JP2020107642A - Thermoelectric conversion material and thermoelectric conversion element using the same - Google Patents

Abstract

To provide a thermoelectric conversion material that achieves both a Seebeck coefficient and conductivity and exhibits a high power factor, and provide a thermoelectric conversion element that exhibits excellent thermoelectric performance using the material.SOLUTION: There is provided a thermoelectric conversion material that includes a carbon material (A), a compound having a perylene skeleton or a pyrrolopyrrole skeleton (B), and a dispersant (C), and also provided a thermoelectric conversion element that includes a thermoelectric conversion film formed using the thermoelectric conversion material.SELECTED DRAWING: Figure 1

Description

The embodiment of the present invention relates to a thermoelectric conversion material and a thermoelectric conversion element using the material.

Thermoelectric conversion materials capable of mutually converting thermal energy and electric energy are used in thermoelectric conversion elements such as thermoelectric generation elements and Peltier elements. The thermoelectric conversion element is an element that converts heat into electric power, and is composed of a combination of semiconductors and metals. Typical thermoelectric conversion elements are classified into a p-type semiconductor alone, an n-type semiconductor alone, or a combination of a p-type semiconductor and an n-type semiconductor. The thermoelectric conversion element utilizes the Seebeck effect in which electromotive force is generated when heat is applied so that a temperature difference occurs between both ends of a semiconductor. In order to obtain a larger potential difference, a thermoelectric conversion element generally uses a combination of a p-type semiconductor and an n-type semiconductor as a material.

The thermoelectric conversion element is used as a thermoelectric module in which a large number of elements are combined in a plate shape or a cylindrical shape. Thermal energy can be directly converted into electric power, and can be used as a power source in wristwatches operating at body temperature, terrestrial power generation and artificial satellite power generation, for example. The performance of the thermoelectric conversion element depends on the performance of the thermoelectric conversion material, the durability of the module, and the like.

As described in Non-Patent Document 1, a dimensionless thermoelectric figure of merit (ZT) is used as an index showing the performance of a thermoelectric conversion material. Further, the power factor PF (=S ² ·σ) may be used as an index showing the performance of the thermoelectric conversion material.
The dimensionless thermoelectric figure of merit "ZT" is represented by the following equation (1).
ZT=(S ² ·σ·T)/κ Equation (1)
Here, S is the Seebeck coefficient (V/K), σ is the electrical conductivity (S·m), T is the absolute temperature (K), and κ is the thermal conductivity (W/(m·K)). The thermal conductivity κ is expressed by the following equation (2).
κ=α・ρ・C Equation (2)
Here, α is the thermal diffusivity (m ² /s), ρ is the density (kg/m ³ ), and C is the specific heat capacity (J/(kg·K)).
That is, in order to improve the performance of thermoelectric conversion (hereinafter, also referred to as thermoelectric property), it is important to improve the Seebeck coefficient or the electrical conductivity, while lowering the thermal conductivity.

Typical thermoelectric conversion materials include, for example, bismuth-tellurium-based (Bi-Te-based) from room temperature to 500K, lead-tellurium-based (Pb-Te-based) from room temperature to 800K, and silicon-based from room temperature to 1000K. Inorganic materials such as germanium (Si-Ge) are used.

However, thermoelectric conversion materials containing these inorganic materials often contain rare elements and are expensive, or may contain harmful substances. Further, since the inorganic material has poor workability, the manufacturing process becomes complicated. Therefore, a thermoelectric conversion material containing an inorganic material has a high production energy and a high production cost, and is difficult to be generalized. Further, since the inorganic material is rigid, it is difficult to form a thermoelectric conversion element having a fluxible property that can be installed in a shape other than a flat surface.

On the other hand, a thermoelectric conversion element using an organic material instead of the conventional inorganic material is being studied. Since the organic material has excellent moldability and flexibility superior to that of the inorganic material, the organic material is highly versatile in a temperature range where it does not decompose by itself. In addition, since printing technology and the like can be easily utilized, it is also advantageous over inorganic materials in terms of manufacturing energy and manufacturing cost.

For example, in Patent Document 1, by binding an organic dye skeleton to a polymer dispersant and containing it together with carbon nanotubes (CNT), a thermoelectric material having good CNT dispersibility, suitable for a coating method, and exhibiting excellent thermoelectromotive force. Is listed.
Further, Patent Document 2 describes a thermoelectric conversion material having a high Seebeck coefficient in which a porphyrin skeleton and a substituent containing an alkyl group are bonded.

International Publication No. 2015/050113 International Publication No. 2015/129877

Takenobu Kajikawa, "Handbook of Thermoelectric Conversion Technology (First Edition)," NTS Publishing, p. 19

However, in the invention of Patent Document 1, the polymer chain of the polymer dispersant hinders the interaction with CNT and sufficient performance has not been obtained. Moreover, in the invention of Patent Document 2, the conductivity is as low as 10 ⁻⁸ to 10 ⁻⁷ S/cm, and a practical value as a thermoelectric element cannot be obtained.
An object of the present invention is to provide a thermoelectric conversion material that achieves both a Seebeck coefficient and conductivity and exhibits a high power factor. Another object is to provide a thermoelectric conversion element that exhibits excellent thermoelectric performance using the material.

The present invention has been made in view of the above problems, and relates to the following inventions [1] to [7].

[1] A thermoelectric conversion material containing a carbon material (A), a compound (B) having a perylene skeleton or a pyrrolopyrrole skeleton, and a dispersant (C).

[2] The thermoelectric conversion material according to [1], wherein the dispersant (C) has a molecular weight of 100 or more and 1,000 or less.

[3] The thermoelectric conversion material according to [1] or [2], wherein the content of the compound (B) is 5 to 200 mass% with respect to the total amount of the carbon material (A).

[4] The thermoelectric conversion material according to any one of [1] to [3], wherein the content of the dispersant (C) is 5 to 200 mass% with respect to the total amount of the carbon material (A). ..

[5] The thermoelectric element according to any one of [1] to [4], wherein the carbon material (A) contains at least one selected from the group consisting of carbon nanotubes, Ketjen black, graphene nanoplates and graphene. Conversion material.

[6] The thermoelectric conversion material according to any one of [1] to [5], wherein the carbon material (A) contains carbon nanotubes.

[7] [1] to [6] A thermoelectric conversion film comprising the thermoelectric conversion material according to any one of the above items and an electrode, wherein the thermoelectric conversion film and the electrode are electrically connected to each other. Conversion element.

According to the present invention, it is possible to provide a thermoelectric conversion material that achieves both a Seebeck coefficient and conductivity and exhibits a high power factor. Moreover, the said material can be used and the thermoelectric conversion element which exhibits the outstanding thermoelectric performance can be provided.

It is a schematic diagram which shows the structure of an example of the thermoelectric conversion element which is embodiment of this invention. It is a schematic diagram explaining the measuring method of the electromotive force of the thermoelectric conversion element which is embodiment of this invention.

The thermoelectric conversion material of the present invention is characterized by containing a carbon material (A), a compound (B) having a perylene skeleton or a pyrrolopyrrole skeleton, and a dispersant (C). By combining the above, it is possible to exhibit excellent thermoelectric performance that exhibits both a Seebeck coefficient and conductivity and that exhibits a high power factor. This is because the dispersibility of the carbon material (A) and the compound (B) having the perylene skeleton or the pyrrolopyrrole skeleton is improved by the effect of the dispersant, so that the conductivity of the carbon material (A) is efficiently exhibited. And that the compound (B) having a perylene skeleton or a pyrrolopyrrole skeleton is homogenized on the surface of the carbon material (A), so that the high Seebeck coefficient of the compound (B) is efficiently exhibited. It is thought to be due to both.
Hereinafter, embodiments of the present invention will be described in detail.

<Carbon material (A)>
The carbon material (A) contributes to the improvement of conductivity. The conductivity can be improved by increasing the content of the carbon material (A).
The carbon material (A) is not particularly limited as long as it is a carbon material having conductivity, and for example, graphite, carbon nanotube, Ketjen black, graphene nanoplate, graphene and the like can be used. From the viewpoint of compatibility between Seebeck coefficient and conductivity, at least one selected from the group consisting of carbon nanotubes, Ketjen black, graphene nanoplates and graphene is preferable, carbon nanotubes are more preferable, and single-wall carbon is particularly preferable. It is a nanotube.

As the carbon material (A), for example, as flaky graphite, CMX, UP-5, UP-10, UP-20, UP-35N, CSSP, CSPE, CSP, CP, CB-150 manufactured by Nippon Graphite Industry Co., Ltd. , CB-100, ACP, ACP-1000, ACB-50, ACB-100, ACB-150, SP-10, SP-20, J-SP, SP-270, HOP, GR-60, LEP, F#1. , F#2, F#3, CX-3000, FBF, BF, CBR, SSC-3000, SSC-600, SSC-3, SSC, CX-600, CPF-8, CPF-3 manufactured by Chuetsu Graphite Co., Ltd. CPB-6S, CPB, 96E, 96L, 96L-3, 90L-3, CPC, S-87, K-3, CF-80, CF-48, CF-32, CP-150, CP-100, CP, HF-80, HF-48, HF-32, SC-120, SC-80, SC-60, SC-32, EC1500, EC1000, EC500, EC300, EC100, EC50 manufactured by Ito Graphite Industry Co., Ltd., manufactured by Nishimura Graphite Co., Ltd. 10099M, PB-99 and the like. Examples of the spherical natural graphite include CGC-20, CGC-50, CGB-20, and CGB-50 manufactured by Nippon Graphite Industry Co., Ltd. Examples of the earth graphite include Blue P, AP, AOP, P#1 manufactured by Nippon Graphite Industry Co., Ltd., and APR, S-3, AP-6, 300F manufactured by Chuetsu Graphite Co., Ltd. Examples of artificial graphite include PAG-60, PAG-80, PAG-120, PAG-5, HAG-10W, HAG-150 manufactured by Nippon Graphite Industry Co., Ltd., RA-3000, RA-15, RA- manufactured by Chuetsu Graphite Co., Ltd. 44, GX-600, G-6S, G-3, G-150, G-100, G-48, G-30, G-50, SEC carbon SGP-100, SGP-50, SGP-25. , SGP-15, SGP-5, SGP-1, SGO-100, SGO-50, SGO-25, SGO-15, SGO-5, SGO-1, SGX-100, SGX-50, SGX-25, SGX. -15, SGX-5 and SGX-1 are mentioned. Examples of commercially available carbon blacks include Toka Black #4300, #4400, #4500, #5500 manufactured by Tokai Carbon Co., Printex L manufactured by Degussa, Raven 7000, 5750, 5250, 5000 ULTRAIII, 5000 ULTRA manufactured by Columbyan. Conductex SC ULTRA, Conductux 975 ULTRA, PUERBLACK 100, 115, 205, Mitsubishi Chemical Corporation #2350, #2400B, #2600B, #3050B, #3030B, #3230B, #3350B, #3400B, #5400B, Cabot Corporation. MONARCH 1400, 1300, 900, Vulcan XC-72R, BlackPearls 2000, TIMCAL's Ensaco 250G, Ensaco 260G, Ensaco 350G, Super P-Li and other furnace blacks), Lion's EC-300J, EC-600JD, and other Ketjen Black. Acetylene black such as Denka Black, Denka Black HS-100, and FX-35 manufactured by Kogyo Co., Ltd. may be mentioned. Commercially available conductive carbon fibers and carbon nanotubes include vapor phase carbon fibers such as VGCF manufactured by Showa Denko KK, EC1.0, EC1.5, EC2.0, EC1.5-P manufactured by Meijo Nano Carbon Co., Ltd. TUBALL manufactured by Kusumoto Kasei Co., single-walled carbon nanotubes such as ZEONANO manufactured by ZEON Nanotechnology, FloTube9000, FloTube9100, FloTube9110, FloTube9200, NC7000 manufactured by Nanocyl, and 100Nano manufactured by Nanoc. .. These are not particularly limited and may be used alone or in combination of two or more.

<Compound (B) Having Perylene Skeleton or Pyrrolopyrrole Skeleton>
The compound (B) having a perylene skeleton or a pyrrolopyrrole skeleton contributes to the improvement of the Seebeck coefficient in the thermoelectric conversion material. The higher the Seebeck coefficient of the compound (B) itself and the higher the affinity for the carbon material (A), the more easily electrons or holes generated by thermal excitation move to the carbon material, resulting in the entire system. The Seebeck coefficient of becomes higher.

When the content of the compound (B) in the thermoelectric conversion material is increased, the Seebeck coefficient is improved, but the insulating property is increased and the conductivity is decreased. Therefore, from the viewpoint of achieving both the Seebeck coefficient and the conductivity, the compound (B) is The content of) is preferably from 3 to 400% by mass, more preferably from 5 to 200% by mass, further preferably from 5 to 120% by mass, and particularly preferably, with respect to the total amount of the carbon material (A). It is 5 to 100% by mass.

Further, in order to promote surface adsorption and homogenization with respect to the carbon material (A) and further increase the molecular ratio, the compound (B) preferably has a small molecular weight, and the mass average molecular weight (Mw) is preferably 2, 000 or less, and more preferably 1,000 or less.
Such compound (B) is preferably a compound represented by the following general formula (1) having a perylene skeleton or a general formula (2) having a pyrrolopyrrole skeleton.

General formula (1)

[In the general formula (1), R _{1 to} R ₁₂ are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted A substituted aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, or a substituted or unsubstituted amino group, , R _{1 to} R ₁₂ may be bonded to each other by two adjacent substituents to form a ring. ]

General formula (2)

[In the general formula (2), X _{1 to} X ₄ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, Y ₁ and Y ₂ each independently represent an oxygen atom, a sulfur atom, or a dicyanomethylene group. ]

First, the substituents R _{1 to} R ₁₂ in the general formula (1) will be described.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

Examples of the substituted or unsubstituted alkyl group include carbon such as methyl group, ethyl group, propyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group and stearyl group. An unsubstituted alkyl group of the number 1 to 30,
2-phenylisopropyl group, trichloromethyl group, trifluoromethyl group, benzyl group, α-phenoxybenzyl group, α,α-dimethylbenzyl group, α,α-methylphenylbenzyl group, α,α-bis(trifluoromethyl group ) A substituted alkyl group having 1 to 30 carbon atoms such as a benzyl group, a triphenylmethyl group and an α-benzyloxybenzyl group,
Alternatively, an unsubstituted cycloalkyl group such as a cyclopentyl group or a cyclohexyl group can be used.

Examples of the substituted or unsubstituted alkoxy group include an unsubstituted alkoxy group having 1 to 20 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a tert-butoxy group, an octyloxy group, and a tert-octyloxy group. Or
Examples thereof include substituted alkoxy groups having 1 to 20 carbon atoms such as 3,3,3-trifluoroethoxy group and benzyloxy group.

Examples of the substituted or unsubstituted aryloxy group include an unsubstituted aryloxy group having 6 to 20 carbon atoms such as a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, and a 9-anthryloxy group, or
A substituted aryloxy group having 6 to 20 carbon atoms such as 4-tert-butylphenoxy group, 4-nitrophenoxy group, 3-fluorophenoxy group, pentafluorophenoxy group, 3-trifluoromethylphenoxy group and the like can be mentioned.

Examples of the substituted or unsubstituted alkylthio group include an unsubstituted alkylthio group having 1 to 20 carbon atoms such as a methylthio group, an ethylthio group, a tert-butylthio group, a hexylthio group, and an octylthio group, or
Examples thereof include a substituted alkylthio group having 1 to 20 carbon atoms such as a 1,1,1-tetrafluoroethylthio group, a benzylylthio group and a trifluoromethylthio group.

Examples of the substituted or unsubstituted arylthio group include an unsubstituted arylthio group having 6 to 20 carbon atoms such as a phenylthio group, a 2-methylphenylthio group, a 4-tert-butylphenylthio group, and a 3-fluorophenyl group. Examples thereof include a substituted arylthio group having 6 to 20 carbon atoms such as a thio group, a pentafluorophenylthio group and a 3-trifluoromethylphenylthio group.

Examples of the substituted or unsubstituted aryl group include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,4-xylyl group, p-cumenyl group, mesityl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 9-phenanthryl group, 1-acenaphthyl group, 2-azulenyl group, 1-pyrenyl group, unsubstituted aryl group having 6 to 30 carbon atoms such as 2-triphenylyl group, or
Number of carbon atoms such as p-cyanophenyl group, p-diphenylaminophenyl group, p-styrylphenyl group, 4-[(2-tolyl)ethenyl]phenyl group, 4-[(2,2-ditolyl)ethenyl]phenyl group 6-30 substituted aryl groups are mentioned.

Examples of the substituted or unsubstituted heterocyclic group include 2-furyl group, 3-furyl group, 2-thienyl group, 3-thienyl group, 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, 2- Pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 2-oxazolyl group, 3-isoxazolyl group, 2-thiazolyl group, 3-isothiazolyl group, 2-imidazolyl group, 3-pyrazolyl group, 2- Quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 2-quinoxalinyl group, 2-benzofuryl group, 2- C3-C20 unsubstituted aromatic heterocyclic group such as benzothienyl group, N-indolyl group, N-carbazolyl group and N-acridinyl group, or 2-(5-phenyl)furyl group, 2-(5 Examples thereof include a substituted aromatic heterocyclic group having 3 to 20 carbon atoms such as -phenyl)thienyl group and 2-(3-cyano)pyridyl group.

Examples of the substituted or unsubstituted amino group include an unsubstituted amino group (NH ₂ ), or
N-methylamino group, N-ethylamino group, N,N-diethylamino group, N,N-diisopropylamino group, N,N-dibutylamino group, N-benzylamino group, N,N-dibenzylamino group, N-phenylamino group, N-phenyl-N-methylamino group, N,N-diphenylamino group, N,N-bis(m-tolyl)amino group, N,N-bis(p-tolyl)amino group, N,N-bis(p-biphenylyl)amino group, bis[4-(4-methyl)biphenylyl]amino group, N-p-biphenylyl-N-phenylamino group, N-α-naphthyl-N-phenylamino group , N-β-naphthyl-N-phenylamino group, N-phenanthryl-N-phenylamino group, N,N-bis(m-fluorophenyl)amino group, N,N-bis(3-(9-phenyl) Carbazole)amino group, N,N-bis(p-cyanophenyl)amino group, bis[4-(α,α'-dimethylbenzyl)phenyl]amino group, and the like substituted amino groups having 1 to 30 carbon atoms. ..

From the viewpoint of material performance and practicality, it is preferable that the compound (B) has a small band gap and is excellent in affinity to a solvent described later. From the above viewpoint, the substituents R _{1 to} R ₁₂ in the general formula (1) are each a hydrogen atom, a cyano group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted Aromatic heterocyclic group, substituted or unsubstituted amino group is preferable, more preferably hydrogen atom, cyano group, substituted or unsubstituted aryl group, substituted or unsubstituted aromatic heterocyclic group, or substituted or unsubstituted Is an amino group, and particularly preferably a hydrogen atom or a substituted amino group.

Among them, R ₁₁ is preferably a substituted or unsubstituted amino group, and more preferably an aryl group or a heterocyclic group, particularly an amino group substituted with an aromatic heterocyclic group such as a carbazolyl group.

Next, the substituents X _{1 to} X ₄ , Y ₁ and Y ₂ in the general formula (2) will be described.

The substituted or unsubstituted alkyl group, the substituted or unsubstituted aryl group, or the substituted or unsubstituted heterocyclic group has the same meaning as described in the general formula (1).

The substituents X ₁ and X ₃ are each independently a substituted or unsubstituted aryl group or a substituted or unsubstituted aryl group expected to have π-conjugation expansion from the viewpoint of reduction of band gap and affinity for the carbon material (A). Unsubstituted heterocyclic groups are preferred.

The substituents X ₂ and X ₄ are each independently preferably a hydrogen atom or a substituted or unsubstituted alkyl group from the viewpoint of affinity with a solvent or the like.

From the viewpoint of environmental toxicity of the compound (B), Y ₁ and Y ₂ are preferably oxygen atoms or sulfur atoms, and particularly preferably oxygen atoms.

Specific examples of the compound represented by formula (1) or (2) are shown in Tables 1 to 28 below, but the invention is not limited thereto.

<Dispersant (C)>
The dispersant (C) is used for uniformly dispersing an inorganic material or an organic material in a medium to prepare a stable dispersion, and is not particularly limited, and a conventionally known dispersant used for dispersing carbon or phthalocyanine is used. Things can be used. The dispersant (C) may be used alone or in combination of two or more kinds.

Examples of the dispersant (C) include acidic dispersants, basic dispersants, amphoteric dispersants, and nonionic dispersants. Examples of the acidic functional group of the acidic dispersant include a carboxylic acid group, a sulfonic acid group and a phosphoric acid group, and the polar functional group of the basic dispersant includes a primary amino group, a secondary amino group, and a tertiary amino group. Examples of the nonionic functional group of the nonionic dispersant include a hydroxyl group, an amide group, a ketone group, an epoxy group, and an ester group.

The basic dispersant is a commercially available product, for example, SOLSPERSE-9000, 11200, 13240, 13650, 13940, 16000, 17,000, 18000, 20000, 22000, 24000SC, 24000GR, 26000, 28000, 32000, 32500 manufactured by Lubrizol Japan. , 32550, 32600, 33000, 34750, 35100, 35200, 37500, 38500, 39000, 53095, 56000, 71000, 76500, X300 and the like, DISKERBYK-108, 109, 112, 116, 130, 161, manufactured by Big Chemie Japan. 162, 163, 164, 166, 167, 168, 182, 183, 184, 185, 2000, 2008, 2009, 2022, 2050, 2150, 2155, 2163, 2164, 9077, 101, 106, 140, 142, 145, 180, 2001, 2020, 2025, 2070, 9076 and the like, Ajinomoto Fine-Techno Co., Ltd., AJISPER PB821, PB822, PB824, PB881 and the like, BASF, EFKA-4015, 4020, 4046, 4047, 4050, 4055, 4080, 4300. , 4330, 4400, 4401, 4402 and the like.

Examples of commercially available acidic dispersants include SOLSPERSE-3000, 5000, 21000, 36000, 36600, 41000, 41090, 43000, 44000, 46000, 47000, 55000 manufactured by Lubrizol Japan, and manufactured by Big Chemie Japan. DISPERBYK-102, 110, 111, 170, 171, 174, P104, P104S, P105, 220S and the like, and Azisper PA111 manufactured by Ajinomoto Fine-Techno Co., Inc. and the like can be mentioned.

Examples of commercially available nonionic dispersants include SOLSPERSE-27000 and 54000 manufactured by Nippon Lubrizol Co., Ltd.

The dispersant (C) may be either a low molecular weight type or a high molecular weight type, but the dispersibility of the carbon material (A), the carbon material (A) and the compound (B) having a perylene skeleton or a pyrrolopyrrole skeleton are used. A low molecular weight system is preferable, and a molecular weight is more preferably 100 or more and 1,000 or less, and particularly preferably 200 or more and 600 or less, since they are brought close to each other to facilitate the expression of the Π-Π interaction. When the molecular weight of the dispersant (C) is 100 or more and 1,000 or less, the adsorption of the compound (B) on the surface of the carbon material (A) is uniformized, and the high Seebeck coefficient of the compound (B) is efficiently obtained. It is preferable because it is exhibited.
When the dispersant (C) is a polymer, the value of the mass average molecular weight (Mw) is the molecular weight.

As the dispersant, an organic dye derivative or a triazine derivative may be used, and a triazine derivative (b2) having an acidic functional group is more preferable.

[Triazine derivative (b2) having an acidic functional group]
The acidic functional group of the triazine derivative (b2) having an acidic functional group is preferably SO ₃ M, CO ₂ M, or P(O)(OM) ₂ , as described below, and more preferably SO. ₃ M or CO ₂ M, and particularly preferably CO ₂ M. M represents one equivalent of a monovalent to trivalent cation, and is preferably a metal cation or a quaternary ammonium cation.

The triazine derivative (b2) having an acidic functional group is preferably a triazine derivative represented by the following general formula (3) or a triazine derivative represented by the following general formula (4).

(Triazine derivative represented by the general formula (3))
General formula (3)

[In the general formula (3),
X ₁ represents NH, O, CONH, SO ₂ NH, CH ₂ NH, CH ₂ NHCOCH ₂ NH or X ₃ YX ₄ .
X ₂ and X ₄ each independently represent NH or O,
X ₃ represents CONH, SO ₂ NH, CH ₂ NH, NHCO or NHSO ₂ ,
Y represents an alkylene group having 1 to 20 carbon atoms, which may have a substituent, and an alkenylene group having 1 to 20 carbon atoms, which may have a substituent, or a substituent, which has 1 to 20 carbon atoms. Represents an arylene group having 1 to 20 carbon atoms, which may have,
Z represents SO ₃ M, CO ₂ M or P(O)(OM) ₂ ,
M represents one equivalent of a cation having a valence of 1 to 3,
R ₁ represents an organic dye residue, a heterocyclic residue which may have a substituent, an aromatic ring residue which may have a substituent, or a group represented by the following general formula (5). Represents
Q represents OR ₂ , NHR ₂ , a halogen atom, X ₁ R ₁ or X ₂ YZ,
R ₂ represents a hydrogen atom, an alkyl group which may have a substituent or an alkenyl group which may have a substituent. ]

General formula (5)

[In the general formula (5),
X ₅ represents NH or O,
X ₆ and X ₇ each independently represent NH, O, CONH, SO ₂ NH, CH ₂ NH or CH ₂ NHCOCH ₂ NH,
R ₃ and R ₄ each independently represent an organic dye residue, a heterocyclic residue which may have a substituent, an aromatic ring residue which may have a substituent, or YZ,
Y represents an alkylene group having 1 to 20 carbon atoms, which may have a substituent, and an alkenylene group having 1 to 20 carbon atoms, which may have a substituent, or a substituent, which has 1 to 20 carbon atoms. Represents an arylene group having 1 to 20 carbon atoms, which may have,
Z represents SO ₃ M, CO ₂ M or P(O)(OM) ₂ . ]

Examples of the organic dye residue represented by R ₁ of the general formula (3) and R ₃ and R ₄ of the general formula (5) include, for example, diketopyrrolopyrrole dyes, azo dyes such as azo, disazo, and polyazo. , Phthalocyanine dyes, diaminodianthraquinone, anthrapyrimidine, flavantron, anthantrone, indanthrone, pyrantrone, violanthrone, and other anthraquinone dyes, quinacridone dyes, dioxazine dyes, perinone dyes, perylene dyes, thioindigo dyes Examples thereof include dyes, isoindoline dyes, isoindolinone dyes, quinophthalone dyes, slene dyes, and metal complex dyes.
In particular, it is preferable to use an organic dye residue that is not a metal complex dye, and among them, the use of an azo dye, a diketopyrrolopyrrole dye, a metal-free phthalocyanine dye, a quinacridone dye, and a dioxazine dye is dispersibility and light absorption. It is preferable because it has excellent properties.

Examples of the heterocyclic residue and the aromatic ring residue represented by R ₁ of the general formula (3) and R ₃ and R ₄ of the general formula (5) include, for example, thiophene, furan, pyridine, pyrazole and pyrrole. , Imidazole, isoindoline, isoindolinone, benzimidazolone, benzthiazole, benztriazol, indole, quinoline, carbazol, acridine, benzene, naphthalene, anthracene, fluorene, phenanthrene, anthraquinone and the like. To be In particular, it is preferable to use a heterocyclic residue containing at least one of S, N and O heteroatoms because of excellent dispersibility.

Y in the general formulas (3) and (5) is preferably an alkylene group having 10 or less carbon atoms which may have a substituted phenylene group, a biphenylene group, a naphthylene group or a substituent. Groups.

The alkyl group and alkenyl group for R ₂ in the general formula (3) preferably have 20 or less carbon atoms, and more preferably an alkyl group having 10 or less carbon atoms which may have a substituent.

Examples of the substituent that may be included include a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, a hydroxyl group and a mercapto group.

Examples of the monovalent to trivalent cation represented by M in the general formula (3) include a hydrogen atom (proton), a metal cation, and a quaternary ammonium cation. When the structure has two or more M, M may be only one of a hydrogen atom (proton), a metal cation, and a quaternary ammonium cation, or a combination thereof.
Examples of the metal of the metal cation include lithium, sodium, potassium, calcium, barium, magnesium, aluminum, nickel and cobalt. The quaternary ammonium cation may be a single compound or a mixture having a structure represented by the following general formula (20).

General formula (20)

[In the general formula (20),
R _{5 to} R ₈ are each independently a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an aryl group which may have a substituent. Represents. ]

R _{5 to} R _{8 in} the general formula (20) may be the same or different. The number of carbon atoms in R _{5 to} R ₈ is 1 to 40, preferably 1 to 30, and more preferably 1 to 20.

Specific examples of the quaternary ammonium include, for example, dimethylammonium, trimethylammonium, diethylammonium, triethylammonium, hydroxyethylammonium, dihydroxyethylammonium, 2-ethylhexylammonium, dimethylaminopropylammonium, laurylammonium, stearylammonium, octylammonium and the like. But is not limited to these.

Further, when the monovalent cation is a metal cation or a quaternary ammonium cation, the cation can be introduced by salt exchange. The salt exchange may be performed at the time of manufacturing the dispersant or at the time of manufacturing the thermoelectric conversion material.

The method for synthesizing the above-mentioned dispersant is not particularly limited, but for example, Japanese Patent Publication No. 39-28884, Japanese Patent Publication No. 45-11026, Japanese Patent Publication No. 45-29755, and Japanese Patent Publication No. 64-5070. It can be synthesized by the method described in Japanese Patent Laid-Open No. 2004-217842 or the like.

The monovalent to trivalent cation represented by M in the general formula (3) is more preferably a metal cation or a quaternary ammonium cation, and particularly preferably a quaternary ammonium cation.

An example of the derivative represented by the general formula (3) is shown below. In addition, the acidic functional group (SO ₃ H, CO ₂ H or P(O)(OH) ₂ ) in the exemplified compound may form a salt with a metal cation or a quaternary ammonium cation.

The triazine derivative represented by the general formula (3) is more preferably an X ₁ R ₁ structure in which X ₁ is NH and R ₁ is a benzimidazolone residue, and M is a metal cation or a quaternary ammonium. It is a cation, and the above-described exemplary derivatives (b2-5), (b2-7), (b2-9), (b2-12) to (b2-15), (b2-18 to b2-26). Is applicable.

(Triazine derivative represented by the general formula (4))
General formula (4)

[In the general formula (4),
R ¹ represents a group represented by X ¹ Y ¹ .
X ¹ represents an arylene group which may have a substituent,
Y ¹ represents SO ₃ M, CO ₂ M or P(O)(OM) ₂ ,
M represents one equivalent of a monovalent to trivalent cation. ]

Examples of the arylene group for X ¹ in the general formula (4) include a phenylene group and a naphthylene group, and a phenylene group is more preferable.
The substituents that the arylene group may have may be the same or different, and specific examples thereof include a sulfo group, a carboxyl group, a hydroxyl group, a halogen atom such as fluorine, chlorine and bromine, a nitro group and an alkyl group. , An alkoxyl group, and the like. Moreover, these substituents may be plural.

The ^{Y 1} in the general formula (4), more preferably SO ₃ M or CO ₂ M, particularly preferably CO ₂ M. The monovalent to trivalent cation represented by M in the general formula (4) has the same meaning as the monovalent to trivalent cation represented by M in the general formula (3), and more preferably Is a metal cation or a quaternary ammonium cation.

The metal cation can be introduced by adding an inorganic base to the triazine derivative represented by the general formula (4) and M is a hydrogen atom, and the inorganic base is an alkali metal. The hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonates, alkali metal phosphates, alkaline earth metal phosphates and the like can be used.

As alkali metal hydroxides, lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.; as alkaline earth metal hydroxides, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, etc.; Alkali metal carbonates include lithium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, etc.; alkaline earth metal carbonates include magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, etc.; alkali As the metal phosphate, lithium phosphate, trisodium phosphate, disodium hydrogen phosphate, tripotassium phosphate, dipotassium hydrogen phosphate, etc.; as the alkaline earth metal phosphate, magnesium phosphate, Calcium phosphate, strontium phosphate, barium phosphate, etc. may be mentioned, and the most suitable one may be selected. The addition amount of the inorganic base is not particularly limited, but is preferably 0.1 mol or more and 5 mol or less, and more preferably 0.3 mol or more and 2 mol or less with respect to 1 mol of the triazine derivative.

An example of the derivative represented by the general formula (4) is shown below. M in the acidic functional groups in the exemplified compounds below are all represented by hydrogen atoms, but are not limited to hydrogen atoms and may be metal cations or quaternary ammonium salts.

As described above, the dispersant (C) is preferably the triazine derivative (b2) having an acidic functional group, more preferably the triazine derivative represented by the general formula (3) or the general formula (4). .. Above all, it is preferable to have either a triazine structure in which two hydroxyl groups are directly bonded or a triazine structure in which a benzimidazolone group is bonded via an NH bond.

From the viewpoint of dispersibility, the content of the dispersant (C) is preferably 5 to 200% by mass, more preferably 30 to 150% by mass, particularly preferably 30% by mass to the total amount of the carbon material (A). It is 80 to 120 mass %.

<Other ingredients>
The thermoelectric conversion material of the present invention may contain an additional component, if necessary, from the viewpoint of improving its properties. For example, by adding the auxiliaries exemplified below, it becomes possible to further improve the coatability, conductivity and thermoelectric properties.

(solvent)
The solvent used in the present invention is used as a dissolution medium or a dispersion medium for the carbon material (A), the compound (B) and the dispersant (C), and it is possible to improve the coatability by forming an ink. The solvent that can be used is not particularly limited as long as the carbon material (A), the compound (B) and the dispersant (C) can be dissolved or well dispersed, and examples thereof include an organic solvent and water. You may use.
Examples of the organic solvent include alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol methyl ether, and diethylene glycol methyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, Ethers such as diethylene glycol dimethyl ether, hydrocarbons such as hexane, heptane, octane, aromatics such as benzene, toluene, xylene, cumene, esters such as ethyl acetate and butyl acetate, terpineol, dihydroterpineol, 2,4- It can be appropriately selected from diethyl-1,5-pentanediol, 1,3-butylene glycol, isobornylcyclohexanol, N-methylpyrrolidone and the like, if necessary.
As the solvent for dispersing the carbon material (A), the compound (B), and the dispersant (C), N-methylpyrrolidone is particularly preferable.

(Auxiliary agent)
Examples of auxiliaries that can be used include lactams, alcohols, amino alcohols, carboxylic acids, acid anhydrides, and ionic liquids. Although not particularly limited, specific examples are as follows.
Lactams: N-methylpyrrolidone, pyrrolidone, caprolactam, N-methylcaprolactam, N-octylpyrrolidone and the like.
Alcohols: sucrose, glucose, fructose, lactose, sorbitol, mannitol, xylitol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, glycerin, polyethylene glycol, polypropylene glycol, tri Fluoroethanol, m-cresol, thiodiglycol and the like.
Amino alcohols: diethanolamine, triethanolamine and the like.
Carboxylic acids: 2-furancarboxylic acid, 3-furancarboxylic acid, dichloroacetic acid, trifluoroacetic acid and the like.
Acid anhydrides: acetic anhydride, propionic anhydride, acrylic anhydride, methacrylic anhydride, benzoic anhydride, succinic anhydride, maleic anhydride, itaconic anhydride, glutaric anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydro Phthalic anhydride (also known as cyclohexane-1,2-dicarboxylic anhydride), trimellitic anhydride, hexahydro trimellitic anhydride, pyromellitic anhydride, hymic acid anhydride, biphenyl tetracarboxylic anhydride, 1,2,3 , 4-butanetetracarboxylic acid anhydride, naphthalenetetracarboxylic acid anhydride, and 9,9-fluorenylidene bisphthalic anhydride. Styrene-maleic anhydride copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, alkyl vinyl ether-maleic anhydride copolymers, and other copolymers obtained by copolymerizing maleic anhydride with other vinyl monomers.

From the viewpoint of conductivity and thermoelectric properties, it is preferable to use at least one of lactams and alcohols as an auxiliary agent. The content of the auxiliary agent is preferably in the range of 0.1 to 30% by mass, more preferably in the range of 1 to 10% by mass, and further preferably in the range of 1 to 5% by mass, based on the total mass of the thermoelectric conversion material. .. When the content of the auxiliary agent is 0.1% by mass or more, the effect of improving the conductivity and thermoelectric properties can be easily obtained. Further, when the content of the auxiliary agent is 50% by mass or less, the deterioration of the physical properties of the film can be suppressed.

The thermoelectric conversion material may contain a resin for the purpose of adjusting film-forming properties and film strength, etc., within a range that does not affect the conductivity and thermoelectric properties.

Any resin may be used as long as it is compatible with or mixed with each component of the thermoelectric conversion material. Either a thermosetting resin or a thermoplastic resin may be used. Specific examples of usable resins include polyester resin, polyimide resin, polyamide resin, fluororesin, vinyl resin, epoxy resin, xylene resin, aramid resin, polyurethane resin, polyurea resin, melamine resin, phenol resin, polyether resin, and acrylic resin. Examples thereof include resins, acrylamide resins, and copolymer resins of these. Although not particularly limited, in one embodiment, it is preferable to use at least one selected from the group consisting of polyurethane resin, polyether resin, acrylic resin, and acrylamide resin.

The thermoelectric conversion material may contain fine particles made of an inorganic thermoelectric material, if necessary, in order to enhance the thermoelectric conversion performance. As an example of the inorganic thermoelectric material, Bi-(Te, Se) system, Si-Ge system, Mg-Si system, Pb-Te system, GeTe-AgSbTe system, (Co, Ir, Ru)-Sb system, (Ca, sr, Bi) can be exemplified _Co 2 _{O 5} system and the like. More specifically, Bi ₂ Te ₃ , PbTe, AgSbTe ₂ , GeTe, Sb ₂ Te ₃ , NaCo ₂ O ₄ , CaCoO ₃ , SrTiO ₃ , ZnO, SiGe, Mg ₂ Si, FeSi ₂ , Ba ₈ Si ₄₆ , At least one selected from the group consisting of MnSi _1.73 , ZnSb, Zn ₄ Sb ₃ , GeFe ₃ CoSb ₁₂ , and LaFe ₃ CoSb ₁₂ can be used. At this time, the inorganic thermoelectric material may be added with impurities to control the polarity (p-type, n-type) or the conductivity and used. When an inorganic thermoelectric material is used, the amount used is adjusted within a range that does not affect the film forming property or film strength.

<Thermoelectric conversion element>
A thermoelectric conversion element that is an embodiment of the present invention is characterized by being configured using the thermoelectric conversion material. In one embodiment, the thermoelectric conversion element has a thermoelectric conversion film formed using the thermoelectric conversion material and an electrode, and the thermoelectric conversion film and the electrode are electrically connected to each other. The thermoelectric conversion film is excellent in heat resistance and flexibility in addition to conductivity and thermoelectric properties. Therefore, according to this embodiment, a high-quality thermoelectric conversion element can be easily realized.

The thermoelectric conversion film may be a film obtained by applying a thermoelectric conversion material on a base material. Since the thermoelectric conversion material has excellent moldability, it is easy to obtain a good film by the coating method. A wet film forming method is mainly used for forming the thermoelectric conversion film. Specifically, spin coating method, spraying method, roller coating method, gravure coating method, die coating method, comma coating method, roll coating method, curtain coating method, bar coating method, inkjet method, dispenser method, silk screen printing, flexo method. Examples include methods using various means such as printing. The method can be appropriately selected from the above methods depending on the thickness to be applied, the viscosity of the material, and the like.

The thickness of the thermoelectric conversion film is not particularly limited, but as described below, it has a certain thickness or more so that a temperature difference can be generated and transmitted in the thickness direction or the surface direction of the thermoelectric conversion film. Is preferably formed as follows. In one embodiment, from the viewpoint of thermoelectric characteristics, the film thickness of the thermoelectric conversion film is preferably 0.1 to 200 μm, more preferably 1 to 100 μm, and further preferably 1 to 50 μm.

In addition, as a substrate for applying the thermoelectric conversion material, a plastic film made of a material such as polyethylene, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polypropylene, polyimide, polycarbonate, and cellulose triacetate, or glass is used. Can be used.

Various treatments can be performed on the surface of the substrate for the purpose of improving the adhesion between the substrate and the thermoelectric conversion film. Specifically, prior to applying the thermoelectric conversion material, UV ozone treatment, corona treatment, plasma treatment, or easy adhesion treatment may be performed.

The thermoelectric conversion element that is an embodiment of the present invention can be configured by applying a technique well known in the technical field, except that the thermoelectric conversion material is used. As a representative, a more specific configuration of the thermoelectric conversion element and a method for manufacturing the same will be described.

In one embodiment, the thermoelectric conversion element has a thermoelectric conversion film obtained by using a thermoelectric conversion material, and a pair of electrodes that are electrode-connected to the thermoelectric conversion film. Here, “electrically connected” means being in a state in which they are joined to each other or can be energized via another component such as a wire.

The material of the electrodes can be selected from metals, alloys and semiconductors. In one embodiment, metals and alloys are preferable because of their high conductivity and low contact resistance with the thermoelectric conversion material of the present invention which constitutes the thermoelectric conversion film. As a specific example, the electrode preferably contains at least one selected from the group consisting of gold, silver, copper, and aluminum. More preferably, the electrode comprises silver.

The electrode can be formed by a method such as vacuum deposition, thermocompression bonding of a film having an electrode material foil or an electrode material film, and application of a paste in which fine particles of the electrode material are dispersed. From the viewpoint of simple process, a method of thermocompression bonding of a film having an electrode material foil or a film having an electrode material film and applying a paste in which an electrode material is dispersed is preferable.

Specific examples of the structure of the thermoelectric conversion element include (1) a structure in which electrodes are formed at both ends of the thermoelectric conversion film according to the present invention, and (2) the thermoelectric conversion film according to the present invention, based on the positional relationship between the thermoelectric conversion film and the pair of electrodes. It is roughly classified into a structure in which the conversion film is sandwiched by two electrodes.
For example, the thermoelectric conversion element having the above structure (1) is obtained by forming a thermoelectric conversion film on a base material and then applying silver paste to both ends thereof to form first and second electrodes. be able to. In such a thermoelectric conversion element in which electrodes are formed on both ends of the thermoelectric conversion film, it is easy to increase the distance between the two electrodes. Therefore, it is easy to generate a large temperature difference between the two electrodes and efficiently perform thermoelectric conversion.

In the thermoelectric conversion element having the structure of (2), for example, a silver paste is applied on a base material to form a first electrode, the thermoelectric conversion film of the present invention is formed on the first electrode, and the first electrode is further formed on the first electrode. It can be obtained by applying a silver paste to form the second electrode. As described above, in the thermoelectric conversion element in which the thermoelectric conversion film of the present invention is sandwiched by the two electrodes, it is difficult to widen the distance between the two electrodes. Therefore, it is difficult to generate a large temperature difference between the two electrodes, but it is possible to increase the temperature difference by increasing the film thickness of the thermoelectric conversion film. Further, since the thermoelectric conversion element having such a structure can utilize the temperature difference in the direction perpendicular to the base material, it can be used in the form of being attached to the heating element. Therefore, it is preferable in that it is easy to utilize a large area of the heat source.

The thermoelectric conversion elements can generate a high voltage when connected in series, and can generate a large current when connected in parallel. Further, the thermoelectric conversion element may be one in which two or more thermoelectric conversion elements are connected. According to the present invention, since the thermoelectric conversion element has excellent flexibility, it can be installed satisfactorily following a heat source having a non-planar shape.

In one embodiment, it is also effective to combine the thermoelectric conversion element of the present invention with a thermoelectric conversion element made of another thermoelectric material. For example, as the inorganic thermoelectric material, Bi-(Te, Se) system, Si-Ge system, Mg-Si system, Pb-Te system, GeTe-AgSbTe system, (Co, Ir, Ru)-Sb system, (Ca, sr, Bi) can be exemplified _Co 2 _{O 5} system, etc., _{specifically, Bi 2 Te 3, PbTe,} AgSbTe 2, GeTe, Sb 2 Te 3, NaCo 2 O 4, CaCoO 3, SrTiO 3, ZnO the use _{SiGe, Mg 2 Si, FeSi 2} , Ba 8 Si 46, MnSi 1.73, ZnSb, the _{Zn 4 Sb 3, GeFe 3 CoSb} 12, which and at least one selected from the group consisting of a LaFe ₃ CoSb ₁₂ can do. At this time, an impurity may be added to the inorganic thermoelectric material to control the polarity (p-type, n-type) or the conductivity and to use. In addition, at least one selected from the group consisting of polythiophene, polyaniline, polyacetylene, fullerene, and derivatives thereof can be used as the organic thermoelectric material. When another thermoelectric conversion element composed of these materials is combined, it is preferable to produce another thermoelectric conversion element within a range that does not impair the flexibility of the element.

When connecting a plurality of thermoelectric conversion elements, they can be used by connecting them in a state of being integrated on one base material. In such an embodiment, a combination of the thermoelectric conversion element according to the present invention and a thermoelectric conversion element made of a thermoelectric material exhibiting n-type polarity is preferable, and it is more preferable to connect these in series. According to this embodiment, it becomes easy to densely integrate the thermoelectric conversion elements.

Hereinafter, the present invention will be described more specifically with reference to experimental examples. In the examples, "parts" means "parts by mass" and "%" means "% by mass". NMP means N-methylpyrrolidone.

<Measurement method of mass average molecular weight (Mw)>
To measure Mw, GPC (gel permeation chromatography) “HPC-8020” manufactured by Tosoh Corporation was used. GPC is a liquid chromatography in which a substance dissolved in a solvent (THF; tetrahydrofuran) is separated and quantified by the difference in its molecular size. The measurement in the present invention was performed by connecting two "LF-604" (Showa Denko KK: GPC column for rapid analysis: 6 mm ID x 150 mm size) connected in series to the column, using a flow rate of 0.6 ml/min and a column temperature. The measurement was carried out under the condition of 40° C., and the mass average molecular weight (Mw) was determined in terms of polystyrene.

<Synthesis of Compound (B)>
(Synthesis Example 1: Compound (B4))
To 20 ml of nitrobenzene, 5.0 g of 3-aminoperylene, 15.2 g of 3-bromo-9-phenylcarbazole, 1.5 g of sodium hydroxide, and 1.0 g of copper oxide were added, and the mixture was heated to 200° C. under a nitrogen atmosphere at 50° C. The mixture was heated and stirred for an hour. After cooling, the mixture was diluted with 500 ml of water and extracted with toluene. The extract was concentrated and then purified by column chromatography using silica gel to obtain 7.3 g of compound (B4).

Compound (B4)

(Synthesis Example 2: Compound (B30))
5.0 g of 3-aminoperylene, 12.3 g of 4-bromobiphenyl, 1.5 g of sodium hydroxide, and 1.0 g of copper oxide were added to 20 ml of nitrobenzene, and the mixture was heated and stirred at 200° C. for 50 hours under a nitrogen atmosphere. .. After cooling, the mixture was diluted with 500 ml of water and extracted with toluene. The extract was concentrated and then purified by column chromatography using silica gel to obtain 5.6 g of compound (B30).

Compound (B30)

(Synthesis Example 3: Compound (B40))
5.0 g of 3,9-diaminoperylene, 15.3 g of 4-bromotoluene, 3.0 g of sodium hydroxide and 2.0 g of copper oxide were added to 20 ml of nitrobenzene, and heated at 200° C. for 50 hours under a nitrogen atmosphere. It was stirred. After cooling, the mixture was diluted with 500 ml of water and extracted with toluene. The extract was concentrated and then purified by column chromatography using silica gel to obtain 6.1 g of compound (B40).

Compound (B40)

(Synthesis Example 4: Compound (B54))
5.0 g of 3-aminoperylene, 13.7 g of 4-bromoisoquinoline, 1.5 g of sodium hydroxide, and 1.0 g of copper oxide were added to 20 ml of nitrobenzene, and the mixture was heated and stirred at 200° C. for 50 hours under a nitrogen atmosphere. .. After cooling, the mixture was diluted with 500 ml of water and extracted with toluene. The extract was concentrated and then purified by column chromatography using silica gel to obtain 4.3 g of compound (B54).

Compound (B54)

(Synthesis Example 5: Compound (B128))
18.5 g of dimethyl succinate, 30 g of 2-cyanothiophene, and 13.5 g of sodium hydride were dissolved in 300 g of amyl alcohol and refluxed for 8 hours. After cooling, the precipitate was filtered and washed with acetic acid and methanol to obtain 17.67 g of a reddish brown solid. Thereafter, 10 g of the obtained solid, 26.1 g of 1-iodo-2-methylpropane and 10.3 g of sodium tert-butoxide were dissolved in 300 g of dimethylacetamide, and the mixture was refluxed for 8 hours. After cooling, the above mixture was put into 1000 ml of methanol to precipitate a solid, which was collected by filtration and purified by column chromatography using silica gel to obtain 9.58 g of compound (B128).

Compound (B128)

(Synthesis Example 6: Compound (B166))
Dimethyl succinate 18.5 g, 2-cyanofuran 28.5 g, and sodium hydride 13.5 g were dissolved in amyl alcohol 300 g, and the mixture was refluxed for 8 hours. After cooling, the precipitate was filtered and washed with acetic acid and methanol to obtain 15.67 g of compound (B166).

Compound (B166)

(Synthesis Example 7: Compound (B187))
20.2 g of diisopropyl succinate, 59.6 g of di(p-tolyl)aminobenzonitrile, and 22.4 g of potassium tert-butoxide were dissolved in 150 g of tert-pentyl alcohol, and the mixture was refluxed for 8 hours. After cooling, the precipitate was filtered and washed with acetic acid and methanol to obtain 36.8 g of a red solid. After suspending 34 g of this red solid in 340 g of nitrobenzene, 75 g of ethyl p-toluenesulfonate and 41.4 g of potassium carbonate were added. The temperature was raised to 200° C., and the mixture was stirred at this temperature in a nitrogen atmosphere for 3 hours. Then, the mixture was cooled to room temperature, the precipitate was filtered and then washed with methanol. Next, it was suspended in 1700 g of water, stirred at 80 to 90° C. for 30 minutes, filtered, washed with water, and dried to obtain 27.6 g of compound (B187).

Compound (B187)

(Synthesis Example 8: Compound (B192))
18.4 g of dimethyl succinate, 53.1 g of 4-trifluoromethylbenzonitrile and 25.3 g of sodium butoxide were dissolved in 200 g of amyl alcohol and refluxed for 8 hours. After cooling, the precipitate was filtered and washed with acetic acid and methanol to obtain 21.2 g of compound (B192).

Compound (B192)

<Synthesis of polymer with organic dye introduced into side chain>
(Synthesis Example 9: Dye-introducing polymer 1)
With reference to paragraphs 0219 to 0229 of JP-A-2016-180095, a dye-introduced polymer which is an acrylic polymer having a mass average molecular weight (Mw) of about 22,000 and having a phthalocyanine skeleton introduced into a side chain represented by the following structure. Got 1.

Dye-introducing polymer 1

<Synthesis of resin component>
(Synthesis example 10: Binder resin 1)
A polyester polyol (manufactured by Kuraray Co., Ltd.) obtained from terephthalic acid, adipic acid, and 3-methyl-1,5-pentanediol in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube. "Kuraray polyol P-2011", Mn=2,011) 455.5 parts, dimethylolbutanoic acid 16.5 parts, isophorone diisocyanate 105.2 parts, and toluene 140 parts were charged and reacted at 90°C for 3 hours under a nitrogen atmosphere. Then, 360 parts of toluene was added thereto to obtain a urethane prepolymer solution having an isocyanate group. Next, a mixture of 19.9 parts of isophorone diamine, 0.63 part of di-n-butylamine, 294.5 parts of 2-propanol, and 335.5 parts of toluene was added to the resulting urethane prepolymer solution having an isocyanate group. Binder resin 1 which is a urethane urea resin having a mass average molecular weight (Mw) of 61,000 after adding 969.5 parts and reacting at 50° C. for 3 hours and then at 70° C. for 2 hours, followed by vacuum drying at 100° C. Got

<Synthesis of Dispersant (C)>
(Synthesis Example 11: Dispersant 9 (organic dye derivative having an acidic functional group))
A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introducing tube was charged with 10 parts of quinacridone dye (CI Pigment Violet 19) and 50 parts of 98% sulfuric acid, and stirred at 80° C. for 8 hours. Thus, a dispersant 9 represented by the following structure, which is a quinacridone derivative having an acidic functional group, was obtained.

(Synthesis Example 12: Dispersant 10 (organic dye derivative having a basic functional group))
A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introducing tube was charged with 10 parts of CI Solvent Yellow 33, 50 parts of 98% sulfuric acid and 15 parts of thionyl chloride, and the mixture was heated to 70° C. for 6 hours. After stirring for an hour, 15 parts of N,N-dimethylethyldiamine is added, and the mixture is stirred at 60° C. for 2 hours to give Dispersant 10 represented by the following structure, which is a quinophthalone derivative having a basic functional group. Obtained.

<Manufacture of thermoelectric conversion material>
[Example 1]
(Dispersion 1)
Kusumoto Kasei Co., Ltd. single-walled carbon nanotube "TUBALL" (SWCNT) 0.4 parts, compound (B4) 0.4 parts, dispersant 1 (b2-12) 0.4 parts, NMP 78.8 parts were weighed respectively. Mixed. Further, 140 parts of zirconia beads (φ1.25 mm) were added, and the mixture was shaken with Scandex for 2 hours, and then filtered to remove the zirconia beads to obtain a dispersion liquid 1 of thermoelectric conversion material.

[Examples 2 to 45]
(Dispersions 2-45)
Dispersions 2 to 45 of thermoelectric conversion materials were obtained in the same manner as Dispersion 1, except that the constituent components and the contents thereof were changed to those shown in Table 29.
In addition, as the dispersant described in Table 29, the dispersant 2 is b2-8, the dispersant 3 is b2-18, the dispersant 4 is b2-26, the dispersant 5 is b2-109, and the dispersant 6 is b2-. 118, dispersant 7 is SOLSPERSE-41000 manufactured by Lubrizol Japan, dispersant 8 is Marialim AKM-0531 manufactured by NOF CORPORATION, dispersant 9 is a quinacridone derivative having an acidic functional group described in Synthesis Example 11, dispersant 10 Was the quinophthalone derivative having a basic functional group described in Synthesis Example 12. As the binder resin 1 described in “Others”, the synthetic compound described in Synthesis Example 10 was used.

[Comparative Example 1]
(Dispersion liquid 101)
Dispersion liquid 101 containing a dye-introduced polymer was obtained in the same manner as in dispersion liquid 1 except that the compound (B4) in dispersion liquid 1 was changed to dye-introduced polymer 1.

<Evaluation of thermoelectric conversion material>
The resulting dispersions 1 to 45 and 101 were applied on a PET film having a thickness of 75 μm, which is a sheet-shaped base material, using an applicator, and then dried by heating at 120° C. for 30 minutes to form a PET base material. A laminate having a thermoelectric conversion film with a thickness of 5 μm was obtained.
With respect to the laminate having the obtained thermoelectric conversion film (hereinafter, also referred to as a coating film), the conductivity (conductivity), Seebeck coefficient, power factor (PF) and coating suitability were evaluated as follows. The results are shown in Table 29.

(conductivity)
The obtained laminated body was cut into 2.5 cm×5 cm, and the electrical conductivity was measured by a four-terminal method using Loresta GX MCP-T700 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) according to JIS-K7194.

(Seebeck coefficient)
The obtained laminated body was cut into 3 mm×10 mm, and the Seebeck coefficient (μW/K) at 80° C. was measured using ZEM-3LW manufactured by Advance Riko Co., Ltd.

(Power factor (PF))
PF (=S ² ·σ) at 80° C. was calculated using the obtained conductivity and Seebeck coefficient, and evaluated according to the following criteria. If the PF is 2.5 μW/(mK ² ) or more, it is at a practical level.
⊚: PF is 20 μW/(mK ² ) or more (very good)
○: PF is 10μW / (mK ²⁾ or more, less than 20μW / (mK ²⁾ (good)
Δ: PF is 2.5 μW/(mK ² ) or more and less than 10 μW/(mK ² ) (practical)
X: PF is less than 2.5 μW/(mK ² ) (not practical)

(Applicability)
The coating suitability of the dispersion was evaluated using a grind gauge (groove depth: 50 μm).
⊚: No scoring or coarse particles due to coarse particles of 10 μm or more (very good)
◯: There is scoring or coarse particles due to coarse particles of 10 μm or more, but no scoring or coarse particles due to coarse particles of 20 μm or more (good)
Δ: There is scoring or coarse particles due to coarse particles of 20 μm or more, but no scoring or coarse particles due to coarse particles of 30 μm or more (usable)
X: There is scoring due to coarse particles of 30 μm or more and coarse particles (cannot be used)

The abbreviations in Table 29 are as follows.
≪Carbon material (A)≫
SWCNT: Kusumoto Kasei's single-walled carbon nanotube "TUBALL"
MWCNT: Multi-walled carbon nanotube "100P" manufactured by Kano
GNP: Tokyo Kasei Graphene Nanoplate Let KB: Lion Ketjen Black EC-300J
CB: Carbon black CGC-50 manufactured by Nippon Graphite Industry Co., Ltd.
<<Compound (B)>>
B4: Compound obtained in Synthesis Example 1 B30: Compound obtained in Synthesis Example 2 B40: Compound obtained in Synthesis Example 3 B54: Compound obtained in Synthesis Example 4 B128: Compound obtained in Synthesis Example 5 B166: Synthesis Example 6 Compound B187 obtained in 1.: Compound B192 obtained in Synthesis Example 7: Compound obtained in Synthesis Example 8 <<Dispersant (C)>>
Dispersant 1: the compound (b2-12) described above
Dispersant 2: the above compound (b2-8)
Dispersant 3: the above compound (b2-18)
Dispersant 4: the above compound (b2-26)
Dispersant 5: compound (b2-109) described above
Dispersant 6: the above compound (b2-118)
Dispersant 7: Acidic resin type dispersant (SOLSPERSE-41000 manufactured by Nippon Lubrizol Co., Ltd.)
Dispersant 8: Basic resin type dispersant (Marialim AKM-0531 manufactured by NOF CORPORATION)
Dispersant 9: Quinacridone derivative having acidic functional group obtained in Synthesis Example 11 Dispersant 10: Quinophthalone derivative having basic functional group obtained in Synthesis Example 12

From the results of Table 29, the thermoelectric conversion material of the present invention has both a high electrical conductivity and a Seebeck coefficient, and exhibits a high power factor. Furthermore, all the thermoelectric conversion materials of the present invention showed good coatability (coating state). Particularly, in Example 18, a high power factor was exhibited by using the compound (B) having a high Seebeck coefficient and a small amount of the dispersant (C) having a high dispersibility.
On the other hand, in Comparative Example 1 using the dye-introduced polymer, since the density of the dye unit for improving the Seebeck coefficient was low, the Seebeck coefficient was lowered and the power factor was low.

<Production of thermoelectric conversion element>
[Example 46]
(Thermoelectric conversion element 1)
The dispersion liquid 1 of the thermoelectric conversion material prepared in Example 1 was applied onto a PET film having a thickness of 50 μm, and five thermoelectric conversion films each having a shape of 5 mm×30 mm were formed at intervals of 10 mm (reference numeral 2 in FIG. 1). See). Next, four silver circuits having a shape of 5 mm×33 mm were prepared using silver paste so that the respective thermoelectric conversion films were connected in series (see reference numeral 3 in FIG. 1), and the thermoelectric conversion element 1 Got REXALPHA RA FS 074 manufactured by Toyochem Co., Ltd. was used as the silver paste.

[Examples 47 to 90]
(Thermoelectric conversion elements 2-45)
Thermoelectric conversion elements 2 to 45 were obtained in the same manner as the thermoelectric conversion element 1, except that the dispersion liquid of the thermoelectric conversion material used in the thermoelectric conversion element 1 was changed to the dispersion liquid shown in Table 30.

<Evaluation of thermoelectric conversion element>
The electromotive force of the obtained thermoelectric conversion element was evaluated as follows. The results are shown in Table 30.

(Measurement of electromotive force)
Each thermoelectric conversion element was bent so that the thermoelectric conversion film and the silver circuit were on the inner side (along the line AA′ shown in FIG. 2), and placed in that state on a hot plate heated to 100° C. did. The degree of bending was adjusted so that the distance between BB′ in FIG. 2 was 10 mm. The sample bent as described above was placed on a hot plate, and the electromotive force between the coating films after 10 minutes was measured using a voltmeter. The measurement was performed at room temperature (20° C.). The thermoelectric properties were evaluated from the measured values according to the following criteria.
⊚: Electromotive force is 1 mV or more (good)
◯: Electromotive force is 500 μV or more and less than 1 mV (practical)
×: electromotive force is less than 500 μV (defective)

From the results of Table 3, the thermoelectric conversion element of the present invention had excellent thermoelectric properties. From the above, according to the embodiment of the present invention, it is possible to realize a thermoelectric conversion material that has excellent Seebeck coefficient and conductivity, exhibits a high power factor, and has excellent thermoelectric characteristics, and provides an efficient thermoelectric conversion element. I see that it can be realized.

The thermoelectric conversion material which is an embodiment of the present invention has excellent thermoelectric properties in which both conductivity and Seebeck coefficient are compatible, and further coating suitability is good, so that a uniform coating film can be formed. A high performance thermoelectric conversion element can be provided.

1: Base material (pet film),
2: Thermoelectric conversion film,
3: Circuit,
10: Test sample of thermoelectric conversion element,
20: Hot plate

Claims (7)

A thermoelectric conversion material containing a carbon material (A), a compound (B) having a perylene skeleton or a pyrrolopyrrole skeleton, and a dispersant (C). The thermoelectric conversion material according to claim 1, wherein the dispersant (C) has a molecular weight of 100 or more and 1,000 or less. The thermoelectric conversion material according to claim 1 or 2, wherein the content of the compound (B) is 5 to 200 mass% with respect to the total amount of the carbon material (A). Content of the said dispersing agent (C) is 5-200 mass% with respect to the total amount of the said carbon material (A), The thermoelectric conversion material in any one of Claims 1-3. The thermoelectric conversion material according to any one of claims 1 to 4, wherein the carbon material (A) contains at least one selected from the group consisting of carbon nanotubes, Ketjen black, graphene nanoplates, and graphene. The thermoelectric conversion material according to any one of claims 1 to 5, wherein the carbon material (A) contains carbon nanotubes. A thermoelectric conversion element comprising a thermoelectric conversion film made of the thermoelectric conversion material according to claim 1 and an electrode, wherein the thermoelectric conversion film and the electrode are electrically connected to each other.