WO2019021908A1 - Carbon nanotube composite body and method for producing same - Google Patents

Carbon nanotube composite body and method for producing same Download PDF

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WO2019021908A1
WO2019021908A1 PCT/JP2018/026930 JP2018026930W WO2019021908A1 WO 2019021908 A1 WO2019021908 A1 WO 2019021908A1 JP 2018026930 W JP2018026930 W JP 2018026930W WO 2019021908 A1 WO2019021908 A1 WO 2019021908A1
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carbon nanotube
carbon
carbon nanotubes
nanotube composite
semiconducting
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PCT/JP2018/026930
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French (fr)
Japanese (ja)
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斐之 野々口
壯 河合
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国立大学法人 奈良先端科学技術大学院大学
日本ゼオン株式会社
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Priority to JP2019532536A priority Critical patent/JP7221496B2/en
Priority to CN201880047426.9A priority patent/CN110915008A/en
Publication of WO2019021908A1 publication Critical patent/WO2019021908A1/en

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    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
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    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/159—Carbon nanotubes single-walled
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/168—After-treatment
    • C01B32/172—Sorting
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    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/168—After-treatment
    • C01B32/174—Derivatisation; Solubilisation; Dispersion in solvents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L65/00—Compositions of macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain; Compositions of derivatives of such polymers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/85—Thermoelectric active materials
    • H10N10/851—Thermoelectric active materials comprising inorganic compositions
    • H10N10/855—Thermoelectric active materials comprising inorganic compositions comprising compounds containing boron, carbon, oxygen or nitrogen
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/85—Thermoelectric active materials
    • H10N10/856—Thermoelectric active materials comprising organic compositions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/549—Organic PV cells

Definitions

  • the present invention relates to a carbon nanotube composite and a method for producing the same.
  • thermoelectric conversion elements have attracted attention as materials that can be used in fields such as thermoelectric conversion elements, field effect transistors, sensors, integrated circuits, rectifying elements, solar cells, catalysts, and electroluminescence.
  • a carbon-based thermoelectric conversion material represented by carbon nanotubes is considered to be a portable and flexible material for a thermoelectric conversion device because of its light weight and the flexibility of the structure derived from carbon-carbon bonds.
  • thermoelectric conversion material For example, a composite of carbon nanotubes and a conductive polymer has been proposed as a thermoelectric conversion material.
  • Patent Document 1 discloses a thermoelectric conversion material containing a conductive polymer and a thermal excitation assist agent.
  • Patent Document 2 discloses a thermoelectric conversion material containing carbon nanotubes and a conjugated polymer.
  • Non-Patent Document 1 describes a composite material using a composite of PEDOT and poly (styrenesulfonic acid) (PEDOT: PSS) or meso-tetra (4-carboxyphenyl) porphine (TCPP) and a carbon nanotube. ing.
  • Non-Patent Document 2 describes that p-type and n-type carbon nanotube composites are obtained by using conjugated polyelectrolytes.
  • Non-Patent Document 3 reports the thermoelectric conversion characteristics of a semiconducting carbon nanotube film obtained using a polyfluorene derivative.
  • thermoelectric conversion characteristics such as the Seebeck coefficient, the conductivity, and the power factor
  • An aspect of the present invention aims to realize a carbon nanotube composite having excellent thermoelectric conversion characteristics.
  • the present invention includes the following aspects.
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more) Or the following formula (2)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more)
  • the conductive polymer has the following formula (3)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more
  • the carbon nanotube composite according to ⁇ 1> characterized in that
  • ⁇ 4> The carbon nanotube composite according to any one of ⁇ 1> to ⁇ 3>, further comprising a p-type dopant or an n-type dopant.
  • An ink comprising the carbon nanotube complex according to any one of ⁇ 1> to ⁇ 4> and a solvent.
  • the ⁇ 6> carbon nanotube is represented by the following formula (1)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more) Or the following formula (2)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more) From the dispersion step of dispersing in a solvent containing a conductive polymer represented by and the carbon nanotube dispersion obtained by the above dispersion step, separating a carbon nanotube composite containing 90 mass% or more of semiconductive carbon nanotubes as carbon nanotubes And a separation step of forming a carbon nanotube composite.
  • the ⁇ 7> above-mentioned conductive polymer has the following formula (3)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more
  • thermoelectric conversion characteristics it is possible to provide a carbon nanotube composite having excellent thermoelectric conversion characteristics.
  • FIG. 2 is a diagram showing an infrared spectrum of the carbon nanotube film of Example 1.
  • FIG. 6 is a view showing an infrared spectrum of a carbon nanotube film of Comparative Example 1;
  • FIG. 6 is a graph showing the thermoelectric conversion characteristics of the carbon nanotube films of Examples 1 to 4 and the carbon nanotube films of Comparative Examples 2 and 3.
  • FIG. 6 is a graph showing the thermoelectric conversion characteristics of the p-type carbon nanotube film of Example 5, the n-type carbon nanotube film of Example 6, and the p-type carbon nanotube film of Comparative Example 4.
  • FIG. 2 is a view showing a scanning electron microscope image of the carbon nanotube film of Example 1.
  • thermoelectric Conversion Characteristics First, an index relating to the thermoelectric conversion characteristic will be described.
  • PF ⁇ 2 ⁇ (i)
  • PF is a power factor
  • ⁇ is a Seebeck coefficient
  • ⁇ is conductivity
  • the output factor is 100 .mu.W / mK 2 or more at 310K, more preferably 200 ⁇ W / mK 2 or more, 400 W / mK 2 It is particularly preferable to be the above. It is preferable that the output factor of the carbon nanotube complex is 100 ⁇ W / mK 2 or more at 310 K, because it is equal to or greater than that of the conventional carbon nanotube complex. In order to obtain such a high output carbon nanotube composite, it is conceivable to improve either the Seebeck coefficient or the conductivity or both.
  • the Seebeck coefficient refers to the ratio of the open circuit voltage to the temperature difference between the high-temperature junction and the low-temperature junction of a circuit exhibiting the Seebeck effect (from "McGrow Hill Technical Term Third Edition").
  • the Seebeck coefficient can be measured, for example, using a Seebeck effect measurement apparatus (manufactured by MMR Technologies) or a thermoelectric conversion characteristic evaluation apparatus (manufactured by Advance Riko, ZEM-3) used in the examples described later.
  • the larger the Seebeck coefficient absolute value the larger the thermoelectromotive force.
  • the Seebeck coefficient can be an index for determining the polarity of an electronic material such as a carbon nanotube. Specifically, for example, it can be said that an electronic material having a positive Seebeck coefficient has p-type conductivity. On the other hand, it can be said that an electronic material having a negative Seebeck coefficient has n-type conductivity.
  • the absolute value of the Seebeck coefficient is preferably 20 ⁇ V / K or more, more preferably 30 ⁇ V / K or more, and still more preferably 40 ⁇ V / K or more.
  • the conductivity can be determined, for example, by using a resistivity meter (Loresta GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) or a four-probe method using a thermoelectric conversion characteristic evaluation device (ZEM-3, manufactured by Advance Riko) used in the examples described later. It can be measured by
  • the conductivity is preferably 10 S / cm or more, and more preferably 100 S / cm or more.
  • the conductivity is preferably 1500 S / cm or less, more preferably 1000 S / cm or less. If the conductivity is in the above-mentioned range, it is preferable because it becomes a high output carbon nanotube composite in which the Seebeck coefficient and the conductivity are well balanced.
  • thermoelectric conversion characteristic Another index related to the thermoelectric conversion characteristic is the dimensionless figure of merit ZT.
  • ZT is calculated
  • ZT PF ⁇ T / ⁇ (ii)
  • T is temperature
  • ⁇ thermal conductivity.
  • thermoelectric conversion material in order to increase ZT, the smaller the thermal conductivity, the better. This corresponds to the fact that the thermoelectric conversion material utilizes a temperature difference.
  • the thermal conductivity of the thermoelectric conversion material is large, the temperature in the substance is easily made uniform, and it is difficult to cause a temperature difference. Therefore, thermoelectric conversion materials having a large thermal conductivity tend to be difficult to efficiently generate power.
  • a carbon nanotube complex according to an embodiment of the present invention comprises a carbon nanotube, and a compound represented by the following formula (1):
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more) Or the following formula (2)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more) And 90% by mass or more of the carbon nanotube is a semiconducting carbon nanotube.
  • Metallic carbon nanotubes and semiconductive carbon nanotubes exist in carbon nanotubes.
  • the conductive polymer encases the semiconducting carbon nanotube with high selectivity due to its structure and electronic properties. Therefore, semiconducting carbon nanotubes are dispersed in a solvent with good selectivity.
  • a carbon nanotube composite containing semiconducting carbon nanotubes with high purity can be obtained. That is, in the carbon nanotube composite, the conductive polymer is in a state of being entangled with the carbon nanotube.
  • the carbon nanotube composite may be used in various applications and applications as a thermoelectric conversion device or the like.
  • the thermoelectric conversion device composed of the carbon nanotube composite has flexibility. Therefore, the thermoelectric conversion device can be in close contact with a complex three-dimensional surface such as a human body and piping, and can efficiently use body temperature, waste heat, and the like.
  • the carbon nanotube composite may be formed into a desired shape.
  • the carbon nanotube composite may be accumulated to form a film.
  • the film may have a thickness of, for example, 0.1 ⁇ m to 1000 ⁇ m.
  • the density of the film is not particularly limited, but may be 0.05 to 1.0 g / cm 3 or 0.1 to 0.5 g / cm 3 .
  • the film may form a non-woven structure so that the carbon nanotube complexes entangle each other. Therefore, the film is lightweight and flexible.
  • Such a film can be suitably used as a thermoelectric conversion device.
  • Carbon nanotube> The carbon nanotube composite contains carbon nanotubes. Further, 90% by mass or more of the carbon nanotubes are semiconducting carbon nanotubes. In other words, 90% by mass or more of the carbon nanotubes contained in the carbon nanotube complex are semiconductive carbon nanotubes.
  • Carbon nanotubes synthesized by a known synthesis method or commercially available carbon nanotubes usually contain metallic carbon nanotubes and semiconductive carbon nanotubes in a mass ratio of about 1: 2 (Cambre, S. et al. , ACS Nano, vol.4, no. 11, 6717-6724, 2010).
  • a thermoelectric conversion material is manufactured using such carbon nanotubes, the thermal conductivity may be high and the Seebeck coefficient may be low due to the metallic carbon nanotubes. Therefore, when the content ratio of metallic carbon nanotubes is large, ZT is small, and sufficient thermoelectric conversion characteristics can not be obtained. Therefore, the carbon nanotube composite preferably contains semiconducting carbon nanotubes with high purity.
  • Patent Documents 1 and 2 and Non-patent Documents 1 and 2 make no mention at all to increase the content ratio of semiconducting carbon nanotubes. Therefore, it is considered that the prior art described in these documents can not derive sufficient thermoelectric conversion characteristics.
  • the mass ratio of metallic carbon nanotubes to semiconductive carbon nanotubes can be measured, for example, by infrared spectroscopy.
  • an infrared spectrum is obtained for a sample that does not contain a substance that can affect the mass ratio of metallic carbon nanotubes and semiconductive carbon nanotubes (for example, the conductive polymer used in one embodiment of the present invention). Let this be the infrared spectrum of the control. It is considered that the sample contains metallic carbon nanotubes and semiconducting carbon nanotubes at a mass ratio of 1: 2 as described above.
  • the infrared spectrum of the sample for which it is desired to know the mass ratio of metallic carbon nanotubes and semiconducting carbon nanotubes is compared with the infrared spectrum of the above control, and the size of the absorbance band derived from plasmon resonance of metallic carbon nanotubes Rate the change in From the extent of the change in the size of this band, it is possible to calculate the amount of change in the content ratio of metallic carbon nanotubes compared to the control sample. Thereby, the mass ratio of the metallic carbon nanotube to the semiconductive carbon nanotube in the desired sample can be determined.
  • the content of the semiconductive carbon nanotube is preferably 95% by mass or more, more preferably 99% by mass or more, and still more preferably 99.9% by mass or more in 100% by mass of the carbon nanotube.
  • the diameter of the carbon nanotube can be appropriately determined in consideration of the structure of the conductive polymer and the like.
  • the diameter of a carbon nanotube means the diameter in the cross section perpendicular
  • the diameter of the carbon nanotube is preferably 1 to 5 nm, more preferably 1 to 2 nm, still more preferably 1 to 1.7 nm, and particularly preferably 1 to 1.4 nm. .
  • the diameter of the carbon nanotube is in the above range, the conductive polymer described later is easily adsorbed.
  • the diameter of the carbon nanotube can be measured by observation with an electron microscope or a spectroscopic method.
  • Carbon nanotubes can form bundles (small bundles).
  • the diameter of the bundle is preferably 5 nm or less, more preferably 3 nm or less. If the diameter of the bundle is 5 nm or less, it is considered that the carbon nanotubes are well dispersed, and uniform doping is possible.
  • the carbon nanotube may have a single-layered structure or a multi-layered (two-layered, three-layered, four-layered or more multi-layered) structure. That is, the carbon nanotubes may be single-wall carbon nanotubes (SWNTs) or multi-wall carbon nanotubes (MWNTs). However, multi-walled carbon nanotubes may have both a semiconductive layer and a metallic layer. Therefore, it is preferable to use a single-walled carbon nanotube from the viewpoint of increasing the purity of the semiconducting carbon nanotube.
  • SWNTs single-wall carbon nanotubes
  • MWNTs multi-wall carbon nanotubes
  • multi-walled carbon nanotubes may have both a semiconductive layer and a metallic layer. Therefore, it is preferable to use a single-walled carbon nanotube from the viewpoint of increasing the purity of the semiconducting carbon nanotube.
  • the content of carbon nanotubes in 100% by mass of the carbon nanotube composite is preferably 50 to 90% by mass, and more preferably 65 to 85% by mass. If the content of the carbon nanotube is in the above range, the performance derived from the carbon nanotube can be sufficiently exhibited in the carbon nanotube composite.
  • the carbon nanotube complex is represented by the following formula (1)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more) Or the following formula (2)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more) Containing a conductive polymer represented by The alkyl group is considered to be easily entangled with carbon nanotubes. In addition to such a structure, the conductive polymer is considered to be easily adsorbed to the semiconductive carbon nanotube also by the electronic physical properties of the aromatic group. Therefore, the conductive polymer can selectively adsorb semiconducting carbon nanotubes. Two or more kinds of the conductive polymers may be mixed and used.
  • Non-Patent Document 3 The polyfluorene derivative described in Non-Patent Document 3 is insulating. Therefore, in Non-Patent Document 3, when a polyfluorene derivative is used as a dispersant, it is necessary to remove the polyfluorene derivative in order to improve the conductivity. On the other hand, if it is the said conductive polymer, it is not necessary to remove.
  • the carbon number of the alkyl group is more preferably 7 to 20, and still more preferably 10 to 14. If the carbon number is in the above range, the alkyl group is more easily entangled with the carbon nanotube.
  • n is preferably an integer of 5 or more.
  • the upper limit of n is not particularly limited, but from the viewpoint of high solubility of the conductive polymer, n is preferably an integer of 10 or less, and more preferably an integer of 9 or less.
  • the conductive polymer may have an arbitrary structure in addition to the repeating unit represented by the formula (1) or the formula (2), but the above-mentioned formula (1) or the formula (2) It is preferable to consist of a repeating unit represented by
  • a divalent aromatic group intends a structure having at least one aromatic ring and two bonds. That is, it can be said that the divalent aromatic group has a structure derived from a bifunctional aromatic compound.
  • the conductive polymer has X, it exhibits more preferable electronic properties. More preferably, X is a benzothiadiazole skeleton. That is, the conductive polymer has the following formula (3)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more).
  • the conductive polymer has the following formula (4)
  • n is an integer of 3 or more
  • the mass ratio of carbon nanotubes to the conductive polymer in the carbon nanotube composite may be adjusted depending on the application, and may be 1:99 to 99: 1.
  • the conductive polymer is preferably 1 to 40 parts by mass, and more preferably 10 to 35 parts by mass with respect to 100 parts by mass of carbon nanotubes. If the content ratio of the conductive polymer is in the above range, the conductive polymer can be thinly adsorbed to the carbon nanotube.
  • the carbon nanotube composite may further contain a p-type dopant or an n-type dopant. Thereby, the carbon nanotube complex can be made into a p-type thermoelectric conversion material or an n-type thermoelectric conversion material.
  • the p-type dopant means a dopant which has a positive value of the Seebeck coefficient of the object to be doped.
  • the p-type dopant e.g., thiocyanate ion (SCN -), perchlorate ion (ClO 4 -), permanganate ion (MnO 4 -), tetrafluoroborate ion (BF 4 -), iodate (IO 3 -), hexafluorophosphate ion (PF 6 -), trifluoromethanesulfonate anion (TfO -), bis (trifluoromethanesulfonyl) amine anion (TFSI -), iodide ion (I -), bromide ion (Br -), chloride ion (Cl -), nitrate ion (NO 3 -) or tosylate ion (Tos -) include hydrochlor
  • the n-type dopant means a dopant having a negative target Seebeck coefficient.
  • the n-type dopant such as hydroxy ion (OH -), alkoxy ion (CH 3 O -, CH 3 CH 2 O -, i-PrO - and t-BuO -, etc.), Chioion (SH - and alkylthio ion ( CH 3 S - and C 2 H 5 S - or the like)), Shianuruion (CN -) or carboxylate ion (CH 3 COO -, etc.), and complexes of alkali metal salts and cyclic ethylene oxide.
  • the alkali metal contained in the alkali metal salt include lithium ion, sodium ion and potassium ion.
  • Cyclic ethylene oxide includes crown ether.
  • Anions contained in these p-type dopants or n-type dopants are presumed to interact with the nanomaterial to be doped or to induce a chemical reaction based on their non-covalent electron pairs.
  • An ink according to an embodiment of the present invention includes a carbon nanotube composite according to an embodiment of the present invention and a dispersion medium.
  • the ink is preferably a dispersion medium in which the carbon nanotube composite (unformed carbon nanotube composite) is dispersed.
  • the component can be provided with a thermoelectric conversion function by applying the ink to a desired component and then removing the dispersion medium.
  • the dispersion medium is not particularly limited as long as the dispersion medium can disperse the carbon nanotube complex.
  • a dispersion medium water and an organic solvent are mentioned, for example.
  • the organic solvent include toluene, o-dichlorobenzene, o-xylene, m-xylene, p-xylene, tetrahydrofuran and chloroform.
  • the method for producing a carbon nanotube complex comprises a carbon nanotube represented by the following formula (1):
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more) Or the following formula (2)
  • R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more) From the dispersion step of dispersing in a solvent containing a conductive polymer represented by and the carbon nanotube dispersion obtained by the above dispersion step, separating a carbon nanotube composite containing 90 mass% or more of semiconductive carbon nanotubes as carbon nanotubes And separating. [1. Index on thermoelectric conversion characteristics] to [3. Regarding the items already described in [Ink], the description is omitted below, and the above description is used as appropriate.
  • the conductive polymer encases the semiconducting carbon nanotube with high selectivity due to its structure and electronic properties. Therefore, the semiconducting carbon nanotubes can be dispersed with high selectivity in the solvent in the dispersing step.
  • metallic carbon nanotubes are difficult to disperse as compared to semiconducting carbon nanotubes encased in a conductive polymer. Therefore, since the metallic carbon nanotubes can be easily removed in the separation step, it is possible to separate the carbon nanotube composite containing the semiconductive carbon nanotubes with high purity.
  • the dispersing step is a step of dispersing the carbon nanotube in a solvent containing the conductive polymer represented by the above formula (1) or the above formula (2).
  • the conductive polymer is adsorbed to the semiconducting carbon nanotubes, and the semiconducting carbon nanotubes are dispersed with high selectivity.
  • the solvent is not particularly limited as long as it dissolves the above-mentioned conductive polymer, and includes organic solvents such as toluene, o-xylene, m-xylene, p-xylene, o-dichlorobenzene, tetrahydrofuran and chloroform.
  • organic solvents such as toluene, o-xylene, m-xylene, p-xylene, o-dichlorobenzene, tetrahydrofuran and chloroform.
  • the solvent is preferably toluene, o-xylene, m-xylene or p-xylene.
  • a method of dispersing carbon nanotubes in a solvent for example, a method using a homogenizing apparatus can be mentioned.
  • a homogenization apparatus a stirring homogenizer, an ultrasonic homogenizer, etc. are mentioned, for example. From the viewpoint of more uniformly dispersing, it is preferable to disperse carbon nanotubes in a solvent using an ultrasonic homogenizer.
  • the temperature in the dispersion step is preferably 0 to 10 ° C. from the viewpoint of suppressing the defect introduction.
  • the separation step is a step of separating a carbon nanotube composite containing 90% by mass or more of semiconductive carbon nanotubes as carbon nanotubes from the carbon nanotube dispersion obtained by the above dispersion step.
  • the separation step is a step of removing most of the metallic carbon nanotubes to which the conductive polymer is not adsorbed.
  • the separation step it is preferable to separate a carbon nanotube composite containing 95% by mass or more of semiconductive carbon nanotubes as carbon nanotubes.
  • a carbon nanotube composite having more excellent thermoelectric conversion characteristics.
  • the method of performing the separation step is not particularly limited as long as the method can separate the semiconductive carbon nanotubes with high purity.
  • Such methods include, for example, methods using a centrifuge. By centrifuging the carbon nanotube dispersion using a centrifuge, most of metallic carbon nanotubes can be precipitated to separate a supernatant containing semiconducting carbon nanotubes with high purity. By collecting the supernatant, it is possible to separate a carbon nanotube complex containing 90% by mass or more of semiconducting carbon nanotubes as carbon nanotubes.
  • the ink according to an embodiment of the present invention may be obtained by replacing the solvent with the above-described dispersion medium.
  • the above manufacturing method may include a forming step of forming the carbon nanotube composite obtained by the separation step into a desired shape (for example, a film).
  • a desired shape for example, a film
  • Examples of the method for forming the carbon nanotube composite into a desired shape include a method for forming the desired shape by accumulating the carbon nanotube composite.
  • a method of forming a film by filtering a dispersion containing a carbon nanotube complex on a membrane filter there may be mentioned a method of forming a film by filtering a dispersion containing a carbon nanotube complex on a membrane filter.
  • the dispersion containing the carbon nanotube complex is suction filtered using a membrane filter with 0.1 to 2 ⁇ m pores, and the carbon nanotube complex accumulated on the membrane filter is dried to obtain a film. It can be molded.
  • the dispersion may be the above-described supernatant, or may be the ink according to an embodiment of the present invention.
  • the above manufacturing method may include a doping step of contacting the carbon nanotube composite with a p-type dopant or an n-type dopant. Thereby, the carbon nanotube complex can be made into a p-type thermoelectric conversion material or an n-type thermoelectric conversion material.
  • a method of performing a doping step after the forming step for example, a method of immersing a carbon nanotube composite formed into a desired shape in a solution containing a p-type dopant or an n-type dopant, or carbon formed into a desired shape
  • a method of applying a solution containing a p-type dopant or an n-type dopant to the nanotube complex for example, a method of immersing a carbon nanotube composite formed into a desired shape in a solution containing a p-type dopant or an n-type dopant, or carbon formed into a desired shape.
  • the solvent in the solution containing the p-type dopant or the n-type dopant may be water or an organic solvent.
  • the solvent is preferably an organic solvent, more preferably methanol, ethanol, propanol, butanol, acetonitrile, N, N-dimethylformamide, dimethylsulfoxide or N-methylpyrrolidone. These solvents can be removed by drying the carbon nanotube composite after the above-mentioned immersion or application.
  • the concentration of the p-type dopant or the n-type dopant in the solution may be adjusted according to the thermoelectric property to be determined.
  • the concentration may be, for example, 0.001 to 1 mol / L, or may be 0.01 to 0.1 mol / L.
  • the doping step can be performed before or after the dispersing step or the separating step.
  • a method of adding a p-type dopant or an n-type dopant to a solvent containing the above-described conductive polymer, a carbon nanotube dispersion liquid, or a supernatant recovered by a separation step can be employed.
  • a compound of the formula (4) having a poly (cyclopentadithiophene) skeleton is referred to as PCPDT
  • a compound of the formula (5) having a poly (cyclopentadithiophene) skeleton and a benzothiadiazole skeleton is PCPDTBT.
  • Carbon nanotubes may also be referred to as CNTs.
  • (B) Seebeck Coefficient The Seebeck coefficient of the films obtained in Examples and Comparative Examples described later was measured using a thermoelectric conversion characteristic evaluation device (ZEM-3, manufactured by Advance Riko Co., Ltd.). The measurement temperature was 310 K (37 ° C.).
  • 8 mg of single-walled carbon nanotubes manufactured by Raymor, RN-020, diameter: about 1.1 to 1.7 nm was charged.
  • the single-walled carbon nanotubes were dispersed in the toluene at about 4 ° C. for 60 minutes using an ultrasonic homogenizer (Q125, manufactured by Qsonica).
  • the dispersion thus obtained was centrifuged at 10000 rpm for 60 minutes using a centrifuge (Kubota Corporation, table top cooling centrifuge 5500). 70% by volume of the supernatant was recovered from the dispersion after centrifugation.
  • the collected supernatant was suction filtered onto a 0.2 ⁇ m pore membrane filter (manufactured by Merck Millipore, Omnipore membrane filter JGWP02500) to deposit a CNT film.
  • the infrared spectrum and the thermoelectric conversion characteristic were measured in the state which mounted the obtained CNT film on PET film.
  • FIG. 1 is an infrared spectrum of the CNT film of Example 1.
  • the vertical axis represents normalized absorbance and the horizontal axis represents photon energy.
  • 5, 6, 7, 8, 9 of 0.1 eV or less of a horizontal axis represents 0.05, 0.06, 0.07, 0.08, 0.09, respectively.
  • 2, 3, 4, 5, 6, 7, 8 and 9 between 0.1 eV and 1 eV on the horizontal axis are 0.2, 0.3, 0.4, 0.5, 0. 0, respectively. 6, 0.7, 0.8, 0.9.
  • the black line (F127 dispersion) represents the data obtained from the dispersion using Pluronic F127 and the gray line (PCPDTBT dispersion) represents the data obtained from the dispersion using PCPDTBT.
  • F127 dispersion represents the data obtained from the dispersion using Pluronic F127
  • PCPDTBT dispersion represents the data obtained from the dispersion using PCPDTBT.
  • the peak of the interband transitions S 11 of semiconducting CNT, the center of the diameter distribution of the CNT is found to be 1.0 ⁇ 1.2 nm.
  • Example 1 In addition, in the case of commercially available semiconducting CNTs, plasmon resonance bands are observed even if the purity is high because of doping during preparation (Morimoto, T., et al. ACS Nano, vol. 8, no. 10) , 9897-9904, 2014).
  • the semiconducting CNTs obtained in Example 1 have similar plasmon resonances below the observation limit, so it can be seen that not only the semiconductor purity is extremely high, but significant doping has not been received. That is, Example 1 can be said to be a method for producing a semiconducting CNT of much higher quality than the conventional one.
  • FIG. 5 is a view showing a scanning electron microscope image of the carbon nanotube film of Example 1.
  • the diameter of each of the CNTs observed in FIG. 5 is 5 nm (resolution) or less. It can be seen that the CNTs are well dispersed, considering that a typical CNT bundle is 20 to 30 nm. That is, it is considered that the semiconducting CNTs are well dispersed by the conductive polymer being entangled with the semiconducting CNTs with high selectivity.
  • Comparative Example 1 A CNT film is obtained in the same manner as in Example 1 except that Tuball (registered trademark) (diameter about 1.75 to 1.85 nm) manufactured by OCSiAl Co., Ltd. is used as a single-walled carbon nanotube, and the infrared spectrum and the thermoelectric spectrum are obtained. The conversion characteristics were measured.
  • Tuball registered trademark
  • OCSiAl Co., Ltd. is used as a single-walled carbon nanotube, and the infrared spectrum and the thermoelectric spectrum are obtained. The conversion characteristics were measured.
  • FIG. 2 is an infrared spectrum of the CNT film of Comparative Example 1.
  • the vertical and horizontal axes are the same as in FIG.
  • the black line (F127 dispersion) represents the data obtained from the dispersion using Pluronic F127 and the gray line (PCPDTBT dispersion) represents the data obtained from the dispersion using PCPDTBT.
  • F127 dispersion represents the data obtained from the dispersion using Pluronic F127
  • PCPDTBT dispersion represents the data obtained from the dispersion using PCPDTBT.
  • thermoelectric conversion characteristics The measurement results of the thermoelectric conversion characteristics of Example 1 and Comparative Example 1 are shown in Table 1.
  • Example 1 including the semiconducting CNT at high purity, the Seebeck coefficient is dramatically improved, and this CNT film behaves as a semiconductor.
  • Example 2 A CNT film was obtained in the same manner as in Example 1 except that PCPDT was used instead of PCPDTBT.
  • Example 3 A CNT film was obtained in the same manner as Example 1, except that HP manufactured by KH Chemicals was used instead of RN-020 manufactured by Raymor as CNT.
  • Example 4 A CNT film was obtained in the same manner as in Example 2 except that HP manufactured by KH Chemicals was used instead of RN-020 manufactured by Raymor as CNT.
  • Comparative Example 2 A CNT film was obtained in the same manner as in Example 1 except that a compound represented by the following formula (6) having a polyfluorene skeleton (hereinafter also referred to as PFD) having a polyfluorene skeleton instead of PCPDTBT was used.
  • PFD polyfluorene skeleton
  • Comparative Example 3 A CNT film was obtained in the same manner as in Comparative Example 2 except that HP manufactured by KH Chemicals was used instead of RN-020 manufactured by Raymor as CNT.
  • thermoelectric conversion characteristics The obtained CNT films of Examples 2 to 4 and Comparative Examples 2 and 3 were placed on a PET film to measure the thermoelectric conversion characteristics. Although not shown, the same method as in Example 1 is that semiconductive CNTs with respect to 100 mass% of CNTs contained in the CNT film are 90 mass% or more in Examples 2 to 4 and Comparative Examples 2 and 3. Confirmed.
  • FIG. 3 is a graph showing the thermoelectric conversion characteristics of the CNT films of Examples 1 to 4 and Comparative Examples 2 and 3.
  • FIG. 3 shows the relationship between the conductivity ⁇ and the Seebeck coefficient ⁇ .
  • 6 of 100 or less represent 60, 80 respectively, and 2, 4, 6, 8 between 100 and 1000 represent 200, 400, 600, 800 respectively.
  • 2 of 1000 or more represent 2000.
  • 6 less than or equal to 0.1 represents 0.06
  • 2 4 and 6 between 0.1 and 1 represent 0.2, 0.4, and 0.6, respectively.
  • 10 or more 2 represents 20.
  • Examples 1 and 2 have a high Seebeck coefficient as compared to Comparative Example 2.
  • the purity of the semiconducting CNT was Example 1> Example 2> Comparative Example 2.
  • Examples 3 and 4 have a high Seebeck coefficient as compared to Comparative Example 3.
  • the purity of the semiconducting CNT was Example 3> Example 4> Comparative Example 3.
  • Example 5 The CNT film obtained by the same method as Example 1 was immersed for 5 minutes in a 0.01 to 4 mg / mL AgTFSI butanol solution. Thereafter, the CNT film was dried at room temperature under reduced pressure for 60 minutes to obtain a p-type CNT film. The thermoelectric conversion characteristic was measured in the state which mounted the obtained p-type CNT film on PET film.
  • Example 6 An n-type CNT film was obtained in the same manner as in Example 2 except that a 0.005-0.075 mol / mL KOH / benzo-18-crown-6-ether butanol solution was used instead of the AgTFSI butanol solution. . The thermoelectric conversion characteristic was measured in the state which mounted the obtained n-type CNT film on PET film.
  • Comparative Example 4 In an aqueous solution containing 1% by mass of Pluronic® F127 (manufactured by BASF), 5 mg of single-walled carbon nanotubes (manufactured by Raymor, RN-020, diameter: about 1.1 to 1.7 nm) was placed. The single-walled carbon nanotubes were dispersed in the aqueous solution at about 4 ° C. for 60 minutes using an ultrasonic homogenizer (Q125, manufactured by Qsonica).
  • Pluronic® F127 manufactured by BASF
  • the dispersion thus obtained was centrifuged at 10000 rpm for 60 minutes using a centrifuge (Kubota Corporation, table top cooling centrifuge 5500). 70% by volume of the supernatant was recovered from the dispersion after centrifugation.
  • the collected supernatant was suction filtered onto a 0.2 ⁇ m pore membrane filter (manufactured by Merck Millipore, Omnipore membrane filter JGWP02500) to deposit a CNT film.
  • the obtained CNT film was immersed in a 0.01 to 4 mg / mL AgTFSI butanol solution for 5 minutes. Thereafter, the CNT film was dried at room temperature under reduced pressure for 60 minutes to obtain a p-type CNT film.
  • the thermoelectric conversion characteristic was measured in the state which mounted the obtained p-type CNT film on PET film.
  • the p-type CNT film contained metallic CNT and semiconducting CNT in a mass ratio of about 1: 2.
  • FIG. 4 is a view showing the thermoelectric conversion characteristics of the p-type CNT film of Example 5, the n-type CNT film of Example 6, and the p-type CNT film of Comparative Example 4.
  • FIG. 4A shows the relationship between the conductivity ⁇ and the absolute value of the Seebeck coefficient
  • FIG. 4 is a view showing the relationship between the conductivity ⁇ and the output factor PF in the p-type CNT film of Example 5, the n-type CNT film of Example 6, and the p-type CNT film of Comparative Example 4. .
  • PCPDTBT is used to improve the purity of semiconducting CNT
  • a high output factor is obtained in both p-type doping and n-type doping when the conductivity is 100 S / cm or more. It is understood that it can be obtained.
  • the conductivity is about 100 S / cm in the p-type CNT film of Example 5
  • an output factor exceeding 400 ⁇ W / mK 2 was obtained, and some showed an output factor exceeding 500 ⁇ W / mK 2 .
  • the present invention can be used, for example, for a thermoelectric conversion material.

Abstract

Provided is a carbon nanotube composite body which has excellent thermoelectric conversion characteristics. A carbon nanotube composite body according to one embodiment of the present invention contains carbon nanotubes and a conductive polymer that has a specific structure; and 90% by mass or more of the carbon nanotubes are composed of semiconductive carbon nanotubes.

Description

カーボンナノチューブ複合体およびその製造方法Carbon nanotube composite and method for producing the same
　本発明は、カーボンナノチューブ複合体およびその製造方法に関する。 The present invention relates to a carbon nanotube composite and a method for producing the same.
　近年、熱電変換素子、電界効果トランジスタ、センサー、集積回路、整流素子、太陽電池、触媒、またはエレクトロルミネッセンス等の分野に利用可能である材料として、カーボンナノチューブが注目されている。カーボンナノチューブに代表されるカーボン系の熱電変換材料は、軽量であることおよび炭素－炭素結合に由来する構造のしなやかさから、持ち運びが可能でフレキシブルな熱電変換デバイスの材料と考えられている。 BACKGROUND ART In recent years, carbon nanotubes have attracted attention as materials that can be used in fields such as thermoelectric conversion elements, field effect transistors, sensors, integrated circuits, rectifying elements, solar cells, catalysts, and electroluminescence. A carbon-based thermoelectric conversion material represented by carbon nanotubes is considered to be a portable and flexible material for a thermoelectric conversion device because of its light weight and the flexibility of the structure derived from carbon-carbon bonds.
　例えば、カーボンナノチューブと導電性高分子との複合体が熱電変換材料として提案されている。特許文献１には、導電性高分子と熱励起アシスト剤とを含有する熱電変換材料が開示されている。また、特許文献２には、カーボンナノチューブおよび共役高分子を含有する熱電変換材料が開示されている。非特許文献１には、ＰＥＤＯＴおよびポリ（スチレンスルホン酸）の複合体（ＰＥＤＯＴ：ＰＳＳ）またはメソ－テトラ（４－カルボキシフェニル）ポルフィン（ＴＣＰＰ）と、カーボンナノチューブとを利用した複合材料が記載されている。非特許文献２では、共役多価電解質を用いることによってｐ型およびｎ型のカーボンナノチューブ複合体を得ることが記載されている。また、非特許文献３では、ポリフルオレン誘導体を用いて得られた半導体性カーボンナノチューブフィルムの熱電変換特性が報告されている。 For example, a composite of carbon nanotubes and a conductive polymer has been proposed as a thermoelectric conversion material. Patent Document 1 discloses a thermoelectric conversion material containing a conductive polymer and a thermal excitation assist agent. Patent Document 2 discloses a thermoelectric conversion material containing carbon nanotubes and a conjugated polymer. Non-Patent Document 1 describes a composite material using a composite of PEDOT and poly (styrenesulfonic acid) (PEDOT: PSS) or meso-tetra (4-carboxyphenyl) porphine (TCPP) and a carbon nanotube. ing. Non-Patent Document 2 describes that p-type and n-type carbon nanotube composites are obtained by using conjugated polyelectrolytes. Further, Non-Patent Document 3 reports the thermoelectric conversion characteristics of a semiconducting carbon nanotube film obtained using a polyfluorene derivative.
国際公開第２０１３／０４７７３０号（２０１３年４月４日公開）International Publication No. 2013/047730 (Apr. 4, 2013) 国際公開第２０１３／０６５６３１号（２０１３年５月１０日公開）International Publication No. 2013/065631 (May 10, 2013)
　しかしながら、上述のような従来技術は、ゼーベック係数、導電率および出力因子等の熱電変換特性が十分ではなく、改善の余地があった。 However, the conventional techniques as described above have insufficient thermoelectric conversion characteristics such as the Seebeck coefficient, the conductivity, and the power factor, and there is room for improvement.
　本発明の一態様は、優れた熱電変換特性を有するカーボンナノチューブ複合体を実現することを目的とする。 An aspect of the present invention aims to realize a carbon nanotube composite having excellent thermoelectric conversion characteristics.
　上記の課題を解決するために、本発明者らが鋭意研究を行った結果、特定の構造を有する導電性ポリマーを用いることによって半導体性カーボンナノチューブを高純度で含有するカーボンナノチューブ複合体を実現できることを見出し、本発明を完成させるに至った。本発明は以下の態様を含む。 As a result of intensive studies conducted by the present inventors to solve the above problems, it is possible to realize a carbon nanotube composite containing semiconducting carbon nanotubes with high purity by using a conductive polymer having a specific structure. To complete the present invention. The present invention includes the following aspects.
　＜１＞カーボンナノチューブと、下記式（１） <1> Carbon nanotube, the following formula (1)
Figure JPOXMLDOC01-appb-C000007
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
または下記式（２）
Figure JPOXMLDOC01-appb-C000007
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
Or the following formula (2)
Figure JPOXMLDOC01-appb-C000008
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、Ｘは２価の芳香族基であり、ｎは３以上の整数である）
で表される導電性ポリマーと、を含み、上記カーボンナノチューブの９０質量％以上が半導体性カーボンナノチューブであることを特徴とする、カーボンナノチューブ複合体。
Figure JPOXMLDOC01-appb-C000008
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more)
And a conductive polymer represented by the formula: wherein 90% by mass or more of the carbon nanotubes are semiconductive carbon nanotubes.
　＜２＞上記導電性ポリマーは、下記式（３） <2> The conductive polymer has the following formula (3)
Figure JPOXMLDOC01-appb-C000009
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
で表されることを特徴とする、＜１＞に記載のカーボンナノチューブ複合体。
Figure JPOXMLDOC01-appb-C000009
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
The carbon nanotube composite according to <1>, characterized in that
　＜３＞上記カーボンナノチューブの９５質量％以上が半導体性カーボンナノチューブであることを特徴とする、＜１＞または＜２＞に記載のカーボンナノチューブ複合体。 <3> The carbon nanotube composite according to <1> or <2>, wherein 95% by mass or more of the carbon nanotube is a semiconducting carbon nanotube.
　＜４＞ｐ型ドーパントまたはｎ型ドーパントをさらに含むことを特徴とする、＜１＞～＜３＞のいずれか１項に記載のカーボンナノチューブ複合体。 <4> The carbon nanotube composite according to any one of <1> to <3>, further comprising a p-type dopant or an n-type dopant.
　＜５＞＜１＞～＜４＞のいずれか１つに記載のカーボンナノチューブ複合体と溶媒とを含むことを特徴とする、インク。 <15> An ink comprising the carbon nanotube complex according to any one of <1> to <4> and a solvent.
　＜６＞カーボンナノチューブを、下記式（１） The <6> carbon nanotube is represented by the following formula (1)
Figure JPOXMLDOC01-appb-C000010
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
または下記式（２）
Figure JPOXMLDOC01-appb-C000010
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
Or the following formula (2)
Figure JPOXMLDOC01-appb-C000011
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、Ｘは２価の芳香族基であり、ｎは３以上の整数である）
で表される導電性ポリマーを含む溶媒中に分散させる分散工程と、上記分散工程によって得られたカーボンナノチューブ分散液から、カーボンナノチューブとして半導体性カーボンナノチューブを９０質量％以上含むカーボンナノチューブ複合体を分離する分離工程と、を含むことを特徴とするカーボンナノチューブ複合体の製造方法。
Figure JPOXMLDOC01-appb-C000011
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more)
From the dispersion step of dispersing in a solvent containing a conductive polymer represented by and the carbon nanotube dispersion obtained by the above dispersion step, separating a carbon nanotube composite containing 90 mass% or more of semiconductive carbon nanotubes as carbon nanotubes And a separation step of forming a carbon nanotube composite.
　＜７＞上記導電性ポリマーは、下記式（３） The <7> above-mentioned conductive polymer has the following formula (3)
Figure JPOXMLDOC01-appb-C000012
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
で表されることを特徴とする、＜６＞に記載のカーボンナノチューブ複合体の製造方法。
Figure JPOXMLDOC01-appb-C000012
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
The manufacturing method of the carbon nanotube composite as described in <6> characterized by being represented.
　＜８＞上記分離工程において、カーボンナノチューブとして半導体性カーボンナノチューブを９５質量％以上含むカーボンナノチューブ複合体を分離することを特徴とする、＜６＞または＜７＞に記載のカーボンナノチューブ複合体の製造方法。 <8> The process for producing a carbon nanotube composite according to <6> or <7>, wherein a carbon nanotube composite containing 95% by mass or more of semiconductive carbon nanotubes as a carbon nanotube is separated in the separation step. Method.
　＜９＞上記カーボンナノチューブ複合体に、ｐ型ドーパントまたはｎ型ドーパントを接触させるドーピング工程を含むことを特徴とする、＜６＞～＜８＞のいずれか１つに記載のカーボンナノチューブ複合体の製造方法。 <9> The carbon nanotube composite according to any one of <6> to <8>, including a doping step of bringing a p-type dopant or an n-type dopant into contact with the carbon nanotube composite. Production method.
　本発明の一態様によれば、優れた熱電変換特性を有するカーボンナノチューブ複合体を提供することができるという効果を奏する。 According to one aspect of the present invention, it is possible to provide a carbon nanotube composite having excellent thermoelectric conversion characteristics.
実施例１のカーボンナノチューブフィルムの赤外スペクトルを示した図である。FIG. 2 is a diagram showing an infrared spectrum of the carbon nanotube film of Example 1. 比較例１のカーボンナノチューブフィルムの赤外スペクトルを示した図である。FIG. 6 is a view showing an infrared spectrum of a carbon nanotube film of Comparative Example 1; 実施例１～４のカーボンナノチューブフィルム、並びに比較例２および３のカーボンナノチューブフィルムの熱電変換特性を示した図である。FIG. 6 is a graph showing the thermoelectric conversion characteristics of the carbon nanotube films of Examples 1 to 4 and the carbon nanotube films of Comparative Examples 2 and 3. 実施例５のｐ型カーボンナノチューブフィルム、実施例６のｎ型カーボンナノチューブフィルムおよび比較例４のｐ型カーボンナノチューブフィルムの熱電変換特性を示した図である。FIG. 6 is a graph showing the thermoelectric conversion characteristics of the p-type carbon nanotube film of Example 5, the n-type carbon nanotube film of Example 6, and the p-type carbon nanotube film of Comparative Example 4. 実施例１のカーボンナノチューブフィルムの走査型電子顕微鏡像を示した図である。FIG. 2 is a view showing a scanning electron microscope image of the carbon nanotube film of Example 1.
　以下、本発明の実施の形態の一例について詳細に説明するが、本発明は、これらに限定されない。なお、本明細書において特記しない限り、数値範囲を表す「Ａ～Ｂ」は、「Ａ以上、Ｂ以下」を意味する。 Hereinafter, although an example of an embodiment of the present invention is described in detail, the present invention is not limited to these. In the present specification, unless otherwise specified, “A to B” representing a numerical range means “A or more and B or less”.
　〔１．熱電変換特性に関する指標〕
　まず、熱電変換特性に関する指標について説明する。 [1. Index on Thermoelectric Conversion Characteristics]
First, an index relating to the thermoelectric conversion characteristic will be described.
　＜１－１．出力因子＞
　出力因子（パワーファクター）は、以下の式（ｉ）によって求められる。 <1-1. Output factor>
The output factor (power factor) is determined by the following equation (i).
　ＰＦ＝α２σ　　　　　　　　（ｉ）
　式（ｉ）中、ＰＦは出力因子、αはゼーベック係数、σは導電率を示す。 PF = α 2 σ (i)
In Formula (i), PF is a power factor, α is a Seebeck coefficient, and σ is conductivity.
　本発明の一実施形態に係るカーボンナノチューブ複合体においては、例えば、出力因子が３１０Ｋにて１００μＷ／ｍＫ２以上であることが好ましく、２００μＷ／ｍＫ２以上であることがより好ましく、４００μＷ／ｍＫ２以上であることが特に好ましい。カーボンナノチューブ複合体の出力因子が３１０Ｋにて１００μＷ／ｍＫ２以上であれば、従来のカーボンナノチューブ複合体と同等またはそれを上回る値であるため、好ましい。このような高出力のカーボンナノチューブ複合体を得るためには、ゼーベック係数または導電率のいずれか一方、もしくはその両方を向上させることが考えられる。 In the carbon nanotube composite according to an embodiment of the present invention, for example, preferably the output factor is 100 .mu.W / mK 2 or more at 310K, more preferably 200μW / mK 2 or more, 400 W / mK 2 It is particularly preferable to be the above. It is preferable that the output factor of the carbon nanotube complex is 100 μW / mK 2 or more at 310 K, because it is equal to or greater than that of the conventional carbon nanotube complex. In order to obtain such a high output carbon nanotube composite, it is conceivable to improve either the Seebeck coefficient or the conductivity or both.
　＜１－２．ゼーベック係数＞
　ゼーベック係数とは、ゼーベック効果を示す回路の、高温接合点と低温接合点との間の温度差に対する、開放回路電圧の比をいう（「マグローヒル科学技術用語大辞典　第３版」より）。ゼーベック係数は、例えば、ゼーベック効果測定装置（ＭＭＲ　Ｔｅｃｈｎｏｌｏｇｉｅｓ社製）または後述する実施例で用いた熱電変換特性評価装置（アドバンス理工社製、ＺＥＭ－３）等を用いて測定することができる。ゼーベック係数の絶対値が大きいほど、熱起電力が大きいことを表す。 <1-2. Seebeck coefficient>
The Seebeck coefficient refers to the ratio of the open circuit voltage to the temperature difference between the high-temperature junction and the low-temperature junction of a circuit exhibiting the Seebeck effect (from "McGrow Hill Technical Term Third Edition"). The Seebeck coefficient can be measured, for example, using a Seebeck effect measurement apparatus (manufactured by MMR Technologies) or a thermoelectric conversion characteristic evaluation apparatus (manufactured by Advance Riko, ZEM-3) used in the examples described later. The larger the Seebeck coefficient absolute value, the larger the thermoelectromotive force.
　また、ゼーベック係数は、カーボンナノチューブ等の電子材料の極性を判別するための指標となり得る。具体的には、例えば、ゼーベック係数が正の値を示す電子材料は、ｐ型導電性を有しているといえる。これに対して、ゼーベック係数が負の値を示す電子材料は、ｎ型導電性を有しているといえる。 Also, the Seebeck coefficient can be an index for determining the polarity of an electronic material such as a carbon nanotube. Specifically, for example, it can be said that an electronic material having a positive Seebeck coefficient has p-type conductivity. On the other hand, it can be said that an electronic material having a negative Seebeck coefficient has n-type conductivity.
　上記カーボンナノチューブ複合体においては、ゼーベック係数の絶対値が２０μＶ／Ｋ以上であることが好ましく、３０μＶ／Ｋ以上であることがより好ましく、４０μＶ／Ｋ以上であることがさらに好ましい。 In the carbon nanotube composite, the absolute value of the Seebeck coefficient is preferably 20 μV / K or more, more preferably 30 μV / K or more, and still more preferably 40 μV / K or more.
　＜１－３．導電率＞
　導電率は、例えば、抵抗率計（三菱化学アナリテック社製、ロレスタＧＰ）または後述する実施例で用いた熱電変換特性評価装置（アドバンス理工社製、ＺＥＭ－３）を用いた４探針法により測定することができる。 <1-3. Conductivity>
The conductivity can be determined, for example, by using a resistivity meter (Loresta GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) or a four-probe method using a thermoelectric conversion characteristic evaluation device (ZEM-3, manufactured by Advance Riko) used in the examples described later. It can be measured by
　上記カーボンナノチューブ複合体においては、導電率が１０Ｓ／ｃｍ以上であることが好ましく、１００Ｓ／ｃｍ以上であることがより好ましい。また、導電率が１５００Ｓ／ｃｍ以下であることが好ましく、１０００Ｓ／ｃｍ以下であることがより好ましい。導電率が上記範囲であれば、ゼーベック係数と導電率とのバランスが取れた高出力のカーボンナノチューブ複合体となるため、好ましい。 In the carbon nanotube composite, the conductivity is preferably 10 S / cm or more, and more preferably 100 S / cm or more. The conductivity is preferably 1500 S / cm or less, more preferably 1000 S / cm or less. If the conductivity is in the above-mentioned range, it is preferable because it becomes a high output carbon nanotube composite in which the Seebeck coefficient and the conductivity are well balanced.
　＜１－４．ＺＴ＞
　熱電変換特性に関する別の指標としては、無次元性能指数ＺＴが挙げられる。ＺＴは以下の式（ｉｉ）によって求められる。 <1-4. ZT>
Another index related to the thermoelectric conversion characteristic is the dimensionless figure of merit ZT. ZT is calculated | required by the following formula (ii).
　ＺＴ＝ＰＦ・Ｔ／κ　　　　　　　　（ｉｉ）
　式（ｉｉ）中、ＰＦは出力因子（＝α２σ）、Ｔは温度、κは熱伝導率を示す。ＺＴが大きいほど、優れた熱電変換材料であることを表している。式（ｉｉ）から、ＺＴを大きくするためには、出力因子、すなわちゼーベック係数の絶対値および導電率を大きくすることが好ましいことがわかる。 ZT = PF · T / κ (ii)
In formula (ii), PF is a power factor (= α 2 σ), T is temperature, and κ is thermal conductivity. The larger the ZT, the better the thermoelectric conversion material. From equation (ii), it can be seen that in order to increase ZT, it is preferable to increase the power factor, that is, the absolute value of the Seebeck coefficient and the conductivity.
　また、式（ｉｉ）から、ＺＴを大きくするためには、熱伝導率は小さいほうが好ましいことがわかる。このことは、熱電変換材料が温度差を利用するものであることに対応している。熱電変換材料の熱伝導率が大きい場合、物質中の温度が容易に均一になってしまい、温度差を生じにくい。そのため、熱伝導率が大きい熱電変換材料は、効率的に発電することが困難となる傾向にある。 Further, it can be understood from formula (ii) that in order to increase ZT, the smaller the thermal conductivity, the better. This corresponds to the fact that the thermoelectric conversion material utilizes a temperature difference. When the thermal conductivity of the thermoelectric conversion material is large, the temperature in the substance is easily made uniform, and it is difficult to cause a temperature difference. Therefore, thermoelectric conversion materials having a large thermal conductivity tend to be difficult to efficiently generate power.
　〔２．カーボンナノチューブ複合体〕
　本発明の一実施形態に係るカーボンナノチューブ複合体は、カーボンナノチューブと、下記式（１） [2. Carbon nanotube composite]
A carbon nanotube complex according to an embodiment of the present invention comprises a carbon nanotube, and a compound represented by the following formula (1):
Figure JPOXMLDOC01-appb-C000013
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
または下記式（２）
Figure JPOXMLDOC01-appb-C000013
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
Or the following formula (2)
Figure JPOXMLDOC01-appb-C000014
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、Ｘは２価の芳香族基であり、ｎは３以上の整数である）
で表される導電性ポリマーと、を含み、上記カーボンナノチューブの９０質量％以上が半導体性カーボンナノチューブである。
Figure JPOXMLDOC01-appb-C000014
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more)
And 90% by mass or more of the carbon nanotube is a semiconducting carbon nanotube.
　カーボンナノチューブには、金属性カーボンナノチューブと半導体性カーボンナノチューブとが存在する。上記導電性ポリマーは、その構造および電子物性に起因し、半導体性カーボンナノチューブを選択性良く包み込む。そのため、溶媒中で半導体性カーボンナノチューブを選択性良く分散させる。その結果、上記導電性ポリマーを用いることによって半導体性カーボンナノチューブを高純度で含有するカーボンナノチューブ複合体が得られる。すなわち、カーボンナノチューブ複合体において、導電性ポリマーがカーボンナノチューブに絡みついた状態となっている。 Metallic carbon nanotubes and semiconductive carbon nanotubes exist in carbon nanotubes. The conductive polymer encases the semiconducting carbon nanotube with high selectivity due to its structure and electronic properties. Therefore, semiconducting carbon nanotubes are dispersed in a solvent with good selectivity. As a result, by using the conductive polymer, a carbon nanotube composite containing semiconducting carbon nanotubes with high purity can be obtained. That is, in the carbon nanotube composite, the conductive polymer is in a state of being entangled with the carbon nanotube.
　上記カーボンナノチューブ複合体は、熱電変換デバイス等として、様々な応用および用途が考えられる。上記カーボンナノチューブ複合体から構成される熱電変換デバイスは、柔軟性を有する。それゆえ、上記熱電変換デバイスは、人体および配管等の複雑な三次元表面に密着させることができ、体温および廃熱等を効率的に利用できる。 The carbon nanotube composite may be used in various applications and applications as a thermoelectric conversion device or the like. The thermoelectric conversion device composed of the carbon nanotube composite has flexibility. Therefore, the thermoelectric conversion device can be in close contact with a complex three-dimensional surface such as a human body and piping, and can efficiently use body temperature, waste heat, and the like.
　上記カーボンナノチューブ複合体は、所望の形状に成形されていてもよい。例えば、上記カーボンナノチューブ複合体を集積させてフィルムの形状としてもよい。上記フィルムは、例えば、０．１μｍ～１０００μｍの厚みであってもよい。フィルムの密度は特に限定されないが、０．０５～１．０ｇ／ｃｍ３であってもよく、０．１～０．５ｇ／ｃｍ３であってもよい。上記フィルムは、カーボンナノチューブ複合体同士が互いに絡み合うように不織布状の構造を形成し得る。そのため、前記フィルムは軽量であり、且つ、柔軟性を有している。このようなフィルムは熱電変換デバイスとして好適に利用できる。 The carbon nanotube composite may be formed into a desired shape. For example, the carbon nanotube composite may be accumulated to form a film. The film may have a thickness of, for example, 0.1 μm to 1000 μm. The density of the film is not particularly limited, but may be 0.05 to 1.0 g / cm 3 or 0.1 to 0.5 g / cm 3 . The film may form a non-woven structure so that the carbon nanotube complexes entangle each other. Therefore, the film is lightweight and flexible. Such a film can be suitably used as a thermoelectric conversion device.
　＜２－１．カーボンナノチューブ＞
　上記カーボンナノチューブ複合体は、カーボンナノチューブを含んでいる。また、上記カーボンナノチューブの９０質量％以上が半導体性カーボンナノチューブである。換言すれば、上記カーボンナノチューブ複合体に含まれるカーボンナノチューブを１００質量％とすると、その９０質量％以上が半導体性カーボンナノチューブである。 <2-1. Carbon nanotube>
The carbon nanotube composite contains carbon nanotubes. Further, 90% by mass or more of the carbon nanotubes are semiconducting carbon nanotubes. In other words, 90% by mass or more of the carbon nanotubes contained in the carbon nanotube complex are semiconductive carbon nanotubes.
　公知の合成方法にて合成されたカーボンナノチューブまたは市販のカーボンナノチューブは、通常、金属性カーボンナノチューブと半導体性カーボンナノチューブとを、約１：２の質量比にて含有する（Cambre, S. et al., ACS Nano, vol.4, no. 11, 6717-6724, 2010参照）。このようなカーボンナノチューブを用いて熱電変換材料を作製した場合、金属性カーボンナノチューブに起因し、熱伝導率が高く、且つゼーベック係数が低くなり得る。従って、金属性カーボンナノチューブの含有比率が多い場合、ＺＴが小さくなるため、十分な熱電変換特性を得られない。よって、上記カーボンナノチューブ複合体は、高純度にて半導体性カーボンナノチューブを含むことが好ましい。 Carbon nanotubes synthesized by a known synthesis method or commercially available carbon nanotubes usually contain metallic carbon nanotubes and semiconductive carbon nanotubes in a mass ratio of about 1: 2 (Cambre, S. et al. , ACS Nano, vol.4, no. 11, 6717-6724, 2010). When a thermoelectric conversion material is manufactured using such carbon nanotubes, the thermal conductivity may be high and the Seebeck coefficient may be low due to the metallic carbon nanotubes. Therefore, when the content ratio of metallic carbon nanotubes is large, ZT is small, and sufficient thermoelectric conversion characteristics can not be obtained. Therefore, the carbon nanotube composite preferably contains semiconducting carbon nanotubes with high purity.
　上述の特許文献１および２、並びに非特許文献１および２では、半導体性カーボンナノチューブの含有比率を高めることについて何ら言及されていない。従って、これらの文献に記載の先行技術では十分な熱電変換特性を引き出せていないと考えられる。 The above-mentioned Patent Documents 1 and 2 and Non-patent Documents 1 and 2 make no mention at all to increase the content ratio of semiconducting carbon nanotubes. Therefore, it is considered that the prior art described in these documents can not derive sufficient thermoelectric conversion characteristics.
　金属性カーボンナノチューブと半導体性カーボンナノチューブとの質量比は、例えば、赤外分光法によって測定することができる。まず、金属性カーボンナノチューブと半導体性カーボンナノチューブとの質量比に影響を与え得る物質（例えば、本発明の一実施形態にて用いられる導電性ポリマー）を含まないサンプルにおいて、赤外スペクトルを得る。これをコントロールの赤外スペクトルとする。当該サンプルには、上述のように１：２の質量比にて金属性カーボンナノチューブと半導体性カーボンナノチューブとが含有されていると考えられる。そして、金属性カーボンナノチューブと半導体性カーボンナノチューブとの質量比を知りたいサンプルの赤外スペクトルと、上記コントロールの赤外スペクトルとを比較し、金属性カーボンナノチューブのプラズモン共鳴由来の吸光度のバンドの大きさの変化を評価する。このバンドの大きさの変化の程度から、コントロールのサンプルと比べた金属性カーボンナノチューブの含有比率の変化量を算出することができる。これにより、所望のサンプルにおける金属性カーボンナノチューブと半導体性カーボンナノチューブとの質量比を決定することができる。 The mass ratio of metallic carbon nanotubes to semiconductive carbon nanotubes can be measured, for example, by infrared spectroscopy. First, an infrared spectrum is obtained for a sample that does not contain a substance that can affect the mass ratio of metallic carbon nanotubes and semiconductive carbon nanotubes (for example, the conductive polymer used in one embodiment of the present invention). Let this be the infrared spectrum of the control. It is considered that the sample contains metallic carbon nanotubes and semiconducting carbon nanotubes at a mass ratio of 1: 2 as described above. Then, the infrared spectrum of the sample for which it is desired to know the mass ratio of metallic carbon nanotubes and semiconducting carbon nanotubes is compared with the infrared spectrum of the above control, and the size of the absorbance band derived from plasmon resonance of metallic carbon nanotubes Rate the change in From the extent of the change in the size of this band, it is possible to calculate the amount of change in the content ratio of metallic carbon nanotubes compared to the control sample. Thereby, the mass ratio of the metallic carbon nanotube to the semiconductive carbon nanotube in the desired sample can be determined.
　半導体性カーボンナノチューブは、上記カーボンナノチューブ１００質量％中、９５質量％以上含まれることが好ましく、９９質量％以上含まれることがより好ましく、９９．９質量％以上含まれることがさらに好ましい。半導体性カーボンナノチューブの含有比率が高いほど、出力因子およびＺＴを向上させることができる。 The content of the semiconductive carbon nanotube is preferably 95% by mass or more, more preferably 99% by mass or more, and still more preferably 99.9% by mass or more in 100% by mass of the carbon nanotube. The higher the content ratio of semiconducting carbon nanotubes, the more the power factor and the ZT can be improved.
　カーボンナノチューブの直径は、導電性ポリマーの構造等を考慮して適宜決定され得る。なお、カーボンナノチューブの直径とは、長手方向に垂直な断面における直径を意味する。例えば、カーボンナノチューブの直径は、１～５ｎｍであることが好ましく、１～２ｎｍであることがより好ましく、１～１．７ｎｍであることがさらに好ましく、１～１．４ｎｍであることが特に好ましい。カーボンナノチューブの直径が上記範囲であれば、後述の導電性ポリマーが吸着しやすい。なお、カーボンナノチューブの直径は、電子顕微鏡による観察または分光学的な方法等によって測定され得る。 The diameter of the carbon nanotube can be appropriately determined in consideration of the structure of the conductive polymer and the like. In addition, the diameter of a carbon nanotube means the diameter in the cross section perpendicular | vertical to a longitudinal direction. For example, the diameter of the carbon nanotube is preferably 1 to 5 nm, more preferably 1 to 2 nm, still more preferably 1 to 1.7 nm, and particularly preferably 1 to 1.4 nm. . When the diameter of the carbon nanotube is in the above range, the conductive polymer described later is easily adsorbed. The diameter of the carbon nanotube can be measured by observation with an electron microscope or a spectroscopic method.
　カーボンナノチューブは、バンドル（小さな束）を形成し得る。当該バンドルの直径は、５ｎｍ以下であることが好ましく、３ｎｍ以下であることがより好ましい。バンドルの直径が５ｎｍ以下であれば、カーボンナノチューブが良く分散していると考えられ、均一なドーピングが可能である。 Carbon nanotubes can form bundles (small bundles). The diameter of the bundle is preferably 5 nm or less, more preferably 3 nm or less. If the diameter of the bundle is 5 nm or less, it is considered that the carbon nanotubes are well dispersed, and uniform doping is possible.
　カーボンナノチューブは、単層の構造を有していても、多層（二層、三層、四層、またはそれよりも多層）の構造を有していてもよい。すなわち、上記カーボンナノチューブは、単層カーボンナノチューブ（single-wall carbon nanotube：ＳＷＮＴ）であってもよいし、多層カーボンナノチューブ（multi-wall carbon nanotube：ＭＷＮＴ）であってもよい。ただし、多層カーボンナノチューブは、半導体性の層と金属性の層とを併せ持つ場合がある。よって、半導体性カーボンナノチューブの純度を高めるという観点からは、単層カーボンナノチューブを用いることが好ましい。 The carbon nanotube may have a single-layered structure or a multi-layered (two-layered, three-layered, four-layered or more multi-layered) structure. That is, the carbon nanotubes may be single-wall carbon nanotubes (SWNTs) or multi-wall carbon nanotubes (MWNTs). However, multi-walled carbon nanotubes may have both a semiconductive layer and a metallic layer. Therefore, it is preferable to use a single-walled carbon nanotube from the viewpoint of increasing the purity of the semiconducting carbon nanotube.
　上記カーボンナノチューブ複合体１００質量％におけるカーボンナノチューブの含有量は、５０～９０質量％であることが好ましく、６５～８５質量％であることがより好ましい。カーボンナノチューブの含有量が上記範囲であれば、カーボンナノチューブ複合体においてカーボンナノチューブに起因する性能を十分に発揮することができる。 The content of carbon nanotubes in 100% by mass of the carbon nanotube composite is preferably 50 to 90% by mass, and more preferably 65 to 85% by mass. If the content of the carbon nanotube is in the above range, the performance derived from the carbon nanotube can be sufficiently exhibited in the carbon nanotube composite.
　＜２－２．導電性ポリマー＞
　上記カーボンナノチューブ複合体は、下記式（１） <2-2. Conductive polymer>
The carbon nanotube complex is represented by the following formula (1)
Figure JPOXMLDOC01-appb-C000015
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
または下記式（２）
Figure JPOXMLDOC01-appb-C000015
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
Or the following formula (2)
Figure JPOXMLDOC01-appb-C000016
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、Ｘは２価の芳香族基であり、ｎは３以上の整数である）
で表される導電性ポリマーを含む。上記アルキル基はカーボンナノチューブに絡みつきやすいと考えられる。このような構造に加え、芳香族基の電子物性によっても上記導電性ポリマーは半導体性カーボンナノチューブに吸着しやすいと考えられる。それゆえ、上記導電性ポリマーは、半導体性カーボンナノチューブを選択性良く吸着し得る。上記導電性ポリマーとしては２種以上を混合して用いてもよい。
Figure JPOXMLDOC01-appb-C000016
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more)
Containing a conductive polymer represented by The alkyl group is considered to be easily entangled with carbon nanotubes. In addition to such a structure, the conductive polymer is considered to be easily adsorbed to the semiconductive carbon nanotube also by the electronic physical properties of the aromatic group. Therefore, the conductive polymer can selectively adsorb semiconducting carbon nanotubes. Two or more kinds of the conductive polymers may be mixed and used.
　なお、非特許文献３に記載のポリフルオレン誘導体は絶縁性である。そのため、非特許文献３では、ポリフルオレン誘導体を分散剤として用いた場合、導電率を改善するためにはポリフルオレン誘導体を除去しなければならない。これに対し、上記導電性ポリマーであれば、除去する必要はない。 The polyfluorene derivative described in Non-Patent Document 3 is insulating. Therefore, in Non-Patent Document 3, when a polyfluorene derivative is used as a dispersant, it is necessary to remove the polyfluorene derivative in order to improve the conductivity. On the other hand, if it is the said conductive polymer, it is not necessary to remove.
　上記アルキル基の炭素数は、７～２０であることがより好ましく、１０～１４であることがさらに好ましい。炭素数が上記範囲であれば、アルキル基がカーボンナノチューブに対して、より絡みつきやすい。 The carbon number of the alkyl group is more preferably 7 to 20, and still more preferably 10 to 14. If the carbon number is in the above range, the alkyl group is more easily entangled with the carbon nanotube.
　半導体性カーボンナノチューブの分離効率が良好であるという観点からは、上記ｎは、５以上の整数であることが好ましい。ｎの上限は特に限定されないが、導電性ポリマーの溶解性が高いという観点からは、ｎは１０以下の整数であることが好ましく、９以下の整数であることがより好ましい。 From the viewpoint of good separation efficiency of the semiconducting carbon nanotubes, n is preferably an integer of 5 or more. The upper limit of n is not particularly limited, but from the viewpoint of high solubility of the conductive polymer, n is preferably an integer of 10 or less, and more preferably an integer of 9 or less.
　また、上記導電性ポリマーは、上記式（１）または式（２）で表される繰り返し単位に加えて、任意の構造を有していてもよいが、上記式（１）または式（２）で表される繰り返し単位からなることが好ましい。 The conductive polymer may have an arbitrary structure in addition to the repeating unit represented by the formula (1) or the formula (2), but the above-mentioned formula (1) or the formula (2) It is preferable to consist of a repeating unit represented by
　上記Ｘ（２価の芳香族基）としては、２，１，３－ベンゾチアジアゾール骨格（ベンゾチアジアゾール骨格）、５－フルオロ－２，１，３－ベンゾチアジアゾール骨格、５，６－ジフルオロ－２，１，３－ベンゾチアジアゾール骨格、チエノ［３，４－ｃ］ピロール－４，６－ジオン骨格（チエノピロールジオン骨格）、１，４，５，８－ナフタレンジカルボキシミド骨格、２，５－ジヒドロピロロ［３，４－ｃ］ピロール－１，４－ジオン骨格（ジケトピロロピロール骨格）およびナフト［１，２－ｃ：５，６－ｃ’］ビス［１，２，５］チアジアゾール骨格（ナフトビスチアジアゾール骨格）等が挙げられる。なお、本明細書において、２価の芳香族基とは、少なくとも１つの芳香環と２つの結合手とを有する構造を意図している。すなわち、２価の芳香族基は、２官能性の芳香族化合物に由来する構造を有するとも言える。上記導電性ポリマーが上記Ｘを有する場合、より好ましい電子物性を示す。Ｘは、ベンゾチアジアゾール骨格であることがより好ましい。すなわち、導電性ポリマーは下記式（３） As the above-mentioned X (divalent aromatic group), 2,1,3-benzothiadiazole skeleton (benzothiadiazole skeleton), 5-fluoro-2,1,3-benzothiadiazole skeleton, 5,6-difluoro-2, 1,3-benzothiadiazole skeleton, thieno [3,4-c] pyrrole-4,6-dione skeleton (thienopyrroledione skeleton), 1,4,5,8-naphthalenedicarboximide skeleton, 2,5-dihydro Pyrrolo [3,4-c] pyrrole-1,4-dione skeleton (diketopyrrolopyrrole skeleton) and naphtho [1,2-c: 5,6-c '] bis [1,2,5] thiadiazole skeleton ( Naphthobis thiadiazole skeleton) etc. are mentioned. In the present specification, a divalent aromatic group intends a structure having at least one aromatic ring and two bonds. That is, it can be said that the divalent aromatic group has a structure derived from a bifunctional aromatic compound. When the conductive polymer has X, it exhibits more preferable electronic properties. More preferably, X is a benzothiadiazole skeleton. That is, the conductive polymer has the following formula (3)
Figure JPOXMLDOC01-appb-C000017
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）で表されることがより好ましい。
Figure JPOXMLDOC01-appb-C000017
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more).
　以上のことを考慮すると、導電性ポリマーは、下記式（４） Taking the above into consideration, the conductive polymer has the following formula (4)
Figure JPOXMLDOC01-appb-C000018
 　（式中、ｎは３以上の整数である）
または下記式（５）
Figure JPOXMLDOC01-appb-C000018
 (Wherein n is an integer of 3 or more)
Or the following formula (5)
Figure JPOXMLDOC01-appb-C000019
 　（式中、ｎは３以上の整数である）
で表されることがさらに好ましい。
Figure JPOXMLDOC01-appb-C000019
 (Wherein n is an integer of 3 or more)
It is further preferred that
　カーボンナノチューブ複合体におけるカーボンナノチューブと導電性ポリマーとの質量比は用途によって調整すればよく、１：９９～９９：１であってもよい。熱電変換材料として用いる場合は、カーボンナノチューブ１００質量部に対して、導電性ポリマー１～４０質量部であることが好ましく、１０～３５質量部であることがより好ましい。導電性ポリマーの含有比が上記範囲であれば、カーボンナノチューブに対して導電性ポリマーを薄く吸着させることができる。 The mass ratio of carbon nanotubes to the conductive polymer in the carbon nanotube composite may be adjusted depending on the application, and may be 1:99 to 99: 1. When used as a thermoelectric conversion material, the conductive polymer is preferably 1 to 40 parts by mass, and more preferably 10 to 35 parts by mass with respect to 100 parts by mass of carbon nanotubes. If the content ratio of the conductive polymer is in the above range, the conductive polymer can be thinly adsorbed to the carbon nanotube.
　＜２－３．ｐ型ドーパントおよびｎ型ドーパント＞
　上記カーボンナノチューブ複合体は、ｐ型ドーパントまたはｎ型ドーパントをさらに含んでいてもよい。これにより、上記カーボンナノチューブ複合体をｐ型熱電変換材料またはｎ型熱電変換材料とすることができる。 <2-3. p-type dopant and n-type dopant>
The carbon nanotube composite may further contain a p-type dopant or an n-type dopant. Thereby, the carbon nanotube complex can be made into a p-type thermoelectric conversion material or an n-type thermoelectric conversion material.
　本明細書において、ｐ型ドーパントとは、ドーピングした対象のゼーベック係数が正の値となるドーパントを意味する。ｐ型ドーパントとしては、例えば、チオシアン酸イオン（ＳＣＮ－）、過塩素酸イオン（ＣｌＯ４ －）、過マンガン酸イオン（ＭｎＯ４ －）、テトラフルオロホウ酸イオン（ＢＦ４ －）、ヨウ素酸イオン（ＩＯ３ －）、ヘキサフルオロリン酸イオン（ＰＦ６ －）、トリフルオロメタンスルホナートアニオン（ＴｆＯ－）、ビス（トリフルオロメタンスルホニル）アミンアニオン（ＴＦＳＩ－）、ヨウ化物イオン（Ｉ－）、臭化物イオン（Ｂｒ－）、塩化物イオン（Ｃｌ－）、硝酸イオン（ＮＯ３ －）またはトシラートイオン（Ｔｏｓ－）の水素酸および金属塩が挙げられる。金属塩としては、銀塩および銅塩が挙げられる。 In the present specification, the p-type dopant means a dopant which has a positive value of the Seebeck coefficient of the object to be doped. The p-type dopant, e.g., thiocyanate ion (SCN -), perchlorate ion (ClO 4 -), permanganate ion (MnO 4 -), tetrafluoroborate ion (BF 4 -), iodate (IO 3 -), hexafluorophosphate ion (PF 6 -), trifluoromethanesulfonate anion (TfO -), bis (trifluoromethanesulfonyl) amine anion (TFSI -), iodide ion (I -), bromide ion (Br -), chloride ion (Cl -), nitrate ion (NO 3 -) or tosylate ion (Tos -) include hydrochloric acid and metal salts of. Metal salts include silver salts and copper salts.
　本明細書において、ｎ型ドーパントとは、ドーピングした対象のゼーベック係数が負の値となるドーパントを意味する。ｎ型ドーパントとしては、例えば、ヒドロキシイオン（ＯＨ－）、アルコキシイオン（ＣＨ３Ｏ－、ＣＨ３ＣＨ２Ｏ－、ｉ－ＰｒＯ－およびｔ－ＢｕＯ－等）、チオイオン（ＳＨ－およびアルキルチオイオン（ＣＨ３Ｓ－およびＣ２Ｈ５Ｓ－等））、シアヌルイオン（ＣＮ－）またはカルボキシイオン（ＣＨ３ＣＯＯ－等）のアルカリ金属塩と環状エチレンオキシドとの錯体が挙げられる。アルカリ金属塩に含まれるアルカリ金属としては、リチウムイオン、ナトリウムイオンおよびカリウムイオン等が挙げられる。環状エチレンオキシドとしては、クラウンエーテルが挙げられる。 In the present specification, the n-type dopant means a dopant having a negative target Seebeck coefficient. The n-type dopant, such as hydroxy ion (OH -), alkoxy ion (CH 3 O -, CH 3 CH 2 O -, i-PrO - and t-BuO -, etc.), Chioion (SH - and alkylthio ion ( CH 3 S - and C 2 H 5 S - or the like)), Shianuruion (CN -) or carboxylate ion (CH 3 COO -, etc.), and complexes of alkali metal salts and cyclic ethylene oxide. Examples of the alkali metal contained in the alkali metal salt include lithium ion, sodium ion and potassium ion. Cyclic ethylene oxide includes crown ether.
　これらのｐ型ドーパントまたはｎ型ドーパントに含まれるアニオンは、その非共有電子対に基づいて、ドーピングの対象となるナノ材料と相互作用するか、または化学反応を誘起すると推測される。 Anions contained in these p-type dopants or n-type dopants are presumed to interact with the nanomaterial to be doped or to induce a chemical reaction based on their non-covalent electron pairs.
　〔３．インク〕
　本発明の一実施形態に係るインクは、本発明の一実施形態に係るカーボンナノチューブ複合体と分散媒とを含む。この場合、当該インクは、分散媒に上記カーボンナノチューブ複合体（成形されていないカーボンナノチューブ複合体）を分散させたものであることが好ましい。例えば、上記インクを所望の部品に塗布し、次いで分散媒を除去することによって、当該部品に熱電変換機能を付与することができる。 [3. ink〕
An ink according to an embodiment of the present invention includes a carbon nanotube composite according to an embodiment of the present invention and a dispersion medium. In this case, the ink is preferably a dispersion medium in which the carbon nanotube composite (unformed carbon nanotube composite) is dispersed. For example, the component can be provided with a thermoelectric conversion function by applying the ink to a desired component and then removing the dispersion medium.
　＜３－１．分散媒＞
　上記分散媒は、カーボンナノチューブ複合体を分散させることができる分散媒であれば特に限定されない。分散媒としては、例えば、水および有機溶媒が挙げられる。有機溶媒としては、トルエン、ｏ－ジクロロベンゼン、ｏ－キシレン、ｍ－キシレン、ｐ－キシレン、テトラヒドロフランおよびクロロホルム等が挙げられる。 <3-1. Dispersion medium>
The dispersion medium is not particularly limited as long as the dispersion medium can disperse the carbon nanotube complex. As a dispersion medium, water and an organic solvent are mentioned, for example. Examples of the organic solvent include toluene, o-dichlorobenzene, o-xylene, m-xylene, p-xylene, tetrahydrofuran and chloroform.
　〔４．カーボンナノチューブ複合体の製造方法〕
　本発明の一実施形態に係るカーボンナノチューブ複合体の製造方法は、カーボンナノチューブを、下記式（１） [4. Method for producing carbon nanotube composite]
The method for producing a carbon nanotube complex according to one embodiment of the present invention comprises a carbon nanotube represented by the following formula (1):
Figure JPOXMLDOC01-appb-C000020
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
または下記式（２）
Figure JPOXMLDOC01-appb-C000020
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
Or the following formula (2)
Figure JPOXMLDOC01-appb-C000021
 　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、Ｘは２価の芳香族基であり、ｎは３以上の整数である）
で表される導電性ポリマーを含む溶媒中に分散させる分散工程と、上記分散工程によって得られたカーボンナノチューブ分散液から、カーボンナノチューブとして半導体性カーボンナノチューブを９０質量％以上含むカーボンナノチューブ複合体を分離する分離工程と、を含む。なお、〔１．熱電変換特性に関する指標〕～〔３．インク〕にて既に説明した事項について、以下では説明を省略し、適宜、上述の記載を援用する。
Figure JPOXMLDOC01-appb-C000021
 (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more)
From the dispersion step of dispersing in a solvent containing a conductive polymer represented by and the carbon nanotube dispersion obtained by the above dispersion step, separating a carbon nanotube composite containing 90 mass% or more of semiconductive carbon nanotubes as carbon nanotubes And separating. [1. Index on thermoelectric conversion characteristics] to [3. Regarding the items already described in [Ink], the description is omitted below, and the above description is used as appropriate.
　上記導電性ポリマーは、その構造および電子物性に起因し、半導体性カーボンナノチューブを選択性良く包み込む。そのため、分散工程にて、溶媒中で半導体性カーボンナノチューブを選択性良く分散させることができる。一方、金属性カーボンナノチューブは、導電性ポリマーに包み込まれた半導体性カーボンナノチューブに比べて分散しにくい。よって、分離工程において、金属性カーボンナノチューブを除去しやすいため、半導体性カーボンナノチューブを高純度で含有するカーボンナノチューブ複合体を分離することができる。 The conductive polymer encases the semiconducting carbon nanotube with high selectivity due to its structure and electronic properties. Therefore, the semiconducting carbon nanotubes can be dispersed with high selectivity in the solvent in the dispersing step. On the other hand, metallic carbon nanotubes are difficult to disperse as compared to semiconducting carbon nanotubes encased in a conductive polymer. Therefore, since the metallic carbon nanotubes can be easily removed in the separation step, it is possible to separate the carbon nanotube composite containing the semiconductive carbon nanotubes with high purity.
　＜４－１．分散工程＞
　分散工程は、カーボンナノチューブを、上記式（１）または上記式（２）で表される導電性ポリマーを含む溶媒中に分散させる工程である。これにより、導電性ポリマーが半導体性カーボンナノチューブに吸着し、当該半導体性カーボンナノチューブは選択性良く分散される。 <4-1. Dispersion process>
The dispersing step is a step of dispersing the carbon nanotube in a solvent containing the conductive polymer represented by the above formula (1) or the above formula (2). Thus, the conductive polymer is adsorbed to the semiconducting carbon nanotubes, and the semiconducting carbon nanotubes are dispersed with high selectivity.
　溶媒としては、上記導電性ポリマーを溶解する溶媒であれば特に限定されないが、トルエン、ｏ－キシレン、ｍ－キシレン、ｐ－キシレン、ｏ－ジクロロベンゼン、テトラヒドロフランおよびクロロホルム等の有機溶媒が挙げられる。なかでも、溶媒極性の観点から、溶媒はトルエン、ｏ－キシレン、ｍ－キシレンまたはｐ－キシレンであることが好ましい。 The solvent is not particularly limited as long as it dissolves the above-mentioned conductive polymer, and includes organic solvents such as toluene, o-xylene, m-xylene, p-xylene, o-dichlorobenzene, tetrahydrofuran and chloroform. Among them, from the viewpoint of solvent polarity, the solvent is preferably toluene, o-xylene, m-xylene or p-xylene.
　カーボンナノチューブを溶媒中に分散させる方法としては、例えば、均質化装置を用いる方法が挙げられる。均質化装置としては、例えば、撹拌ホモジナイザーおよび超音波ホモジナイザー等が挙げられる。より均一に分散させる観点から、超音波ホモジナイザーを用いてカーボンナノチューブを溶媒中に分散させることが好ましい。 As a method of dispersing carbon nanotubes in a solvent, for example, a method using a homogenizing apparatus can be mentioned. As a homogenization apparatus, a stirring homogenizer, an ultrasonic homogenizer, etc. are mentioned, for example. From the viewpoint of more uniformly dispersing, it is preferable to disperse carbon nanotubes in a solvent using an ultrasonic homogenizer.
　分散工程における温度は、欠陥導入を抑制するという観点から、０～１０℃であることが好ましい。 The temperature in the dispersion step is preferably 0 to 10 ° C. from the viewpoint of suppressing the defect introduction.
　＜４－２．分離工程＞
　分離工程は、上記分散工程によって得られたカーボンナノチューブ分散液から、カーボンナノチューブとして半導体性カーボンナノチューブを９０質量％以上含むカーボンナノチューブ複合体を分離する工程である。換言すれば、分離されたカーボンナノチューブ複合体に含まれるカーボンナノチューブを１００質量％とすると、その９０質量％以上が半導体性カーボンナノチューブである。すなわち、分離工程は、導電性ポリマーが吸着していない金属性カーボンナノチューブの大部分を除去する工程である。 <4-2. Separation process>
The separation step is a step of separating a carbon nanotube composite containing 90% by mass or more of semiconductive carbon nanotubes as carbon nanotubes from the carbon nanotube dispersion obtained by the above dispersion step. In other words, when the carbon nanotubes contained in the separated carbon nanotube composite are 100% by mass, 90% by mass or more of the carbon nanotubes are semiconductive carbon nanotubes. That is, the separation step is a step of removing most of the metallic carbon nanotubes to which the conductive polymer is not adsorbed.
　上記分離工程において、カーボンナノチューブとして半導体性カーボンナノチューブを９５質量％以上含むカーボンナノチューブ複合体を分離することが好ましい。半導体性カーボンナノチューブの純度を向上することによって、より優れた熱電変換特性を有するカーボンナノチューブ複合体を得ることができる。 In the separation step, it is preferable to separate a carbon nanotube composite containing 95% by mass or more of semiconductive carbon nanotubes as carbon nanotubes. By improving the purity of the semiconducting carbon nanotubes, it is possible to obtain a carbon nanotube composite having more excellent thermoelectric conversion characteristics.
　分離工程を行う方法は、半導体性カーボンナノチューブを高純度にて分離することができる方法であれば、特に限定されない。そのような方法としては、例えば、遠心分離器を用いた方法が挙げられる。遠心分離器を用いて上記カーボンナノチューブ分散液を遠心分離することによって、金属性カーボンナノチューブの大部分を沈殿させて、半導体性カーボンナノチューブを高純度にて含む上清を分離することができる。この上清を回収することにより、カーボンナノチューブとして半導体性カーボンナノチューブを９０質量％以上含むカーボンナノチューブ複合体を分離することができる。 The method of performing the separation step is not particularly limited as long as the method can separate the semiconductive carbon nanotubes with high purity. Such methods include, for example, methods using a centrifuge. By centrifuging the carbon nanotube dispersion using a centrifuge, most of metallic carbon nanotubes can be precipitated to separate a supernatant containing semiconducting carbon nanotubes with high purity. By collecting the supernatant, it is possible to separate a carbon nanotube complex containing 90% by mass or more of semiconducting carbon nanotubes as carbon nanotubes.
　回収した上清から、さらに溶媒を除去してもよい。また、当該溶媒を上述の分散媒と置換することにより、本発明の一実施形態に係るインクを得てもよい。 Further solvent may be removed from the collected supernatant. In addition, the ink according to an embodiment of the present invention may be obtained by replacing the solvent with the above-described dispersion medium.
　＜４－３．成形工程＞
　上記製造方法は、分離工程によって得られたカーボンナノチューブ複合体を所望の形状（例えば、フィルム）に成形する成形工程を含んでいてもよい。カーボンナノチューブ複合体を所望の形状に成形する方法としては、例えば、カーボンナノチューブ複合体を集積させることにより、所望の形状に成形する方法が挙げられる。 <4-3. Molding process>
The above manufacturing method may include a forming step of forming the carbon nanotube composite obtained by the separation step into a desired shape (for example, a film). Examples of the method for forming the carbon nanotube composite into a desired shape include a method for forming the desired shape by accumulating the carbon nanotube composite.
　このような方法としては、カーボンナノチューブ複合体を含む分散液をメンブレンフィルター上で濾過することによってフィルムを成形する方法が挙げられる。具体的には、カーボンナノチューブ複合体を含む分散液を、０．１～２μｍ孔のメンブレンフィルターを用いて吸引濾過を行い、メンブレンフィルター上に集積したカーボンナノチューブ複合体を乾燥させることにより、フィルムを成形することができる。上記分散液は、上述の上清であってもよく、本発明の一実施形態に係るインクであってもよい。 As such a method, there may be mentioned a method of forming a film by filtering a dispersion containing a carbon nanotube complex on a membrane filter. Specifically, the dispersion containing the carbon nanotube complex is suction filtered using a membrane filter with 0.1 to 2 μm pores, and the carbon nanotube complex accumulated on the membrane filter is dried to obtain a film. It can be molded. The dispersion may be the above-described supernatant, or may be the ink according to an embodiment of the present invention.
　＜４－４．ドーピング工程＞
　上記製造方法は、上記カーボンナノチューブ複合体に、ｐ型ドーパントまたはｎ型ドーパントを接触させるドーピング工程を含んでいてもよい。これにより、上記カーボンナノチューブ複合体をｐ型熱電変換材料またはｎ型熱電変換材料とすることができる。 <4-4. Doping process>
The above manufacturing method may include a doping step of contacting the carbon nanotube composite with a p-type dopant or an n-type dopant. Thereby, the carbon nanotube complex can be made into a p-type thermoelectric conversion material or an n-type thermoelectric conversion material.
　成型工程の後にドーピング工程を行う方法としては、例えば、所望の形状に成形したカーボンナノチューブ複合体を、ｐ型ドーパントまたはｎ型ドーパントを含む溶液に浸漬する方法、または、所望の形状に成形したカーボンナノチューブ複合体に、ｐ型ドーパントまたはｎ型ドーパントを含む溶液を塗布する方法が挙げられる。 As a method of performing a doping step after the forming step, for example, a method of immersing a carbon nanotube composite formed into a desired shape in a solution containing a p-type dopant or an n-type dopant, or carbon formed into a desired shape There is a method of applying a solution containing a p-type dopant or an n-type dopant to the nanotube complex.
　上記ｐ型ドーパントまたはｎ型ドーパントを含む溶液における溶媒は、水であってもよく有機溶媒であってもよい。当該溶媒は、好ましくは有機溶媒であり、より好ましくはメタノール、エタノール、プロパノール、ブタノール、アセトニトリル、Ｎ，Ｎ－ジメチルホルムアミド、ジメチルスルホキシドまたはＮ－メチルピロリドン等である。これらの溶媒は、上述の浸漬または塗布を行った後のカーボンナノチューブ複合体を乾燥させることによって除去され得る。 The solvent in the solution containing the p-type dopant or the n-type dopant may be water or an organic solvent. The solvent is preferably an organic solvent, more preferably methanol, ethanol, propanol, butanol, acetonitrile, N, N-dimethylformamide, dimethylsulfoxide or N-methylpyrrolidone. These solvents can be removed by drying the carbon nanotube composite after the above-mentioned immersion or application.
　上記溶液におけるｐ型ドーパントまたはｎ型ドーパントの濃度は、求められる熱電特性に応じて調節すればよい。当該濃度は、例えば、０．００１～１ｍｏｌ／Ｌであってもよく、０．０１～０．１ｍｏｌ／Ｌであってもよい。 The concentration of the p-type dopant or the n-type dopant in the solution may be adjusted according to the thermoelectric property to be determined. The concentration may be, for example, 0.001 to 1 mol / L, or may be 0.01 to 0.1 mol / L.
　また、分散工程または分離工程の前後にドーピング工程を行うこともできる。この場合は、上述の導電性ポリマーを含む溶媒、カーボンナノチューブ分散液、または分離工程によって回収された上清等にｐ型ドーパントまたはｎ型ドーパントを添加する方法を採用できる。 Also, the doping step can be performed before or after the dispersing step or the separating step. In this case, a method of adding a p-type dopant or an n-type dopant to a solvent containing the above-described conductive polymer, a carbon nanotube dispersion liquid, or a supernatant recovered by a separation step can be employed.
　本発明は上述した各実施形態に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。 The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.
　以下、実施例に基づいて本発明をより詳細に説明するが、本発明は以下の実施例に限定されるものではない。なお、以下では、ポリ（シクロペンタジチオフェン）骨格を有する式（４）の化合物を、ＰＣＰＤＴと称し、ポリ（シクロペンタジチオフェン）骨格およびベンゾチアジアゾール骨格を有する式（５）の化合物を、ＰＣＰＤＴＢＴと称することもある。また、カーボンナノチューブをＣＮＴと称することもある。 Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples. In the following, a compound of the formula (4) having a poly (cyclopentadithiophene) skeleton is referred to as PCPDT, and a compound of the formula (5) having a poly (cyclopentadithiophene) skeleton and a benzothiadiazole skeleton is PCPDTBT. Sometimes called. Carbon nanotubes may also be referred to as CNTs.
　〔物性の評価〕
　＜赤外スペクトル＞
　後述の実施例１および比較例１にて得られたフィルムについて、赤外顕微鏡（ブルカーオプティクス社製、ＨＹＰＥＲＩＯＮ　２０００）を用いたフーリエ変換赤外分光法によって吸光度を測定した。また、実施例１および比較例１においてＰＣＰＤＴＢＴの代わりに１質量％のＰｌｕｒｏｎｉｃ（登録商標）Ｆ１２７（ＢＡＳＦ社製）を含む水溶液を用いてカーボンナノチューブを分散させたサンプルについても、同様に吸光度を測定した。当該サンプルは、未ソーティングのサンプル（コントロールのサンプル）として用いる。すなわち、当該サンプルには、金属性ＣＮＴと半導体性ＣＮＴが、約１：２の質量比にて含有されている。得られた赤外スペクトルを比較し、金属性ＣＮＴのプラズモン共鳴由来のバンドの減少から、半導体性ＣＮＴの分離の程度を評価した。 [Evaluation of physical properties]
<Infrared spectrum>
The absorbance of the films obtained in Example 1 and Comparative Example 1 described below was measured by Fourier transform infrared spectroscopy using an infrared microscope (HYPERION 2000, manufactured by Bruker Optics, Inc.). Further, the absorbance was similarly measured for a sample in which carbon nanotubes were dispersed using an aqueous solution containing 1% by mass of Pluronic® F 127 (manufactured by BASF Corp.) instead of PCPDTBT in Example 1 and Comparative Example 1. did. The sample is used as an unsorted sample (control sample). That is, the metallic CNT and the semiconducting CNT are contained in the sample at a mass ratio of about 1: 2. The obtained infrared spectra were compared, and the degree of separation of the semiconducting CNT was evaluated from the decrease in the band derived from the plasmon resonance of the metallic CNT.
　＜熱電変換特性＞
　（ａ）導電率
　後述の実施例および比較例にて得られたフィルムについて、熱電変換特性評価装置（アドバンス理工社製、ＺＥＭ－３）を用いた４探針法によって導電率を測定した。測定温度は３１０Ｋ（３７℃）であった。 <Thermal conversion characteristics>
(A) Conductivity The conductivity of each of the films obtained in Examples and Comparative Examples described below was measured by a four-probe method using a thermoelectric conversion characteristic evaluation device (manufactured by Advance Riko, ZEM-3). The measurement temperature was 310 K (37 ° C.).
　（ｂ）ゼーベック係数
　後述の実施例および比較例にて得られたフィルムのゼーベック係数を、熱電変換特性評価装置（アドバンス理工社製、ＺＥＭ－３）を用いて測定した。測定温度は３１０Ｋ（３７℃）であった。 (B) Seebeck Coefficient The Seebeck coefficient of the films obtained in Examples and Comparative Examples described later was measured using a thermoelectric conversion characteristic evaluation device (ZEM-3, manufactured by Advance Riko Co., Ltd.). The measurement temperature was 310 K (37 ° C.).
　（ｃ）出力因子
　後述の実施例および比較例にて得られたフィルムについて、上述の方法で得られた導電率σおよびゼーベック係数αを用いて、上述の式（ｉ）により出力因子ＰＦを算出した。 (C) Output factor The output factor PF is calculated by the above equation (i) using the conductivity σ and the Seebeck coefficient α obtained by the above method for the films obtained in the examples and comparative examples described later. did.
　〔ドーピングしていないＣＮＴ複合体の熱電変換特性（Ｉ）〕
　＜実施例１＞
　既報（Kettle, J. et. al., Solar Energy Materials and Solar Cells, Volume 95, Issue 8, Pages 2186-2193, 2011）を参考にして、ＰＣＰＤＴＢＴを合成した。得られたＰＣＰＤＴＢＴは上述の式（５）においてｎ＝５～１０程度であった。ＰＣＰＤＴＢＴ２．５ｍｇを溶解させたトルエン２０ｍＬに、単層カーボンナノチューブ（Ｒａｙｍｏｒ社製、ＲＮ－０２０、直径約１．１～１．７ｎｍ）８ｍｇを投入した。超音波ホモジナイザー（Ｑｓｏｎｉｃａ社製、Ｑ１２５）を用いて、上記単層カーボンナノチューブを上記トルエン中に約４℃で６０分間分散させた。 [Thermoelectric conversion characteristic (I) of the non-doped CNT composite]
Example 1
PCPDTBT was synthesized with reference to the previous report (Kettle, J. et. Al., Solar Energy Materials and Solar Cells, Volume 95, Issue 8, Pages 2186-2193, 2011). The obtained PCPDTBT was approximately n = 5 to 10 in the above formula (5). In 20 mL of toluene in which 2.5 mg of PCPDTBT was dissolved, 8 mg of single-walled carbon nanotubes (manufactured by Raymor, RN-020, diameter: about 1.1 to 1.7 nm) was charged. The single-walled carbon nanotubes were dispersed in the toluene at about 4 ° C. for 60 minutes using an ultrasonic homogenizer (Q125, manufactured by Qsonica).
　このように得られた分散液を、遠心分離機（久保田商事、テーブルトップ冷却遠心機　５５００）によって６０分間１００００ｒｐｍで遠心分離した。遠心分離後の分散液から上清の７０体積％を回収した。 The dispersion thus obtained was centrifuged at 10000 rpm for 60 minutes using a centrifuge (Kubota Corporation, table top cooling centrifuge 5500). 70% by volume of the supernatant was recovered from the dispersion after centrifugation.
　回収した上清を、０．２μｍ孔のメンブレンフィルター（メルクミリポア社製、オムニポアメンブレンフィルター　ＪＧＷＰ０２５００）上に吸引濾過することにより、ＣＮＴフィルムを堆積させた。得られたＣＮＴフィルムをＰＥＴ製フィルム上に載せた状態で赤外スペクトルおよび熱電変換特性を測定した。 The collected supernatant was suction filtered onto a 0.2 μm pore membrane filter (manufactured by Merck Millipore, Omnipore membrane filter JGWP02500) to deposit a CNT film. The infrared spectrum and the thermoelectric conversion characteristic were measured in the state which mounted the obtained CNT film on PET film.
　図１は、実施例１のＣＮＴフィルムの赤外スペクトルを示した図である。縦軸は正規化された吸光度を表し、横軸は光子エネルギーを表す。なお、横軸の０．１ｅＶ以下の、５、６、７、８、９は、それぞれ０．０５、０．０６、０．０７、０．０８、０．０９を表す。また、横軸の０．１ｅＶと１ｅＶとの間の２、３、４、５、６、７、８、９は、それぞれ０．２、０．３、０．４、０．５、０．６、０．７、０．８、０．９を表す。黒い線（Ｆ１２７分散）はＰｌｕｒｏｎｉｃ　Ｆ１２７を用いた分散液から得られたデータを表し、グレーの線（ＰＣＰＤＴＢＴ分散）はＰＣＰＤＴＢＴを用いた分散液から得られたデータを表す。図１において、Ｆ１２７分散では０．０９ｅＶ未満の領域に金属性ＣＮＴのプラズモン共鳴由来のバンドが存在するが、これらのバンドがＰＣＰＤＴＢＴ分散ではほぼ消失していることがわかる。従って、実施例１のＣＮＴフィルムに含まれるＣＮＴ１００質量％に対して半導体性ＣＮＴが９９質量％以上含まれていると考えられる。 FIG. 1 is an infrared spectrum of the CNT film of Example 1. The vertical axis represents normalized absorbance and the horizontal axis represents photon energy. In addition, 5, 6, 7, 8, 9 of 0.1 eV or less of a horizontal axis represents 0.05, 0.06, 0.07, 0.08, 0.09, respectively. In addition, 2, 3, 4, 5, 6, 7, 8 and 9 between 0.1 eV and 1 eV on the horizontal axis are 0.2, 0.3, 0.4, 0.5, 0. 0, respectively. 6, 0.7, 0.8, 0.9. The black line (F127 dispersion) represents the data obtained from the dispersion using Pluronic F127 and the gray line (PCPDTBT dispersion) represents the data obtained from the dispersion using PCPDTBT. In FIG. 1, in F127 dispersion, bands derived from plasmon resonance of metallic CNT exist in a region of less than 0.09 eV, but it can be seen that these bands are almost disappeared in PCPDTBT dispersion. Therefore, it is considered that semiconducting CNT is contained 99 mass% or more with respect to 100 mass% of CNT contained in the CNT film of Example 1.
　なお、半導体性ＣＮＴのバンド間遷移Ｓ１１のピークから、ＣＮＴの直径分布の中心が１．０～１．２ｎｍであることがわかる。 Incidentally, the peak of the interband transitions S 11 of semiconducting CNT, the center of the diameter distribution of the CNT is found to be 1.0 ~ 1.2 nm.
　また、市販の半導体性ＣＮＴでは、調製過程においてドーピングを受けているために、純度が高くてもプラズモン共鳴バンドが見られる（Morimoto, T., et al. ACS Nano, vol.8, no. 10, 9897-9904, 2014参照）。実施例１で得られた半導体性ＣＮＴは同様のプラズモン共鳴が観測限界以下であることから、半導体純度が極めて高いことのみならず、顕著なドーピングを受けていないことがわかる。すなわち、実施例１は従来よりもはるかに高品質な半導体性ＣＮＴを製造する方法と言える。 In addition, in the case of commercially available semiconducting CNTs, plasmon resonance bands are observed even if the purity is high because of doping during preparation (Morimoto, T., et al. ACS Nano, vol. 8, no. 10) , 9897-9904, 2014). The semiconducting CNTs obtained in Example 1 have similar plasmon resonances below the observation limit, so it can be seen that not only the semiconductor purity is extremely high, but significant doping has not been received. That is, Example 1 can be said to be a method for producing a semiconducting CNT of much higher quality than the conventional one.
　図５は、実施例１のカーボンナノチューブフィルムの走査型電子顕微鏡像を示した図である。図５で観察されるＣＮＴの直径はいずれも５ｎｍ（分解能）以下である。一般的なＣＮＴバンドルは２０～３０ｎｍとされていることを考慮すると、ＣＮＴが良く分散されていることがわかる。すなわち、導電性ポリマーが選択性良く半導体性ＣＮＴに絡みつくことによって、半導体性ＣＮＴが良く分散されていると考えられる。 FIG. 5 is a view showing a scanning electron microscope image of the carbon nanotube film of Example 1. The diameter of each of the CNTs observed in FIG. 5 is 5 nm (resolution) or less. It can be seen that the CNTs are well dispersed, considering that a typical CNT bundle is 20 to 30 nm. That is, it is considered that the semiconducting CNTs are well dispersed by the conductive polymer being entangled with the semiconducting CNTs with high selectivity.
　＜比較例１＞
　単層カーボンナノチューブとしてＯＣＳｉＡｌ社製、Ｔｕｂａｌｌ（登録商標）（直径約１．７５～１．８５ｎｍ）を用いたこと以外は実施例１と同様にしてＣＮＴフィルムを得て、その赤外スペクトルおよび熱電変換特性を測定した。 Comparative Example 1
A CNT film is obtained in the same manner as in Example 1 except that Tuball (registered trademark) (diameter about 1.75 to 1.85 nm) manufactured by OCSiAl Co., Ltd. is used as a single-walled carbon nanotube, and the infrared spectrum and the thermoelectric spectrum are obtained. The conversion characteristics were measured.
　図２は、比較例１のＣＮＴフィルムの赤外スペクトルを示した図である。縦軸および横軸は、図１と同様である。黒い線（Ｆ１２７分散）はＰｌｕｒｏｎｉｃ　Ｆ１２７を用いた分散液から得られたデータを表し、グレーの線（ＰＣＰＤＴＢＴ分散）はＰＣＰＤＴＢＴを用いた分散液から得られたデータを表す。図２から、Ｆ１２７分散における０．０９ｅＶ未満の領域に存在する金属性ＣＮＴのプラズモン共鳴由来のバンドは、ＰＣＰＤＴＢＴ分散ではわずかに（約１５％程度）減少したにすぎないことがわかる。通常、市販のＣＮＴにおける金属性ＣＮＴと半導体性ＣＮＴとの質量比が１：２であることを考慮すると、比較例１のＣＮＴフィルムに含まれるＣＮＴ１００質量％に対して半導体性ＣＮＴが８０質量％程度含まれていると考えられる。 FIG. 2 is an infrared spectrum of the CNT film of Comparative Example 1. The vertical and horizontal axes are the same as in FIG. The black line (F127 dispersion) represents the data obtained from the dispersion using Pluronic F127 and the gray line (PCPDTBT dispersion) represents the data obtained from the dispersion using PCPDTBT. It can be seen from FIG. 2 that the plasmon resonance-derived band of metallic CNT present in the region of less than 0.09 eV in the F127 dispersion is only slightly decreased (about 15% or so) in the PCPDTBT dispersion. Generally, considering that the mass ratio of metallic CNT to semiconducting CNT in commercially available CNT is 1: 2, semiconducting CNT is 80% by mass with respect to 100% by mass of CNT contained in the CNT film of Comparative Example 1 It is thought that the degree is included.
　＜熱電変換特性の比較＞
　実施例１および比較例１の熱電変換特性の測定結果を表１に示す。 <Comparison of thermoelectric conversion characteristics>
The measurement results of the thermoelectric conversion characteristics of Example 1 and Comparative Example 1 are shown in Table 1.
Figure JPOXMLDOC01-appb-T000022
 　表１から、半導体性ＣＮＴを高純度にて含む実施例１では、ゼーベック係数が飛躍的に向上しており、このＣＮＴフィルムは半導体として振る舞っていることがわかる。
Figure JPOXMLDOC01-appb-T000022
 It can be seen from Table 1 that, in Example 1 including the semiconducting CNT at high purity, the Seebeck coefficient is dramatically improved, and this CNT film behaves as a semiconductor.
　〔ドーピングしていないＣＮＴ複合体の熱電変換特性（ＩＩ）〕
　＜実施例２＞
　ＰＣＰＤＴＢＴの代わりにＰＣＰＤＴを用いたこと以外は実施例１と同様にしてＣＮＴフィルムを得た。用いたＰＣＰＤＴは上述の式（４）においてｎ＝２５～３５程度であった。 [Thermoelectric conversion characteristics of non-doped CNT composite (II)]
Example 2
A CNT film was obtained in the same manner as in Example 1 except that PCPDT was used instead of PCPDTBT. The PCPDT used was about n = 25 to 35 in the above formula (4).
　＜実施例３＞
　ＣＮＴとして、Ｒａｙｍｏｒ社製ＲＮ－０２０の代わりにＫＨ　Ｃｈｅｍｉｃａｌｓ社製ＨＰを用いたこと以外は実施例１と同様にしてＣＮＴフィルムを得た。 Example 3
A CNT film was obtained in the same manner as Example 1, except that HP manufactured by KH Chemicals was used instead of RN-020 manufactured by Raymor as CNT.
　＜実施例４＞
　ＣＮＴとして、Ｒａｙｍｏｒ社製ＲＮ－０２０の代わりにＫＨ　Ｃｈｅｍｉｃａｌｓ社製ＨＰを用いたこと以外は実施例２と同様にしてＣＮＴフィルムを得た。 Example 4
A CNT film was obtained in the same manner as in Example 2 except that HP manufactured by KH Chemicals was used instead of RN-020 manufactured by Raymor as CNT.
　＜比較例２＞
　ＰＣＰＤＴＢＴの代わりにポリフルオレン骨格を有する下記式（６）で表される化合物（以下では、ＰＦＤとも称する）を用いたこと以外は実施例１と同様にしてＣＮＴフィルムを得た。用いたＰＦＤは式（６）においてｎ＝３００～７４０程度であった。 Comparative Example 2
A CNT film was obtained in the same manner as in Example 1 except that a compound represented by the following formula (6) having a polyfluorene skeleton (hereinafter also referred to as PFD) having a polyfluorene skeleton instead of PCPDTBT was used. The PFD used was about n = 300 to 740 in the formula (6).
Figure JPOXMLDOC01-appb-C000023
 　＜比較例３＞
　ＣＮＴとして、Ｒａｙｍｏｒ社製ＲＮ－０２０の代わりにＫＨ　Ｃｈｅｍｉｃａｌｓ社製ＨＰを用いたこと以外は比較例２と同様にしてＣＮＴフィルムを得た。
Figure JPOXMLDOC01-appb-C000023
 Comparative Example 3
A CNT film was obtained in the same manner as in Comparative Example 2 except that HP manufactured by KH Chemicals was used instead of RN-020 manufactured by Raymor as CNT.
　＜熱電変換特性の比較＞
　実施例２～４、並びに比較例２および３について、得られたＣＮＴフィルムをＰＥＴ製フィルム上に載せて熱電変換特性を測定した。なお、図示しないが、ＣＮＴフィルムに含まれるＣＮＴ１００質量％に対する半導体性ＣＮＴが、実施例２～４、並びに比較例２および３では９０質量％以上であることを、実施例１と同様の方法にて確認した。 <Comparison of thermoelectric conversion characteristics>
The obtained CNT films of Examples 2 to 4 and Comparative Examples 2 and 3 were placed on a PET film to measure the thermoelectric conversion characteristics. Although not shown, the same method as in Example 1 is that semiconductive CNTs with respect to 100 mass% of CNTs contained in the CNT film are 90 mass% or more in Examples 2 to 4 and Comparative Examples 2 and 3. Confirmed.
　図３は、実施例１～４、並びに比較例２および３のＣＮＴフィルムの熱電変換特性を示した図である。図３は、導電率σとゼーベック係数αとの関係を表している。なお、図３の縦軸において、１００以下の６、８はそれぞれ、６０、８０を表し、１００と１０００との間の２、４、６、８はそれぞれ、２００、４００、６００、８００を表し、１０００以上の２は２０００を表す。また、図３の横軸において、０．１以下の６は０．０６を表し、０．１と１との間の２、４、６はそれぞれ、０．２、０．４、０．６を表し、１０以上の２は２０を表す。 FIG. 3 is a graph showing the thermoelectric conversion characteristics of the CNT films of Examples 1 to 4 and Comparative Examples 2 and 3. FIG. 3 shows the relationship between the conductivity σ and the Seebeck coefficient α. In the vertical axis of FIG. 3, 6, 8 of 100 or less represent 60, 80 respectively, and 2, 4, 6, 8 between 100 and 1000 represent 200, 400, 600, 800 respectively. , 2 of 1000 or more represent 2000. Further, in the horizontal axis of FIG. 3, 6 less than or equal to 0.1 represents 0.06, and 2, 4 and 6 between 0.1 and 1 represent 0.2, 0.4, and 0.6, respectively. And 10 or more 2 represents 20.
　図３から、実施例１および２は、比較例２に比べてゼーベック係数が高いことがわかる。また、半導体性ＣＮＴの純度は、実施例１＞実施例２＞比較例２であった。同様に、図３から、実施例３および４は、比較例３に比べてゼーベック係数が高いことがわかる。半導体性ＣＮＴの純度は、実施例３＞実施例４＞比較例３であった。 It can be seen from FIG. 3 that Examples 1 and 2 have a high Seebeck coefficient as compared to Comparative Example 2. In addition, the purity of the semiconducting CNT was Example 1> Example 2> Comparative Example 2. Similarly, it can be seen from FIG. 3 that Examples 3 and 4 have a high Seebeck coefficient as compared to Comparative Example 3. The purity of the semiconducting CNT was Example 3> Example 4> Comparative Example 3.
　〔ドーピングしたＣＮＴ複合体の熱電変換特性〕
　＜実施例５＞
　０．０１～４ｍｇ／ｍＬのＡｇＴＦＳＩ　ブタノール溶液に、実施例１と同じ方法にて得られたＣＮＴフィルムを５分間浸漬させた。その後、ＣＮＴフィルムを室温減圧下で６０分乾燥させることにより、ｐ型ＣＮＴフィルムを得た。得られたｐ型ＣＮＴフィルムをＰＥＴ製フィルム上に載せた状態で熱電変換特性を測定した。 [Thermoelectric conversion characteristics of the doped CNT composite]
Example 5
The CNT film obtained by the same method as Example 1 was immersed for 5 minutes in a 0.01 to 4 mg / mL AgTFSI butanol solution. Thereafter, the CNT film was dried at room temperature under reduced pressure for 60 minutes to obtain a p-type CNT film. The thermoelectric conversion characteristic was measured in the state which mounted the obtained p-type CNT film on PET film.
　＜実施例６＞
　ＡｇＴＦＳＩ　ブタノール溶液の代わりに０．００５～０．０７５ｍｏｌ／ｍＬのＫＯＨ／ベンゾ－１８－クラウン－６－エーテル　ブタノール溶液を用いたこと以外は実施例２と同様にして、ｎ型ＣＮＴフィルムを得た。得られたｎ型ＣＮＴフィルムをＰＥＴ製フィルム上に載せた状態で熱電変換特性を測定した。 Example 6
An n-type CNT film was obtained in the same manner as in Example 2 except that a 0.005-0.075 mol / mL KOH / benzo-18-crown-6-ether butanol solution was used instead of the AgTFSI butanol solution. . The thermoelectric conversion characteristic was measured in the state which mounted the obtained n-type CNT film on PET film.
　＜比較例４＞
　１質量％のＰｌｕｒｏｎｉｃ（登録商標）Ｆ１２７（ＢＡＳＦ社製）を含む水溶液中に、単層カーボンナノチューブ（Ｒａｙｍｏｒ社製、ＲＮ－０２０、直径約１．１～１．７ｎｍ）５ｍｇを投入した。超音波ホモジナイザー（Ｑｓｏｎｉｃａ社製、Ｑ１２５）を用いて、上記単層カーボンナノチューブを上記水溶液中に約４℃で６０分間分散させた。 Comparative Example 4
In an aqueous solution containing 1% by mass of Pluronic® F127 (manufactured by BASF), 5 mg of single-walled carbon nanotubes (manufactured by Raymor, RN-020, diameter: about 1.1 to 1.7 nm) was placed. The single-walled carbon nanotubes were dispersed in the aqueous solution at about 4 ° C. for 60 minutes using an ultrasonic homogenizer (Q125, manufactured by Qsonica).
　このように得られた分散液を、遠心分離機（久保田商事、テーブルトップ冷却遠心機　５５００）によって６０分間１００００ｒｐｍで遠心分離した。遠心分離後の分散液から上清の７０体積％を回収した。 The dispersion thus obtained was centrifuged at 10000 rpm for 60 minutes using a centrifuge (Kubota Corporation, table top cooling centrifuge 5500). 70% by volume of the supernatant was recovered from the dispersion after centrifugation.
　回収した上清を、０．２μｍ孔のメンブレンフィルター（メルクミリポア社製、オムニポアメンブレンフィルター　ＪＧＷＰ０２５００）上に吸引濾過することにより、ＣＮＴフィルムを堆積させた。 The collected supernatant was suction filtered onto a 0.2 μm pore membrane filter (manufactured by Merck Millipore, Omnipore membrane filter JGWP02500) to deposit a CNT film.
　得られたＣＮＴフィルムを０．０１～４ｍｇ／ｍＬのＡｇＴＦＳＩ　ブタノール溶液に５分間浸漬させた。その後、ＣＮＴフィルムを室温減圧下で６０分乾燥させることにより、ｐ型ＣＮＴフィルムを得た。得られたｐ型ＣＮＴフィルムをＰＥＴ製フィルム上に載せた状態で熱電変換特性を測定した。当該ｐ型ＣＮＴフィルムは、金属性ＣＮＴと半導体性ＣＮＴとを約１：２の質量比で含んでいた。 The obtained CNT film was immersed in a 0.01 to 4 mg / mL AgTFSI butanol solution for 5 minutes. Thereafter, the CNT film was dried at room temperature under reduced pressure for 60 minutes to obtain a p-type CNT film. The thermoelectric conversion characteristic was measured in the state which mounted the obtained p-type CNT film on PET film. The p-type CNT film contained metallic CNT and semiconducting CNT in a mass ratio of about 1: 2.
　＜熱電変換特性の比較＞
　図４は、実施例５のｐ型ＣＮＴフィルム、実施例６のｎ型ＣＮＴフィルムおよび比較例４のｐ型ＣＮＴフィルムの熱電変換特性を示した図である。図４の（ａ）は、実施例５のｐ型ＣＮＴフィルム、実施例６のｎ型ＣＮＴフィルムおよび比較例４のｐ型ＣＮＴフィルムにおける導電率σとゼーベック係数の絶対値｜α｜との関係を表す図である。なお、図４の（ａ）において、縦軸の読み方は図３と同様である。図４の（ａ）から、ＰＣＰＤＴＢＴを用いて半導体性ＣＮＴの純度を向上させた場合、ｐ型ドーピングおよびｎ型ドーピングのいずれにおいても、導電率の変化とともにゼーベック係数の絶対値が変化していることがわかる。 <Comparison of thermoelectric conversion characteristics>
FIG. 4 is a view showing the thermoelectric conversion characteristics of the p-type CNT film of Example 5, the n-type CNT film of Example 6, and the p-type CNT film of Comparative Example 4. FIG. 4A shows the relationship between the conductivity σ and the absolute value of the Seebeck coefficient | α | in the p-type CNT film of Example 5, the n-type CNT film of Example 6, and the p-type CNT film of Comparative Example 4. FIG. Note that in (a) of FIG. 4, how to read the vertical axis is the same as that of FIG. 3. From (a) of FIG. 4, when the purity of the semiconducting CNT is improved using PCPDTBT, the absolute value of the Seebeck coefficient changes with the change of the conductivity in both p-type doping and n-type doping. I understand that.
　図４の（ｂ）は、実施例５のｐ型ＣＮＴフィルム、実施例６のｎ型ＣＮＴフィルムおよび比較例４のｐ型ＣＮＴフィルムにおける導電率σと出力因子ＰＦとの関係を表す図である。図４の（ｂ）から、ＰＣＰＤＴＢＴを用いて半導体性ＣＮＴの純度を向上させると、導電率が１００Ｓ／ｃｍ以上である場合において、ｐ型ドーピングおよびｎ型ドーピングのいずれにおいても、高い出力因子が得られることがわかる。特に実施例５のｐ型ＣＮＴフィルムにおいて導電率が約１００Ｓ／ｃｍである場合、４００μＷ／ｍＫ２を超える出力因子が得られ、中には５００μＷ／ｍＫ２を超える出力因子を示すものもあった。 (B) of FIG. 4 is a view showing the relationship between the conductivity σ and the output factor PF in the p-type CNT film of Example 5, the n-type CNT film of Example 6, and the p-type CNT film of Comparative Example 4. . From (b) of FIG. 4, when PCPDTBT is used to improve the purity of semiconducting CNT, a high output factor is obtained in both p-type doping and n-type doping when the conductivity is 100 S / cm or more. It is understood that it can be obtained. Particularly when the conductivity is about 100 S / cm in the p-type CNT film of Example 5, an output factor exceeding 400 μW / mK 2 was obtained, and some showed an output factor exceeding 500 μW / mK 2 .
　本発明は、例えば、熱電変換材料に利用することができる。 The present invention can be used, for example, for a thermoelectric conversion material.

Claims (9)

  1. 　カーボンナノチューブと、下記式（１）
    Figure JPOXMLDOC01-appb-C000001
     　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
    または下記式（２）
    Figure JPOXMLDOC01-appb-C000002
     　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、Ｘは２価の芳香族基であり、ｎは３以上の整数である）
    で表される導電性ポリマーと、を含み、
    　上記カーボンナノチューブの９０質量％以上が半導体性カーボンナノチューブであることを特徴とする、カーボンナノチューブ複合体。     Carbon nanotube and the following formula (1)
    Figure JPOXMLDOC01-appb-C000001
     (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
    Or the following formula (2)
    Figure JPOXMLDOC01-appb-C000002
     (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more)
    And a conductive polymer represented by
    A carbon nanotube composite characterized in that 90% by mass or more of the carbon nanotubes are semiconducting carbon nanotubes.
  2. 　上記導電性ポリマーは、下記式（３）
    Figure JPOXMLDOC01-appb-C000003
     　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
    で表されることを特徴とする、請求項１に記載のカーボンナノチューブ複合体。     The conductive polymer has the following formula (3)
    Figure JPOXMLDOC01-appb-C000003
     (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
    The carbon nanotube composite according to claim 1, characterized in that
  3. 　上記カーボンナノチューブの９５質量％以上が半導体性カーボンナノチューブであることを特徴とする、請求項１または２に記載のカーボンナノチューブ複合体。 The carbon nanotube composite according to claim 1 or 2, wherein 95% by mass or more of the carbon nanotube is a semiconducting carbon nanotube.
  4. 　ｐ型ドーパントまたはｎ型ドーパントをさらに含むことを特徴とする、請求項１～３のいずれか１項に記載のカーボンナノチューブ複合体。 The carbon nanotube composite according to any one of claims 1 to 3, further comprising a p-type dopant or an n-type dopant.
  5. 　請求項１～４のいずれか１項に記載のカーボンナノチューブ複合体と溶媒とを含むことを特徴とする、インク。 An ink comprising the carbon nanotube complex according to any one of claims 1 to 4 and a solvent.
  6. 　カーボンナノチューブを、下記式（１）
    Figure JPOXMLDOC01-appb-C000004
     　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
    または下記式（２）
    Figure JPOXMLDOC01-appb-C000005
     　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、Ｘは２価の芳香族基であり、ｎは３以上の整数である）
    で表される導電性ポリマーを含む溶媒中に分散させる分散工程と、
    　上記分散工程によって得られたカーボンナノチューブ分散液から、カーボンナノチューブとして半導体性カーボンナノチューブを９０質量％以上含むカーボンナノチューブ複合体を分離する分離工程と、を含むことを特徴とするカーボンナノチューブ複合体の製造方法。     The carbon nanotube is represented by the following formula (1)
    Figure JPOXMLDOC01-appb-C000004
     (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
    Or the following formula (2)
    Figure JPOXMLDOC01-appb-C000005
     (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, X is a divalent aromatic group, and n is an integer of 3 or more)
    Dispersing in a solvent containing the conductive polymer represented by
    And a separation step of separating a carbon nanotube composite containing 90% by mass or more of semiconducting carbon nanotubes as carbon nanotubes from the carbon nanotube dispersion obtained by the above dispersion step. Method.
  7. 　上記導電性ポリマーは、下記式（３）
    Figure JPOXMLDOC01-appb-C000006
     　（式中、Ｒ１およびＲ２はそれぞれ独立して、炭素数４～２４のアルキル基であり、ｎは３以上の整数である）
    で表されることを特徴とする、請求項６に記載のカーボンナノチューブ複合体の製造方法。     The conductive polymer has the following formula (3)
    Figure JPOXMLDOC01-appb-C000006
     (Wherein, R 1 and R 2 are each independently an alkyl group having 4 to 24 carbon atoms, and n is an integer of 3 or more)
    The method for producing a carbon nanotube composite according to claim 6, characterized in that
  8. 　上記分離工程において、カーボンナノチューブとして半導体性カーボンナノチューブを９５質量％以上含むカーボンナノチューブ複合体を分離することを特徴とする、請求項６または７に記載のカーボンナノチューブ複合体の製造方法。 The method for producing a carbon nanotube composite according to claim 6 or 7, wherein the carbon nanotube composite containing 95% by mass or more of semiconducting carbon nanotubes as the carbon nanotubes is separated in the separation step.
  9. 　上記カーボンナノチューブ複合体に、ｐ型ドーパントまたはｎ型ドーパントを接触させるドーピング工程を含むことを特徴とする、請求項６～８のいずれか１項に記載のカーボンナノチューブ複合体の製造方法。 The method for producing a carbon nanotube composite according to any one of claims 6 to 8, comprising a doping step of bringing a p-type dopant or an n-type dopant into contact with the carbon nanotube composite.
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JP7400442B2 (en) 2019-12-23 2023-12-19 東洋インキＳｃホールディングス株式会社 Thermoelectric conversion materials and thermoelectric conversion elements

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