JP2014146681A - Thermoelectric conversion material, thermoelectric conversion device and article for thermoelectric power generation and power source for sensor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a thermoelectric conversion material and a thermoelectric conversion device which have excellent thermoelectric conversion performance and good electrode adhesion; and an article for thermoelectric power generation and a power source for a sensor using the same.SOLUTION: A thermoelectric conversion device 1 has, on a base material 12, a first electrode 13, a thermoelectric conversion layer 14, and a second electrode 15. In the thermoelectric conversion device 1, the thermoelectric conversion layer 14 includes a nano conductive material, and copolymer expressed by the general formula (1). Also provided are an article for thermoelectric power generation and a power source for a sensor using the thermoelectric conversion device 1, and a thermoelectric conversion material comprising the polymer and the nano conductive material. (In the general formula (1) below, A and B represent an aniline derivative-originating copolymer unit or pyrrole derivative-originating copolymer unit independently of each other, where the copolymer units represented by A and B respectively are different from each other.)

Description

  The present invention relates to a thermoelectric conversion material, an article for thermoelectric power generation using the thermoelectric conversion material, and a sensor power source.

  Thermoelectric conversion materials that can mutually convert thermal energy and electrical energy are used in thermoelectric conversion elements such as thermoelectric power generation elements and Peltier elements. Thermoelectric power generation using thermoelectric conversion materials and thermoelectric conversion elements can directly convert thermal energy into electric power, does not require moving parts, and is used for wristwatches that operate at body temperature, power supplies for remote areas, power supplies for space, etc. ing.

One of the indexes for evaluating the thermoelectric conversion performance of the thermoelectric conversion element is a dimensionless figure of merit ZT (hereinafter, simply referred to as a figure of merit ZT). This figure of merit ZT is expressed by the following formula (A). For improvement of thermoelectric conversion performance, improvement of thermoelectromotive force (hereinafter sometimes referred to as thermoelectromotive force) S and conductivity σ per absolute temperature 1K, Reduction of thermal conductivity κ is important.
Figure of merit ZT = S ² · σ · T / κ (A)
In the formula (A), S (V / K): thermoelectromotive force per 1 K absolute temperature (Seebeck coefficient)
σ (S / m): conductivity
κ (W / mK): thermal conductivity
T (K): Absolute temperature

Thermoelectric conversion materials are required to have good thermoelectric conversion performance, so the processing process for thermoelectric conversion elements is complicated, and expensive and may contain harmful substances. Material.
On the other hand, organic thermoelectric conversion elements can be manufactured at a relatively low cost, and processing such as film formation is easy. Therefore, research has been actively conducted in recent years, such as thermoelectric conversion materials and thermoelectric conversions using conductive polymers. Devices have been reported. For example, Patent Document 1 describes emeraldine-type conductive polyanilines, and Patent Document 2 describes an emeraldine-type conductive polyaniline film-like product.

  By the way, in a thermoelectric conversion material and a thermoelectric conversion element, one using polyaniline together with carbon nanotubes as one of conductive polymers is known. For example, Non-Patent Document 1 discloses a nanocomposite of multi-walled carbon nanotubes coated with porous polyaniline (a nanometer-sized composite), and Non-Patent Document 2 discloses a carbon nanotube coated with a polyaniline coating layer. Nanocomposites are described.

JP 2001-326393 A JP 2002-100815 A

Nanotechnology, 23 (2012), 385701 Adv. Mater 2010, 22, 535-539

The emeraldine type conductive polyaniline described in Patent Document 1 and the emeraldine type conductive polyaniline film-formed product described in Patent Document 2 both contain polyaniline but have a physical internal factor (TPF) of 5 ( The dimensionless thermoelectric figure of merit at about 10 ⁻⁶ Wm ⁻¹ K ⁻² ) or 300 K is only about 0.12. Further, as in Patent Documents 3 and 4, when polyaniline or polypyrrole and a carbon nanotube are used in combination, thermoelectric conversion performance can be expected to some extent, but there is room for further improvement.
In addition, since the thermoelectric conversion layer of the thermoelectric conversion element is disposed in contact with the electrode surface, the thermoelectric conversion layer is required to be highly adhered to the electrode from the viewpoint of thermoelectric conversion characteristics and quality stability. Has been.

  Therefore, the present invention provides a thermoelectric conversion material that is excellent in thermoelectric conversion performance and exhibits high adhesion to the electrode, a thermoelectric conversion layer having excellent adhesion to the electrode (also referred to as electrode adhesion) and thermoelectric conversion performance. It is an object of the present invention to provide a conversion element, a thermoelectric power generation article using the thermoelectric conversion element, and a sensor power source.

  In order to achieve the above-mentioned problems, the present inventors have used various conductive polymers as conductive polymers that coexist with a nanoconductive material (a nanometer-sized conductive material) in a thermoelectric conversion layer of a thermoelectric conversion element. As a result of investigation, polyaniline copolymer and polypyrrole copolymer (including poly (aniline-pyrrole) copolymer) having at least two kinds of copolymer units derived from aniline or copolymer derived from pyrrole, which are different from each other. However, it has been found that, by increasing dispersibility in the presence of the nano-conductive material, the thermoelectric conversion layer has excellent thermoelectric conversion performance and electrode adhesion. The present invention has been completed based on these findings.

That is, said subject was achieved by the following means.
<1> A thermoelectric conversion element having a first electrode, a thermoelectric conversion layer, and a second electrode on a substrate, wherein the thermoelectric conversion layer is a nano-conductive material and the following general formula (1) A thermoelectric conversion element containing the represented copolymer.

(In general formula (1), A and B each independently represent a copolymer unit derived from an aniline derivative or a copolymer unit derived from a pyrrole derivative, provided that A and B are different from each other. M and n represent the degree of polymerization.)

<2> The thermoelectric conversion element according to <1>, wherein the ratio (m / n) of the degree of polymerization of the copolymer units A and B is 1/99 to 99/1.

<3> Copolymer units A and B are each independently a copolymer unit selected from the group consisting of copolymer units represented by the following general formulas (2) to (5) <1> Or the thermoelectric conversion element as described in <2>.

(In the general formulas (2) to (5), R ^{11 to} R ¹⁴ each independently represents a monovalent substituent. A 1 and c 1 each independently represent an integer of 0 to 4, and b 1 represents an integer of 0 to 2. Represents an integer, and d1 represents an integer of 0 to 6. X ^{11 to} X ¹⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and * represents a connecting site of a copolymer unit. Represents.)

<4> Copolymer unit A is a copolymer unit represented by general formula (2) in which a1 is 0, a copolymer unit represented by general formula (3) in which b1 is 0, and c1 is A copolymer unit selected from the group consisting of a copolymer unit represented by general formula (4) being 0 and a copolymer unit represented by general formula (5) wherein d1 is 0, The polymer unit B is a copolymer unit represented by the general formula (2) in which a1 is an integer of 1 to 4, a copolymer unit represented by the general formula (3) in which b1 is 1 or 2, Selected from the group consisting of a copolymer unit represented by the general formula (4) wherein c1 is an integer of 1-4 and a copolymer unit represented by the general formula (5) wherein d1 is an integer of 1-6 The thermoelectric conversion element according to <3>, which is a copolymer unit.
<5> The thermoelectric conversion element according to <3> or <4>, in which X ^{11 to} X ¹⁴ are hydrogen atoms.
<6> The thermoelectric conversion element according to any one of <3> to <5>, wherein the copolymer units A and B are both copolymer units represented by the general formula (2).
<7> The thermoelectric conversion element according to any one of <3> to <5>, wherein the copolymer units A and B are both copolymer units represented by the general formula (3).
<8> The thermoelectric conversion element according to any one of <1> to <7>, wherein the copolymer unit A has a molecular weight smaller than that of the copolymer unit B.
<9> An article for thermoelectric power generation using the thermoelectric conversion element according to any one of <1> to <8>.
<10> A power supply for sensors using the thermoelectric conversion element according to any one of <1> to <8>.
<11> A thermoelectric conversion material for forming a thermoelectric conversion layer of a thermoelectric conversion element, comprising a nano-conductive material and a copolymer represented by the following general formula (1).

(In general formula (1), A and B each independently represent a copolymer unit derived from an aniline derivative or a copolymer unit derived from a pyrrole derivative, provided that A and B are different from each other. Represents.)

<12> The thermoelectric conversion material according to <11>, which contains an organic solvent.
<13> The thermoelectric conversion material according to <12>, wherein the organic solvent is at least one selected from halogenated solvents.

In the present invention, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In the present invention, when the xxx group is referred to as a substituent, the xxx group may have an arbitrary substituent. In addition, when there are a plurality of groups indicated by the same reference numerals, they may be the same or different.

The thermoelectric conversion material of the present invention has a high Seebeck coefficient, that is, a figure of merit ZT, is excellent in thermoelectric conversion performance, and exhibits high adhesion to an electrode.
In addition, the heat conversion element of the present invention, the thermoelectric power generation article of the present invention using the heat conversion element of the present invention, the sensor power supply, and the like exhibit excellent thermoelectric conversion performance and electrode adhesion.

It is a figure which shows typically an example of the thermoelectric conversion element of this invention. The arrows in FIG. 1 indicate the direction of the temperature difference applied when the element is used. It is a figure which shows typically another example of the thermoelectric conversion element of this invention. The arrows in FIG. 2 indicate the direction of the temperature difference applied when the element is used.

  The thermoelectric conversion element of the present invention has a first electrode, a thermoelectric conversion layer, and a second electrode on a substrate, and the thermoelectric conversion layer is represented by the nanoconductive material and the general formula (1). Containing a copolymer. This thermoelectric conversion layer is formed on a substrate by the thermoelectric conversion material of the present invention containing a nano-conductive material and the copolymer.

The thermoelectric conversion performance of the thermoelectric conversion material and the thermoelectric conversion element of the present invention can be measured by a figure of merit ZT represented by the following formula (A).
Figure of merit ZT = S ² · σ · T / κ (A)
In the formula (A), S (V / K): thermoelectromotive force per 1 K absolute temperature (Seebeck coefficient)
σ (S / m): conductivity
κ (W / mK): thermal conductivity
T (K): Absolute temperature

As is clear from the above formula (A), it is important to increase the thermoelectromotive force S and the conductivity σ and decrease the thermal conductivity κ for improving the thermoelectric conversion performance. In this way, factors other than the conductivity σ greatly affect the thermoelectric conversion performance, so even if it is a material that is generally considered to have a high conductivity σ, whether it functions effectively as a thermoelectric conversion material is actually However, it is unknown. In addition, even if the thermoelectric conversion material is excellent in thermoelectric conversion material, if the thermoelectric conversion material is difficult to adhere to the electrode, the thermoelectric conversion performance when the thermoelectric conversion layer is formed decreases, and the thermoelectric conversion layer peels off from the electrode. It is easy to use as a thermoelectric conversion material. Therefore, as described above, high electrode adhesion is also required for thermoelectric conversion materials and thermoelectric conversion elements.
The present invention responds to such requirements regarding thermoelectric conversion characteristics and electrode adhesion. That is, the thermoelectric conversion material of the present invention and the thermoelectric conversion element of the present invention have high electrode adhesion enough to be used as a thermoelectric conversion material and are used as a thermoelectric conversion material as shown in Examples described later. High thermoelectric conversion performance, specifically, a thermoelectromotive force S per unit temperature difference and a figure of merit ZT. Since the thermoelectric conversion material of the present invention has high electrode adhesion and is difficult to peel from the electrode, the yield is improved when the thermoelectric conversion element of the present invention is manufactured, and the production cost is also reduced.

  Further, as will be described later, the thermoelectric conversion element of the present invention functions to transmit a temperature difference in the thickness direction or the surface direction in a state where a temperature difference is generated in the thickness direction or the surface direction of the thermoelectric conversion layer. Therefore, it is necessary to form the thermoelectric conversion layer by forming the thermoelectric conversion material of the present invention into a shape having a certain thickness. For this reason, when the thermoelectric conversion layer is formed by coating, the thermoelectric conversion material is required to have good coatability and film formability. The present invention can also meet such requirements for coating properties and film forming properties. That is, the thermoelectric conversion material of the present invention has good dispersibility of the nano-conductive material and the copolymer, is excellent in coating property and film forming property, and is suitable for molding and processing into a thermoelectric conversion layer. In addition, a thermoelectric conversion layer with excellent thermoelectric properties and electrode adhesion can be formed without impairing coating properties and film formation even when a halogen-based solvent is used to disperse the copolymer in the presence of a nano-conductive material. it can.

  Hereinafter, the thermoelectric conversion material of the present invention and then the thermoelectric conversion element of the present invention will be described.

[Thermoelectric conversion material]
The thermoelectric conversion material of the present invention is a thermoelectric conversion composition for forming a thermoelectric conversion layer of a thermoelectric conversion element, and contains a nano-conductive material and a copolymer represented by the above general formula (1). ing.

  First, each component used for the thermoelectric conversion material of this invention is demonstrated.

<Nano conductive material>
The nano-conductive material used in the present invention may be a nanometer-sized and conductive material, and may be a nanometer-sized conductive carbon material (hereinafter referred to as nano-carbon material). And a metal material having a nanometer size (hereinafter sometimes referred to as a nano metal material).
The nano conductive material used in the present invention is preferably a carbon nanotube, carbon nanofiber, graphite, graphene and carbon nanoparticle nanocarbon material, and metal nanowire, which will be described later, among nanocarbon materials and nanometal materials. Carbon nanotubes are particularly preferable from the viewpoints of improving conductivity and improving dispersibility in a solvent.

The content of the nano conductive material in the thermoelectric conversion material is preferably 2 to 60% by mass in the total solid content of the thermoelectric conversion material, that is, in the thermoelectric conversion layer, and more preferably 5 to 55% by mass. Preferably, it is 10-50 mass%, and it is especially preferable.
A nano electroconductivity material may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types together as a nano electroconductive material, you may use together at least 1 type of nano carbon material and nano metal material, and may use together 2 types of nano carbon materials or nano metal materials, respectively. .

1. Nanocarbon material As described above, a nanocarbon material is a carbon material having a size of nanometer size and conductivity. For example, a carbon-carbon bond composed of sp ² hybrid orbitals of carbon atoms. Is a nanometer-sized conductive material formed by chemically bonding carbon atoms together. Specifically, fullerenes (including metal-encapsulated fullerenes and onion-like fullerenes), carbon nanotubes (including peapods), carbon nanohorns with one side closed, carbon nanofibers, carbon nanowalls, carbon Examples thereof include nanofilaments, carbon nanocoils, vapor grown carbon (VGCF), graphite, graphene, carbon nanoparticles, and cup-shaped nanocarbon materials having holes at the heads of carbon nanotubes. Various carbon blacks having a graphite-type crystal structure and exhibiting conductivity can be used as the nanocarbon material, and examples thereof include ketjen black, acetylene black, and vulcan.

  These nanocarbon materials can be manufactured by a conventional manufacturing method. Specifically, catalytic hydrogen reduction of carbon dioxide, arc discharge method, laser evaporation method, CVD method, vapor phase growth method, gas phase flow method, carbon monoxide is reacted with iron catalyst at high temperature and high pressure in the gas phase. Examples include HiPco method for growth. The nanocarbon material produced in this way can be used as it is, or a material purified by washing, centrifugation, filtration, oxidation, chromatography, or the like can be used. Furthermore, the nanocarbon material should be pulverized using a ball-type kneading device such as a ball mill, vibration mill, sand mill, roll mill, etc., or cut short by chemical or physical treatment, etc., as necessary. You can also.

  The size of the nano conductive material used in the present invention is not particularly limited as long as it is a nanometer size. When the nano conductive material is a carbon nanotube, carbon nanohorn, carbon nanofiber, carbon nanofilament, carbon nanocoil, vapor grown carbon (VGCF), cup-shaped nanocarbon substance, etc. The average length is not particularly limited, but the average length is preferably 0.01 μm or more and 1000 μm or less, and preferably 0.1 μm or more and 100 μm or less, from the viewpoints of manufacturability, film formability, conductivity, and the like. More preferred. The diameter is not particularly limited, but is preferably 0.4 nm or more and 100 nm or less, more preferably 50 nm or less, and still more preferably 15 nm or less from the viewpoint of durability, transparency, film formability, conductivity, and the like. is there.

  Among the above-mentioned nanocarbon materials, carbon nanotubes, carbon nanofibers, graphite, graphene, and carbon nanoparticles are preferable, and carbon nanotubes are particularly preferable.

Hereinafter, the carbon nanotube (hereinafter also referred to as CNT) will be described. CNT is a single-layer CNT in which a single carbon film (graphene sheet) is wound in a cylindrical shape, a double-layer CNT in which two graphene sheets are wound in a concentric shape, and a plurality of graphene sheets in a concentric shape There are multi-walled CNTs wound around. In the present invention, single-walled CNTs, double-walled CNTs, and multilayered CNTs may be used alone, or two or more kinds may be used in combination. In particular, it is preferable to use single-walled CNT and double-walled CNT having excellent properties in terms of conductivity and semiconductor properties, and more preferably single-walled CNT.
In the case of single-walled CNT, the symmetry of the helical structure based on the hexagonal orientation of graphene on the graphene sheet is called axial chiral, and the two-dimensional lattice vector from the reference point of a 6-membered ring on graphene is a chiral vector. That's it. The (n, m) obtained by indexing this chiral vector is called a chiral index, and is divided into metallicity and semiconductivity by this chiral index. More specifically, a material having nm that is a multiple of 3 indicates metallicity, and a semiconductor material that is not a multiple of 3 indicates a semiconductor.
The single-walled CNT that can be used in the present invention may be semiconductive or metallic, and both may be used in combination. In addition, a metal or the like may be included in the CNT, and a substance in which a molecule such as fullerene is included (in particular, a substance in which fullerene is included is referred to as a peapod) may be used.

CNT can be produced by an arc discharge method, a chemical vapor deposition method (hereinafter referred to as a CVD method), a laser ablation method, or the like. The CNT used in the present invention may be obtained by any method, but is preferably obtained by an arc discharge method and a CVD method.
When producing CNTs, fullerenes, graphite, and amorphous carbon may be produced as by-products at the same time. You may refine | purify in order to remove these by-products. The method for purifying CNTs is not particularly limited. In addition to the above-described purification methods, acid treatment with nitric acid, sulfuric acid or the like and ultrasonic treatment are effective for removing impurities. In addition, it is more preferable to perform separation and removal using a filter from the viewpoint of improving purity.

After purification, the obtained CNT can be used as it is. Moreover, since CNT is generally produced in a string shape, it may be cut into a desired length depending on the application. CNTs can be cut into short fibers by acid treatment with nitric acid, sulfuric acid or the like, ultrasonic treatment, freeze pulverization method or the like. In addition, it is also preferable to perform separation using a filter from the viewpoint of improving purity.
In the present invention, not only cut CNTs but also CNTs produced in the form of short fibers in advance can be used in the same manner. Such short fibrous CNTs form, for example, a catalytic metal such as iron or cobalt on a substrate, and thermally decompose carbon compounds on the surface at 700 to 900 ° C. by CVD to cause vapor growth of the CNTs. Thus, a shape oriented in the direction perpendicular to the substrate surface is obtained. The short fiber CNTs thus produced can be taken out by a method such as peeling off from the substrate. In addition, the short fibrous CNTs can be obtained by supporting a catalytic metal on a porous support such as porous silicon or an anodic oxide film of alumina and growing the CNTs on the surface by the CVD method. Using oriented molecules such as iron phthalocyanine containing a catalytic metal in the molecule as a raw material and producing CNTs on a substrate by performing CVD in an argon / hydrogen gas flow, producing oriented short fiber CNTs You can also. Furthermore, it is also possible to obtain short fiber CNTs oriented on the SiC single crystal surface by an epitaxial growth method.

2. Nano metal material A nano metal material is a nanometer-sized fibrous or particulate metal material. Specifically, a fibrous metal material (also referred to as metal fiber), a particulate metal material (metal nanoparticle). Also). The metal nanowire described later is preferable as the nanometal material.

  The metal fiber preferably has a solid structure or a hollow structure. A metal fiber having a solid structure with an average minor axis length of 1 to 1,000 nm and an average major axis length of 1 to 100 μm is referred to as a metal nanowire, and an average minor axis length of 1 to 1,000 nm. A metal fiber having an average major axis length of 0.1 to 1,000 μm and having a hollow structure is called a metal nanotube.

The metal fiber material may be any metal having electrical conductivity, and can be appropriately selected according to the purpose. For example, the long period table (International Pure and Applied Chemical Association (IUPAC), 1991 revision) At least one metal selected from the group consisting of 4 periods, 5th period and 6th period is preferable, at least one metal selected from Group 2 to Group 14 is more preferable, Group 2 and Group 8 At least one metal selected from Group 9, Group 10, Group 11, Group 12, Group 12, Group 13 and Group 14 is more preferable, and it is particularly preferable that it contains as a main component.
Examples of such metals include copper, silver, gold, platinum, palladium, nickel, tin, cobalt, rhodium, iridium, iron, ruthenium, osmium, manganese, molybdenum, tungsten, niobium, tantel, titanium, bismuth, antimony, Lead or an alloy thereof can be used. Among these, silver and an alloy with silver are preferable in terms of excellent conductivity. Examples of the metal used in the alloy with silver include platinum, osmium, palladium, and iridium. A metal may be used individually by 1 type and may use 2 or more types together.

  The shape of the metal nanowire is not particularly limited as long as the metal nanowire is made of the above-described metal and has a solid structure, and can be appropriately selected according to the purpose. For example, it can take any shape such as a columnar shape, a rectangular parallelepiped shape, a columnar shape with a polygonal cross section, and the corners of the cylindrical shape and the polygonal shape of the cross section are rounded in that the transparency of the thermoelectric conversion layer is increased. A cross-sectional shape is preferred. The cross-sectional shape of the metal nanowire can be examined by observing with a transmission electron microscope (TEM).

The average minor axis length of the metal nanowire (sometimes referred to as “average minor axis diameter” or “average diameter”) is preferably 50 nm or less, more preferably 1 to 50 nm, from the same viewpoint as the above-described nanoconductive material. Preferably, 10 to 40 nm is more preferable, and 15 to 35 nm is particularly preferable. The average short axis length can be calculated as an average value of the short axis lengths of 300 metal nanowires using, for example, a transmission electron microscope (TEM; manufactured by JEOL Ltd., JEM-2000FX). In addition, the shortest axis length when the short axis of the metal nanowire is not circular is the longest axis.
Similarly, the average major axis length (sometimes referred to as the average length) of the metal nanowire is preferably 1 μm or more, more preferably 1 to 40 μm, still more preferably 3 to 35 μm, and particularly preferably 5 to 30 μm. The average major axis length can be calculated as an average value of the major axis lengths of 300 metal nanowires using, for example, a transmission electron microscope (TEM; manufactured by JEOL Ltd., JEM-2000FX). In addition, when the metal nanowire is bent, the value calculated from the radius and the curvature is taken as the major axis length in consideration of a circle having the arc.

  Metal nanowires may be produced by any production method, but metal ions are reduced while heating in a solvent in which a halogen compound and a dispersion additive are dissolved, as described in JP2012-230881A. A manufacturing method is preferred. Details of halogen compounds, dispersion additives and solvents, heating conditions, and the like are described in JP 2012-230881 A. In addition to this manufacturing method, for example, JP 2009-215594 A, JP 2009-242880 A, JP 2009-299162 A, JP 2010-84173 A, and JP 2010-86714 A. A metal nanowire can also be manufactured by the manufacturing method described in each of the above.

The shape of the metal nanotube is not particularly limited as long as it is formed of the above-described metal in a hollow structure, and may be a single layer or a multilayer. It is preferable that the metal nanotube is a single wall from the viewpoint of excellent conductivity and heat conductivity.
The thickness of the metal nanotube (difference between the outer diameter and the inner diameter) is preferably 3 to 80 nm, more preferably 3 to 30 nm, from the viewpoints of durability, transparency, film formability, conductivity, and the like. The average major axis length of the metal nanotube is preferably 1 to 40 μm, more preferably 3 to 35 μm, and still more preferably 5 to 30 μm, from the same viewpoint as the above-described nanoconductive material. The average minor axis length of the metal nanotube is preferably the same as the average minor axis length of the metal nanowire.

  The metal nanotube may be manufactured by any manufacturing method, for example, by the manufacturing method described in US Patent Application Publication No. 2005/0056118.

  The metal nanoparticles may be any of the above-mentioned metal-formed, particulate or powdered metal fine particles. The metal fine particles and the metal fine particles may have a surface coated with a protective agent. It may be dispersed in a dispersion medium. Preferred examples of the metal used for the metal nanoparticles include silver, copper, gold, palladium, nickel, rhodium and the like. Also, an alloy composed of at least two of these, an alloy of at least one of these and iron, and the like can be used. As an alloy consisting of two kinds, for example, platinum-gold alloy, platinum-palladium alloy, gold-silver alloy, silver-palladium alloy, palladium-gold alloy, platinum-gold alloy, rhodium-palladium alloy, silver-rhodium alloy, Examples thereof include a copper-palladium alloy and a nickel-palladium alloy. Examples of the alloy with iron include an iron-platinum alloy, an iron-platinum-copper alloy, an iron-platinum-tin alloy, an iron-platinum-bismuth alloy, and an iron-platinum-lead alloy. These metals or alloys can be used alone or in combination of two or more.

  The average particle diameter (dynamic light scattering method) of the metal nanoparticles is preferably 1 to 150 nm in terms of excellent conductivity.

  As the protective agent for metal fine particles, for example, a protective agent described in JP2012-2222055 is preferably exemplified, and a protective agent having a linear or branched alkyl chain having 10 to 20 carbon atoms, particularly a fatty acid. More preferable examples include aliphatic amines, aliphatic amines, aliphatic thiols, and aliphatic alcohols. Here, when the carbon number is 10 to 20, the storage stability of the metal nanoparticles is high and the conductivity is also excellent. The fatty acids, aliphatic amines, aliphatic thiols and aliphatic alcohols are preferably those described in JP-A-2012-2222055.

  The metal nanoparticles may be produced by any production method, for example, gas deposition method, sputtering method, metal vapor synthesis method, colloid method, alkoxide method, coprecipitation method, uniform precipitation method, thermal decomposition. Method, chemical reduction method, amine reduction method, solvent evaporation method and the like. Each of these production methods has unique characteristics, but it is preferable to use a chemical reduction method or an amine reduction method particularly for the purpose of mass production. In carrying out these production methods, a known reducing agent or the like can be appropriately used in addition to selecting and using the above-mentioned protective agent as necessary.

<Copolymer>
The copolymer used in the present invention is a copolymer represented by the following general formula (1).

(In general formula (1), A and B each independently represent a copolymer unit derived from an aniline derivative or a copolymer unit derived from a pyrrole derivative, provided that A and B are different from each other. Represents.)

That is, the copolymer used in the present invention is a polyaniline copolymer and a polypyrrole copolymer having two different copolymer units A and B. Therefore, the copolymer used for this invention does not contain the homopolymer which consists of a single repeating unit.
Here, the copolymer units different from each other refer to copolymer units having different basic skeletons or types, numbers, or substitution positions of substituents, and the bonding mode of the copolymer units (for example, Head to Head, Head to Tail). , Tail to Tail) does not include the difference in copolymer units apparently produced in the copolymer. For example, polyaniline formed by bonding 2-methylaniline units with Head to Tail apparently has two types of copolymer units, but in the present invention, it has only one type of 2-methylaniline copolymer unit. Suppose you are.

  Such copolymers having two different copolymer units A and B exhibit excellent dispersibility in the coexistence of the nanoconductive material, and have high thermoelectric conversion performance in the thermoelectric conversion layer. Electrode adhesion can be expressed.

  In the general formula (1), the aniline derivative that becomes a copolymer unit of the copolymer is not particularly limited as long as it has an aniline structure, but includes unsubstituted aniline and substituted aniline. The aniline derivative is preferably an aniline derivative that becomes a precursor of a copolymer unit represented by the general formula (2) described later. Moreover, the pyrrole derivative which becomes a copolymer unit of the copolymer is not particularly limited as long as it has a pyrrole structure, but includes unsubstituted pyrrole, substituted pyrrole and condensed pyrrole. The pyrrole derivative is preferably a pyrrole derivative that becomes a precursor of a copolymer unit represented by the general formulas (3) to (5) described later, and more preferably in terms of thermoelectric conversion characteristics and electrode adhesion. Examples include pyrrole derivatives that are precursors of copolymer units represented by general formulas (3) and (4) described below, and more preferably precursors of copolymer units represented by general formula (3) described below. The pyrrole derivative which becomes a body is mentioned.

As the copolymer units A and B, those different from the above-mentioned copolymer units are selected. At this time, as copolymer units A and B, it is preferable to select two copolymer units having different molecular weights from the above copolymer units in terms of thermoelectric conversion characteristics and electrode adhesion. It is preferable that a copolymer unit having a small molecular weight is selected as the coalescing unit A, and a copolymer unit having a large molecular weight is selected as the copolymer unit B. Here, the molecular weight of the copolymer unit can be adjusted by the difference in the basic skeleton of the copolymer unit, the difference in substituents, the number of substituents, and the like. The difference in molecular weight is preferably due to the difference in substituents and the number of substituents, and more preferably due to differences in substituents. The difference in the molecular weights of the copolymer units A and B is not particularly limited, but is, for example, 1 to 20 in terms of carbon atoms constituting the substituent.
Copolymer units A and B are preferably selected from aniline derivative-derived copolymer units or pyrrole derivative-derived copolymer units, both in terms of thermoelectric conversion characteristics and electrode adhesion. More preferably, it is selected from copolymer units derived from aniline derivatives. At this time, the copolymer unit A is particularly preferably an unsubstituted aniline-derived copolymer unit or a pyrrole derivative-derived copolymer unit.

The ratio (m / n) of the degree of polymerization of the copolymer units A and B is preferably 99/1 to 1/99, more preferably 80/20 to 10/90 in terms of thermoelectric conversion characteristics and electrode adhesion. More preferably, it is 75/25 to 20/80.
The copolymer used in the present invention may be any of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer of at least two kinds of the above-mentioned copolymer units. Polymers, alternating copolymers and block copolymers are preferred.

  The copolymer used in the present invention may be doped or undoped, but is preferably doped. When the copolymer is doped, higher thermoelectric conversion performance is exhibited. Here, the dope means that a part of the main chain of the copolymer, that is, the copolymer units A and B are preferably oxidized with a dopant described later. The proportion of the copolymer units that form the main chain of the copolymer is referred to as the doping ratio, and in the present invention, the doping ratio is the copolymer weight that forms the main chain in that the thermoelectric conversion performance is further improved. Preferably it is 10-90 mol% with respect to the total number of moles of united unit A and B, More preferably, it is 20-80 mol%.

  In the general formula (1), the copolymer units A and B are preferably each independently selected from the group consisting of copolymer units represented by the following general formulas (2) to (5). When the copolymer used in the present invention has two kinds of copolymer units represented by these general formulas, nanoconductivity that cannot be realized by conventional polyaniline and polypyrrole, particularly homopolyaniline and homopolypyrrole. Highly dispersible copolymer in the presence of materials.

(In the general formulas (2) to (5), R ^{11 to} R ¹⁴ each independently represents a monovalent substituent. A 1 and c 1 each independently represent an integer of 0 to 4, and b 1 represents an integer of 0 to 2. Represents an integer, and d1 represents an integer of 0 to 6. X ^{11 to} X ¹⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and * represents a connecting site of a copolymer unit. Represents.)
The substituent R ^{14 in} the general formula (5) may be substituted on any of the two benzene rings.

  In the copolymer unit represented by the general formula (2), the linking site is usually the 4-position and nitrogen atom of the benzene ring, but may be the 2-position and nitrogen atom of the benzene ring. Similarly, in the copolymer unit represented by the general formula (3), the connecting site is usually at the 2nd and 5th positions of the pyrrole ring, but may be at the 2nd and 3rd positions of the pyrrole ring. Good. Furthermore, in the copolymer unit represented by the general formula (5), the linking site is usually located at the 2nd and 7th positions of the carbazole ring, but may be located at other positions.

Monovalent substituents as R ^{11 to} R ¹⁴ are halogen atoms such as fluorine and chlorine, alkyl groups, alkoxy groups, aryloxy groups, alkyloxycarbonyl groups, alkylthio groups, arylthio groups, crown ether ring groups, aryl groups , Heteroaryl group, dialkylamino group and the like. In addition, the monovalent substituent may be further substituted with the same substituent or different substituents, and examples of the monovalent substituent substituted with the substituent include a fluoroalkyl group, a substituted alkyl group, and a substituted alkoxy group. Groups and the like.
Among these, the monovalent substituent is particularly excellent in electrode adhesion, and R ^{11 to} R ¹⁴ are preferably a halogen atom, an alkyl group, an alkoxy group, an aryloxy group, an aryl group, or a heteroaryl group. A group, an alkoxy group, and an aryl group are more preferable.

  The alkyl group preferably has 1 to 20 carbon atoms, more preferably 2 to 20 carbon atoms, and still more preferably 4 to 10 carbon atoms. The alkyl group includes a linear, branched or cyclic alkyl group, and a linear or branched alkyl group is preferable. Examples of the linear alkyl group include methyl, ethyl, propyl, butyl, hexyl, heptyl, octyl and dodecyl. Examples of the branched alkyl group include i-propyl, sec-butyl, t-butyl, and 2-ethylhexyl. The cyclic alkyl group (cycloalkyl group) preferably has 3 to 14 carbon atoms, and examples thereof include cyclopropy, cyclopentyl, cyclohexyl, bicyclooctyl, norbornyl, and adamantyl.

The alkoxy group preferably has 1 to 20 carbon atoms, more preferably 4 to 15 carbon atoms. The alkyl part of the alkoxy group has the same meaning as the above-described alkyl group except that the number of carbon atoms is different. Such an alkoxy group is preferably a linear or branched alkoxy group, and preferred alkoxy groups include methoxy, butoxy, hexyloxy, octyloxy, 2-ethylhexyloxy, and pentadecyloxy.
The aryloxy group preferably has 6 to 26 carbon atoms, and examples thereof include phenoxy and 1-naphthyloxy.

The alkyloxycarbonyl group is also called an alkoxycarbonyl group and preferably has 2 to 20 carbon atoms, and examples thereof include methoxycarbonyl, ethoxycarbonyl, 2-ethylhexyloxycarbonyl and the like.
The alkylthio group preferably has 1 to 20 carbon atoms, and examples thereof include methylthio, ethylthio, propylthio and the like.
The arylthio group preferably has 6 to 20 carbon atoms, and examples thereof include phenylthio and naphthylthio.

  The crown ether ring group preferably has 8 to 20 carbon atoms, and includes a thia crown ether or an aza crown ether in which at least one oxygen atom is substituted with a sulfur atom or a nitrogen atom. Examples of such a crown ether ring group include 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6, diaza-18-crown-6 and the like.

The aryl group may be a single ring or a condensed ring. The aryl group preferably has 4 to 50 carbon atoms, more preferably 6 to 40 carbon atoms, such as a benzene ring. Group, naphthalene ring group, anthracene ring group, phenanthrene ring group, indacene ring group, fluorene ring group, pyrene ring group and the like, and benzene ring group is preferable.
The heteroaryl group may be a single ring or a condensed ring, and the heteroaryl group preferably has 4 to 50 carbon atoms, more preferably 6 to 40 carbon atoms. Examples of the hetero atom as the atom include a 5- or 6-membered heterocyclic group having at least one nitrogen atom, sulfur atom, oxygen atom, silicon atom, phosphorus atom, selenium atom, or tellurium atom. Examples of such heteroaryl groups include aromatic heteroaryl groups, aliphatic heteroaryl groups, and benzo- and dibenzodi-fused rings thereof. Examples of the aromatic heteroaryl group and these benzo or dibenzo condensed rings include, for example, a pyrrole ring group, a thiophene ring group, a furan ring group, a selenophene ring group, a tellurophen ring group, an imidazole ring group, a pyrazole ring group, and an oxazole ring group. , Isoxazole ring group, thiazole ring group, isothiazole ring group, thiadiazole ring group, pyridine ring group, 2-pyridone ring group, pyrimidine ring group, pyridazine ring group, pyrazine ring group, triazine ring group, selenopyran ring group, telluropyran Examples thereof include a ring group, a benzothiophene ring group, a dibenzothiophene ring group, and a carbazole ring group.
An aliphatic heteroaryl group is a heteroaryl ring group that is not aromatic and is a saturated or unsaturated heteroaryl group. Examples of such aliphatic heteroaryl groups and condensed rings thereof include pyrrolidine ring groups, piperidine ring groups, piperazine ring groups, and morpholine ring groups. Among these, the heteroaryl group includes a thiophene ring group, a furan ring group, a pyrrole ring group, an imidazole ring group, an oxazole ring group, a thiazole ring group, a benzothiophene ring group, a pyridine ring group, a dibenzothiophene ring group, and a carbazole ring group. Is preferred.
The aryl group and heteroaryl group described above may be in a cationic state such as an onium salt, but are preferably in a neutral state in that they are conjugated with the conjugated structure constituting the main chain of the copolymer. .

  The dialkylamino group is preferably an amino group having the above-described alkyl group, and examples thereof include N, N-dimethylamino, N, N-diethylamino, N, N-dibutylamino, N, N-dihexylamino and the like.

Examples of the above-described monovalent substituent substituted with a substituent that can be employed as R ^{11 to} R ¹⁴ include a fluoroalkyl group, a substituted alkoxy group, and a substituted alkyl group.

  The fluoroalkyl group is a group in which at least one hydrogen atom of the above alkyl group is substituted with a fluorine atom, and a perfluoroalkyl group in which all the hydrogen atoms of the alkyl group are substituted with fluorine atoms is preferable. The alkyl group of the fluoroalkyl group has the same meaning as the above-described alkyl group, and preferred ones are also the same. Examples of the fluoroalkyl group include trifluoromethyl, pentafluoroethyl, hexafluoropropyl, and the like.

Examples of the substituted alkoxy group include an alkoxyalkyleneoxy group. The number of carbon atoms constituting the alkoxyalkyleneoxy group is preferably 2-20, and more preferably 2-7. Examples of the alkoxyalkyleneoxy group include methoxyethyleneoxy (2-methoxy-1-ethoxy).
Examples of the substituted alkyl group include an aryl group, an alkoxycarbonyl group, an alkyl group substituted with an alkylthio group, and an alkoxyalkyleneoxyalkyl group. Examples of the alkyl substituted with an aryl group (also referred to as an aralkyl group) include benzyl and phenethyl. Examples of the alkyl group substituted with an alkoxycarbonyl group include 2-methoxycarbonylethyl. Examples of the alkyl group substituted with an alkylthio group include 2-propylthioethyl. The number of carbon atoms constituting the alkoxyalkyleneoxyalkyl group is preferably 2-20.

  In addition, as the above-mentioned “substituent different from the monovalent substituent” in which the terminal of each condensed ring structure or the monovalent substituent in the condensed ring of the above-mentioned aryl group and heteroaryl group is substituted, Examples thereof include hydrophilic groups such as a carboxylic acid group, a sulfonic acid group, a hydroxyl group, and a phosphoric acid group.

In general formula (2), a1 represents an integer of 0 to 4, and when it is selected as copolymer unit A, it is preferably 0 in terms of excellent electrode adhesion, and is selected as copolymer unit B. When it is, it is preferably an integer of 1 to 4 and more preferably 1 or 2 in terms of excellent thermoelectric conversion characteristics. Regardless of the number of monovalent substituents R ^11, substituted position of the substituent R ¹¹ is not particularly limited.

In general formula (3), b1 represents an integer of 0 to 2, and when it is selected as the copolymer unit A, it is preferably 0 in terms of excellent electrode adhesion, and is selected as the copolymer unit B. When it is, it is preferably 1 or 2 in terms of excellent thermoelectric conversion characteristics. Regardless of the number of monovalent substituents R ^12, substituted position of the substituent R ¹² is not particularly limited.

In the general formula (4), c1 represents an integer of 0 to 4, and when it is selected as the copolymer unit A, it is preferably 0 in terms of excellent electrode adhesion, and is selected as the copolymer unit B. When it is, it is preferably an integer of 1 to 4 and more preferably 1 or 2 in terms of excellent thermoelectric conversion characteristics. Regardless of the number of monovalent substituents R ^13, substituted position of the substituent R ¹³ is not particularly limited.

In general formula (5), d1 represents an integer of 0 to 6, and when it is selected as copolymer unit A, it is preferably 0 in terms of excellent electrode adhesion, and is selected as copolymer unit B. When it is, it is preferable that it is an integer of 1-6 by the point which is excellent in a thermoelectric conversion characteristic, and it is more preferable that it is 1 or 2. Regardless of the number of monovalent substituents R ¹⁴ , the substituent R ¹⁴ may be substituted with any of the two benzene rings, and the substitution position of the substituent R ¹⁴ in each benzene ring is not particularly limited, For example, the 3rd and 6th positions are preferred.

In the general formulas (2) to (5), when having a plurality of monovalent substituents R ^{11 to} R ¹⁴ , these monovalent substituents may be bonded to each other to form a ring structure.

In the general formulas (2) to (5), X ^{11 to} X ¹⁴ are each independently a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, preferably a hydrogen atom. The alkyl group, aryl group and heteroaryl group in X ^{11 to} X ^{14 have} the same meanings as the alkyl group, aryl group and heteroaryl group in the substituents R ^{11 to} R ¹⁴ described above, and preferred ones are also the same. X ^{11 to} X ¹⁴ are each independently the same as the substituents R ^{11 to} R ¹⁴ described above, and the substituents further included in the substituents R ^{11 to} R ¹⁴ , for example, alkyl groups, aryl groups, heteroaryls. Group and a hydrophilic group.

  As the copolymer units A and B, those different from the copolymer units represented by the above general formulas (2) to (5) are selected. At this time, it is preferable to select two copolymer units having different molecular weights in terms of thermoelectric conversion characteristics and electrode adhesion as the copolymer units A and B, and the copolymer unit A has a small molecular weight. As the copolymer unit, a copolymer unit having a large molecular weight is preferably selected as the copolymer unit B.

Specifically, paying attention to the presence or absence of monovalent substituents R ^{11 to} R ¹⁴ of copolymer units A and B, copolymer unit A in which copolymer unit A does not have monovalent substituents R ^{11 to} R ¹⁴ It is a unit, and the copolymer unit B is preferably a copolymer unit having one or more monovalent substituents R ^{11 to} R ¹⁴ . For example, the copolymer unit A is a copolymer unit represented by the general formula (2) in which a1 is 0, a copolymer unit represented by the general formula (3) in which b1 is 0, and c1 is 0. Selected from the group consisting of a copolymer unit represented by the general formula (4) and a copolymer unit represented by the general formula (5) in which d1 is 0, and the copolymer unit B is a1 A copolymer unit represented by the general formula (2) which is an integer of 1 to 4, a copolymer unit represented by the general formula (3) wherein b1 is 1 or 2, and c1 is an integer of 1 to 4 An excellent thermoelectric power is selected from the group consisting of a copolymer unit represented by a general formula (4) and a copolymer unit represented by a general formula (5) in which d1 is an integer of 1 to 6. This is preferable in that the conversion characteristics and high electrode adhesion are expressed in a balanced manner. As for the copolymer unit A and the copolymer unit B which are selected in this way, it is particularly preferable that X ^{11 to} X ¹⁴ are hydrogen atoms.

  On the other hand, when paying attention to the basic structure of the copolymer units A and B, the copolymer units A and B both have the same basic structure in that they are excellent in thermoelectric conversion characteristics and electrode adhesion. preferable. For example, the copolymer units A and B are preferably both selected from a copolymer unit derived from an aniline derivative or a copolymer unit derived from a pyrrole derivative. When the copolymer units A and B are selected from copolymer units derived from pyrrole derivatives, they are selected from the copolymer units represented by the above general formulas (3) to (5). Preferably, it is more preferably selected from the copolymer units represented by the above general formula (3) or (4), and is selected from the copolymer units represented by the above general formula (3). Is more preferable. As described above, the copolymer units A and B preferably have the same basic structure but different structures from each other. Specifically, the copolymer units A and B have two different kinds represented by the general formula (2). An aniline copolymer having a copolymer unit, a pyrrole copolymer having two different copolymer units represented by the above general formula (3), and each other represented by the above general formula (4) A benzopyrrole copolymer having two different types of copolymer units and a carbazole copolymer having two different types of copolymer units represented by the general formula (5) are preferable, and an aniline copolymer is preferable. More preferred are polymers and pyrrole copolymers.

The copolymer used in the present invention may contain other copolymer units as the third copolymer unit that forms the main chain of the copolymer, in addition to the copolymer units described above. The other copolymer unit preferably has a conjugated structure. Examples of the third copolymer unit include copolymer units represented by the above general formulas (2) to (5). In addition, as a compound containing a copolymer unit having a conjugated structure (sometimes referred to as a conjugated compound), for example, a thiophene compound, a pyrrole compound, an aniline compound, an acetylene compound, a p-fluorenylene compound, a polyacene Compounds, polyphenanthrene compounds, metal phthalocyanine compounds, p-xylylene compounds, vinylene sulfide compounds, m-phenylene compounds, naphthalene vinylene compounds, p-phenylene oxide compounds, phenylene sulfide compounds, furan compounds , Selenophene compounds, azo compounds, benzothiadiazole compounds, carbazole compounds, benzimidazole compounds, imidazole compounds, pyrimidine compounds, and derivatives and condensates of these conjugated compounds That compounds, metal complex compounds which are complexes of these conjugated compound and a metal ion.
The copolymer used in the present invention preferably contains 30 mol% or less of the above-mentioned other structure with respect to a total of 100 mol of the copolymerized units represented by the above formulas.

The terminal of the copolymer used in the present invention is not particularly limited, and examples thereof include a hydrogen atom and a substituent such as the above-described monovalent substituent, such as a hydrogen atom, an unsubstituted aniline or aniline derivative, Substituted pyrrole or pyrrole derivative, amino group NHX ¹¹ , halogen atom (chlorine atom, bromine atom and iodine atom), known boric acid derivative, hydrophilic group (carboxylic acid group, sulfonic acid group, hydroxyl group, phosphoric acid group, etc.) You may have. Here, the aniline derivative may be a copolymer unit represented by the above general formula (2), or a pyrrole derivative may be a copolymer unit represented by the above general formulas (3) to (5). . Furthermore, ^{X 11} amino groups ^{NHX 11} has the same meaning as ^{X 11} described above.

  The molecular weight of the copolymer used in the present invention is not particularly limited, and may be a high molecular weight oligomer or a lower molecular weight oligomer (for example, a weight average molecular weight of about 1,000 to 10,000). In terms of excellent conductivity and thermoelectric conversion performance of the thermoelectric conversion material, the molecular weight is preferably 5,000 to 100,000, more preferably 8,000 to 50,000 in terms of weight average molecular weight. More preferably, it is 2,000-20,000. The weight average molecular weight can be obtained by converting a value measured by gel permeation chromatography (GPC) into standard polystyrene.

  The reason why the above-mentioned copolymer is excellent in thermoelectric conversion performance and allows the thermoelectric conversion layer to exhibit high adhesion with the electrode is presumed as follows. That is, since the copolymer has two different copolymer units, preferably two different copolymer units selected as described above, the copolymer is highly dispersed even in the presence of the nanoconductive material. Therefore, it is presumed that aggregates are hardly formed and high thermoelectric conversion performance and electrode adhesion are exhibited.

Although the specific example of the copolymer used for this invention is shown below as a combination of the copolymer units A and B, this invention is not limited to these. In the following specific examples, * represents a linking site of copolymer units. The molar ratio of copolymer units A and B is in the above-described range.
In the following specific examples, Ph represents C ₆ H ₅ .

  The copolymer having copolymer units A and B described above is prepared by subjecting an aniline derivative or pyrrole derivative having a copolymer unit represented by the general formulas (2) to (5) to a normal oxidative polymerization method or a cup. It can be produced by polymerization by a ring polymerization method.

The content of the copolymer in the thermoelectric conversion material of the present invention is preferably 3 to 80% by mass, more preferably 5 to 60% by mass, based on the total solid content of the thermoelectric conversion material. It is especially preferable that it is 50 mass%.
Moreover, when the thermoelectric conversion material contains the nonconjugated polymer mentioned later, it is preferable that content of the copolymer in the said thermoelectric conversion material is 3-70 mass% in the total solid of material, More preferably, it is 60 mass%, and it is especially preferable that it is 10-50 mass%.
Furthermore, when the thermoelectric conversion material contains a conductive polymer other than the copolymer represented by the above general formula (1), the copolymer represented by the above general formula (1) in the thermoelectric conversion material. The content of the copolymer having a combined unit as a repeating unit is preferably 0 to 70% by mass, more preferably 3 to 50% by mass, and more preferably 5 to 20% by mass in the total solid content of the material. It is particularly preferred that Here, examples of the other conductive polymer include a polymer having at least one other copolymer unit as a repeating unit.

<Non-conjugated polymer>
The thermoelectric conversion material of the present invention preferably contains a non-conjugated polymer in that the thermoelectric conversion characteristics are further improved. The non-conjugated polymer is a polymer compound having no conjugated molecular structure, that is, a compound in which the main chain is not conjugated with a lone pair of π electrons or lone electrons.
In the present invention, the type of the non-conjugated polymer is not particularly limited, and a conventionally known non-conjugated polymer can be used. Preferably, a polymer selected from the group consisting of a polyvinyl polymer obtained by polymerizing a vinyl compound, poly (meth) acrylate, polycarbonate, polyester, polyamide, polyimide, and polysiloxane is used. In the present invention, “(meth) acrylate” represents either or both of acrylate and methacrylate, and includes a mixture thereof.

Specific examples of vinyl compounds that form polyvinyl polymers include styrene, vinyl pyrrolidone, vinyl carbazole, vinyl pyridine, vinyl naphthalene, vinyl phenol, vinyl acetate, styrene sulfonic acid, and vinyl arylamines such as vinyl triphenylamine. And vinyltrialkylamines such as vinyltributylamine.
Specific examples of (meth) acrylate compounds that form poly (meth) acrylates include hydrophobic alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate, 2-hydroxyethyl acrylate, and 1-hydroxy Hydroxyalkyl acrylates such as ethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 1-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, 2-hydroxybutyl acrylate, 1-hydroxybutyl acrylate Examples include acrylate monomers such as esters, and methacrylate monomers obtained by replacing the acryloyl group of these monomers with methacryloyl groups. It is.
Specific examples of the polycarbonate include general-purpose polycarbonate composed of bisphenol A and phosgene, Iupizeta (trade name, manufactured by Mitsubishi Gas Chemical Co., Ltd.), Panlite (trade name, manufactured by Teijin Chemicals Ltd.), and the like.
Examples of the compound forming the polyester include polyalcohols, polycarboxylic acids, and hydroxy acids such as lactic acid. Specific examples of polyester include Byron (trade name, manufactured by Toyobo Co., Ltd.) and the like.
Specific examples of polyamide include PA-100 (trade name, manufactured by T & K TOKA Corporation).
Specific examples of polyimide include Solpy 6,6-PI (trade name, manufactured by Solpy Kogyo Co., Ltd.).
Specific examples of the polysiloxane include polydiphenylsiloxane and polyphenylmethylsiloxane.
If possible, the non-conjugated polymer may be a homopolymer or a copolymer with each of the above-described compounds.
In the present invention, it is more preferable to use a polyvinyl polymer obtained by polymerizing a vinyl compound as the non-conjugated polymer.

  The non-conjugated polymer is preferably hydrophobic, and more preferably has no hydrophilic group such as sulfonic acid or hydroxyl group in the molecule. Further, a non-conjugated polymer having a solubility parameter (SP value) of 11 or less is preferable. In the present invention, the solubility parameter indicates the Hildebrand SP value, and a value based on the Fedors estimation method is adopted.

  The thermoelectric conversion performance of the thermoelectric conversion material can be improved by including a non-conjugated polymer together with the copolymer represented by the general formula (1) in the thermoelectric conversion material. Although the mechanism is not yet clear, (1) since the non-conjugated polymer has a wide gap (band gap) between the HOMO level and the LUMO level, the carrier concentration in the above-mentioned copolymer is appropriately set. In view of the fact that it can be kept low, the Seebeck coefficient can be maintained at a higher level than a system that does not contain a non-conjugated polymer. It is presumed that high conductivity can be maintained. That is, it is possible to improve both the Seebeck coefficient and the conductivity by coexisting three components of the nano-conductive material, the non-conjugated polymer and the aromatic polymer in the material. As a result, the thermoelectric conversion performance ( ZT value) is greatly improved.

  The content of the non-conjugated polymer in the thermoelectric conversion material is preferably 10 to 1500 parts by mass, and 30 to 1200 parts by mass with respect to 100 parts by mass of the copolymer represented by the general formula (1). More preferably, it is more preferably 80 to 1000 parts by mass. When the content of the non-conjugated polymer is within the above range, there is no decrease in Seebeck coefficient and thermoelectric conversion performance (ZT value) due to an increase in carrier concentration, and nano conductive material due to mixing of non-conjugated polymers. This is preferable because there is no deterioration in dispersibility and deterioration in conductivity and thermoelectric conversion performance.

<Solvent>
The thermoelectric conversion material of the present invention preferably contains a solvent. The thermoelectric conversion material of the present invention is more preferably a nanoconductive material dispersion in which a nanoconductive material is dispersed in a solvent.
The solvent should just be able to disperse | distribute or melt | dissolve each component favorably and can use water, an organic solvent, and these mixed solvents. Preferably an organic solvent, alcohol, dichloromethane, chloroform, carbon tetrachloride, ethane dichloride, aliphatic halogen solvents such as trichloroethylene, trichloroethane, tetrachloroethylene, aprotic polar solvents such as DMF, NMP, DMSO, chlorobenzene, Aromatic halogen solvents such as dichlorobenzene, aromatic solvents such as benzene, toluene, xylene, mesitylene, tetralin, tetramethylbenzene and pyridine, ketone solvents such as cyclohexanone, acetone and methylethylkenton, diethyl ether, tetrahydrofuran ( THF), ether solvents such as t-butyl methyl ether, dimethoxyethane, diglyme and the like are preferable, aliphatic halogen solvents, aromatic halogen solvents, aprotic polar solvents, aromatic solvents Medium, ether solvents are more preferred, even more preferably aliphatic halogenated solvents and aromatic halogenated solvent.
In the present invention, the halogen-based solvent is one in which at least one hydrogen atom of a compound serving as a solvent is substituted with a halogen atom. As described above, the halogen-based solvent is classified into an aliphatic halogen-based solvent and an aromatic halogen-based solvent. Therefore, in the present invention, the aliphatic halogen solvent and the aromatic halogen solvent may be collectively referred to as a halogen solvent.

The solvent is preferably degassed in advance. The dissolved oxygen concentration in the solvent is preferably 10 ppm or less. Examples of the degassing method include a method of irradiating ultrasonic waves under reduced pressure, a method of bubbling an inert gas such as argon, and the like.
Further, the solvent is preferably dehydrated in advance. The amount of water in the solvent is preferably 1000 ppm or less, and more preferably 100 ppm or less. When the water content in the solvent is set in the above range in advance, the water content of the thermoelectric conversion material and the thermoelectric conversion layer can be adjusted to 0.01 to 15% by mass. As a method for dehydrating the solvent, a known method such as a method using molecular sieve or distillation can be used.

  The amount of the solvent in the thermoelectric conversion material is preferably 25 to 99.99% by mass, more preferably 30 to 99.95% by mass, and more preferably 30 to 99.9% with respect to the total amount of the thermoelectric conversion material. More preferably, it is mass%.

  The thermally conductive material of the present invention comprising a nanoconductive material and a solvent, particularly an organic solvent, together with the above-mentioned copolymer exhibits good nanoconductive material dispersibility, and the organic solvent is a halogen-based solvent. The copolymer of the present invention exhibits remarkable dispersibility in the presence of a nanoconductive material. From this viewpoint, as another embodiment of the thermally conductive material of the present invention, the above-mentioned copolymer, nanoconductive material and solvent, preferably an organic solvent, particularly preferably a halogen-based solvent, The nano electroconductive material dispersion dispersed in a solvent, an organic solvent or a halogen-based solvent is included. Since the dispersion has good dispersibility of the nano-conductive material, the nano-conductive material can exhibit high original conductivity, and can be suitably used for various conductive materials including a thermoelectric conversion material. As described above, the copolymer used in the present invention appropriately selects a solvent suitable for the production equipment, application, production environment, etc. from the halogen-based solvent without significantly impairing the coating property and film forming property of the thermoelectric conversion material. Can be used.

<Dopant>
The thermoelectric conversion material of the present invention may contain a dopant as appropriate in order to further improve conductivity by increasing the carrier concentration in the thermoelectric conversion material of the present invention. The dopant is a compound doped in the copolymer represented by the above general formula (1), and the copolymer is protonated or electrons are removed from the π-conjugated system of the aromatic polymer. Any polymer that can dope the polymer with positive charge (p-type doping) may be used. Specifically, the following onium salt compounds, oxidizing agents, acidic compounds, electron acceptor compounds and the like can be used.

1. Onium salt compound The onium salt compound used as a dopant is preferably a compound (acid generator, acid precursor) that generates an acid upon application of energy such as irradiation of active energy rays (radiation, electromagnetic waves, etc.) or application of heat. . Examples of such onium salt compounds include sulfonium salts, iodonium salts, ammonium salts, carbonium salts, phosphonium salts, and the like. Of these, sulfonium salts, iodonium salts, ammonium salts and carbonium salts are preferable, sulfonium salts, iodonium salts and carbonium salts are more preferable, and sulfonium salts and iodonium salts are particularly preferable. Examples of the anion moiety constituting the salt include a strong acid counter anion.

  Specifically, the compound represented by the following general formula (I) or (II) is used as the sulfonium salt, the compound represented by the following general formula (III) is used as the iodonium salt, and the following general formula is used as the ammonium salt. Examples of the compound represented by (IV) and the carbonium salt include compounds represented by the following general formula (V), which are preferably used in the present invention.

In the general formulas (I) to (V), R ^{21 to} R ²³ , R ^{25 to} R ²⁶ and R ^{31 to} R ³³ each independently represent an alkyl group, an aralkyl group, an aryl group, or an aromatic heterocyclic group. Represent. R ^{27 to} R ³⁰ each independently represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, an aromatic heterocyclic group, an alkoxy group, or an aryloxy group. R ²⁴ represents an alkylene group or an arylene group. The substituents of R ^{21 to} R ³³ may be further substituted with a substituent. X ⁻ represents an anion of a strong acid.
Any two groups of ^R 21 ^{to R 23} in the general formula (I) is, ^{R 21} and ^{R 23} in the general formula (II) is, the ^{R 25} and ^{R 26} in formula (III), general formula (IV) Any two groups of R ^{27 to} R ³⁰ are bonded to any two groups of R ^{31 to} R ³³ in the general formula (V) to form an aliphatic ring, an aromatic ring, or a heterocyclic ring. May be.

In R ^{21 to} R ²³ and R ^{25 to} R ³³ , the alkyl group includes a linear, branched or cyclic alkyl group, and the linear or branched alkyl group is preferably an alkyl group having 1 to 20 carbon atoms. Specific examples include methyl, ethyl, propyl, n-butyl, sec-butyl, t-butyl, hexyl, octyl, dodecyl and the like.
The cyclic alkyl group is preferably an alkyl group having 3 to 20 carbon atoms, and specific examples include cyclopropyl, cyclopentyl, cyclohexyl, bicyclooctyl, norbornyl, adamantyl and the like.
The aralkyl group is preferably an aralkyl group having 7 to 15 carbon atoms, and specific examples include benzyl and phenethyl.
As the aryl group, an aryl group having 6 to 20 carbon atoms is preferable, and specific examples include phenyl, naphthyl, anthranyl, phenanthyl, pyrenyl and the like.
As aromatic heterocyclic group, pyridine ring group, pyrazole ring group, imidazole ring group, benzimidazole ring group, indole ring group, quinoline ring group, isoquinoline ring group, purine ring group, pyrimidine ring group, oxazole ring group, Examples include a thiazole ring group and a thiazine ring group.

In R ^{27 to} R ³⁰ , the alkoxy group is preferably a linear or branched alkoxy group having 1 to 20 carbon atoms, and specific examples include methoxy, ethoxy, iso-propoxy, butoxy, hexyloxy and the like.
The aryloxy group is preferably an aryloxy group having 6 to 20 carbon atoms, and specific examples include phenoxy and naphthyloxy.

In R ²⁴ , the alkylene group includes linear, branched and cyclic alkylene groups, and an alkylene group having 2 to 20 carbon atoms is preferable. Specific examples include ethylene, propylene, butylene, hexylene and the like. As the cyclic alkylene group, a cyclic alkylene group having 3 to 20 carbon atoms is preferable, and specific examples include cyclopentylene, cyclohexylene, bicyclooctylene, norbornylene, adamantylene and the like.
As the arylene group, an arylene group having 6 to 20 carbon atoms is preferable, and specific examples include phenylene, naphthylene, and anthranylene.

When the substituent of R ^{21 to} R ³³ further has a substituent, the substituent is preferably an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom (fluorine atom, chlorine atom, iodine). Atom), aryl group having 6 to 10 carbon atoms, aryloxy group having 6 to 10 carbon atoms, alkenyl group having 2 to 6 carbon atoms, cyano group, hydroxy group, carboxy group, acyl group, alkoxycarbonyl group, alkylcarbonylalkyl Group, arylcarbonyl group, arylcarbonylalkyl group, nitro group, alkylsulfonyl group, trifluoromethyl group, -S- ^{R41 and the} like. ^{Incidentally,} the substituents of ^{R 41} has the same meaning as above ^{R 21.}

X ⁻ is preferably an anion of an aryl sulfonic acid, an anion of a perfluoroalkyl sulfonic acid, an anion of a perhalogenated Lewis acid, an anion of a perfluoroalkylsulfonimide, a perhalogenate anion, or an alkyl or aryl borate anion. These may further have a substituent, and examples of the substituent include a fluoro group.
Specific examples of anions of aryl sulfonic acid include p-CH ₃ C ₆ H ₄ SO ₃ ⁻ , C ₆ H ₅ SO ₃ ⁻ , an anion of naphthalene sulfonic acid, an anion of naphthoquinone sulfonic acid, an anion of naphthalenedisulfonic acid, anthraquinone Examples include sulfonic acid anions.
Specific examples of the anion of perfluoroalkylsulfonic acid include CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , and C ₈ F ₁₇ SO ₃ ^— .
Specific examples of the anion of the perhalogenated Lewis acid include PF ₆ ⁻ , SbF ₆ ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , and FeCl ₄ ⁻ .
Specific examples of the anion of perfluoroalkylsulfonimide include CF ₃ SO ₂ —N ^— SO ₂ CF ₃ and C ₄ F ₉ SO ₂ —N ^— SO ₂ C ₄ F ₉ .
Specific examples of the perhalogenate anion include ClO ₄ ⁻ , BrO ₄ ⁻ and IO ₄ ⁻ .
Specific examples of the alkyl or aryl borate anion include (C ₆ H ₅ ) ₄ B ⁻ , (C ₆ F ₅ ) ₄ B ⁻ , (p-CH ₃ C ₆ H ₄ ) ₄ B ⁻ , (C ₆ H _{4 F)} 4 B ^-, and the like.

  Specific examples of the onium salt are shown below, but the present invention is not limited thereto.

In the above specific examples, X ⁻ represents PF ₆ ⁻ , SbF ₆ ⁻ , CF ₃ SO ₃ ⁻ , p-CH ₃ C ₆ H ₄ SO ₃ ⁻ , BF ₄ ⁻ , (C ₆ H ₅ ) ₄ B ^−. , RfSO ₃ ⁻ , (C ₆ F ₅ ) ₄ B ⁻ , or an anion represented by the following formula, Rf represents a perfluoroalkyl group.

  In the present invention, an onium salt compound represented by the following general formula (VI) or (VII) is particularly preferable.

In general formula (VI), Y represents a carbon atom or a sulfur atom, Ar ¹ represents an aryl group, and Ar ^{2 to} Ar ⁴ each independently represents an aryl group or an aromatic heterocyclic group. Ar ^{1 to} Ar ⁴ may be further substituted with a substituent.
Ar ¹ is preferably a fluoro-substituted aryl group or an aryl group substituted with at least one perfluoroalkyl group, more preferably a pentafluorophenyl group or a phenyl group substituted with at least one perfluoroalkyl group And particularly preferably a pentafluorophenyl group.
The aryl group and aromatic heterocyclic group of Ar ^{2 to} Ar ^{4 have} the same meanings as the aryl group and aromatic heterocyclic group of R ^{21 to} R ²³ and R ^{25 to} R ³³ described above, preferably an aryl group. Yes, more preferably a phenyl group. These groups may be further substituted with a substituent, and examples of the substituent include the above-described substituents R ^{21 to} R ³³ .

In General Formula (VII), Ar ¹ represents an aryl group, and Ar ⁵ and Ar ⁶ each independently represent an aryl group or an aromatic heterocyclic group. Ar ¹ , Ar ⁵ and Ar ⁶ may be further substituted with a substituent.
Ar ¹ has the same meaning as Ar ^{1 in the} general formula (VI), and the preferred range is also the same.
Ar ⁵ and Ar ⁶ are synonymous with Ar ^{2 to} Ar ^{4 in} the general formula (VI), and preferred ranges thereof are also the same.

The said onium salt compound can be manufactured by normal chemical synthesis. Moreover, a commercially available reagent etc. can also be used.
As an embodiment of the method for synthesizing the onium salt compound, a method for synthesizing triphenylsulfonium tetrakis (pentafluorophenyl) borate is shown below, but the present invention is not limited to this. Other onium salts can be synthesized by the same method.
2.68 g of triphenylsulfonium bromide (manufactured by Tokyo Chemical Industry), 5.00 g of lithium tetrakis (pentafluorophenyl) borate-ethyl ether complex (manufactured by Tokyo Chemical Industry) and 146 ml of ethanol were placed in a 500 ml three-necked flask and kept at room temperature for 2 hours. After stirring, 200 ml of pure water is added, and the precipitated white solid is collected by filtration. By washing the white solid with pure water and ethanol and vacuum drying, 6.18 g of triphenylsulfonium tetrakis (pentafluorophenyl) borate can be obtained as an onium salt.

2. Oxidizing agent, acidic compound, electron acceptor compound As the oxidizing agent used as a dopant in the present invention, halogen (Cl ₂ , Br ₂ , I ₂ , ICl, ICl ₃ , IBr ₃ , IF), Lewis acid (PF ₅ , AsF _{5) , SbF 5, BF 3, BCl} 3, BBr 3, SO 3), the transition metal compound _{(FeCl 3, FeOCl, TiCl 4} , ZrCl 4, HfCl 4, NbF 5, NbCl 5, TaCl 5, MoF 5, MoCl 5, WF ₆ , WCl ₆ , UF ₆ , LnCl ₃ (Ln = La, Ce, Pr, Nd, Sm and other lanthanoids), O ₂ , O ₃ , XeOF ₄ , (NO ₂ ⁺ ) (SbF ₆ ⁻ ), (NO ₂ ⁺ ) (SbCl ₆ ⁻ ), (NO ₂ ⁺ ) (BF ₄ ⁻ ), FSO ₂ OOSO ₂ F, AgClO ₄ , H ₂ IrCl ₆ , La (NO ₃ ) ₃ · 6H ₂ O, and the like.

Examples of the acidic compound include polyphosphoric acid, hydroxy compound, carboxy compound, or sulfonic acid compound, protonic acid (HF, HCl, HNO ₃ , H ₂ SO ₄ , HClO ₄ , FSO ₃ H, CISO ₃ H, CF ₃₎ SO ₃ H, various organic acids, amino acids, etc.).

  Examples of electron acceptor compounds include TCNQ (tetracyanoquinodimethane), tetrafluorotetracyanoquinodimethane, halogenated tetracyanoquinodimethane, 1,1-dicyanovinylene, 1,1,2-tricyanovinylene, benzoquinone. , Pentafluorophenol, dicyanofluorenone, cyano-fluoroalkylsulfonyl-fluorenone, pyridine, pyrazine, triazine, tetrazine, pyridopyrazine, benzothiadiazole, heterocyclic thiadiazole, porphyrin, phthalocyanine, boron quinolate compound, boron diketonate compound, Boron diisoindomethene compounds, carborane compounds, other boron atom-containing compounds, or Chemistry Letters, 1991, p. And electron accepting compounds described in 1707-1710.

-Polyphosphoric acid-
Polyphosphoric acid includes diphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, metaphosphoric acid and polyphosphoric acid, and salts thereof. A mixture thereof may be used. In the present invention, the polyphosphoric acid is preferably diphosphoric acid, pyrophosphoric acid, triphosphoric acid, or polyphosphoric acid, and more preferably polyphosphoric acid. Polyphosphoric acid can be synthesized by heating H ₃ PO ₄ with sufficient P ₄ O ₁₀ (anhydrous phosphoric acid) or by heating H ₃ PO ₄ to remove water.

-Hydroxy compounds-
The hydroxy compound may be a compound having at least one hydroxyl group, and preferably has a phenolic hydroxyl group. As the hydroxy compound, a compound represented by the following general formula (VIII) is preferable.

In general formula (VIII), R represents a sulfo group, a halogen atom, an alkyl group, an aryl group, a carboxy group, or an alkoxycarbonyl group, n represents 1 to 6, and m represents 0 to 5.
R is preferably a sulfo group, an alkyl group, an aryl group, a carboxy group, or an alkoxycarbonyl group, and more preferably a sulfo group.
n is preferably 1 to 5, more preferably 1 to 4, and still more preferably 1 to 3.
m is 0-5, 0-4 are preferable and 0-3 are more preferable.

-Carboxy compound-
The carboxy compound may be a compound having at least one carboxy group, and a compound represented by the following general formula (IX) or (X) is preferable.

In general formula (IX), A represents a divalent linking group. The divalent linking group is preferably a combination of an alkylene group, an arylene group or an alkenylene group and an oxygen atom, a sulfur atom or a nitrogen atom, and more preferably a combination of an alkylene group or an arylene group and an oxygen atom or a sulfur atom. preferable. When the divalent linking group is a combination of an alkylene group and a sulfur atom, the compound also corresponds to a thioether compound. The use of such a thioether compound is also suitable.
When the divalent linking group represented by A includes an alkylene group, the alkylene group may have a substituent. As the substituent, an alkyl group is preferable, and a carboxy group is more preferable as a substituent.

In general formula (X), R represents a sulfo group, a halogen atom, an alkyl group, an aryl group, a hydroxy group, or an alkoxycarbonyl group, n represents 1 to 6, and m represents 0 to 5.
R is preferably a sulfo group, an alkyl group, an aryl group, a hydroxy group or an alkoxycarbonyl group, more preferably a sulfo group or an alkoxycarbonyl group.
n is preferably 1 to 5, more preferably 1 to 4, and still more preferably 1 to 3.
m is 0-5, 0-4 are preferable and 0-3 are more preferable.

-Sulphonic acid compound-
The sulfonic acid compound is a compound having at least one sulfo group, and a compound having two or more sulfo groups is preferable. The sulfonic acid compound is preferably one substituted with an aryl group or an alkyl group, and more preferably one substituted with an aryl group.
In addition, in the hydroxy compound and carboxy compound demonstrated above, the compound which has a sulfo group as a substituent is classified into a hydroxy compound and a carboxy compound as mentioned above. Therefore, the sulfonic acid compound does not include a hydroxy compound having a sulfo group and a carboxy compound.

  In the present invention, it is not essential to use these dopants. However, the use of dopants is preferable because further improvement in thermoelectric conversion characteristics can be expected due to improvement in conductivity. When using a dopant, it can be used individually by 1 type or in combination of 2 or more types. The dopant is used in an amount of more than 0 parts by mass and 60 parts by mass or less with respect to 100 parts by mass of the copolymer represented by the general formula (1) from the viewpoint of controlling the optimum carrier concentration. It is preferable to use 2 to 50 parts by mass, and it is more preferable to use 5 to 40 parts by mass.

  Of the above dopants, it is preferable to use an onium salt compound from the viewpoint of improving the dispersibility of the thermoelectric conversion material and the film formability. The onium salt compound is neutral in a state before acid release, and decomposes upon application of energy such as light and heat to generate an acid, and this acid exhibits a doping effect. Therefore, after the thermoelectric conversion material is formed and processed into a desired shape, doping can be performed by light irradiation or the like to develop a doping effect. Furthermore, since it is neutral before acid release, each component such as the copolymer and nano-conductive material is uniformly dissolved or dispersed in the thermoelectric conversion material without agglomerating and precipitating the above-mentioned copolymer. To do. Due to the uniform solubility or dispersibility of this thermoelectric conversion material, it is possible to exhibit excellent conductivity after doping, and furthermore, good applicability and film formability can be obtained. Excellent.

<Excitation assist agent>
The thermoelectric conversion material of the present invention preferably contains a thermal excitation assisting agent in terms of further improving thermoelectric conversion characteristics. The thermal excitation assist agent is a substance having a molecular orbital having a specific energy level difference with respect to the energy level of the molecular orbital of the copolymer represented by the general formula (1). By using together, thermal excitation efficiency can be improved and the thermoelectromotive force of a thermoelectric conversion material can be improved.

The thermal excitation assisting agent used in the present invention is a compound having a LUMO having a lower energy level than the LUMO (Lowest Unoccupied Molecular Orbital) of the above-mentioned copolymer, Refers to a compound that does not form The aforementioned dopant is a compound that forms a dope level in the copolymer, and forms a dope level regardless of the presence or absence of a thermal excitation assisting agent.
Whether or not a doped level is formed in the copolymer can be evaluated by measuring an absorption spectrum. In the present invention, the compound that forms the doped level and the compound that does not form the doped level are evaluated by the following method. Say something.

-Evaluation method for the presence or absence of doped level formation-
The copolymer A before doping and the other component B are mixed at a mass ratio of 1: 1, and the absorption spectrum of the thinned sample is observed. As a result, when a new absorption peak different from the absorption peak of copolymer A alone or component B alone is generated, and this new absorption peak wavelength is longer than the absorption maximum wavelength of copolymer A It is determined that a doping level is generated in In this case, component B is defined as a dopant. On the other hand, when a new absorption peak does not exist in the absorption spectrum of the sample, component B is defined as an excitation assist agent.

The LUMO of the thermal excitation assisting agent has a lower energy level than the LUMO of the above-mentioned copolymer, and the acceptor level of thermally excited electrons generated from the HOMO (Highest Occupied Molecular Orbital) of the copolymer. Function as.
Furthermore, when the absolute value of the HOMO energy level of the copolymer and the absolute value of the LUMO energy level of the thermal excitation assist agent satisfy the following formula (I), the thermoelectric conversion material has excellent heat Equipped with an electromotive force.

Formula (I)
0.1 eV ≦ | HOMO of copolymer |-| LUMO of thermal excitation assist agent | ≦ 1.9 eV

The above formula (I) represents the energy difference between the LUMO of the thermal excitation assist agent and the HOMO of the copolymer, and when this is smaller than 0.1 eV (the LUMO energy level of the thermal excitation assist agent is that of the copolymer). Since the activation energy of electron transfer between the HOMO (donor) of the copolymer and the LUMO (acceptor) of the thermal excitation assisting agent is very small, Aggregation may occur due to an oxidation-reduction reaction between the coalescence and the thermal excitation assist agent. As a result, the film formability of the material is deteriorated and the conductivity is deteriorated. On the contrary, when the energy difference between both orbits is larger than 1.9 eV, the energy difference becomes much larger than the thermal excitation energy, so that almost no thermally excited carriers are generated, that is, the addition of the thermal excitation assisting agent. The effect may be almost lost. In order to improve the thermoelectromotive force of the thermoelectric conversion material, it is preferable that the energy difference between both orbits is within the range of the above formula (I).
Regarding the HOMO and LUMO energy levels of the copolymer and the thermal excitation assist agent, regarding the HOMO energy level, a single coating film (glass substrate) of each component was prepared, and the HOMO level was determined by photoelectron spectroscopy. Can be measured. Regarding the LUMO level, the LUMO energy can be calculated by measuring the band gap using an ultraviolet-visible spectrophotometer and then adding it to the HOMO energy measured above. In the present invention, the values measured and calculated by the method are used for the energy levels of HOMO and LUMO of the copolymer and the thermal excitation assist agent.

When the thermal excitation assist agent is used, the thermal excitation efficiency is improved and the number of thermally excited carriers is increased, so that the thermoelectromotive force of the thermoelectric conversion material is improved. Such an effect of improving the thermoelectromotive force by the thermal excitation assisting agent is different from the method of improving the thermoelectric conversion performance by the doping effect of the copolymer.
As can be seen from the above formula (A), in order to increase the thermoelectric conversion performance of the thermoelectric conversion material, the absolute value of the Seebeck coefficient S and the conductivity σ of the thermoelectric conversion material are increased, and the thermal conductivity κ is decreased. Good. The Seebeck coefficient is a thermoelectromotive force per 1 K absolute temperature.
The thermal excitation assist agent improves the thermoelectric conversion performance by increasing the Seebeck coefficient. When a thermal excitation assist agent is used, electrons generated by thermal excitation exist in the LUMO of the thermal excitation assist agent, which is the acceptor level, so that the holes on the copolymer and the electrons on the thermal excitation assist agent Exists physically apart. Therefore, the doped level of the copolymer is less likely to be saturated by electrons generated by thermal excitation, and the Seebeck coefficient can be increased.

  As the thermal excitation assist agent, a polymer containing at least one structure selected from a benzothiadiazole skeleton, a benzothiazole skeleton, a dithienosilol skeleton, a cyclopentadithiophene skeleton, a thienothiophene skeleton, a thiophene skeleton, a fluorene skeleton, and a phenylene vinylene skeleton Compounds, fullerene compounds, phthalocyanine compounds, perylene dicarboxyimide compounds, or tetracyanoquinodimethane compounds are preferred, and are from benzothiadiazole skeleton, benzothiazole skeleton, dithienosilole skeleton, cyclopentadithiophene skeleton, and thienothiophene skeleton. Polymer compound, fullerene compound, phthalocyanine compound, perylene dicarboxyimide compound, or tetracyanoquinodime containing at least one selected structure Emissions-based compounds are more preferable.

  Although the following can be illustrated as a specific example of the thermal excitation assist agent which satisfy | fills the above-mentioned characteristic, this invention is not limited to these. In the following exemplary compounds, n represents an integer (preferably an integer of 10 or more), and Me represents a methyl group.

In the thermoelectric conversion material of the present invention, the thermal excitation assisting agent can be used alone or in combination of two or more.
The content of the thermal excitation assisting agent in the thermoelectric conversion material is preferably 0 to 35% by mass, more preferably 3 to 25% by mass, and 5 to 20% by mass in the total solid content. Is particularly preferred.
The thermal excitation assist agent is preferably used in an amount of 0 to 100 parts by weight, more preferably 5 to 70 parts by weight, and more preferably 10 to 50 parts by weight, based on 100 parts by weight of the copolymer. Is more preferable.

<Metal element>
The thermoelectric conversion material of the present invention preferably contains a metal element as a simple substance, ions, or the like from the viewpoint of improving thermoelectric conversion characteristics. When a metal element is added, the transport of electrons is promoted by the metal element in the formed thermoelectric conversion layer, so that it is considered that the thermoelectric conversion characteristics are improved. The metal element is not particularly limited, but is preferably a metal element having an atomic weight of 45 to 200, more preferably a transition metal element, and zinc, iron, palladium, nickel, cobalt, molybdenum, platinum, and tin in terms of thermoelectric conversion characteristics. It is particularly preferred. Regarding the addition amount of the metal element, if the addition amount is too small, the effect of improving the thermoelectric conversion characteristics will not be sufficiently manifested. May decrease. Therefore, the concentration of the metal element in the solid content of the thermoelectric conversion material of the present invention, that is, in the thermoelectric conversion layer is preferably 50 to 30000 ppm, more preferably 100 to 10000 ppm, and 200 to 5000 ppm. Is particularly preferred.
Regarding the method for measuring the metal element concentration in the thermoelectric conversion material of the present invention, for example, an ICP mass spectrometer (for example, “ICPM-8500” (trade name) manufactured by Shimadzu Corporation), energy dispersive X-ray fluorescence analysis It can be quantified by a known analysis method such as an apparatus (for example, “EDX-720” (trade name) manufactured by Shimadzu Corporation).

<Other ingredients>
The thermoelectric conversion material of the present invention may appropriately contain an antioxidant, a light stabilizer, a heat stabilizer, a plasticizer and the like in addition to the above components. The content of these components is preferably 5% by mass or less, and more preferably 0 to 2% by mass in the total solid content of the material.
Antioxidants include Irganox 1010 (manufactured by Cigabi Nippon), Sumilizer GA-80 (manufactured by Sumitomo Chemical Co., Ltd.), Sumilizer GS (manufactured by Sumitomo Chemical Co., Ltd.), Sumilizer GM (Sumitomo Chemical Industries, Ltd.) Manufactured) and the like. Examples of the light-resistant stabilizer include TINUVIN 234 (manufactured by BASF), CHIMASSORB 81 (manufactured by BASF), and Siasorb UV-3853 (manufactured by Sun Chemical). IRGANOX 1726 (made by BASF) is mentioned as a heat-resistant stabilizer. Examples of the plasticizer include Adeka Sizer RS (manufactured by Adeka).

<Preparation of thermoelectric conversion material>
The thermoelectric conversion material of the present invention can be prepared by mixing the above components. Preferably, the nanoconductive material and the copolymer represented by the above general formula (1) are added to a solvent and mixed, and each component is dissolved or dispersed. At this time, each component in the thermoelectric conversion material is preferably in a dispersed state of the nano-conductive material, and other components such as the copolymer are dispersed or dissolved, and the components other than the nano-conductive material are dissolved. It is more preferable that It is preferable that components other than the nano-conductive material are in a dissolved state because an effect of suppressing the decrease in conductivity due to the grain boundary can be obtained. The dispersed state is an aggregate state of molecules having a particle size that does not settle in a solvent even when stored for a long time (generally 1 month or longer), and a dissolved state is in a solvent. A state in which one molecule is solvated.
There is no restriction | limiting in particular in the preparation method of a thermoelectric conversion material, It can carry out under normal temperature normal pressure using a normal mixing apparatus etc. For example, each component may be prepared by stirring, shaking, kneading, dissolving or dispersing in a solvent. Sonication may be performed to promote dissolution and dispersion.
Further, in the dispersion step, the dispersibility of the nano-conductive material is increased by heating the solvent to a temperature not lower than the room temperature and not higher than the boiling point, extending the dispersion time, or increasing the applied strength of stirring, soaking, kneading, ultrasonic waves, etc. Can be increased.

  The thermoelectric conversion material of the present invention thus prepared preferably has a moisture content of 0.01% by mass to 15% by mass. In the thermoelectric conversion material containing the above-described copolymer and nanoconductive material as essential components, when the moisture content is in the above range, high thermoelectric conversion performance can be obtained while maintaining excellent coatability and film formability. Can do. Further, even when the thermoelectric conversion material is used under high temperature conditions, corrosion of the electrode and decomposition of the material itself can be suppressed. Since thermoelectric conversion materials are used in a high temperature state for a long time, there is a problem that electrode corrosion or decomposition reaction of the material itself is likely to occur due to the influence of moisture in the thermoelectric conversion material. By doing so, various problems caused by moisture in the thermoelectric conversion material can be improved.

The moisture content of the thermoelectric conversion material is more preferably 0.01% by mass or more and 10% by mass or less, and further preferably 0.1% by mass or more and 5% by mass or less.
The moisture content of the thermoelectric conversion material can be evaluated by measuring the equilibrium moisture content at a constant temperature and humidity. The equilibrium moisture content was allowed to stand for 6 hours at 25 ° C. and 60% RH, and then reached equilibrium. Then, Karl Fischer was used with a moisture meter and a sample drying apparatus (CA-03, VA-05, both Mitsubishi Chemical Corporation). The water content (g) can be calculated by dividing the moisture content (g) by the sample weight (g).

  The moisture content of the thermoelectric conversion material is determined by leaving the thermoelectric conversion material in a constant temperature and humidity chamber (temperature 25 ° C., humidity 85% RH) (in the case of improving the moisture content) or in a vacuum dryer (temperature 25 ° C.). It can control by making it dry (when water content is reduced). Further, when preparing the thermoelectric conversion material, a necessary amount of water is added to the solvent (in order to improve the water content), or a dehydrating solvent (for example, various dehydrating solvents manufactured by Wako Pure Chemical Industries, Ltd.) can be mentioned. The water content can also be controlled by mixing each component (when reducing the water content) in a glove box under a nitrogen atmosphere using.

[Thermoelectric conversion element]
The thermoelectric conversion element of the present invention has a first electrode, a thermoelectric conversion layer, and a second electrode on a substrate, and the thermoelectric conversion layer is represented by the nano-conductive material and the general formula (1) described above. Containing a copolymer.

The thermoelectric conversion element of this invention should just have a 1st electrode, a thermoelectric conversion layer, and a 2nd electrode on a base material, The position of a 1st electrode, a 2nd electrode, and a thermoelectric conversion layer There are no particular limitations on other configurations such as relationships. In the thermoelectric conversion element of the present invention, the thermoelectric conversion layer may be disposed on at least one surface thereof so as to be in contact with the first electrode and the second electrode. For example, the thermoelectric conversion layer is sandwiched between the first electrode and the second electrode, that is, the thermoelectric conversion element of the present invention has the first electrode, the thermoelectric conversion layer, and the second electrode in this order on the base material. It may be an embodiment. Further, the thermoelectric conversion layer is disposed on one surface thereof so as to be in contact with the first electrode and the second electrode, that is, the thermoelectric conversion element of the present invention is formed on the substrate so as to be separated from each other. The aspect which has the thermoelectric conversion layer laminated | stacked on the 1st electrode and the 2nd electrode may be sufficient.
As an example of the structure of the thermoelectric conversion element of the present invention, the structure of the element shown in FIGS. 1 and 2, the arrows indicate the direction of temperature difference when the thermoelectric conversion element is used.
The thermoelectric conversion element 1 shown in FIG. 1 includes a pair of electrodes including a first electrode 13 and a second electrode 15 on a first base 12, and the thermoelectric conversion material of the present invention between the electrodes 13 and 15. The thermoelectric conversion layer 14 formed by is provided. A second base material 16 is disposed on the other surface of the second electrode 15, and the metal plates 11 and 17 face each other outside the first base material 12 and the second base material 16. Is arranged.
In the thermoelectric conversion element of the present invention, it is preferable to provide a thermoelectric conversion layer in the form of a film (film) with the thermoelectric conversion material of the present invention on the base material via an electrode, and this base material functions as the first base material. . That is, the thermoelectric conversion element 1 is provided with the first electrode 13 or the second electrode 15 on the surface of the two base materials 12 and 16 (formation surface of the thermoelectric conversion layer 14), and between these electrodes 13 and 15. It is preferable that the structure has a thermoelectric conversion layer 14 formed of the thermoelectric conversion material of the present invention.

  The thermoelectric conversion element 2 shown in FIG. 2 is provided with a first electrode 23 and a second electrode 25 on a first base material 22, and a thermoelectric conversion formed on the thermoelectric conversion material of the present invention on the first electrode 23 and the second electrode 25. A layer 24 is provided.

  One surface of the thermoelectric conversion layer 14 of the thermoelectric conversion element 1 is covered with the first base material 12 via the first electrode 13, while the thermoelectric conversion layer 24 of the thermoelectric conversion element 2 is Is covered with the first electrode 23, the second electrode 25 and the first base material 22, but the second base material 16 or 26 is also applied to the other surface via the second electrode 15. Alternatively, it is preferable to perform pressure bonding without using an electrode from the viewpoint of protecting the thermoelectric conversion layers 14 and 24. That is, it is preferable that the second electrode 15 is formed in advance on the surface of the second base material 16 used for the thermoelectric conversion element 1 (the pressure contact surface of the thermoelectric conversion layer 14). Moreover, in the thermoelectric conversion elements 1 and 2, it is preferable to perform the crimping | compression-bonding with an electrode and a thermoelectric conversion layer by heating to about 100 to 200 degreeC from a viewpoint of adhesive improvement.

  As the base material of the thermoelectric conversion element of the present invention and the first base material 12 and the second base material 16 in the thermoelectric conversion element 1, base materials such as glass, transparent ceramics, metal, and plastic film can be used. In the thermoelectric conversion element of the present invention, it is preferable that the base material has flexibility. Specifically, the flexibility in which the number of bending resistances MIT according to the measurement method specified in ASTM D2176 is 10,000 cycles or more. It is preferable to have. The substrate having such flexibility is preferably a plastic film, specifically, polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), Polyethylene-2,6-phthalenedicarboxylate, polyester film such as polyester film of bisphenol A and iso and terephthalic acid, ZEONOR film (trade name, manufactured by Zeon Corporation), ARTON film (trade name, manufactured by JSR Corporation), Sumilite Polycycloolefin films such as FS1700 (trade name, manufactured by Sumitomo Bakelite), Kapton (trade name, manufactured by Toray DuPont), Apical (trade name, manufactured by Kaneka), Upilex (trade name, Ube Ko) Polyimide films such as Pomilan (trade name, manufactured by Arakawa Chemical Co., Ltd.), polycarbonate films such as Pure Ace (trade name, manufactured by Teijin Kasei Co., Ltd.), Elmec (trade name, manufactured by Kaneka Corporation), Sumilite FS1100 (trade name) Polyether ether ketone films such as Sumitomo Bakelite Co., Ltd., and polyphenyl sulfide films such as Torelina (trade name, manufactured by Toray Industries, Inc.). Although it is appropriately selected depending on the use conditions and environment, commercially available polyethylene terephthalate, polyethylene naphthalate, various polyimides, polycarbonate films, and the like are preferable from the viewpoints of availability, preferably heat resistance of 100 ° C. or higher, economy, and effects.

  In particular, it is preferable to use a base material in which an electrode is provided on the pressure-bonding surface with the thermoelectric conversion layer. As electrode materials for forming the first electrode and the second electrode provided on the base material, transparent electrodes such as ITO and ZnO, metal electrodes such as silver, copper, gold and aluminum, and carbon materials such as CNT and graphene An organic material such as PEDOT / PSS, a conductive paste in which conductive fine particles such as silver and carbon are dispersed, and a conductive paste containing metal nanowires such as silver, copper, and aluminum can be used. Among these, aluminum, gold, silver or copper is preferable. At this time, the thermoelectric conversion element 1 is configured in the order of the base material 11, the first electrode 13, the thermoelectric conversion layer 14, and the second electrode 15, and the second base material is disposed outside the second electrode 15. Even if 16 adjoins, the 2nd electrode 15 may be exposed to air as the outermost surface, without providing the 2nd substrate 16. The thermoelectric conversion element 2 includes a base material 22, a first electrode 23, a second electrode 25, and a thermoelectric conversion layer 24 in this order. A second base material 26 is disposed outside the thermoelectric conversion layer 24. Even if it adjoins, the thermoelectric conversion layer 24 may be exposed to air as the outermost surface, without providing the 2nd base material 26. FIG.

  The thickness of the substrate is preferably 30 to 3000 μm, more preferably 50 to 1000 μm, still more preferably 100 to 1000 μm, and particularly preferably 200 to 800 μm, from the viewpoints of handleability and durability. If the substrate is too thick, the thermal conductivity may decrease, and if it is too thin, the film may be easily damaged by external impact.

  The thermoelectric conversion layer of the thermoelectric conversion element of the present invention is preferably formed of the thermoelectric conversion material of the present invention, and in addition to these, preferably contains at least one of the non-conjugated polymer and the thermal excitation assist agent described above, A dopant or a decomposition product thereof, a metal element, and other components may be contained. These components and contents in the thermoelectric conversion layer are as described above.

The layer thickness of the thermoelectric conversion layer is preferably 0.1 to 1000 μm, and more preferably 1 to 100 μm. If the layer thickness is thin, it is not preferable because it is difficult to provide a temperature difference and the resistance in the layer increases.
In general, a thermoelectric conversion element can be easily manufactured as compared with a photoelectric conversion element such as an organic thin film solar cell element. In particular, when the thermoelectric conversion material of the present invention is used, it is not necessary to consider the light absorption efficiency as compared with the element for an organic thin film solar cell, so that it is possible to increase the film thickness by about 100 to 1000 times. Chemical stability against moisture is improved.

The thermoelectric conversion layer preferably has a moisture content of 0.01% by mass to 15% by mass. When the moisture content of the thermoelectric conversion layer is within the above range, high thermoelectric conversion performance can be obtained. Furthermore, even if the thermoelectric conversion element is used under high temperature conditions, corrosion of the electrode and decomposition of the thermoelectric conversion layer itself can be suppressed. The moisture content of the thermoelectric conversion layer is more preferably 0.01% by mass or more and 10% by mass or less, and further preferably 0.1% by mass or more and 5% by mass or less.
The moisture content of the thermoelectric conversion layer can be evaluated by measuring the equilibrium moisture content at a constant temperature and humidity. The equilibrium moisture content was allowed to stand for 6 hours at 25 ° C. and 60% RH, and then reached equilibrium. Then, Karl Fischer was used with a moisture meter and a sample drying apparatus (CA-03, VA-05, both Mitsubishi Chemical Corporation). It can be calculated by measuring by the method and dividing the amount of water (g) by the sample mass (g).

The method for forming the thermoelectric conversion layer is not particularly limited. For example, spin coating, extrusion die coating, blade coating, bar coating, screen printing, stencil printing, roll coating, curtain coating, spray coating, dip coating, and the like are known. A coating method can be used. Among these, screen printing is particularly preferable from the viewpoint of excellent adhesion of the thermoelectric conversion layer to the electrode.
After application, a drying process is performed as necessary. For example, the solvent can be volatilized and dried by spraying with heat and hot air.

(Moisture content control processing)
The moisture content control process is preferably performed after the thermoelectric conversion material is formed into a film and before or after doping by applying energy, which will be described later, and more preferably before doping. For example, each component of the nano-conductive material and copolymer is mixed and dispersed in a solvent, and the mixture is molded, formed into a film, etc., and then subjected to a moisture content control treatment to obtain a moisture content within the above range. Is preferred. The moisture content control process can employ the above-mentioned method as appropriate.
The moisture content control process is a method for controlling the moisture content of the thermoelectric conversion material of the present invention. The applied thermoelectric conversion material of the present invention is dried in a vacuum dryer (temperature 25 ° C.) (when the moisture content is reduced). The method of making it preferable is.

(Doping by applying energy)
When the thermoelectric conversion material contains the above-described onium salt compound as a dopant, after film formation or after moisture content control treatment, the film is irradiated or heated to perform doping treatment to improve conductivity. It is preferable to make it. By this treatment, an acid is generated from the onium salt compound, and this acid protonates the above-described copolymer, thereby doping the copolymer with a positive charge (p-type doping).
Active energy rays include radiation and electromagnetic waves, and radiation includes particle beams (high-speed particle beams) and electromagnetic radiation. Particle rays include alpha rays (α rays), beta rays (β rays), proton rays, electron rays (which accelerates electrons with an accelerator regardless of nuclear decay), charged particle rays such as deuteron rays, Examples of the electromagnetic radiation include gamma rays (γ rays) and X-rays (X rays, soft X rays). Examples of the electromagnetic wave include radio waves, infrared rays, visible rays, ultraviolet rays (near ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays), X-rays, gamma rays, and the like. The line type used in the present invention is not particularly limited. For example, an electromagnetic wave having a wavelength near the maximum absorption wavelength of the onium salt compound (acid generator) to be used may be appropriately selected.
Among these active energy rays, ultraviolet rays, visible rays, and infrared rays are preferable from the viewpoint of doping effect and safety, specifically, 240 to 1100 nm, preferably 240 to 850 nm, and more preferably 240 to 670 nm. It is a light beam having an emission wavelength.

Radiation or an electromagnetic wave irradiation device is used for irradiation with active energy rays. The wavelength of the radiation or electromagnetic wave to be irradiated is not particularly limited, and a radiation or electromagnetic wave in a wavelength region corresponding to the sensitive wavelength of the onium salt compound to be used may be selected.
Examples of devices that can irradiate radiation or electromagnetic waves include LED lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, deep UV lamps, low-pressure UV lamps and other mercury lamps, halide lamps, xenon flash lamps, metal halide lamps, ArF excimer lamps, and KrF excimer lamps. There are exposure apparatuses using a light source such as an excimer lamp, an extreme ultraviolet light lamp, an electron beam, or an X-ray lamp. The ultraviolet irradiation can be performed using a normal ultraviolet irradiation apparatus, for example, a commercially available ultraviolet irradiation apparatus for curing / adhesion / exposure (USHIO INC. SP9-250UB, etc.).

The exposure time and the amount of light may be appropriately selected in consideration of the type of onium salt compound to be used and the doping effect. Specifically, the light intensity is 10 mJ / cm ^{2 to} 10 J / cm ² , preferably 50 mJ / cm ^{2 to 5} J / cm ² .

  When doping is performed by heating, the formed film may be heated above the temperature at which the onium salt compound generates an acid. The heating temperature is preferably 50 to 200 ° C, more preferably 70 to 150 ° C. The heating time is preferably 1 to 60 minutes, more preferably 3 to 30 minutes.

  Although the timing of the doping treatment is not particularly limited, it is preferably performed after the thermoelectric conversion material of the present invention is processed, such as film formation.

The thermoelectric conversion layer (also referred to as thermoelectric conversion film) formed of the thermoelectric conversion material of the present invention and the thermoelectric conversion element of the present invention have a high thermoelectric conversion performance index ZT, excellent initial thermoelectric conversion performance, and high temperature and high temperature. Even in a severe environment such as humidity, the thermoelectric conversion performance is stable over time and high initial thermoelectric conversion performance can be maintained over a long period of time.
Therefore, the thermoelectric conversion element of the present invention can be suitably used as a power generation element of an article for thermoelectric power generation. Specific examples of such power generation elements include power generators such as hot spring thermal generators, solar thermal generators, waste heat generators, wristwatch power supplies, semiconductor drive power supplies, (small) sensor power supplies, and the like.
The thermoelectric conversion material of the present invention and the thermoelectric conversion layer formed of the thermoelectric conversion material of the present invention are suitably used as the thermoelectric conversion element, thermoelectric power generation element material, thermoelectric power generation film, or various conductive films of the present invention. Specifically, it is suitably used as the above-described thermoelectric conversion material for a power generation element or a film for thermoelectric power generation.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to them.

[Synthesis of copolymer and homopolymer]
Copolymers 1 to 7 and homopolymers 1 to 4 were synthesized as follows using the following monomers as aniline derivatives or pyrrole derivatives.

Synthesis Example 1 (Synthesis of Copolymer 1)
The monomer 1 (1 mmol) and the monomer 2 (99 mmol) were dissolved in 100 mL of a toluene / butyl acetate mixed solvent (volume ratio 80/20) to prepare an aniline derivative solution 1.
As an oxidizing agent, FeCl ₃ (300 mmol) was dissolved in 250 mL of a toluene / butyl acetate mixed solvent (volume ratio 80/20) and filtered through a reactor equipped with a thermometer, a stirrer, and an air introduction tube to remove insoluble matters. Prepared. While blowing air into the reaction solution at 60 mL / h, the aniline derivative solution 1 was dropped from the dropping funnel and reacted at a reaction temperature of 25 ± 5 ° C. for 5 hours. After the reaction, methanol was added to stop the reaction. The following copolymer 1 was obtained by filtering, washing and neutralizing the reaction slurry. The weight average molecular weight of this copolymer 1 was 25,000. This molecular weight was determined by GPC measurement using a mixed solution of dimethylformamide and tetrahydrofuran as a solvent and polystyrene as a standard sample. The following molecular weights were determined in the same manner.

Synthesis Example 2 (Synthesis of Copolymer 2)
Instead of the aniline derivative solution 1, the aniline derivative solution 2 prepared by dissolving the monomer 1 (99 mmol) and the monomer 2 (1 mmol) in 100 mL of a toluene / butyl acetate mixed solvent (volume ratio 80/20) was used. The following copolymer 2 was obtained in the same manner as in Synthesis Example 1. The weight average molecular weight of this copolymer 2 was 35,000.

Synthesis Example 3 (Synthesis of Copolymer 3)
Instead of the aniline derivative solution 1, the aniline derivative solution 3 prepared by dissolving the monomer 3 (50 mmol) and the monomer 4 (50 mmol) in 100 mL of a toluene / butyl acetate mixed solvent (volume ratio 80/20) was used. Produced the following copolymer 3 in the same manner as in Synthesis Example 1. The weight average molecular weight of this copolymer 3 was 27,000.

Synthesis Example 4 (Synthesis of Copolymer 4)
Instead of aniline derivative solution 1, pyrrole derivative solution 1 prepared by dissolving monomer 5 (75 mmol) and monomer 6 (25 mmol) in 100 mL of a toluene / butyl acetate mixed solvent (volume ratio 80/20) was used. The following copolymer 4 was obtained in the same manner as in Synthesis Example 1. The weight average molecular weight of this copolymer 4 was 38,000.

Synthesis Example 5 (Synthesis of Copolymer 5)
Instead of aniline derivative solution 1, pyrrole derivative solution 2 prepared by dissolving monomer 5 (25 mmol) and monomer 7 (75 mmol) in 100 mL of a toluene / butyl acetate mixed solvent (volume ratio 80/20) was used. The following copolymer 5 was obtained in the same manner as in Synthesis Example 1. The weight average molecular weight of this copolymer 5 was 33,000.

Synthesis Example 6 (Synthesis of copolymer 6)
Instead of the aniline derivative solution 1, the pyrrole derivative solution 3 prepared by dissolving the monomer 8 (75 mmol) and the monomer 9 (25 mmol) in 100 mL of a toluene / butyl acetate mixed solvent (volume ratio 80/20) was used. Produced the following copolymer 6 in the same manner as in Synthesis Example 1. The weight average molecular weight of this copolymer 6 was 31,000.

Synthesis Example 7 (Synthesis of Copolymer 7)
Under a nitrogen atmosphere, the monomer 10 (50 mmol) and the monomer 11 (50 mmol) were added to Pd ₂ dba ₃ (1 mmol), tris (o-tolyl) phosphine (4 mmol, 20 mass% tetraethylammonium hydroxide (0.5 mL). After the reaction, the reaction was stopped by adding 300 mL of methanol, and the reaction slurry was filtered, washed, neutralized, and deprotected to give the following copolymer 7. This copolymer 7 had a weight average molecular weight of 12,000.

Comparative Synthesis Example 1 (Synthesis of homopolymer 1)
A reaction was carried out in the same manner as in Synthesis Example 1 using only the monomer 1 (100 mmol) to obtain a homopolymer 1. This homopolymer 1 was insoluble in orthodichlorobenzene, and the weight average molecular weight could not be determined.

Comparative Synthesis Example 2 (Synthesis of homopolymer 2)
Reaction was carried out in the same manner as in Example 1 using only the monomer 2 (100 mmol) to obtain a homopolymer 2 having a weight average molecular weight of 25,000.

Comparative Synthesis Example 3 (Synthesis of homopolymer 3)
A reaction was carried out in the same manner as in Example 1 using only the monomer 5 (100 mmol) to obtain a homopolymer 3. This homopolymer 3 was insoluble in orthodichlorobenzene, and the weight average molecular weight could not be determined.

Comparative Synthesis Example 4 (Synthesis of homopolymer 4)
A reaction was carried out in the same manner as in Example 1 using only the monomer 9 (15 mmol) to obtain a homopolymer 4. This homopolymer 4 was insoluble in orthodichlorobenzene, and the weight average molecular weight could not be determined.

Example 1 [Tape peeling test]
Copolymer 1 4 mg, single-walled CNT (ASP-100F, manufactured by Hanwha Nanotech, dispersion (CNT concentration 60% by mass), CNT average length 10 μm, diameter 1.1 nm) 3 mg and dopant 2 mg shown below, It was added to 4.0 mL of orthodichlorobenzene and dispersed in an ultrasonic water bath for 70 minutes. This mixed solution was applied as a bar to the electrode surface of a polyethylene terephthalate film (thickness: 125 μm) having gold (thickness 20 nm, length 1 cm, width 1 cm) as an electrode on one side surface, and heated to 80 ° C. After removing the solvent by heating for 80 minutes. Then, the thermoelectric conversion layer 101 of this invention which is the thermoelectric conversion layer 14 was formed into a film by making it dry under a 80 degreeC vacuum for 8 hours. In addition, the polyethylene terephthalate film used in Example 1 had the flexibility that the number of bending resistances MIT by the measurement method specified in the above-mentioned ASTM D2176 was 50,000 cycles or more.

  The thermoelectric conversion layers 102 to 111 of the present invention and the comparative thermoelectric conversion layer are the same as the thermoelectric conversion layer 101 except that the type of copolymer, the presence or absence of dopants, and / or the type of solvent are changed as shown in Table 1. c101 to c104 were deposited.

Each of the thermoelectric conversion layers 101 to 111 (excluding 108) and c101 to c104 produced as described above is dried and then irradiated with ultraviolet rays using an ultraviolet irradiation machine (ECS-401GX, manufactured by Eye Graphics Co., Ltd.). (Light amount: 1.06 J / cm ² ) was doped. Then, scotch tape (trade name, manufactured by Sumitomo 3M Co., Ltd.) is affixed to the surface of the thermoelectric conversion layer so that bubbles do not enter, and the scotch tape is peeled off vigorously to perform a peel test. It was.
The peel test was evaluated in five stages according to the peel area of the thermoelectric conversion layer. That is, A when the thermoelectric conversion layer was not peeled at all, B when the area was peeled off more than 0% and 25% or less, and C and 75% when the area was peeled more than 25% and 75% or less. The case where it exceeded and less than 100% peeled was set to D, and the case where it peeled the whole surface was set to E. In the tape peeling test, it can be determined that the smaller the area of the peeled thermoelectric conversion layer is, the better the adhesion to the first electrode 12 is. When the evaluation result is B or more, practically sufficient electrode adhesion is exhibited. . The results are shown in Table 1.

As is clear from Table 1, the thermoelectric of the present invention comprising a polyaniline copolymer having two types of copolymer units derived from aniline or pyrrole, copolymers 1 to 7 containing a polypyrrole copolymer, and CNTs. All of the conversion layers 101 to 111 had high adhesion to the first electrode 12. This is highly dispersed even in the presence of carbon nanotubes, which are suitable nano-conductive materials for polyaniline copolymers and polypyrrole copolymers having two types of copolymer units derived from aniline or pyrrole. Thus, it is difficult to form aggregates, and it is considered that the thermoelectric conversion layer containing these polyaniline copolymer and polypyrrole copolymer and carbon nanotubes exhibited high electrode adhesion.
The thermoelectric conversion layers 101 and 108 to 110 of the present invention using the copolymer 1 and the halogen-based solvent have an evaluation result of A for the tape peeling test, and the thermoelectric conversion of the present invention using the copolymer 1 and tetrahydrofuran. It was superior to the evaluation result B of the layer 111 and had high adhesion.
On the other hand, since homopolymers 1, 3 and 4 are all insoluble in orthodichlorobenzene, and homopolymer 2 is soluble in orthodichlorobenzene, the influence of hydrophobic substituents is large. The comparative thermoelectric conversion layers c101 to c104 using the homopolymers 1 to 4 were all inferior in adhesion to the first electrode 12.

Example 2 [Measurement of Thermoelectric Characteristics (Thermoelectric Power S)]
4 mg of the copolymer 1, 3 mg of single-walled CNT (ASP-100F, manufactured by Hanwha Nanotech) and 2 mg of the above-mentioned dopant were added to 4.0 mL of orthodichlorobenzene, and dispersed in an ultrasonic water bath for 70 minutes. This mixed solution is used as a first electrode 12 (thickness 20 nm, length 1 cm, width: 1 cm) on a surface of the electrode 12 of a base material 11 made of a polyethylene terephthalate film (thickness: 125 μm) having gold on one surface. After removing the solvent by heating at 80 ° C. for 80 minutes. Then, the thermoelectric conversion layer 14 was formed by making it dry under a 80 degreeC vacuum for 8 hours. After drying, the thermoelectric conversion layer 14 was doped by irradiating with ultraviolet rays (light quantity: 1.06 J / cm ² ) with an ultraviolet irradiator (ECS-401GX, manufactured by Eye Graphics Co., Ltd.). Thereafter, a base material 16 made of a polyethylene terephthalate film (thickness: 125 μm) on which gold was vapor-deposited as a second electrode 15 (thickness 20 nm, length 1 cm, width: 1 cm) was formed on the thermoelectric conversion layer 14. The thermoelectric conversion element 201 of the present invention, which is the thermoelectric conversion element 1 shown in FIG. 1, was manufactured by bonding at 80 ° C. so that the electrode 15 was opposed to the thermoelectric conversion layer 14. In addition, the polyethylene terephthalate film used in Example 2 had the flexibility that the number of bending resistances MIT according to the measurement method specified in ASTM D2176 was 50,000 cycles or more.

  The thermoelectric conversion layers 202 to 211 of the present invention and comparative thermoelectrics are the same as the thermoelectric conversion element 201 except that the type or presence of the copolymer, the presence or absence of the dopant, and / or the type of the solvent are changed as shown in Table 2. Conversion layers c201 to c205 were formed. In addition, when the dopant is not used, the doping process by the above-mentioned ultraviolet irradiation is not implemented.

About each thermoelectric conversion element 201-211 and c201-c205 produced as mentioned above, the thermoelectromotive force per unit temperature difference (it is also called a thermoelectric characteristic) was measured with the following method.
The first electrode 13 of the thermoelectric conversion element was placed on a hot plate maintained at a constant temperature, and a temperature control Peltier element was placed on the second electrode 15. While maintaining the temperature of the hot plate constant (100 ° C.), the temperature of the Peltier element was lowered to give a temperature difference (over 0K to 10K or less) between both electrodes. At this time, the thermoelectromotive force S (μV / K) per unit temperature difference is obtained by dividing the thermoelectromotive force (μV) generated between both electrodes by the specific temperature difference (K) generated between both electrodes. This value was calculated as the thermoelectric characteristic value of the thermoelectric conversion element. The calculated thermoelectric characteristic values are shown in Table 2 as relative values to the calculated values of the comparative thermoelectric conversion element c205 (the calculated value of the thermoelectric conversion element c205 is set to “50”).

As is apparent from Table 2, the thermoelectric of the present invention comprising a polyaniline copolymer having two types of copolymer units derived from aniline or pyrrole, copolymers 1 to 7 containing a polypyrrole copolymer, and CNT. All of the conversion elements 201 to 211 exhibited high thermoelectric conversion performance. The reason for this is considered to be that the copolymers 1 to 7 are highly dispersed even in the presence of suitable carbon nanotubes as described in Example 1.
Moreover, the thermoelectric conversion layers 201 and 208 to 210 of the present invention using the copolymer 1 and the halogen-based solvent have higher thermoelectric conversion performance than the thermoelectric conversion layer 211 of the present invention using the copolymer 1 and tetrahydrofuran. Had.
On the other hand, homopolymers 1, 3 and 4 were all insoluble in a solvent such as orthodichlorobenzene, and were not sufficiently dispersed when mixed with carbon nanotubes and aggregated. As a result, the comparative thermoelectric conversion elements c201, c203, and c204 were inferior in thermoelectric characteristics. Although the homopolymer 2 was dissolved in orthodichlorobenzene, the influence of the hydrophobic substituent was great, and the thermoelectric conversion element c202 was inferior in thermoelectric characteristics.

Example 3 [Addition of metal element]
Copolymer 1 4 mg, single-walled CNT (ASP-100F, manufactured by Hanwha Nanotech) 3 mg, and palladium chloride at an addition amount shown in Table 3 were added to 4.0 mL of orthodichlorobenzene, and 70 times in an ultrasonic water bath. Dispersed for minutes. This mixed solution is used as a first electrode 12 (thickness 20 nm, length 1 cm, width: 1 cm) on a surface of the electrode 12 of a base material 11 made of a polyethylene terephthalate film (thickness: 125 μm) having gold on one surface. After removing the solvent by heating at 80 ° C. for 80 minutes. Then, the thermoelectric conversion layer 14 was formed by making it dry under a 80 degreeC vacuum for 8 hours. Thereafter, a base material 16 made of a polyethylene terephthalate film (thickness: 125 μm) on which gold was vapor-deposited as a second electrode 15 (thickness 20 nm, length 1 cm, width: 1 cm) was formed on the thermoelectric conversion layer 14. The thermoelectric conversion element 301 of the present invention, which is the thermoelectric conversion element 1 shown in FIG. 1, was produced by bonding at 80 ° C. so that the electrode 15 faces the thermoelectric conversion layer 14. In addition, the polyethylene terephthalate film used in Example 3 had the flexibility that the number of bending resistances MIT by the measurement method specified in the above-mentioned ASTM D2176 was 50,000 cycles or more.

  Thermoelectric conversion elements 302 to 304 of the present invention were produced in the same manner as the thermoelectric conversion element 301 except that the type or addition amount of the metal salt was changed as shown in Table 3.

  For each of the thermoelectric conversion elements 301 to 304 manufactured as described above, the thermoelectric characteristics were measured in the same manner as in Example 2, and the calculated thermoelectric characteristic value was used as a relative value with respect to the calculated value of the comparative thermoelectric conversion element c205. The results are shown in Table 3.

  As is apparent from Table 3, the thermoelectric conversion elements 301 to 304 of the present invention containing a metal element in addition to a polyaniline copolymer having two types of copolymer units derived from aniline or pyrrole, a polypyrrole copolymer, and CNT. In both cases, the thermoelectric conversion characteristics were improved with respect to the relative value of the comparative thermoelectric conversion element c205.

DESCRIPTION OF SYMBOLS 1, 2 Thermoelectric conversion element 11, 17 Metal plate 12, 22 1st base material 13, 23 1st electrode 14, 24 Thermoelectric conversion layer 15, 25 2nd electrode 16, 26 2nd base material

Claims (13)

A thermoelectric conversion element having a first electrode, a thermoelectric conversion layer, and a second electrode on a substrate, wherein the thermoelectric conversion layer is represented by a nano-conductive material and the following general formula (1) A thermoelectric conversion element containing a copolymer.

(In general formula (1), A and B each independently represent a copolymer unit derived from an aniline derivative or a copolymer unit derived from a pyrrole derivative, provided that A and B are different from each other. M and n represent the degree of polymerization.)   The thermoelectric conversion element according to claim 1, wherein a ratio (m / n) of the degree of polymerization of the copolymer units A and B is from 1/99 to 99/1. The copolymer units A and B are each independently a copolymer unit selected from the group consisting of copolymer units represented by the following general formulas (2) to (5). The thermoelectric conversion element according to 1.

(In the general formulas (2) to (5), R ^{11 to} R ¹⁴ each independently represents a monovalent substituent. A 1 and c 1 each independently represent an integer of 0 to 4, and b 1 represents an integer of 0 to 2. Represents an integer, and d1 represents an integer of 0 to 6. X ^{11 to} X ¹⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and * represents a connecting site of a copolymer unit. Represents.) The copolymer unit A is a copolymer unit represented by the general formula (2) in which a1 is 0, a copolymer unit represented by the general formula (3) in which b1 is 0, and c1 is 0. A copolymer unit selected from the group consisting of a copolymer unit represented by a general formula (4) and a copolymer unit represented by a general formula (5) in which d1 is 0;
The copolymer unit B is a copolymer unit represented by the general formula (2) in which a1 is an integer of 1 to 4, and a copolymer represented by the general formula (3) in which b1 is 1 or 2. A group consisting of a unit, a copolymer unit represented by the general formula (4) wherein c1 is an integer of 1 to 4, and a copolymer unit represented by the general formula (5) wherein d1 is an integer of 1 to 6 The thermoelectric conversion element according to claim 3, wherein the thermoelectric conversion element is a copolymer unit further selected. The thermoelectric conversion element according to claim 3, wherein the X ^{11 to} X ¹⁴ are hydrogen atoms.   The thermoelectric conversion element according to any one of claims 3 to 5, wherein each of the copolymer units A and B is a copolymer unit represented by the general formula (2).   The thermoelectric conversion element according to any one of claims 3 to 5, wherein each of the copolymer units A and B is a copolymer unit represented by the general formula (3).   The thermoelectric conversion element according to any one of claims 1 to 7, wherein the copolymer unit A has a molecular weight smaller than that of the copolymer unit B.   The article for thermoelectric power generation using the thermoelectric conversion element of any one of Claims 1-8.   The power supply for sensors using the thermoelectric conversion element of any one of Claims 1-8. A thermoelectric conversion material for forming a thermoelectric conversion layer of a thermoelectric conversion element, comprising a nano-conductive material and a copolymer represented by the following general formula (1).

(In general formula (1), A and B each independently represent a copolymer unit derived from an aniline derivative or a copolymer unit derived from a pyrrole derivative, provided that A and B are different from each other. Represents.)   The thermoelectric conversion material according to claim 11, comprising an organic solvent. The thermoelectric conversion material according to claim 12, wherein the organic solvent is at least one selected from halogenated solvents.

Images