preferably 1.3 or more, further preferably 1.4 or more, further preferably 1.6 or more, further preferably 2.0 or more, and from the viewpoint of yield, it is preferably 100 or less. In the present invention, the separability of the semiconductor-type SWCNT is a value obtained by the following formula.

[0110] [Mathematical formula 1]

[0111]

[0112] In one or more embodiments, the supernatant obtained in the step (B) is an aqueous dispersion containing the semiconductor SWCNT and the copolymer. That is, the present invention relates in one embodiment to an aqueous dispersion containing semiconductor SWCNT and a copolymer containing a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3).

[0113] [Method for producing semiconductor SWCNT and semiconductor SWCNT]

[0114] If semiconductor SWCNTs are extracted from a semiconductor SWCNT dispersion produced by the method for producing a semiconductor SWCNT dispersion of the present invention, semiconductor SWCNTs can be produced. Extraction of semiconductor SWCNTs from a semiconductor SWCNT dispersion can be carried out, for example, in the following manner: after filtering out semiconductor SWCNTs from a semiconductor SWCNT dispersion using a membrane filter, the semiconductor SWCNTs are dried. In the case of filtering semiconductor SWCNTs from a semiconductor SWCNT dispersion, the semiconductor SWCNTs in the semiconductor SWCNT dispersion can be subjected to pre-treatments such as reprecipitation and then filtered. Alternatively, the semiconductor SWCNT dispersion can be dried and the coexisting polymers can be removed by washing, pyrolysis, and the like. Alternatively, the semiconductor SWCNT dispersion can be used as a semiconductor SWCNT without further separation treatment.

[0115] Therefore, the present invention in one embodiment relates to a method for producing a semiconductor SWCNT (hereinafter also referred to as "method A for producing a semiconductor SWCNT of the present invention"), which includes a step of filtering a semiconductor SWCNT dispersion obtained by the method for producing a semiconductor SWCNT dispersion of the present invention to extract the semiconductor SWCNT.

[0116] In addition, the present invention, in another embodiment, relates to a method for producing a semiconductor SWCNT (hereinafter also referred to as "method B for producing a semiconductor SWCNT of the present invention"), which includes: a step of drying a semiconductor SWCNT dispersion obtained by the method for producing a semiconductor SWCNT dispersion of the present invention to obtain a mixture containing semiconductor single-walled carbon nanotubes and the above-mentioned polymer; and a step of removing the above-mentioned polymer from the above-mentioned mixture to extract the semiconductor single-walled carbon nanotubes.

[0117] In addition, the present invention, in another embodiment, relates to a method for producing a semiconductor single-walled carbon nanotube (hereinafter also referred to as "method C for producing semiconductor SWCNTs of the present invention"), which obtains a semiconductor SWCNT dispersion obtained by the method for producing a semiconductor SWCNT dispersion of the present invention as a semiconductor SWCNT without further separation treatment.

[0118] In another embodiment, the present invention relates to a semiconductor-type SWCNT (hereinafter also referred to as “the semiconductor-type SWCNT of the present invention”) obtained by the semiconductor-type SWCNT production method A, B, or C of the present invention.

[0119] [Method for producing ink containing semiconductor SWCNT]

[0120] The present invention relates in one embodiment to a method for producing an ink containing semiconductor SWCNTs (hereinafter also referred to as "the method for producing an ink containing semiconductor SWCNTs of the present invention"), which includes the method for producing a semiconductor SWCNT dispersion of the present invention or the method for producing a semiconductor SWCNT of the present invention as a process. One embodiment of the method for producing an ink containing semiconductor SWCNTs of the present invention, for example, includes the method for producing semiconductor SWCNTs A, B or C of the present invention as a process, and further includes the step of mixing at least one of an organic solvent and water, the semiconductor SWCNTs, and at least one of a surfactant and a resin as required. In addition, another embodiment of the method for producing an ink containing semiconductor SWCNTs of the present invention, for example, includes the method for producing a semiconductor SWCNT dispersion of the present invention as a process, and includes the step of mixing the semiconductor SWCNT dispersion, and an organic solvent, a surfactant and a resin that can be mixed with the dispersion as required.

[0121] Examples of the organic solvent include aliphatic solvents such as n-hexane, n-octane, and n-decane; alicyclic solvents such as cyclohexane; aromatic solvents such as benzene and toluene; alcohol solvents such as methanol and ethanol; glycol ether solvents such as diethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and butyl cellosolve. From the perspective of improving film-forming properties, the ink containing semiconductor SWCNTs may also contain, for example, polystyrene resins, acrylic resins, vinyl resins, etc. as the above-mentioned resins that can be dissolved or dispersed in a solvent, and may also contain known surfactants and other additives as dispersants. The content of semiconductor SWCNTs in the ink containing semiconductor SWCNTs may be appropriately set according to the intended use.

[0122] [Ink containing semiconductor SWCNT]

[0123] The present invention relates in one embodiment to an ink containing a semiconductor SWCNT (hereinafter also referred to as "the ink containing a semiconductor SWCNT of the present invention"), which contains: at least one of an organic solvent and water, a semiconductor single-layer SWCNT, and a copolymer containing a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3).

[0124] One embodiment of the ink containing semiconductor SWCNTs of the present invention contains at least the semiconductor SWCNTs of the present invention, a copolymer including a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3), and at least one of an organic solvent and water, and optionally contains a surfactant and a resin.

[0125] [Method for manufacturing semiconductor device]

[0126] In one embodiment, the present invention relates to a method for manufacturing a semiconductor device, comprising the step of printing or applying a semiconductor-containing SWCNT ink obtained by the method for manufacturing a semiconductor-containing SWCNT ink of the present invention onto a substrate to form a semiconductor layer.

[0127] In addition, the present invention relates to a method for manufacturing a semiconductor device in another embodiment, which is a method for manufacturing a semiconductor element having a substrate, and a gate electrode, a source electrode, and a drain electrode arranged on the substrate, and includes a step of forming a semiconductor circuit and a semiconductor film (semiconductor layer) by printing or coating the ink containing the semiconductor-type SWCNT. As the printing method of the ink containing the semiconductor-type SWCNT, inkjet printing, screen printing, offset printing, relief printing, etc. can be cited. The following step may also be included: after the semiconductor film is formed by printing or coating, etching is performed to form a circuit.

[0128] Regarding the above-mentioned embodiments, the present invention also discloses the following methods for producing a semiconductor single-walled carbon nanotube dispersion, methods for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes, methods for producing an ink containing semiconductor single-walled carbon nanotubes, and ink containing semiconductor single-walled carbon nanotubes.

[0129] <1> A method for producing a semiconductor single-walled carbon nanotube dispersion or a method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes, comprising:

[0130] A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor-type single-walled carbon nanotubes and metallic-type single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and

[0131] After centrifuging the separated single-walled carbon nanotube dispersion, step B includes extracting a supernatant containing the semiconductor single-walled carbon nanotubes from the centrifuged separated single-walled carbon nanotube dispersion.

[0132] CH2=CH-COOM (1)

[0133] In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2).

[0134] [Chemical formula 7]

[0135]

[0136] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0137] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0138] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

[0139] <2> The method for producing a semiconductor single-walled carbon nanotube dispersion or the method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to <1>, comprising:

[0140] A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor-type single-walled carbon nanotubes and metallic-type single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and

[0141] After centrifuging the separated single-walled carbon nanotube dispersion, step B includes extracting a supernatant containing the semiconductor single-walled carbon nanotubes from the centrifuged separated single-walled carbon nanotube dispersion.

[0142] CH2=CH-COOM (1)

[0143] In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2).

[0144] [Chemical formula 8]

[0145]

[0146] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0147] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0148] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 45.

[0149] <3> The method for producing a semiconductor single-walled carbon nanotube dispersion or the method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to <1> or <2>, comprising:

[0150] A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor-type single-walled carbon nanotubes and metallic-type single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and

[0151] After the separated single-layer carbon nanotube dispersion is centrifuged, step B is performed to extract the supernatant containing the semiconductor type single-layer carbon nanotubes from the separated single-layer carbon nanotube dispersion after centrifugation, wherein the content of structural unit A in all structural units of the copolymer is greater than 55 mol% and less than 100 mol%, and the content of structural unit B in all structural units of the copolymer is greater than 0 mol% and less than 45 mol%.

[0152] CH2=CH-COOM (1)

[0153] In formula (1), M represents a hydrogen atom.

[0154] [Chemical formula 9]

[0155]

[0156] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0157] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0158] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 45.

[0159] <4> The method for producing a semiconducting single-walled carbon nanotube dispersion or the method for separating semiconducting single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to any one of <1> to <3>, comprising:

[0160] A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor-type single-walled carbon nanotubes and metallic-type single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and

[0161] After the separated single-walled carbon nanotube dispersion is centrifuged, a supernatant containing the semiconductor type single-walled carbon nanotubes is extracted from the separated single-walled carbon nanotube dispersion after centrifugation in step B, wherein the content of structural unit A in all structural units of the copolymer is greater than 55 mol% and less than 100 mol%, the content of structural unit B in all structural units of the copolymer is greater than 0 mol% and less than 45 mol%, and the total content of structural unit A and structural unit B in all structural units of the copolymer is greater than 90 mol% and less than 100 mol%.

[0162] CH2=CH-COOM (1)

[0163] In formula (1), M represents a hydrogen atom.

[0164] [Chemical formula 10]

[0165]

[0166] In formula (2), R 1 , R 2 , R 3 , R 4Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0167] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0168] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 45.

[0169] <5> The method for producing a semiconducting single-walled carbon nanotube dispersion or the method for separating semiconducting single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to any one of <1> to <4>, comprising:

[0170] A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor-type single-walled carbon nanotubes and metallic-type single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and

[0171] After the separated single-walled carbon nanotube dispersion is centrifuged, a supernatant containing the semiconductor type single-walled carbon nanotubes is extracted from the separated single-walled carbon nanotube dispersion after centrifugation in step B, wherein the content of structural unit A in all structural units of the copolymer is greater than 55 mol% and less than 100 mol%, the content of structural unit B in all structural units of the copolymer is greater than 0 mol% and less than 45 mol%, the total content of structural unit A and structural unit B in all structural units of the copolymer is greater than 90 mol% and less than 100 mol%, and the molar ratio (A / B) of structural unit A to structural unit B in the copolymer is greater than 2.3 and less than 50.

[0172] CH2=CH-COOM (1)

[0173] In formula (1), M represents a hydrogen atom.

[0174] [Chemical formula 11]

[0175]

[0176] In formula (2), R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group.

[0177] CH2=CR 5 -COO-(CH2CH2O) q -H (3)

[0178] In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 45.

[0179] <6> The method for producing a semiconductor single-walled carbon nanotube dispersion or the method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to any one of <1> to <5>, wherein q in the above formula (3) is 2 to 25.

[0180] <7> The method for producing a semiconductor single-walled carbon nanotube dispersion or the method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to any one of <1> to <6>, wherein the weight average molecular weight of the polymer is greater than or equal to 3,000 and less than or equal to 100,000.

[0181] <8> A method for producing a semiconductor single-walled carbon nanotube dispersion or a method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to any one of <1> to <7>, wherein the pH of the separated single-walled carbon nanotube dispersion is greater than 1 and less than 5.

[0182] <9> A method for producing a semiconductor single-layer carbon nanotube dispersion or a method for separating semiconductor single-layer carbon nanotubes from metallic single-layer carbon nanotubes according to any one of <1> to <8>, wherein the mass ratio of the copolymer to the carbon nanotubes in the separated single-layer carbon nanotube dispersion (copolymer / carbon nanotubes) is greater than 5 and less than 50.

[0183] <10> A method for producing a semiconductor single-walled carbon nanotube dispersion or a method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to any one of <1> to <9>, wherein the content of the above-mentioned copolymer in the above-mentioned separated single-walled carbon nanotube dispersion is greater than 0.5 mass % and less than 5 mass %.

[0184] <11> A method for producing a semiconductor single-walled carbon nanotube dispersion or a method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to any one of <1> to <10>, wherein the content of the carbon nanotubes in the separated single-walled carbon nanotube dispersion is greater than 0.03 mass % and less than 0.5 mass %.

[0185] <12> A method for producing a semiconductor single-walled carbon nanotube dispersion or a method for separating semiconductor single-walled carbon nanotubes from metallic single-walled carbon nanotubes according to any one of <1> to <11>, wherein the average diameter of the single-walled carbon nanotubes used in the preparation of the separated single-walled carbon nanotube dispersion in the above-mentioned step A is greater than 0.5 nm and less than 2 nm.

[0186] <13> A method for producing a semiconductor single-walled carbon nanotube dispersion, comprising:

[0187] A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor-type single-walled carbon nanotubes and metallic-type single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3); and

[0188] After centrifuging the separated single-walled carbon nanotube dispersion, step B includes extracting a supernatant containing the semiconductor single-walled carbon nanotubes from the centrifuged separated single-walled carbon nanotube dispersion.

[0189] The content of the structural unit A in all structural units of the copolymer is 55 mol% or more and less than 100 mol%,

[0190] The molar ratio (A / B) of the structural unit A to the structural unit B in the copolymer is 1.2 or more and 300 or less.

[0191] <14> A method for producing a semiconductor single-walled carbon nanotube dispersion, comprising:

[0192] A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor-type single-walled carbon nanotubes and metallic-type single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3); and

[0193] After centrifuging the separated single-walled carbon nanotube dispersion, step B includes extracting a supernatant containing the semiconductor single-walled carbon nanotubes from the centrifuged separated single-walled carbon nanotube dispersion.

[0194] The average diameter of the single-walled carbon nanotubes used in the preparation of the separated single-walled carbon nanotube dispersion in the step A is 0.5 nm or more and 2 nm or less.

[0195] The content of the structural unit A in all the structural units of the copolymer is 55 mol% or more and less than 100 mol%.

[0196] <15> A method for producing a semiconductor single-walled carbon nanotube dispersion, comprising:

[0197] A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor-type single-walled carbon nanotubes and metallic-type single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3); and

[0198] After centrifuging the separated single-walled carbon nanotube dispersion, step B includes extracting a supernatant containing the semiconductor single-walled carbon nanotubes from the centrifuged separated single-walled carbon nanotube dispersion.

[0199] The average diameter of the single-walled carbon nanotubes used in the preparation of the separated single-walled carbon nanotube dispersion in the step A is 0.5 nm or more and 2 nm or less.

[0200] The content of the structural unit A in all structural units of the copolymer is 55 mol% or more and less than 100 mol%,

[0201] The molar ratio (A / B) of the structural unit A to the structural unit B in the copolymer is 1.2 or more and 300 or less.

[0202] <16> A method for producing semiconducting single-walled carbon nanotubes, comprising the step of filtering a dispersion of semiconducting single-walled carbon nanotubes obtained by the method described in any one of <1> to <15> to extract the semiconducting single-walled carbon nanotubes.

[0203] <17> A method for producing semiconducting single-walled carbon nanotubes, comprising: a process of drying a semiconducting single-walled carbon nanotube dispersion obtained by any one of the methods described in <1> to <15> to obtain a mixture containing semiconducting single-walled carbon nanotubes and the above-mentioned polymer; and a process of removing the above-mentioned copolymer from the above-mentioned mixture to extract the semiconducting single-walled carbon nanotubes.

[0204] <18> A method for producing semiconducting single-walled carbon nanotubes, comprising obtaining the semiconducting single-walled carbon nanotube dispersion obtained by the method according to any one of <1> to <15> as semiconducting single-walled carbon nanotubes without further separation treatment.

[0205] <19> A method for producing an ink containing semiconductor single-walled carbon nanotubes, the method comprising the production method described in any one of <1> to <18> as one step.

[0206] <20> An ink containing semiconducting single-walled carbon nanotubes, comprising: at least one of an organic solvent and water, the semiconducting single-walled carbon nanotubes, and the copolymer defined in any one of <1> to <7>.

[0207] <21> An aqueous dispersion comprising semiconductor single-walled carbon nanotubes and a copolymer including a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3).

[0208] <22> Use of a copolymer comprising a structural unit A derived from a monomer represented by the above formula (1) and a structural unit B derived from a monomer represented by the above formula (3) for isolating semiconductor-type SWCNTs.

[0209] Example

[0210] Hereinafter, the present invention will be described in further detail based on Examples, but these are illustrative only, and the present invention is not limited to these Examples.

[0211] 1. Determination methods of various parameters

[0212] [Measurement of Weight Average Molecular Weight of Copolymer]

[0213] The weight average molecular weight of the copolymer used for preparing the isolated SWCNT dispersion was measured using gel permeation chromatography (hereinafter also referred to as “GPC”) under the following conditions.

[0214] <GPC conditions>

[0215] Measuring device: HLC-8320GPC (manufactured by Tosoh Corporation)

[0216] Column: α-M+α-M (manufactured by Tosoh Corporation)

[0217] Eluent: 60mmol / L H3PO4 and 50mmol / L LiBr in N,N-dimethylformamide (DMF) solution

[0218] Flow rate: 1.0mL / min

[0219] Column temperature: 40°C

[0220] Detection: RI

[0221] Sample volume: 0.5 mg / mL

[0222] Standard material: Monodisperse polystyrene (manufactured by Tosoh Corporation)

[0223] [Measurement of average diameter and average length of SWCNT]

[0224] The average diameter and average length of SWCNTs are calculated by measuring the diameters and lengths of 10 or more CNTs from an image obtained using a transmission electron microscope and averaging the measured diameters and lengths.

[0225] 2. Production of copolymers a to e

[0226] [Copolymer a]

[0227] 30 g of ultrapure water (Fujifilm Wako Pure Chemical Industries, Ltd.) was placed in a reaction container equipped with a stirrer, a reflux tube, a thermometer, and dropping funnels 1 and 2, and the reaction system was replaced with nitrogen while stirring, and then the temperature was raised to 80°C. A mixed solution of 40 g (96.5 mol%) of acrylic acid, 10 g (3.5 mol%) of polyethylene glycol (10) monoacrylate (AE-400) and 10 g of ultrapure water was prepared in a dropping funnel 1, and a mixed solution of 2.57 g (4.0 mol%) of 3-mercapto-1,2-propanediol (Fujifilm Wako Pure Chemical Industries, Ltd.) as a chain transfer agent, 2.51 g (1.0 mol%) of 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]·tetrahydrate (Fujifilm Wako Pure Chemical Industries, Ltd. "VA-057") as a polymerization initiator and 76.7 g of ultrapure water was prepared in a dropping funnel 2, and the mixture was added dropwise simultaneously over 1 hour. After the addition was completed, the mixture was aged for 1 hour while stirring to complete the reaction, thereby obtaining a copolymer a.

[0228] [Copolymer b to e]

[0229] Copolymers b to e were obtained in the same manner as in the production of copolymer a except that the amounts of monomers, chain transfer agents, and polymerization initiators were changed to those shown in Table 1.

[0230] Table 1 shows the compositions and weight average molecular weights of the obtained copolymers a to e.

[0231] The monomers used in the production of the copolymer are as follows.

[0232] AA: Acrylic acid ("Special Grade" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0233] AE-400: polyethylene glycol (10) monoacrylate ("BLEMMER AE-400" manufactured by NOF Corporation), in formula (3), R 5 = methyl, q = 10)

[0234] AE-200: polyethylene glycol (4.5) monoacrylate ("BLEMMER AE-200" manufactured by NOF Corporation), (in formula (3), R 5 = methyl, q = 4.5)

[0235] [Table 1]

[0236] Table 1

[0237]

[0238] 3. Preparation of Semiconducting SWCNT Dispersion

[0239] [Examples 1 to 5]

[0240] To 30 mL of a 3 wt % aqueous solution obtained by dissolving the compounds shown in Table 2 in ultrapure water (manufactured by Wako Pure Chemical Industries, Ltd.) was added 30 mg of a SWCNT mixture synthesized by the HiPco method ("HiPco-Raw" manufactured by NanoIntegris, average diameter: 0.8 to 1.2 nm, average length: 0.4 to 0.7 μm) to obtain a mixed solution.

[0241] Next, the mixed solution was stirred with a stirrer and dispersed with an ultrasonic homogenizer ("450D" manufactured by BRANSON) at an amplitude of 30% and 10°C for 10 minutes to obtain separated SWCNT dispersions of Examples 1 to 5. The types and contents of each component in each separated SWCNT dispersion are shown in Table 2. The contents of the SWCNT mixture and compound in the separated SWCNT dispersion are shown in Table 2, and the water content is the remainder after removing the SWCNT mixture and the compound.

[0242] The obtained separated SWCNT dispersion was centrifuged for 30 minutes using an ultracentrifuge ("CS100GXII", rotor S50A, manufactured by Hitachi Koki Co., Ltd.) at a rotation speed of 50,000 rpm, a gravitational acceleration of 210 kG, and a temperature of 20° C. Thereafter, 80% of the supernatant was extracted from the liquid surface on a volume basis so as not to float the precipitated deposits, thereby obtaining semiconductor-type SWCNT dispersions of Examples 1 to 5.

[0243] [Comparative Example 1]

[0244] The same operation as in Example 1 was carried out except that compound f [polyoxyethylene (100) stearyl ether, ("Brij S100" manufactured by Sigma-Aldrich)] was used instead of the copolymer to obtain a separated SWCNT dispersion and a supernatant (semiconductor-type SWCNT dispersion) of Comparative Example 1. The contents of the SWCNT mixture and the compound in the separated SWCNT dispersion are shown in Table 2, and the water content is the remainder after removing the SWCNT mixture and the compound.

[0245] 4. Evaluation

[0246] [Separability Evaluation]

[0247] The absorbance was measured using an ultraviolet-visible near-infrared spectrophotometer ("UV-3600Plus" manufactured by Shimadzu Corporation) capable of measuring visible light to infrared light. Then, the value obtained by taking the ratio of the peak intensity representing the semiconductor-type SWCNT to the peak intensity representing the metal-type SWCNT was calculated and used as the evaluation criterion for the separation of the metal-type SWCNT and the semiconductor-type SWCNT. The higher the calculated value, the higher the semiconductor-type SCNT separation can be evaluated. The results are shown in Table 2.

[0248] [Mathematical formula 2]

[0249]

[0250] It should be noted that the SWCNT (HIPCO) used has a unique wavelength of semiconductor-type SWCNT at around 730 nm, and has a unique wavelength of metal-type SWCNT at around 480 nm.

[0251] [Table 2]

[0252] Table 2

[0253]

[0254] *1 Polyoxyethylene (100) stearyl ether

[0255] As shown in Table 2, compared with the SWCNT dispersion separated in Comparative Example 1, the SWCNT dispersions separated in Examples 1 to 5 were superior in the separation properties of the semiconductor-type SWCNTs.

[0256] Industrial Applicability

[0257] As described above, according to the method for producing a semiconductor SWCNT dispersion of the present invention, metal SWCNTs and semiconductor SWCNTs can be separated in an aqueous medium without using a density gradient forming agent or the like, using an easily available separation agent and a simple operation, so that it can be expected that the production efficiency of the semiconductor SWCNT dispersion and the method for producing the semiconductor SWCNT itself will be improved.

Claims

1. A method for producing a semiconductor single-walled carbon nanotube dispersion, comprising: A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor single-walled carbon nanotubes and metallic single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and After centrifuging the separated single-walled carbon nanotube dispersion, step B includes extracting a supernatant containing the semiconductor single-walled carbon nanotubes from the centrifuged separated single-walled carbon nanotube dispersion. CH2=CH-COOM (1) In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2): In formula (2), R 1 , R 2 , R 3 , R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group, CH2=CR 5 -COO-(CH2CH2O) q -H (3) In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

2. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1, wherein: In formula (1), M is a hydrogen atom.

3. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: In formula (3), q is 3 or more and 12 or less.

4. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The content of the structural unit A in all structural units of the copolymer is 55 mol % or more and less than 100 mol %.

5. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The content of the structural unit A in all structural units of the copolymer is 85 mol% or more and 98 mol% or less in terms of mol%.

6. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The content of the structural unit A in all structural units of the copolymer is 40 mass % or more and 90 mass % or less in terms of mass %.

7. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The content of the structural unit B in all structural units of the copolymer exceeds 0 mol % and is 45 mol % or less.

8. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The content of the structural unit B in all structural units of the copolymer is 2 mol% or more and 15 mol% or less in terms of mol%.

9. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The content of the structural unit B in all structural units of the copolymer is 10 mass % or more and 60 mass % or less in terms of mass %.

10. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The total content of the structural unit A and the structural unit B in all structural units of the copolymer is 80 mol % or more and 100 mol % or less.

11. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The molar ratio of the structural unit A to the structural unit B in the copolymer, ie, A / B, is 1.2 or more and 300 or less.

12. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The molar ratio of the structural unit A to the structural unit B in the copolymer, ie, A / B, is 5.6 or more and 50 or less.

13. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The mass ratio of the structural unit A to the structural unit B in the copolymer, that is, A / B, is 0.7 or more and 6 or less.

14. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The weight average molecular weight of the copolymer is 3,000 or more and 60,000 or less.

15. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The mass ratio of the copolymer to the single-walled carbon nanotubes SWCNT in the separated single-walled carbon nanotube dispersion, ie, copolymer / SWCNT, is 10 or more and 50 or less.

16. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: In the step A, the single-walled carbon nanotubes used in preparing the separated single-walled carbon nanotube dispersion have an average diameter of 0.5 nm to 2 nm.

17. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The separation efficiency of the semiconductor single-walled carbon nanotubes in the supernatant obtained in the step B is 1.3 or more, Here, the separability of the semiconductor single-walled carbon nanotube, i.e., semiconductor SWCNT, is a value obtained according to the following formula: 。 18. The method for producing a semiconductor single-walled carbon nanotube dispersion according to claim 1 or 2, wherein: The separation efficiency of the semiconductor single-walled carbon nanotubes in the supernatant obtained in step B is 2.0 or more.

19. A method for producing semiconducting single-walled carbon nanotubes, comprising the step of filtering a semiconducting single-walled carbon nanotube dispersion obtained by the method for producing a semiconducting single-walled carbon nanotube dispersion according to any one of claims 1 to 18 to extract the semiconducting single-walled carbon nanotubes.

20. A method for producing a semiconductor single-walled carbon nanotube, comprising: A process of drying a semiconducting single-walled carbon nanotube dispersion obtained by the method for producing a semiconducting single-walled carbon nanotube dispersion according to any one of claims 1 to 18 to obtain a mixture containing semiconducting single-walled carbon nanotubes and the copolymer; and a process of removing the copolymer from the mixture to extract the semiconducting single-walled carbon nanotubes.

21. A method for producing semiconducting single-walled carbon nanotubes, comprising obtaining the semiconducting single-walled carbon nanotube dispersion obtained by the method for producing a semiconducting single-walled carbon nanotube dispersion according to any one of claims 1 to 18 as semiconducting single-walled carbon nanotubes without further separation treatment.

22. A method for separating semiconductor single-layer carbon nanotubes from metallic single-layer carbon nanotubes, comprising: A step A of preparing a separated single-walled carbon nanotube dispersion, wherein the separated single-walled carbon nanotube dispersion contains single-walled carbon nanotubes including semiconductor single-walled carbon nanotubes and metallic single-walled carbon nanotubes, an aqueous medium, and a copolymer containing a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3); and After centrifuging the separated single-walled carbon nanotube dispersion, step B includes extracting a supernatant containing the semiconductor single-walled carbon nanotubes from the centrifuged separated single-walled carbon nanotube dispersion. The separated single-walled carbon nanotube dispersion contains water as the aqueous medium, CH2=CH-COOM (1) In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2): In formula (2), R 1 , R 2 , R 3 , R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group, CH2=CR 5 -COO-(CH2CH2O) q -H (3) In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

23. A method for producing an ink containing semiconductor single-walled carbon nanotubes, comprising the production method according to any one of claims 1 to 21 as one step.

24. An ink containing semiconducting single-walled carbon nanotubes, comprising: at least one of an organic solvent and water, semiconducting single-walled carbon nanotubes, and a copolymer comprising a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3), CH2=CH-COOM (1) In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2): In formula (2), R 1 , R 2 , R 3 , R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group, CH2=CR 5 -COO-(CH2CH2O) q -H (3) In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

25. An aqueous dispersion comprising: Semiconducting single-walled carbon nanotubes, and A copolymer comprising a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3), CH2=CH-COOM (1) In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2): In formula (2), R 1 , R 2 , R 3 , R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group, CH2=CR 5 -COO-(CH2CH2O) q -H (3) In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

26. Use of a copolymer for separating semiconducting single-walled carbon nanotubes, the copolymer comprising a structural unit A derived from a monomer represented by the following formula (1) and a structural unit B derived from a monomer represented by the following formula (3), CH2=CH-COOM (1) In formula (1), M represents a hydrogen atom, a metal atom, or a group having a structure represented by the following formula (2): In formula (2), R 1 , R 2 , R 3 , R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms which may have a hydroxyl group, CH2=CR 5 -COO-(CH2CH2O) q -H (3) In formula (3), R 5 represents a hydrogen atom or a methyl group, and q represents the average number of added moles of ethyleneoxy groups, which is 2 to 120.

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