JP2021082719A - Thermoelectric conversion material and thermoelectric conversion element - Google Patents

Abstract

To provide a thermoelectric conversion material and a thermoelectric conversion element that can achieve both an excellent Seebeck coefficient and conductivity.SOLUTION: A thermoelectric conversion material contains a predetermined compound and at least one conductive material selected from the group consisting of carbon materials, metallic materials, and conductive polymers. A thermoelectric conversion element 10 has a base material 1, a thermoelectric conversion film 2, and a circuit 3.SELECTED DRAWING: Figure 1

Description

An 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 electrical energy are used in thermoelectric conversion elements such as thermoelectric power generation elements and Peltier elements. A 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 p-type semiconductors alone, n-type semiconductors alone, or combinations of p-type semiconductors and n-type semiconductors. The thermoelectric conversion element utilizes the Seebeck effect in which an electromotive force is generated when heat is applied so that a temperature difference is generated at both ends of the 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 materials.

Further, 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 for wristwatches operating at body temperature, ground 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. ^{In addition, 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 expressed by the following equation (1).
^{ZT = (S 2 · σ ·} T) / κ (1)
Here, S is the Seebeck coefficient (V / K), σ is the conductivity (Sm), T is the absolute temperature (K), and κ is the thermal conductivity (W / (mK)). 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 thermoelectric conversion performance (hereinafter, also referred to as thermoelectric characteristics), it is important to improve the Seebeck coefficient or conductivity while lowering the thermal conductivity.

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

However, thermoelectric conversion materials containing these inorganic materials often contain rare elements and are expensive or may contain harmful substances. In addition, the inorganic material has poor processability, which complicates the manufacturing process. Therefore, it is difficult to generalize the thermoelectric conversion material including the inorganic material because the production energy and the production cost are high. Further, since the inorganic material is rigid, it is difficult to form a thermoelectric conversion element having fluxible property, which can be installed even in a shape other than a flat surface.

On the other hand, studies on thermoelectric conversion elements using organic materials instead of conventional inorganic materials are underway. Since organic materials have excellent moldability and flexibility superior to inorganic materials, they are highly versatile in a temperature range in which they do not decompose themselves. In addition, since printing technology and the like can be easily utilized, it is more advantageous than inorganic materials in terms of manufacturing energy and manufacturing cost.

For example, Patent Document 1 discloses a thermoelectric conversion material containing a polymer dispersant having an organic dye skeleton and carbon nanotubes (CNT), and a thermoelectric conversion element using the same. Further, Patent Document 2 discloses a thermoelectric conversion material containing a conductive compound in which a polycyclic aromatic ring having a carrier transport property and a substituent containing an alkyl group are bonded, and a thermoelectric conversion element using the same. .. However, in the invention of Patent Document 1, sufficient performance as a thermoelectric conversion element has not been obtained. Further, in the invention of Patent Document 2, the conductivity ^{is as low as 10 -8} to 10 ^-7 S / cm, and a practical value cannot be obtained as a thermoelectric conversion element.

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

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

An object to be solved by the present invention is to provide a thermoelectric conversion material capable of achieving both an excellent Seebeck coefficient and conductivity, and a thermoelectric conversion element using the same.

The present inventors have reached the present invention as a result of repeated diligent studies to solve the above problems. That is, the present invention contains the compound (A) represented by the general formula (1) and at least one conductive material (B) selected from the group consisting of a carbon material, a metal material and a conductive polymer. Regarding thermoelectric conversion materials.

[In the general formula (1), R _{1 to} R ₈ are independently hydrogen atom, hydroxyl group, halogen atom, cyano group, nitro group, carboxyl group, sodium sulfonato group, substituted or unsubstituted alkyl group, and substituted. Alternatively, an unsubstituted alkoxy group, a substituted or unsubstituted 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 Represents a substituted or unsubstituted amino group. In R _{1 to} R ₈ , adjacent groups may be bonded to each other to form a ring. However, _{at least one of R 1 to} R ₈ is a group other than a hydrogen atom. ]

The present invention also relates to the thermoelectric conversion material in which the content of the compound (A) is 400% by mass or less with respect to the total amount of the conductive material (B).

The present invention also relates to the thermoelectric conversion material, wherein the conductive material (B) contains at least one selected from the group consisting of carbon nanotubes, Ketjen black, graphene nanoplates and graphene.

The present invention also relates to the thermoelectric conversion material in which the conductive material (B) contains carbon nanotubes.

The present invention also relates to a thermoelectric conversion element having a thermoelectric conversion film containing the thermoelectric conversion material and an electrode, and the thermoelectric conversion film and the electrode are electrically connected to each other.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a thermoelectric conversion material that achieves both a Seebeck coefficient and conductivity. In addition, the material can be used to provide a thermoelectric conversion element that exhibits excellent thermoelectric performance.

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

<Thermoelectric conversion material>
The thermoelectric conversion material of the present invention is characterized by containing the compound (A) and the conductive material (B), and can achieve both a high Seebeck coefficient and conductivity, and can exhibit excellent thermoelectric performance. This is because holes or electrons (carriers) efficiently move from the compound (A) to the conductive material (B), and the holes or electrons (carriers) move in the conductive material, resulting in a high Seebeck coefficient. It is presumed that conductivity can be obtained.
Hereinafter, embodiments of the present invention will be described in detail.

<Compound (A)>

<Compound (A)>
The mechanism of thermoelectric conversion is considered as follows. Holes or electrons (carriers) are generated in the thermally excited compound (A), and the holes or electrons (carriers) move to the conductive material (B), causing a potential difference in the conductive material (B). It is generated and current flows. That is, the more efficient the carrier transfer between the compound (A) and the conductive material (B), the larger the potential difference in the conductive material (B) and the higher the Seebeck coefficient. Although the specific method for efficient carrier transfer is not clearly known, the closeness of the distance due to the affinity between the compound (A) and the conductive material (B), the compound (A) and the conductive material (B) ), The length of the excited state of compound (A) (excited lifetime), etc. are considered to have an effect.

The compound (A) in which the carrier transfer between the compound (A) and the conductive material (B) becomes efficient due to the above conditions or the like is represented by the general formula (1). _{First, the substituents R 1 to} R ₈ of the general formula (1) will be described.

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

Substituted or unsubstituted alkyl groups include carbons 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. Alkyl groups of numbers 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) ) Substituted alkyl groups having 1 to 30 carbon atoms such as a benzyl group, a triphenylmethyl group and an α-benzyloxybenzyl group can be mentioned.

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. ,
Substituted alkoxy groups having 1 to 20 carbon atoms such as 3,3,3-trifluoroethoxy group and benzyloxy group can be mentioned.

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

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, a benzylthio group and a trifluoromethylthio group. Examples thereof include a substituted alkylthio group having 1 to 20 carbon atoms.

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 and a 4-tert-butylphenylthio group, and a 3-fluorophenylthio group. Examples thereof include a substituted arylthio group having 6 to 20 carbon atoms such as a pentafluorophenylthio group and a 3-trifluoromethylphenylthio group.

Examples of the substituted or unsubstituted aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 2,4-xylyl group, a p-cumenyl group, a mesityl group, and a 1-naphthyl group. An unsubstituted aryl group having 6 to 30 carbon atoms such as a 2-naphthyl group, a 1-anthryl group, a 9-phenanthryl group, a 1-acenaphthyl group, a 2-azurenyl group, a 1-pyrenyl group, and a 2-triphenylel group, p- 6 to 6 carbon atoms of cyanophenyl group, p-diphenylaminophenyl group, p-styrylphenyl group, 4-[(2-tolyl) ethenyl] phenyl group, 4-[(2,2-ditril) ethenyl] phenyl group, etc. 30 substituted aryl groups can be mentioned.

Examples of the substituted or unsubstituted heterocyclic group include 2-furyl group, 3-furyl group, 2-thienyl group, 3-thienyl group, 1-pyrrolill group, 2-pyrrolill group, 3-pyrrolill group and 2-. Pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 2-oxazolyl group, 3-isooxazolyl group, 2-thiazolyl group, 3-isothiazolyl group, 2-imidazolyl group, 3-pyrazolyl group, 2- Kinolyl 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- Unsubstituted aromatic heterocyclic groups having 3 to 20 carbon atoms such as benzothienyl group, N-indrill group, N-carbazolyl group and N-acrydinyl group, 2- (5-phenyl) furyl group, 2- (5-phenyl). ) Substituted aromatic heterocyclic groups having 3 to 20 carbon atoms such as a thienyl group and a 2- (3-cyano) pyridyl group can be mentioned.

Examples of the substituted or unsubstituted amino group include an amino group, an N-methylamino group, an N-ethylamino group, an N, N-diethylamino group, an N, N-diisopropylamino group, and an 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-1-naphthyl-N-phenylamino group, N-2-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- (1,1'-dimethylbenzyl) phenyl ] Substituted amino groups having 1 to 30 carbon atoms such as amino groups can be mentioned.

_{In R 1 to} R ₈ of the general formula (1), adjacent groups may be bonded to each other to form a ring.
Specific examples of the compound (A) represented by the specific general formula (1) are shown in Tables 1 to 9. In the table, "C ₃ H ₇ " represents a propyl group.

Only one type of compound (A) may be used, or two or more types may be used at the same time.

The lifetime of the triplet excited state of compound (A) is preferably 1 μs or more, more preferably 100 μs or more, more preferably 1 ms or more, still more preferably 100 ms or more.

The intersystem crossing rate constant is indicative of the rate of intersystem transfer from a singlet excited state to the triplet excited state, preferably 10 ⁶ s ^-1 or more, more preferably 10 ⁷ s ^-1 or more, more It is preferably 10 ⁸ s ^-1 or more, more preferably 10 ⁹ s ^-1 or more, and further preferably 10 ¹⁰ s ^-1 or more and 10 ¹¹ s ^-1 or less.

The quantum yield, which is an index of the efficiency of intertermic transfer from the singlet excited state to the triplet excited state, is preferably 0.5 or more, more preferably 0.6 or more, and further preferably 0.7 or more. It is particularly preferably 0.8 or more, and further particularly preferably 0.9 or more. The upper limit of the quantum yield is 1.

Further, the efficiency of carrier transfer in the above mechanism is preferably that the distance between the compound (A) and the conductive material (B) is short. Therefore, it is preferable that the affinity between the two is excellent. For example, for the conductive material (B) having a π plane such as CNT, the compound (A) is preferably an aromatic ring, a heterocycle, or a compound having an acidic functional group.

Further, in order to promote surface adsorption and homogenization to the conductive material (B) and further increase the molecular ratio, the molecular weight of the compound (A) is preferably small. The molecular weight is preferably 2,000 or less, more preferably 1,000 or less.

<Conductive material (B)>
The conductive material (B) contributes to the improvement of conductivity. The conductivity can be improved by increasing the content of the conductive material (B).
The conductive material (B) is not particularly limited as long as it is a conductive material (carbon material, metal material, conductive polymer, etc.), and examples of the carbon material include graphite, carbon nanotube, carbon black, and graphene. Examples of metal materials include gold, silver, copper, nickel, chromium, palladium, rhodium, ruthenium, indium, silicon, aluminum, tungsten, molybdenum, germanium, gallium and platinum. Examples thereof include metal powders, alloys of ZnSe, CdS, InP, GaN, SiC, and SiGe, and composite powders thereof. Further, a nucleolus and fine particles coated with a substance different from the nucleolus substance, specifically, silver-coated copper powder having copper as a nucleolus and its surface coated with silver can be mentioned. Further, for example, powders of metal oxides such as silver oxide, indium oxide, tin oxide, zinc oxide, ruthenium oxide, ITO (tin-doped indium oxide), AZO (aluminum-doped zinc oxide), and GZO (gallium-doped zinc oxide), and Examples thereof include powders surface-coated with these metal oxides, and examples of the conductive polymer include PEDOT / PSS (complex composed of poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid), polyaniline, and polyacetylene. , Polypyrrole, polythiophene, polyparaphenylene and the like.
The type of conductive material used may be one type, or two or more types may be used in combination.

The shape of the conductive material (B) is not particularly limited, and an amorphous shape, an aggregated shape, a scaly shape, a microcrystalline shape, a spherical shape, a flake shape, a wire shape, or the like can be appropriately used.

From the viewpoint of achieving both the Seebeck coefficient and the conductivity, at least one selected from the group consisting of carbon nanotubes, carbon black, and graphene (including graphene nanoplates) is preferable, more preferably carbon nanotubes, and particularly preferably single. It is a layered carbon nanotube.

As the carbon material, for example, as flaky graphite, CMX, UP-5, UP-10, UP-20, UP-35N, CSSP, CSPE, CSP, CP, CB-150, CB- manufactured by Nippon Graphite Industry Co., Ltd. 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, BF-3AK, FBF, BF-15AK, CBR, CPB-6S, CPB-3, 96L, 96L-3, K-3, SC-120, SC-60 manufactured by Chuetsu Graphite Industry Co., Ltd. , HLP, CP-150, SB-1, EC1500, EC1000, EC500, EC300, EC100, EC50 manufactured by Ito Graphite Industry Co., Ltd., 10099M, PB-99 manufactured by Nishimura Graphite Co., Ltd. and the like. Examples of spherical natural graphite include CGC-20, CGC-50, CGB-20, and CGB-50 manufactured by Nippon Graphite Industry Co., Ltd. Examples of earth-like graphite include blue P, AP, AOP, P # 1 manufactured by Nippon Graphite Industry Co., Ltd., and APR, K-5, AP-2000, AP-6, 300F, 150F manufactured by Chuetsu Graphite Co., Ltd. As artificial graphite, PAG-60, PAG-80, PAG-120, PAG-5, HAG-10W, HAG-150 manufactured by Nippon Graphite Industry Co., Ltd., G-4AK, G-6S, G-150 manufactured by Chuetsu Graphite Co., Ltd. 3G-150, G-30, G-80, G-50, SMF, EMF, SFF, SFF-80B, SS-100, BSP-15AK, BSP-100AK, WF-15C, SGP-100 manufactured by SEC Carbon Co., Ltd. , 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, SGX-1 can be mentioned.

Commercially available conductive carbon fibers and carbon nanotubes include vapor-phase carbon fibers such as VGCF manufactured by Showa Denko, EC1.5 and EC1.5-P manufactured by Meijo Nanocarbon, and TUBALL and Zeon Nano manufactured by OCSiAl. Examples thereof include single-walled carbon nanotubes such as ZEONANO manufactured by Technology Co., Ltd., FloTube9000 and FloTube7000 manufactured by CNano, FloTube2000, NC7000 manufactured by Nanocyl, and 100T and 200P manufactured by Knano.

Examples of commercially available carbon black include Tokai Carbon's Toka Black # 4300, # 4400, # 4500, # 5500, Degussa's Printex L, Colombian's Raven 7000, 5750, 5250, 5000 ULTRAIII, 5000 ULTRA, Conductex SC ULTRA, Conductex 975 ULTRA, PUERBLACK100, 115, 205, Mitsubishi Chemical # 2350, # 2400B, # 2600B, # 3050B, # 3030B, # 3230B, # 3350B, # 3400B, # 5400B, Cabot MONARCH1400, 1300, 900, VulcanXC-72R, BlackPearls2000, Ensaco250G, Ensaco260G, Ensaco350G, SuperP-Li, etc. Furness Black manufactured by TIMCAL), EC-300J, EC-600JD, etc. Examples thereof include acetylene black such as Denka Black, Denka Black HS-100, and FX-35 manufactured by Kogyo Co., Ltd. These are not particularly limited.

In addition, the compound (A) contributes to the improvement of the Seebeck coefficient in the thermoelectric conversion material. The Seebeck coefficient can be improved by increasing the content of compound (A), but since increasing the content of compound (A) increases the insulating property and lowers the conductivity, the Seebeck coefficient and the conductivity are From the viewpoint of compatibility, the upper limit of the content of the compound (A) is preferably 400% by mass or less, more preferably 200% by mass or less, and 120% by mass or less, based on the total amount of the carbon material (B). More preferably, 100% by mass or less is particularly preferable. The lower limit is preferably 5% by mass or more, more preferably 20% by mass or more.

In order to maintain the thermoelectric properties, the thermoelectric conversion material of the present invention preferably does not contain a compound that generates radicals, and more preferably consists only of the compound (A) and the conductive material (B). From the viewpoint of work and film formation, other components may be contained if necessary.

(solvent)
The solvent is used as a medium when the compound (A) and the conductive material (B) are mixed, and can improve the coatability by inking. The solvent that can be used is not particularly limited as long as the conductive material (B) and the compound (A) can be dissolved or well dispersed, and examples thereof include organic solvents and water, and two or more kinds may be used in combination.
Examples of the organic solvent include methanol, ethanol, propanol, butanol, ethylene glycol methyl ether, diethylene glycol methyl ether, tarpineol, dihydroterpineol, 2,4-diethyl-1,5-pentanediol, 1,3-butylene glycol, and iso. Bornylcyclohexanol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, glycerin, polyethylene glycol, polypropylene glycol, trifluoroethanol, m-cresol, thiodiglycol, etc. Alcohols, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and other ketones, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and other ethers, hexane, heptane, octane and other hydrocarbons, benzene, toluene, xylene, cumene Etc., esters such as ethyl acetate and butyl acetate, N-methylpyrrolidone and the like can be appropriately selected as necessary.
N-methylpyrrolidone is particularly preferable as the solvent for dispersing the compound (A) and the conductive material (B).

(Auxiliary agent)
The auxiliaries that can be used are not particularly limited, and examples thereof include lactams, alcohols, aminoalcohols, carboxylic acids, acid anhydrides, and ionic liquids. Specific examples are as follows.
Lactams :, pyrrolidone, caprolactam, N-methylcaprolactam, N-octylpyrrolidone and the like.
Alcohols: sucrose, glucose, fructose, lactose, sorbitol, mannitol, xylitol, etc.
Amino alcohols: diethanolamine, triethanolamine, etc.
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, glutacon anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydro Phthalic anhydride (also known as cyclohexane-1,2-dicarboxylic acid anhydride), trimellitic anhydride, hexahydrotrimeric anhydride, pyromellitic anhydride, hymic anhydride, biphenyltetracarboxylic acid anhydride, 1,2,3 , 4-Butanetetracarboxylic acid anhydride, naphthalenetetracarboxylic acid anhydride, and 9,9-fluorenilidenbis anhydride phthalic acid and the like. Copolymers obtained by copolymerizing maleic anhydride with other vinyl monomers such as styrene-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, alkyl vinyl ether-maleic anhydride copolymer and the like.

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, still more preferably in the range of 1 to 5% by mass, based on the total mass of the thermoelectric conversion material. .. By setting the content of the auxiliary agent to 0.1% by mass or more, the effect of improving the conductivity and thermoelectric characteristics can be easily obtained. Further, when the content of the auxiliary agent is 50% by mass or less, the deterioration of the physical characteristics of the film can be suppressed.

(resin)
The thermoelectric conversion material of the present invention may contain a resin as long as it does not affect the conductivity and thermoelectric properties for the purpose of adjusting the film forming property and the film strength.
The resin may be compatible with or mixed and dispersed 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. Examples thereof include resins, acrylamide resins, and copolymer resins thereof. 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.

From the viewpoint of conductivity, the content of the resin is preferably in the range of 0 to 90% by mass, more preferably in the range of 0 to 50% by mass, based on the total mass of the compound (A) and the conductive material (B). It is preferable, and the range of 0 to 20% by mass is more preferable.

(Inorganic thermoelectric conversion material)
The thermoelectric conversion material of the present invention may contain an inorganic thermoelectric conversion 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) Co ₂ O ₅ system and the like can be mentioned. 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, impurities may be added to the inorganic thermoelectric conversion material to control the polarity (p-type, n-type) and conductivity for use. When an inorganic thermoelectric conversion material is used, the amount used should be adjusted within a range that does not affect the film forming property or the film strength.

The method for producing the thermoelectric conversion dispersion is not particularly limited as long as the thermoelectric conversion dispersion satisfying the conditions of the present invention can be obtained, and can be appropriately selected. For example, it can be obtained by mixing a thermoelectric conversion material, a dispersion medium, and other components as necessary, and then dispersing them using a disperser or ultrasonic waves.

The disperser is not particularly limited, and for example, a kneader, an attritor, a ball mill, a sand mill using glass beads, zirconia beads, etc., a scandex, an Eiger mill, a paint conditioner, a media disperser such as a paint shaker, a colloid mill, etc. are used. can do.

<Thermoelectric conversion element>
The thermoelectric conversion element of the present invention has a thermoelectric conversion film formed by 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, a high-quality thermoelectric conversion element can be easily manufactured.

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 a thermoelectric conversion film. Specifically, spin coating method, spray 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, flexography. A method using various means such as printing can be mentioned. It can be appropriately selected from the above methods according to the thickness to be applied, the viscosity of the material, and the like.

The film thickness of the thermoelectric conversion film is not particularly limited, but as will be described later, the film has a certain thickness or more so that a temperature difference can be generated in the thickness direction or the surface direction of the thermoelectric conversion film and can be transmitted. It is preferable that the film is formed as follows. From the viewpoint of thermoelectric characteristics, the film thickness of the thermoelectric conversion film is preferably in the range of 0.1 to 200 μm, preferably in the range of 1 to 100 μm, and more preferably in the range of 1 to 50 μm.

The base material is not particularly limited, but is a plastic film made of a material such as non-woven fabric, paper, polyethylene, polyethylene terephthalate (PET), polyethylene naphthalate, polyether sulfone, polypropylene, polyimide, polycarbonate, and cellulose triacetate. Alternatively, glass or the like can be used.

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

The thermoelectric conversion element according to the embodiment of the present invention can be configured by applying a technique well known in the art except that the thermoelectric conversion material is used. A more specific configuration of the thermoelectric conversion element and a method for manufacturing the same will be described.

In the thermoelectric conversion element, the thermoelectric conversion film and the electrode are electrically connected. Here, "electrically connected" means that they are joined to each other or can be energized via other constituent members such as wires.

The electrode material can be selected from metals, alloys, and semiconductors. In one embodiment, metals and alloys are preferable because they preferably have high conductivity and low contact resistance of 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. The electrodes more preferably contain silver.

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

As a typical example of the structure of the thermoelectric conversion element, from the positional relationship between the thermoelectric conversion film and the pair of electrodes, (1) a structure in which electrodes are formed at both ends of the thermoelectric conversion film according to the present invention, and (2) the present invention. It is roughly classified into a structure in which a thermoelectric conversion film is sandwiched between two electrodes.
For example, the thermoelectric conversion element having the 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, respectively. be able to. In the thermoelectric conversion element in which electrodes are formed at both ends of the thermoelectric conversion film in this way, 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 (2), for example, a silver paste is applied on a base material to form a first electrode, a thermoelectric conversion film of the present invention is formed on the first electrode, and the thermoelectric conversion film of the present invention is further formed on the first electrode. It can be obtained by applying a silver paste to form a second electrode. In the thermoelectric conversion element in which the thermoelectric conversion film of the present invention is sandwiched between the two electrodes as described above, it is difficult to increase 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 a 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 by connecting them in series, and can generate a large current by connecting them 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 satisfactorily installed even with respect to 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) 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. , SiGe, Mg ₂ Si, FeSi ₂ , Ba ₈ Si ₄₆ , MnSi _1.73 , ZnSb, Zn ₄ Sb ₃ , GeFe ₃ CoSb ₁₂ , and LaFe ₃ CoSb _{12 and the} like. Can be done. At this time, impurities may be added to the inorganic thermoelectric material to control the polarity (p-type, n-type) and conductivity for use. In addition, as the organic thermoelectric material, at least one selected from the group consisting of polythiophene, polyaniline, polyacetylene, fullerene, and derivatives thereof can be used. When combining other thermoelectric change elements made of these materials, it is preferable to manufacture other thermoelectric conversion elements within a range that does not impair the flexibility of the elements.

Hereinafter, the present invention will be described in more detail with reference to experimental examples. In the example, "part" means "part by mass", and "%" means "% by mass". NMP also represents N-methylpyrrolidone.

<Measurement method of mass average molecular weight (Mw)>
For the measurement of Mw, GPC (gel permeation chromatography) "HPC-8020" manufactured by Tosoh Corporation was used. In the measurement in the present invention, two "LF-604" (manufactured by Showa Denko KK: GPC column for rapid analysis: 6 mm ID x 150 mm size) are connected in series and used, and a developing solvent (eluent) THF (tetrahydrofuran) is used. ), The flow rate was 0.6 ml / min, and the column temperature was 40 ° C. The mass average molecular weight (Mw) was determined in terms of using polystyrene as a standard substance.

<Synthesis of polymer with organic dye introduced in side chain>
(Synthesis Example 1: Dye-introduced Polymer 1)
With reference to paragraphs [0074] and [0075] of International Publication No. 2015/050113, an acrylic polymer having a mass average molecular weight (Mw) of about 21,000 and having a perylene skeleton introduced into a side chain represented by the following structure. A dye-introduced polymer 1 was obtained.

<Synthesis of resin components>
(Synthesis Example 2: Resin 1)
Polyester polyol obtained from terephthalic acid, adipic acid, and 3-methyl-1,5-pentanediol in a reaction vessel equipped with a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube, manufactured by Kuraray Co., Ltd. "Clare 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. , 360 parts of toluene was added thereto to obtain a urethane prepolymer solution having an isocyanate group. Next, a urethane prepolymer solution having an isocyanate group obtained by mixing 19.9 parts of isophoronediamine, 0.63 parts of di-n-butylamine, 294.5 parts of 2-propanol, and 335.5 parts of toluene. 969.5 parts was added, and after reacting at 50 ° C. for 3 hours and then at 70 ° C. for 2 hours, vacuum drying was performed at 100 ° C. to obtain resin 1 which is a urethane urea resin having a mass average molecular weight (Mw) = 61,000. Obtained.

(Synthesis Example 3: Resin 2)
Prepol 1009 (manufactured by Crowder Japan Co., Ltd., acid value 194 mgKOH /) as a polybasic acid compound having 36 carbon atoms in a 4-port flask equipped with a stirrer, a reflux cooling tube equipped with a water content metering receiver, a nitrogen introduction tube, and a thermometer. g) is 70.78 parts, 5-hydroxyisophthalic acid (manufactured by Sugai Chemical Co., Ltd., hereinafter also referred to as “5-HIPA”) is 5.24 parts as a polybasic acid compound having a phenolic hydroxyl group, and a polyamine compound having 36 carbon atoms. As a result, 82.84 parts of preamine 1074 (manufactured by Claude Japan Co., Ltd., acid value 210 KOHmg / g) and 4.74 parts of toluene were charged, the temperature was raised to 220 ° C. with stirring, and dehydration was performed while distilling off water. The reaction continued. Sampling was performed every hour to confirm that the mass average molecular weight was 50,000, and after cooling, a resin 2 which was a phenolic hydroxyl group-containing polyamide resin having Mw50432 was obtained.

<Synthesis of compound (A)>

(Synthesis Example 4: A13)
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen introduction tube, 5 parts of phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.) and 100 parts of 67% nitric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) are charged to create a nitrogen atmosphere. The reaction was carried out at 100 ° C. for 3 hours. After cooling, the mixture was poured into 3000 parts of water, and the precipitated solid was collected by filtration and purified by column chromatography to obtain 0.5 parts of A13.

(Synthesis Example 5: A35)
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen introduction tube, a part of 4,7-dihydroxy-1,10-phenanthroline (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and bromobenzene (Tokyo Kasei Kogyo Co., Ltd.) 2 parts of potassium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) and 200 parts of ethanol were charged and reacted at 50 ° C. for 12 hours in a nitrogen atmosphere. After cooling, the mixture was dried by an evaporator and purified by column chromatography to obtain 0.59 parts of A35.

(Synthesis Example 6: A34)
A34 was prepared in the same manner as in Synthesis Example 5 except that 4,7-dihydroxy-1,10-phenanthroline and bromobenzene were changed to 9-dihydroxy-1,10-phenanthroline and 2-bromo-2-methylpropane. Obtained.

(Synthesis Example 7: A38)
A38 was obtained in the same manner as in Synthesis Example 5 except that bromobenzene was changed to 2-bromoethyl ethyl ether.

(Synthesis Example 8: A41)
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen introduction tube, 5 parts of 4,7-dibromo-1,10-phenanthroline (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and mercaptoethane (Tokyo Kasei Kogyo Co., Ltd.) 4 parts, sodium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) 1 part, and DMF 100 parts were charged and reacted at 80 ° C. for 3 hours in a nitrogen atmosphere. After cooling, it was washed with water and filtered to obtain a solid. Purification by column chromatography gave 3.7 parts of A41.

(Synthesis Example 9: A42)
A42 was obtained in the same manner as in Synthesis Example 8 except that 4,7-dibromo-1,10-phenanthroline and mercaptoethane were changed to 3,6-dibromo-1,10-phenanthroline and 4-mercaptopyridine. ..

(Synthesis Example 10: A114)
A114 was obtained in the same manner as in Synthesis Example 8 except that 4,7-dibromo-1,10-phenanthroline and mercaptoethane were changed to 3-bromo-1,10-phenanthroline and mercaptobenzene.

(Synthesis Example 11: A115)
A115 was obtained in the same manner as in Synthesis Example 8 except that 4,7-dibromo-1,10-phenanthroline and mercaptoethane were changed to 3-bromo-1,10-phenanthroline and 4-fluorobenzenethiol.

(Synthesis Example 12: A53)
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen introduction tube, 2 parts of 3,8-dibromo-1,10-phenanthroline (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and phenylboronic acid (Tokyo Kasei Kogyo Co., Ltd.) 2 parts, tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry) 0.25 parts, potassium carbonate (manufactured by Tokyo Chemical Industry) 3 parts, water 30 parts, ethanol 5 parts, toluene 100 The parts were charged and reacted at 100 ° C. for 3 hours in a nitrogen atmosphere. After cooling, the mixture was dried by an evaporator and purified by column chromatography to obtain 0.29 parts of A53.

(Synthesis Example 13: A54)
A54 was obtained in the same manner as in Synthesis Example 12, except that 3,8-dibromo-1,10-phenanthroline and phenylboronic acid were changed to 3-bromo-1,10-phenanthroline and 1-naphthaleneboronic acid. ..

(Synthesis Example 14: A56)
Similar to Synthesis Example 12 except that 3,8-dibromo-1,10-phenanthroline and phenylboronic acid were changed to 3,8-dibromo-1,10-phenanthroline and 4- (trifluoromethyl) phenylboronic acid. By the method, A56 was obtained.

(Synthesis Example 15: A60)
A60 was prepared in the same manner as in Synthesis Example 12 except that 3,8-dibromo-1,10-phenanthroline and phenylboronic acid were changed to 4,7-dibromo-1,10-phenanthroline and 3-pyridylboronic acid. Obtained.

(Synthesis Example 16: A62)
A62 was obtained in the same manner as in Synthesis Example 12, except that 3,8-dibromo-1,10-phenanthroline and phenylboronic acid were changed to 3-bromo-1,10-phenanthroline and 3-pyridylboronic acid. ..

(Synthesis Example 17: A65)
A65 was obtained in the same manner as in Synthesis Example 12, except that 3,8-dibromo-1,10-phenanthroline and phenylboronic acid were changed to 4,7-dibromo-1,10-phenanthroline and 2-furylboronic acid. It was.

(Synthesis Example 18: A68)
A68 was prepared in the same manner as in Synthesis Example 12, except that 3,8-dibromo-1,10-phenanthroline and phenylboronic acid were changed to 3,8-dibromo-1,10-phenanthroline and 2-thiophenanthroline. Obtained.

(Synthesis Example 19: A71)
A71 was prepared in the same manner as in Synthesis Example 12 except that 3,8-dibromo-1,10-phenanthroline and phenylboronic acid were changed to 3,8-dibromo-1,10-phenanthroline and 2-thiophenanthroline. Obtained.

(Synthesis Example 20: A74)
The same method as in Synthesis Example 12 except that 3,8-dibromo-1,10-phenanthroline and phenylboronic acid were changed to 4,7-dibromo-1,10-phenanthroline and 9-ethylcarbazole-3-boronic acid. So I got A74.

(Synthesis Example 21: A110)
3,8-Dibromo-1,10-phenanthroline to 3,5,6,8-tetrabromo-1,10-phenanthroline, phenylboronic acid to 4-biphenylboronic acid, 9-anthracemboronic acid, 2-furylboronic acid and A110 was obtained in the same manner as in Synthesis Example 12, except that the mixture was changed to a mixture of benzo [b] thiophen-2-boronic acid.

(Synthesis Example 22: A75)
0.5 part of magnesium (manufactured by Tokyo Chemical Industry Co., Ltd.) and 20 parts of THF were charged in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and the mixture was stirred at 25 ° C. under a nitrogen atmosphere. 0.1 part of iodine (manufactured by Tokyo Chemical Industry Co., Ltd.), 2.5 parts of 3-bromo-1,10-phenanthroline and 100 ml of THF were put into the dropping device, dropped, and stirred for 6 hours. Then, 2.5 parts of 3-bromo-1,10-phenanthroline and 0.3 part of [1,2-bis (diphenylphosphino) ethane] dichloronickel (II) (manufactured by Sigma-Aldrich) were added, and the temperature was 60 ° C. It was reacted for 12 hours. After cooling, the mixture was dried by an evaporator and purified by column chromatography to obtain 0.98 parts of A75.

(Synthesis Example 23: A82)
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen introduction tube, 3 parts of 3-bromo-1,10-phenanthroline (manufactured by Tokyo Chemical Industry) and dipropylamine (manufactured by Tokyo Chemical Industry) ) 1.57 parts, palladium (II) acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.13 parts, tri-tert-butylphosphine (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.18 parts, tert-butoxysodium (manufactured by Tokyo Chemical Industry Co., Ltd.) (Manufactured) 1.73 parts and 50 parts of toluene were charged and reacted at 70 ° C. for 5 hours in a nitrogen atmosphere. After cooling, it was washed with water and methanol, and filtered to obtain a solid. Purification by column chromatography gave 1.39 parts of A82.

(Synthesis Example 24: A89)
A89 was obtained in the same manner as in Synthesis Example 12, except that 3-bromo-1,10-phenanthroline and dipropylamine were changed to 7-dibromo-1,10-phenanthroline and p, p'-ditrimethylamine. ..

(Synthesis Example 25: A109)
3-Bromo-1,10-phenanthroline and dipropylamine in a mixture of 2,3,4,5,6,7,8,9-octabromo-1,10-phenanthroline and piperidine, pyrrole and dimethylamine A109 was obtained in the same manner as in Synthesis Example 12, except that it was changed.

<Manufacturing of thermoelectric conversion materials>
[Example 1]
(Dispersion liquid 1)
0.4 parts of 1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.4 parts of GNP (graphene nanoplatelet "xGNP-M-5" manufactured by XGScienses), and 79.2 parts of NMP were weighed and mixed. .. Further, 140 parts of zirconia beads (φ1.25 mm) were added, shaken with Scandex for 4 hours, and then filtered to remove the zirconia beads to obtain a dispersion liquid 1 of a thermoelectric conversion material.

[Examples 2-72, Comparative Example 1]
(Dispersions 2-72, 101)
Dispersions 2 to 72 and 101 of the thermoelectric conversion material were obtained in the same manner as in the method for producing the dispersion 1 except that the types and amounts of the materials were changed to the contents shown in Table 10, respectively.

The materials listed in Table 10 used in addition to those described in the above synthesis example are shown below.
Compound (A)
A1: 2,9-Dimethyl-5-picrylamino-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A3: 4,7-Dibromo-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A4: 3-Bromo-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A5: 2-Bromo-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A6: 2-Chloro-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A7: 5-Chloro-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A8: 4,7-dichloro-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A9: 2,9-dichloro-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A10: 3,5,6,8-Tetrabromo-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A11: 4,7-Dihydroxy-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A17: 1,10-Phenanthroline-2-carboxylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
A20: 5-Methyl-1,10-phenanthroline hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.)
A21: 4,7-Dimethyl-1,10-Phenanthroline hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.)
A22: 2,9-dimethyl-1,10-phenanthroline hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.)
A23: 5,6-dimethyl-1,10-phenanthroline hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.)
A24: 2-Methyl-1,10-phenanthroline hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.)
A26: 3,4,7,8-Tetramethyl-1,10-phenanthroline hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.)
A27: 2,9-dibutyl-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A46: 2,9-diphenyl-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A48: Basophenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A49: Basok Proin (manufactured by Tokyo Chemical Industry Co., Ltd.)
A51: Disodium basophenanthroline disulfonate hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.)
A78: 5-Amino-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A103: Disodium Basokproindisulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.)
A104: 2,9-dibutyl-5-picrylamino-1,10-phenanthroline (manufactured by Tokyo Chemical Industry Co., Ltd.)
A105: (1S) -3- (1,10-phenanthroline-2-yl) -2'-phenyl- [1,1'-binaphthalene] -2-ol (manufactured by Tokyo Chemical Industry Co., Ltd.)
A106: Dipyrido [3,2-a: 2', 3'-c] Phenazine (manufactured by Tokyo Chemical Industry Co., Ltd.)
A112: 2-Cyano-1,10-phenanthroline (manufactured by ATK CHEMICAL)
A113: 3-Benzyl-1,10-phenanthroline

Conductive material (B)
GNP (Graphene nanoplatelet "xGNP-M-5" manufactured by XGSciences)
CB (Lion's Ketjen Black "EC-300J")
Graphite (Expanded Graphite SMF manufactured by Chuetsu Graphite Co., Ltd.)
MWCNT (multi-walled carbon nanotube "Knanos100P" manufactured by KUMHO PETROCHEMICAL)
SWCNT (single-walled carbon nanotube "TUBALL" manufactured by OCSiAl)
"Clevios PH1000" manufactured by PEDOT / PSS Heraeus
Ag powder DOWA "FA-D-5"
Cu powder DOWA "2.5 μm-Type A"

Resin Resin 3 Polymethylmethacrylate resin (NeoCryl B-728 manufactured by Kusumoto Kasei Co., Ltd.)

<Evaluation of thermoelectric conversion material>
The obtained dispersion liquids 1 to 72 and 101 were applied onto a PET film having a thickness of 75 μm, which is a sheet-like base material, using an applicator, and then heat-dried at 120 ° C. for 30 minutes on the PET base material. A laminate having a thermoelectric conversion film having a film thickness of 5 μm was obtained. The coating suitability when the dispersion liquid was applied to the substrate was evaluated according to the method shown below. In addition, the conductivity (conductivity) and Seebeck coefficient of the obtained laminate having the thermoelectric conversion film (hereinafter, also referred to as a coating film) were evaluated according to the following method. The results are shown in Table 10.

(Conductivity (resistivity))
The obtained laminate was cut into a size of 2.5 cm × 5 cm, and the conductivity was measured by a 4-probe method using a Loresta GX MCP-T700 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) according to JIS-K7194. .. Table 10 shows the relative values when the conductivity of Comparative Example 1 is 1.

(Seebeck coefficient)
The obtained laminate was cut into a size of 3 mm × 10 mm, and the Seebeck coefficient (μV / K) at 80 ° C. was measured using ZEM-3LW manufactured by Advance Riko Co., Ltd. Table 10 shows the relative values of the Seebeck coefficient in each example with respect to the absolute value, assuming that the absolute value of the Seebeck coefficient of Comparative Example 1 is 1.

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

As shown in Table 10, the thermoelectric conversion material of the present invention showed high conductivity and Seebeck coefficient.
Further, all the dispersions containing the thermoelectric conversion material of the present invention showed good coating suitability (coating film state). On the other hand, in Comparative Example 1 using the dye-introduced polymer 1, low conductivity and Seebeck coefficient were shown.

<Manufacturing of thermoelectric conversion element>
[Example 73]
(Thermoelectric conversion element 1)
The dispersion liquid 1 prepared in Example 1 was applied onto a PET film having a thickness of 50 μm, and five conductive layers having a thickness of 20 μm and a shape of 5 mm × 30 mm were prepared at intervals of 10 mm (reference numerals in FIG. 1). See 2). Next, four silver circuits (electrodes) having a thickness of 10 μm and a shape of 5 mm × 33 mm were produced using silver paste so that the conductive layers were connected in series (see reference numeral 3 in FIG. 1). ), The thermoelectric conversion element 1 was obtained. As the silver paste, REXALPHA RA FS 074 manufactured by Toyochem Co., Ltd. was used.

[Examples 74 to 144, Comparative Example 2]
(Thermoelectric conversion elements 2-72, 101)
The thermoelectric conversion elements 2 to 72 and 101 were obtained in the same manner as in the thermoelectric conversion element 1 except that the dispersion liquid 1 used in the thermoelectric conversion element 1 was changed to the dispersion liquid shown in Table 11, respectively.
<Evaluation of thermoelectric conversion element>
The electromotive force of the obtained thermoelectric conversion element was evaluated as follows. The results are shown in Table 11.

(Measurement of electromotive force)
For each thermoelectric conversion element, bend it so that the thermoelectric conversion film and the silver circuit are on the inside (along the AA'line shown in FIG. 2), and in that state, install it 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 10 minutes later was measured using a voltmeter. The measurement was carried out at room temperature (20 ° C.). The thermoelectric characteristics were evaluated from the measured values according to the following criteria.
⊚: Electromotive force is 1 mV or more (good)
〇: Electromotive force is 500 μV or more and less than 1 mV (practical)
X: Electromotive force is less than 500 μV (defective)

As shown in Table 11, the thermoelectric conversion element of the present invention had excellent thermoelectric characteristics as compared with the thermoelectric conversion element of Comparative Example 2. From the above, according to the embodiment of the present invention, it is possible to realize a thermoelectric conversion material having excellent Seebeck coefficient and conductivity, exhibiting high PF, and excellent thermoelectric characteristics, and a highly efficient thermoelectric conversion element can be realized. It turns out that it can be realized.

Since the thermoelectric conversion material according to the embodiment of the present invention has both conductivity and Seebeck coefficient and is excellent in thermoelectric characteristics, it is possible to provide a high-performance thermoelectric conversion element by using the above material.

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

Claims (5)

Thermoelectric conversion comprising the compound (A) represented by the general formula (1) and at least one conductive material (B) selected from the group consisting of a carbon material, a metal material and a conductive polymer. material.

[In the general formula (1), R _{1 to} R ₈ are independently hydrogen atom, hydroxyl group, halogen atom, cyano group, nitro group, carboxyl group, sodium sulfonato group, substituted or unsubstituted alkyl group, and substituted. Alternatively, an unsubstituted alkoxy group, a substituted or unsubstituted 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 Represents a substituted or unsubstituted amino group. In R _{1 to} R ₈ , adjacent groups may be bonded to each other to form a ring. However, _{at least one of R 1 to} R ₈ is a group other than a hydrogen atom. ] The thermoelectric conversion material according to claim 1, wherein the content of the compound (A) is 400% by mass or less based on the total amount of the conductive material (B). The thermoelectric conversion material according to claim 1 or 2, wherein the conductive material (B) contains at least one selected from the group consisting of carbon nanotubes, Ketjen black, graphene nanoplates and graphene. The thermoelectric conversion material according to claim 3, wherein the conductive material (B) contains carbon nanotubes. A thermoelectric conversion element having a thermoelectric conversion film containing the thermoelectric conversion material according to any one of claims 1 to 4 and an electrode, and the thermoelectric conversion film and the electrode are electrically connected to each other. ..

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