WO2020203612A1 - Thermoelectric material layer and method for producing same - Google Patents

Thermoelectric material layer and method for producing same Download PDF

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Publication number
WO2020203612A1
WO2020203612A1 PCT/JP2020/013552 JP2020013552W WO2020203612A1 WO 2020203612 A1 WO2020203612 A1 WO 2020203612A1 JP 2020013552 W JP2020013552 W JP 2020013552W WO 2020203612 A1 WO2020203612 A1 WO 2020203612A1
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Prior art keywords
material layer
conversion material
thermoelectric conversion
thermoelectric
thermoelectric semiconductor
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PCT/JP2020/013552
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French (fr)
Japanese (ja)
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佑太 関
昌也 戸▲高▼
邦久 加藤
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リンテック株式会社
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Priority to JP2021511900A priority Critical patent/JPWO2020203612A1/ja
Priority to CN202080024639.7A priority patent/CN113632252A/en
Publication of WO2020203612A1 publication Critical patent/WO2020203612A1/en

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02NELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N11/00Generators or motors not provided for elsewhere; Alleged perpetua mobilia obtained by electric or magnetic means
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/01Manufacture or treatment
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80Constructional details
    • H10N10/85Thermoelectric active materials
    • H10N10/851Thermoelectric active materials comprising inorganic compositions
    • H10N10/852Thermoelectric active materials comprising inorganic compositions comprising tellurium, selenium or sulfur
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80Constructional details
    • H10N10/85Thermoelectric active materials
    • H10N10/856Thermoelectric active materials comprising organic compositions
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80Constructional details
    • H10N10/85Thermoelectric active materials
    • H10N10/857Thermoelectric active materials comprising compositions changing continuously or discontinuously inside the material

Definitions

  • the present invention relates to a thermoelectric conversion material layer and a method for producing the same.
  • thermoelectric conversion module having a thermoelectric effect such as the Seebeck effect and the Peltier effect.
  • thermoelectric conversion module the use of a so-called ⁇ -type thermoelectric conversion element is known.
  • a pair of electrodes separated from each other are provided on the substrate, for example, a P-type thermoelectric element is provided on the-one electrode and an N-type thermoelectric element is provided on the other electrode, also separated from each other.
  • It is configured by connecting the top surfaces of both thermoelectric materials to the electrodes of the opposing substrates.
  • in-plane type thermoelectric conversion element is known.
  • thermoelectric elements and N-type thermoelectric elements are alternately provided in the in-plane direction of the substrate.
  • the lower part of the joint between the two thermoelectric elements is connected in series via electrodes.
  • a resin substrate such as polyimide is used from the viewpoint of heat resistance and flexibility.
  • thermoelectric semiconductor material As the N-type thermoelectric semiconductor material and the P-type thermoelectric semiconductor material, a bismasterlide-based material is used from the viewpoint of thermoelectric performance, and for example, a resin and a thermoelectric semiconductor material are included from the viewpoint of flexibility and thinning.
  • the thermoelectric semiconductor composition is formed in the form of a coating film by using a screen printing method or the like. (Patent Document 1 etc.).
  • thermoelectric semiconductor material used for the thermoelectric conversion module is formed as a thermoelectric conversion material layer in the form of a coating film from a thermoelectric semiconductor composition containing a resin, a thermoelectric semiconductor material, etc.
  • the obtained thermoelectric conversion material layer is not available. , High electrical conductivity could not be obtained sufficiently, and thermoelectric performance was not sufficient.
  • the present invention provides a thermoelectric conversion material layer having high thermoelectric performance and a method for producing the same, in which the electric conductivity of the thermoelectric conversion material in the thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition is improved. That is the issue.
  • thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition, wherein the thermoelectric conversion material layer has voids, and the thermoelectric semiconductor composition in a vertical cross-sectional area including a central portion of the thermoelectric conversion material layer.
  • thermoelectric conversion material layer having a filling rate of 0.800 or more and less than 1.000, where the filling rate is taken as a proportion of the area of an object.
  • the thermoelectric semiconductor composition contains a thermoelectric semiconductor material, and the thermoelectric semiconductor material is a bismuth-tellu-based thermoelectric semiconductor material, a telluride-based thermoelectric semiconductor material, an antimony-tellu-based thermoelectric semiconductor material, or a bismuth selenide-based thermoelectric semiconductor material.
  • thermoelectric conversion material layer according to (1) or (2) above, wherein the thermoelectric semiconductor composition further contains a heat-resistant resin.
  • the thermoelectric semiconductor composition further contains an ionic liquid and / or an inorganic ionic compound.
  • the filling rate is 0.850 to 0.999.
  • thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition, wherein (A) a step of forming a thermoelectric conversion material layer, and (B) the step obtained in the step (A). The step of drying the thermoelectric conversion material layer, (C) the step of pressurizing the thermoelectric conversion material layer after drying obtained in the step (B), and (D) the addition obtained in the step (C).
  • a method for producing a thermoelectric conversion material layer which comprises a step of annealing a compressed thermoelectric conversion material layer. (9) The method for producing a thermoelectric conversion material layer according to (8) above, wherein the annealing treatment is performed at a temperature of 250 to 600 ° C. (10) The method for producing a thermoelectric conversion material layer according to (8) or (9) above, wherein the pressurization is performed at 1.0 to 60 MPa.
  • thermoelectric conversion material layer having high thermoelectric performance and a method for producing the same, in which the electric conductivity of the thermoelectric conversion material in the thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition is improved. it can.
  • thermoelectric conversion material layer of this invention It is a figure for demonstrating the definition of the longitudinal section of the thermoelectric conversion material layer of this invention. It is sectional drawing for demonstrating the vertical cross section of the thermoelectric conversion element layer obtained in the Example or the comparative example of this invention. It is explanatory drawing which shows an example of the manufacturing method of the thermoelectric conversion material layer of this invention in process order.
  • thermoelectric conversion material layer of the present invention is a thermoelectric conversion material layer made of a coating film of a thermoelectric semiconductor composition, and the thermoelectric conversion material layer has voids and has a vertical cross section including a central portion of the thermoelectric conversion material layer.
  • the filling rate is 0.800 or more and less than 1.000.
  • FIG. 1 is a diagram for explaining the definition of a vertical cross section of the thermoelectric conversion material layer of the present invention
  • FIG. 1A is a plan view of the thermoelectric conversion material layer 2
  • the thermoelectric conversion material layer 2 is in the width direction.
  • thermoelectric conversion material layer 2 has a length X and a length Y in the depth direction
  • (b) is a vertical cross section of the thermoelectric conversion material layer 2 including the voids 3 formed on the substrate 1a, and the vertical cross section is the above-mentioned ( It includes the central portion C of a), and is composed of a length X and a thickness D obtained when cutting between A and A'in the width direction (rectangular in the figure).
  • FIG. 2 is a schematic cross-sectional view for explaining a vertical cross section of the thermoelectric conversion material layer of the example or comparative example of the present invention, and FIG. 2A is formed on the alumina substrate 1b obtained in Comparative Example 1. It is a vertical cross section of the thermoelectric conversion material layer 2s, and the thermoelectric conversion material layer 2s has a vertical cross section consisting of a curve having a length X in the width direction and Dmin and Dmax values in the thickness direction. The upper part of the is provided with a concave portion and a convex portion, and a gap portion 3b exists in the vertical cross section.
  • (b) is a vertical cross section of the thermoelectric conversion material layer 2t formed on the alumina substrate 1b obtained in Example 1, and the vertical cross section of the thermoelectric conversion material layer 2t has a length X in the width direction.
  • the thickness in the thickness direction is D [when the values of Dmin and Dmax in (a) of FIG. 2 are small], the upper part of the vertical cross section is substantially linear, and there are voids in the vertical cross section. There are voids 4b in which the number and volume are suppressed.
  • Dmin means the minimum value of the thickness in the thickness direction of the vertical cross section
  • Dmax means the maximum value of the thickness in the thickness direction of the vertical cross section.
  • thermoelectric semiconductor composition in the thermoelectric conversion material layer is defined by the ratio of the area of the thermoelectric semiconductor composition to the area of the longitudinal section including the central portion of the thermoelectric conversion material layer.
  • the filling rate of is 0.800 or more and less than 1.000, and there are few voids in the thermoelectric conversion material layer.
  • the filling rate of the thermoelectric semiconductor composition in the thermoelectric conversion material layer is less than 0.800, the number of voids in the thermoelectric conversion material layer increases, it becomes difficult to obtain excellent electric conductivity, and high thermoelectric performance can be obtained. I can't.
  • the filling rate is preferably 0.810 to 0.999, more preferably 0.850 to 0.999, still more preferably 0.900 to 0.999, and particularly preferably 0.950 to 0.999. When the rate is in this range, excellent electrical conductivity is obtained, and the thermoelectric conversion material layer has high thermoelectric performance.
  • thermoelectric conversion material layer of the present invention (hereinafter, may be referred to as “thin film composed of a thermoelectric conversion material layer”) is made of a coating film of a thermoelectric semiconductor composition.
  • the thermoelectric semiconductor composition preferably contains a thermoelectric semiconductor material and a heat-resistant resin from the viewpoint of shape stability of the thermoelectric conversion material layer, and from the viewpoint of thermoelectric performance, the thermoelectric semiconductor material, the heat-resistant resin, and an ionic liquid and / Or more preferably it consists of a thermoelectric semiconductor composition containing an inorganic ionic compound.
  • the thermoelectric semiconductor material is preferably used as thermoelectric semiconductor particles (hereinafter, the thermoelectric semiconductor material may be referred to as "thermoelectric semiconductor particles").
  • the thickness of the thermoelectric conversion material layer is not particularly limited, but is preferably 1 nm to 1000 ⁇ m, more preferably 3 to 600 ⁇ m, and further preferably 5 to 400 ⁇ m from the viewpoint of flexibility, thermoelectric performance, and film strength.
  • thermoelectric semiconductor material used in the present invention is not particularly limited as long as it is a material capable of generating thermoelectromotive force by applying a temperature difference.
  • bismuth such as P-type bismasterlide and N-type bismasterlide.
  • Tellur-based thermoelectric semiconductor material Telluride-based thermoelectric semiconductor material such as GeTe, PbTe; Antimon-Teruru-based thermoelectric semiconductor material; Zinc-antimon-based thermoelectric semiconductor material such as ZnSb, Zn 3 Sb 2, Zn 4 Sb 3 ; Silicon such as SiGe -Germanium-based thermoelectric semiconductor material; Bismus selenide-based thermoelectric semiconductor material such as Bi 2 Se 3 ; VDD-based thermoelectric semiconductor material such as ⁇ -FeSi 2 , CrSi 2 , MnSi 1.73 , Mg 2 Si; Oxide-based thermoelectric semiconductor Materials: Whistler materials such as FeVAl, FeVALSi, and FeVTiAl, sulfide-based thermoelectric semiconductor materials such as TiS 2 , and the like are used. Among these, bismuth-tellu-based thermoelectric semiconductor materials, telluride-based thermoelectric semiconductor materials, antimony-tellu-based thermoelectric semiconductor materials, or bismuth selenide-based thermoelectric
  • a bismuth-tellurium-based thermoelectric semiconductor material such as P-type bismuthellide or N-type bismuthellide is more preferable.
  • P-type bismuth telluride those having holes as carriers and a positive Seebeck coefficient, for example, represented by Bi X Te 3 Sb 2-X , are preferably used.
  • X is preferably 0 ⁇ X ⁇ 0.8, more preferably 0.4 ⁇ X ⁇ 0.6.
  • the Seebeck coefficient and the electric conductivity become large, and the characteristics as a P-type thermoelectric element are maintained, which is preferable.
  • N-type bismuth telluride one having an electron carrier and a negative Seebeck coefficient, for example, represented by Bi 2 Te 3-Y Se Y is preferably used.
  • the Seebeck coefficient and the electric conductivity become large, and the characteristics as an N-type thermoelectric element are maintained, which is preferable.
  • thermoelectric semiconductor particles used in the thermoelectric semiconductor composition are obtained by pulverizing the above-mentioned thermoelectric semiconductor material to a predetermined size by a fine pulverizer or the like.
  • the blending amount of the thermoelectric semiconductor particles in the thermoelectric semiconductor composition is preferably 30 to 99% by mass. It is more preferably 50 to 96% by mass, and even more preferably 70 to 95% by mass.
  • the Seebeck coefficient absolute value of the Peltier coefficient
  • the decrease in the electric conductivity is suppressed, and only the thermal conductivity is decreased, so that high thermoelectric performance is exhibited.
  • a film having sufficient film strength and flexibility can be obtained, which is preferable.
  • the average particle size of the thermoelectric semiconductor particles is preferably 10 nm to 200 ⁇ m, more preferably 10 nm to 30 ⁇ m, still more preferably 50 nm to 10 ⁇ m, and particularly preferably 1 to 6 ⁇ m. Within the above range, uniform dispersion can be facilitated and the electric conductivity can be increased.
  • the method of pulverizing the thermoelectric semiconductor material to obtain thermoelectric semiconductor particles is not particularly limited, and it may be pulverized to a predetermined size by a known pulverizer such as a jet mill, a ball mill, a bead mill, a colloid mill, a roller mill or the like. ..
  • the average particle size of the thermoelectric semiconductor particles was obtained by measuring with a laser diffraction type particle size analyzer (Mastersizer 3000 manufactured by Malvern), and was used as the median value of the particle size distribution.
  • thermoelectric semiconductor particles are preferably heat-treated in advance (the "heat treatment” referred to here is the “annealing treatment” performed in the annealing treatment step in the method for producing a thermoelectric conversion material layer of the present invention described later. Is different).
  • the heat treatment is not particularly limited, but before preparing the thermoelectric semiconductor composition, the gas flow rate is controlled so as not to adversely affect the thermoelectric semiconductor particles under an atmosphere of an inert gas such as nitrogen or argon.
  • thermoelectric semiconductor particles It is preferably performed in a reducing gas atmosphere such as hydrogen or under vacuum conditions, and more preferably in a mixed gas atmosphere of an inert gas and a reducing gas.
  • a reducing gas atmosphere such as hydrogen or under vacuum conditions
  • a mixed gas atmosphere of an inert gas and a reducing gas The specific temperature condition depends on the thermoelectric semiconductor particles used, but it is usually preferable to carry out the temperature at a temperature equal to or lower than the melting point of the particles and at 100 to 1500 ° C. for several minutes to several tens of hours.
  • thermoelectric semiconductor composition used in the present invention a heat-resistant resin is preferably used from the viewpoint of annealing the thermoelectric semiconductor material at a high temperature. It acts as a binder between thermoelectric semiconductor materials (thermoelectric semiconductor particles), can increase the flexibility of the thermoelectric conversion module, and facilitates the formation of a thin film by coating or the like.
  • the heat-resistant resin is not particularly limited, but when a thin film made of a thermoelectric semiconductor composition is subjected to crystal growth of thermoelectric semiconductor particles by annealing or the like, various factors such as mechanical strength and thermal conductivity as the resin are obtained. A heat-resistant resin that maintains its physical properties without being impaired is preferable.
  • the heat-resistant resin is preferably a polyamide resin, a polyamideimide resin, a polyimide resin, or an epoxy resin, and has excellent flexibility, because it has higher heat resistance and does not adversely affect the crystal growth of thermoelectric semiconductor particles in the thin film. From this point of view, polyamide resin, polyamideimide resin and polyimide resin are more preferable.
  • the polyimide resin is a general term for polyimide and its precursor.
  • the heat-resistant resin preferably has a decomposition temperature of 300 ° C. or higher. As long as the decomposition temperature is within the above range, the flexibility can be maintained without losing the function as a binder even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
  • the heat-resistant resin preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and further preferably 1% or less at 300 ° C. by thermogravimetric analysis (TG). ..
  • TG thermogravimetric analysis
  • the blending amount of the heat-resistant resin in the thermoelectric semiconductor composition is 0.1 to 40% by mass, preferably 0.5 to 20% by mass, more preferably 1 to 20% by mass, still more preferably 2 to 15. It is mass%.
  • the blending amount of the heat-resistant resin is within the above range, it functions as a binder for the thermoelectric semiconductor material, facilitates the formation of a thin film, and provides a film having both high thermoelectric performance and film strength.
  • the ionic liquid used in the present invention is a molten salt formed by combining a cation and an anion, and refers to a salt that can exist as a liquid in any temperature range of ⁇ 50 to 400 ° C.
  • the ionic liquid is an ionic compound having a melting point in the range of ⁇ 50 ° C. or higher and lower than 400 ° C.
  • the melting point of the ionic liquid is preferably ⁇ 25 ° C. or higher and 200 ° C. or lower, and more preferably 0 ° C. or higher and 150 ° C. or lower.
  • Ionic liquids have features such as extremely low vapor pressure, non-volatility, excellent thermostability and electrochemical stability, low viscosity, and high ionic conductivity. Therefore, as a conductive auxiliary agent, it is possible to effectively suppress the reduction of the electric conductivity between the thermoelectric semiconductor particles. Further, since the ionic liquid exhibits high polarity based on the aprotic ionic structure and has excellent compatibility with the heat-resistant resin, the electric conductivity of the thermoelectric conversion material layer can be made uniform.
  • ionic liquid known or commercially available ones can be used.
  • nitrogen-containing cyclic cation compounds such as pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, imidazolium and their derivatives; amine-based cations of tetraalkylammonium and their derivatives; phosphine such as phosphonium, trialkylsulfonium, tetraalkylphosphonium. systems cations and their derivatives; and cationic components, such as lithium cations and derivatives thereof, Cl -, AlCl 4 -, Al 2 Cl 7 -, ClO 4 - chloride or ion, Br -, etc.
  • the cation component of the ionic liquid is a pyridinium cation and its derivatives from the viewpoints of high temperature stability, compatibility with thermoelectric semiconductor particles and resins, and suppression of decrease in electrical conductivity between thermoelectric semiconductor particle gaps.
  • At least one selected from imidazolium cations and derivatives thereof is preferably contained.
  • Anionic component of the ionic liquid preferably contains a halide anion, Cl -, Br - and I - is more preferably contains at least one selected from.
  • an ionic liquid in which the cation component contains a pyridinium cation and a derivative thereof include 4-methyl-butylpyridinium chloride, 3-methyl-butylpyridinium chloride, 4-methyl-hexylpyridinium chloride, and 3-methyl-hexylpyridinium.
  • Chloride 4-methyl-octylpyridinium chloride, 3-methyl-octylpyridinium chloride, 3,4-dimethyl-butylpyridinium chloride, 3,5-dimethyl-butylpyridinium chloride, 4-methyl-butylpyridinium tetrafluoroborate, 4- Methyl-butylpyridinium hexafluorophosphate, 1-butylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium hexafluorophosphate, 1-butyl-4-methylpyridinium iodide and the like. Be done.
  • 1-butylpyridinium bromide 1-butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium hexafluorophosphate, and 1-butyl-4-methylpyridinium iodide are preferable.
  • the ionic liquid in which the cation component contains an imidazolium cation and a derivative thereof [1-butyl-3- (2-hydroxyethyl) imidazolium bromide] and [1-butyl-3- (2) -Hydroxyethyl) imidazolium tetrafluoroborate], 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3 -Methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium bromide, 1-dodecyl-3-methylimidazolium chloride, 1-Tetradecyl-3-methylimidazolium chloride, 1-ethyl-3- (2-hydroxyeth
  • the above-mentioned ionic liquid preferably has an electric conductivity of 10-7 S / cm or more, and more preferably 10-6 S / cm or more.
  • the electric conductivity is in the above range, the reduction of the electric conductivity between the thermoelectric semiconductor particles can be effectively suppressed as a conductivity auxiliary agent.
  • the above-mentioned ionic liquid preferably has a decomposition temperature of 300 ° C. or higher. As long as the decomposition temperature is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
  • the above-mentioned ionic liquid preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and further preferably 1% or less at 300 ° C. by thermogravimetric analysis (TG). ..
  • TG thermogravimetric analysis
  • the blending amount of the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 20% by mass.
  • the blending amount of the ionic liquid is within the above range, the decrease in electrical conductivity is effectively suppressed, and a film having high thermoelectric performance can be obtained.
  • the inorganic ionic compound used in the present invention is a compound composed of at least cations and anions.
  • the inorganic ionic compound is solid at room temperature, has a melting point in any temperature in the temperature range of 400 to 900 ° C., and has characteristics such as high ionic conductivity. Therefore, it can be used as a conductive auxiliary agent. It is possible to suppress a decrease in electrical conductivity between thermoelectric semiconductor particles.
  • a metal cation is used as the cation.
  • the metal cation include alkali metal cations, alkaline earth metal cations, typical metal cations and transition metal cations, and alkali metal cations or alkaline earth metal cations are more preferable.
  • the alkali metal cation include Li + , Na + , K + , Rb + , Cs +, Fr + and the like.
  • Examples of the alkaline earth metal cation include Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ .
  • the anion such as, F -, Cl -, Br -, I -, OH -, CN -, NO 3 -, NO 2 -, ClO -, ClO 2 -, ClO 3 -, ClO 4 -, CrO 4 2 -, HSO 4 -, SCN - , BF 4 -, PF 6 - , and the like.
  • a cation component such as potassium cation, sodium cation, or lithium cations, Cl -, AlCl 4 -, Al 2 Cl 7 -, ClO 4 - chloride or ion, Br -, etc. of bromide ion, I -, etc. iodide ion, BF 4 -, PF 6 - fluoride ions, F (HF) n, such as - such as halide anions of, NO 3 -, OH -, CN - and the ones mentioned consists the anion component of such Be done.
  • a cation component such as potassium cation, sodium cation, or lithium cations
  • the cationic component of the inorganic ionic compound is potassium from the viewpoints of high temperature stability, compatibility with thermoelectric semiconductor particles and resins, and suppression of decrease in electrical conductivity between thermoelectric semiconductor particle gaps.
  • Sodium, and lithium are preferably included.
  • the anion component of the inorganic ionic compound preferably contains a halide anion, and more preferably contains at least one selected from Cl ⁇ , Br ⁇ , and I ⁇ .
  • Cationic component is, as a specific example of the inorganic ionic compound containing a potassium cation, KBr, KI, KCl, KF , KOH, K 2 CO 3 and the like. Of these, KBr and KI are preferable.
  • Specific examples of the inorganic ionic compound whose cation component contains a sodium cation include NaBr, NaI, NaOH, NaF, Na 2 CO 3 and the like. Of these, NaBr and NaI are preferable.
  • Specific examples of the inorganic ionic compound whose cation component contains a lithium cation include LiF, LiOH, and LiNO 3 . Of these, LiF and LiOH are preferable.
  • the above-mentioned inorganic ionic compound preferably has an electric conductivity of 10-7 S / cm or more, and more preferably 10-6 S / cm or more.
  • the electric conductivity is within the above range, the reduction of the electric conductivity between the thermoelectric semiconductor particles can be effectively suppressed as a conductivity auxiliary agent.
  • the decomposition temperature of the above-mentioned inorganic ionic compound is preferably 400 ° C. or higher. As long as the decomposition temperature is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
  • the above-mentioned inorganic ionic compound preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and preferably 1% or less at 400 ° C. by thermogravimetric analysis (TG). More preferred. As long as the mass reduction rate is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
  • TG thermogravimetric analysis
  • the blending amount of the inorganic ionic compound in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 10% by mass. ..
  • the blending amount of the inorganic ionic compound is within the above range, the decrease in electrical conductivity can be effectively suppressed, and as a result, a film having improved thermoelectric performance can be obtained.
  • the total content of the inorganic ionic compound and the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass. It is preferably 0.5 to 30% by mass, more preferably 1.0 to 10% by mass.
  • thermoelectric semiconductor composition used in the present invention further contains, if necessary, a dispersant, a film-forming aid, a light stabilizer, an antioxidant, a tackifier, a plasticizer, a colorant, and the like. It may contain other additives such as resin stabilizers, fillers, pigments, conductive fillers, conductive polymers and hardeners. These additives can be used alone or in combination of two or more.
  • thermoelectric conversion material layer of the present invention has improved electrical conductivity, and by applying it as a thermoelectric conversion material layer of a thermoelectric conversion module, a thermoelectric conversion module having high thermoelectric performance can be obtained.
  • the method for producing a thermoelectric conversion material layer of the present invention is a method for producing a thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition, wherein (A) a step of forming a thermoelectric conversion material layer, (B) the above-mentioned (). A step of drying the thermoelectric conversion material layer obtained in the step A, (C) a step of pressurizing the dried thermoelectric conversion material layer obtained in the step (B), and (D) the step (D). It is characterized by including a step of annealing the pressurized thermoelectric conversion material layer obtained in the step of C).
  • thermoelectric conversion material layer of the present invention After forming the thermoelectric conversion material layer, it is dried at a predetermined temperature, and then the upper surface of the thermoelectric conversion material layer is pressed with a predetermined pressure to form the thermoelectric conversion material layer. By reducing the volume of the voids and then annealing, a thermoelectric conversion material layer with improved electrical conductivity can be obtained.
  • FIG. 3 is an explanatory view showing an example of a method for manufacturing a thermoelectric conversion material layer of the present invention in order of steps
  • FIG. 3A is a cross-sectional view showing an embodiment in which a thermoelectric conversion material layer 2s is formed on a substrate 1a.
  • a thermoelectric conversion material layer 2s is formed on 1a as a coating film (including a gap 3a) and dried at a predetermined temperature
  • (B) is a cross-sectional view showing an aspect after the press pressurizing portion 5 is opposed to the upper surface of the thermoelectric conversion material layer 2s, and the dried thermoelectric conversion material layer 2s obtained in (a) is cooled to room temperature.
  • thermoelectric conversion material layer 2s and the press pressurizing section 5 face each other;
  • (C) is a cross-sectional view showing an aspect after pressurizing the upper surface of the thermoelectric conversion material layer 2s by the press pressurizing section 5 and then releasing the press pressurizing section 5 from the thermoelectric conversion material layer 2s. Then, by performing an annealing treatment, the thermoelectric conversion material layer 2t of the present invention (including the void portion 4a in which the number of voids and the volume are reduced) can be obtained.
  • the thermoelectric conversion material layer may be formed on a substrate in the form of a solid film, and then individualized into a desired chip size. Further, as another preferred embodiment, a coating film may be formed on the substrate in the size of the chip of the thermoelectric conversion material described above. Further, from the viewpoint of shape controllability of the thermoelectric conversion material layer, as a more preferable embodiment, a grid-like pattern frame member including a separated opening having a chip shape of the thermoelectric conversion material may be used.
  • the chip size is, for example, about 0.1 to 20 mm on the short side and 0.2 to 25 mm on the long side.
  • thermoelectric conversion material layer when the grid-like pattern frame member including the separated openings having the chip shape of the thermoelectric conversion material is used is as follows, for example.
  • P A grid-like pattern frame member including a separated opening having a chip shape of a thermoelectric conversion material is placed on the substrate;
  • Q A coating film of a thermoelectric conversion material layer is formed in the opening of the pattern frame member and dried at a predetermined temperature;
  • R After cooling the dried thermoelectric conversion material layer obtained in (q) to room temperature, the thermoelectric conversion material layer and the press pressurizing section (corresponding to the press pressurizing section 5 in FIG.
  • thermoelectric conversion material layer of the present invention is obtained by subjecting the thermoelectric conversion material layer reflecting the shape of the opening of the pattern frame member obtained on the substrate to an annealing treatment.
  • the opening is not particularly limited, but may be rectangular, square, or circular as long as it has a shape that is reflected in the shape of the chip of the thermoelectric conversion material after the pattern frame member is released. Is preferable, and it is more preferable that the shape is rectangular or square.
  • the pattern frame member stainless steel, copper or the like can be used from the viewpoint of ease of formation.
  • thermoelectric conversion material layer forming step is a step of forming a thermoelectric conversion material layer on a substrate.
  • a thermoelectric semiconductor composition is formed on a substrate 1a. This is a step of coating and forming a thermoelectric conversion material layer 2s.
  • the substrate is not particularly limited, and examples thereof include glass, silicon, ceramic, metal, and plastic. Glass, silicon, ceramic and metal are preferable from the viewpoint of performing the annealing treatment at a high temperature, and glass, silicon and ceramic are more preferable from the viewpoint of dimensional stability after heat treatment. From the viewpoint of process and dimensional stability, the thickness of the substrate can be 100 to 10000 ⁇ m.
  • thermoelectric semiconductor composition As the thermoelectric semiconductor composition used in the present invention, the same thermoelectric semiconductor composition as described above can be used. The same applies to preferable materials, blending amounts, etc. for thermoelectric semiconductor materials, heat-resistant resins, ionic liquids, inorganic ionic compounds, and the like.
  • thermoelectric semiconductor composition used in the present invention is not particularly limited, and the thermoelectric semiconductor particles and the heat-resistant resin are prepared by a known method such as an ultrasonic homogenizer, a spiral mixer, a planetary mixer, a disperser, and a hybrid mixer. , One or both of the ionic liquid and the inorganic ionic compound, and if necessary, the other additive and a solvent may be added and mixed and dispersed to prepare the thermoelectric semiconductor composition.
  • the solvent examples include solvents such as toluene, ethyl acetate, methyl ethyl ketone, alcohol, tetrahydrofuran, methylpyrrolidone, and ethyl cellosolve.
  • solvents such as toluene, ethyl acetate, methyl ethyl ketone, alcohol, tetrahydrofuran, methylpyrrolidone, and ethyl cellosolve.
  • solvents such as toluene, ethyl acetate, methyl ethyl ketone, alcohol, tetrahydrofuran, methylpyrrolidone, and ethyl cellosolve.
  • One of these solvents may be used alone, or two or more of these solvents may be mixed and used.
  • the solid content concentration of the thermoelectric semiconductor composition is not particularly limited as long as the composition has a viscosity suitable for coating.
  • the thin film made of the thermoelectric semiconductor composition can be formed, for example, by applying the thermoelectric semiconductor composition on the substrate and drying it.
  • thermoelectric semiconductor composition As a method of applying the thermoelectric semiconductor composition on a substrate, a screen printing method, a flexographic printing method, a gravure printing method, a spin coating method, a dip coating method, a die coating method, a spray coating method, a bar coating method, a doctor blade method, etc.
  • Known methods such as the applicator method can be mentioned and are not particularly limited.
  • the coating film is formed into a pattern, screen printing, stencil printing, slot die coating, etc., which can easily form a pattern using a screen plate having a desired pattern, are preferably used.
  • thermoelectric conversion material layer drying step is a step of drying the thermoelectric conversion material layer obtained in the step (A). For example, in FIG. 3A, on the substrate 1a. This is a step of drying the thermoelectric conversion material layer 2s.
  • drying method conventionally known drying methods such as a hot air drying method, a hot roll drying method, and an infrared irradiation method can be adopted.
  • the heating temperature is usually 80 to 170 ° C., preferably 100 to 150 ° C., more preferably 110 to 145 ° C., still more preferably 120 to 140 ° C.
  • the heating time varies depending on the heating method, but is usually 30 seconds to 5 hours, preferably 1 minute to 3 hours, more preferably 5 minutes to 2 hours, and further preferably 10 minutes to 50 minutes.
  • the heating temperature and the heating time are within this range, it is easy to improve the electric conductivity of the thermoelectric conversion material layer after pressurization and annealing treatment.
  • the heating temperature may be in a temperature range in which the solvent used can be dried or in a temperature range lower than that.
  • thermoelectric conversion material layer pressurizing step is a step of pressurizing the dried thermoelectric conversion material layer obtained in the step (B), for example, in FIG. 3 (b). Is a step of pressurizing the upper surface of the thermoelectric conversion material layer 2s with the press pressurizing section 5.
  • the pressurization is preferably performed in an atmospheric pressure atmosphere after the dried thermoelectric conversion material layer obtained in the step (B) is cooled to room temperature. Further, as another embodiment, the pressurization is performed by maintaining the drying temperature without cooling the thermoelectric conversion material layer after drying obtained in the step (B) to room temperature, and an annealing treatment step described later, which is a next step. It is preferable to put it in.
  • the pressurizing method include a method using a physical pressurizing means such as a hydraulic press, a vacuum press, and a weight.
  • the amount of pressurization varies depending on the viscosity of the thermoelectric conversion material layer, the amount of voids, etc., but is usually 0.1 to 80 MPa, preferably 1.0 to 60 MPa, more preferably 5 to 50 MPa, still more preferable. Is 10 to 42 MPa.
  • the pressurization may be performed by increasing the pressurization amount to a predetermined amount at once, but the shape stability of the thermoelectric conversion material layer is maintained and the voids in the thermoelectric conversion material layer are further reduced to reduce the filling rate of the thermoelectric conversion material.
  • the pressure is adjusted as appropriate from the viewpoint of improving the above pressure, but is usually 0.1 to 50 MPa / min, preferably 0.5 to 30 MPa / min, and more preferably 1.0 to 10 MPa / min to a predetermined pressurization amount.
  • the pressurization time varies depending on the pressurization method, but is usually 5 seconds to 5 hours, preferably 30 seconds to 3 hours, more preferably 5 minutes to 2 hours, and further preferably 10 minutes to 1 hour. When the pressurization amount and the pressurization time are within this range, the filling rate increases, and the electric conductivity of the thermoelectric conversion material layer after the annealing treatment tends to improve.
  • the annealing treatment step is a step of annealing the pressurized thermoelectric conversion material layer obtained in the step (C) above. For example, in FIG. 3C, after pressurization. This is a step of annealing the thermoelectric conversion material layer 2s of No. 2 at the temperature of the annealing treatment (after the annealing treatment, the thermoelectric conversion material layer 2t is obtained).
  • the thermoelectric conversion material layer is formed as a thin film, dried, and then annealed to stabilize the thermoelectric performance, and the thermoelectric semiconductor particles in the thin film can be crystal-grown to further improve the thermoelectric performance. it can.
  • the annealing treatment is performed with or without pressurizing the thermoelectric conversion material layer.
  • the amount of pressurization in the case of pressurization is usually 0.1 to 80 MPa, preferably 1.0 to 60 MPa, more preferably 5 to 50 MPa, still more preferably 10 to 42 MPa.
  • a thermoelectric semiconductor material used in a thermoelectric semiconductor composition which is usually carried out under an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere, or under vacuum conditions in which the gas flow rate is controlled.
  • the temperature of the annealing treatment is usually 100 to 600 ° C. for several minutes to several tens of hours, preferably 250 to 450 ° C. for several minutes to several tens of hours. Do time.
  • the thickness of the thermoelectric conversion material layer is not particularly limited as long as the shape stability and thermoelectric performance are not impaired by pressurization, and are as described above.
  • thermoelectric conversion material layer of the present invention According to the method for producing a thermoelectric conversion material layer of the present invention, a thermoelectric conversion material layer having improved electrical conductivity can be produced by a simple method.
  • thermoelectric conversion material layer produced in Examples and Comparative Examples The evaluation of the filling rate and the electric conductivity of the thermoelectric semiconductor composition in the thermoelectric conversion material layer produced in Examples and Comparative Examples was carried out by the following methods.
  • (A) Evaluation of filling rate A vertical cross section of the thermoelectric conversion material layer produced in Examples and Comparative Examples including the central portion of the thermoelectric conversion material layer by a polishing device (manufactured by Refine Tech, model name: Refine Polisher HV). After taking out, the vertical cross section was observed using FE-SEM / EDX (FE-SEM: manufactured by Hitachi High-Technologies Corporation, model name: S-4700), and then Image J (image processing software, ver.1.
  • the filling rate defined by the ratio of the area of the thermoelectric semiconductor composition to the area of the longitudinal section of the thermoelectric conversion material layer was calculated.
  • an SEM image longitudinal cross section
  • the measurement range is surrounded by 1280 pixels in the width direction and 220 pixels in the thickness direction with reference to the boundary between the thermoelectric conversion material layer and the alumina substrate. It was taken as a range and cut out as an image.
  • the cut-out image is binarized from "Brightness / Contrast" with the maximum contrast value, and the dark part and the bright part in the binarization process are regarded as the thermoelectric semiconductor composition, and the thermoelectric semiconductor is used in "Throld".
  • the filling rate of the composition was calculated.
  • the filling rate was calculated for three SEM images and used as the average value thereof.
  • the image to be cut out is selected within the region portion of the vertical cross section.
  • the void portion (air layer portion) around the thermoelectric conversion material layer is not captured.
  • a region not exceeding X in the width direction and Dmin in the thickness direction of the vertical cross section was selected.
  • (B) Evaluation of Electrical Conductivity The thermoelectric conversion material layers produced in Examples and Comparative Examples were subjected to an environment of 25 ° C. and 60% RH using a low resistance measuring device (manufactured by Hioki Co., Ltd., model name: RM3545). The surface resistance value was measured by the four-terminal method, and the electric conductivity was calculated.
  • thermoelectric conversion material layer ⁇ Preparation of thermoelectric conversion material layer> (1) Preparation of thermoelectric semiconductor composition (production of thermoelectric semiconductor particles) P-type bismuth tellurium Bi 0.4 Te 3 Sb 1.6 (manufactured by High Purity Chemical Laboratory, particle size: 180 ⁇ m), which is a bismuth-tellurium thermoelectric semiconductor material, is used in a planetary ball mill (manufactured by Fritsch Japan, Premium line P). Thermoelectric semiconductor particles having an average particle size of 2.0 ⁇ m were produced by pulverizing in a nitrogen gas atmosphere using -7). The thermoelectric semiconductor particles obtained by pulverization were subjected to particle size distribution measurement with a laser diffraction type particle size analyzer (Mastersizer 3000 manufactured by Malvern).
  • thermoelectric semiconductor composition P-type bismuthellide Bi 0.4 Te 3 Sb 1.6 particles 82.5% by mass obtained above, polyamic acid which is a polyimide precursor as a heat-resistant resin (manufactured by Ube Kosan Co., Ltd., U-Wanis A, solvent: A coating liquid consisting of a thermoelectric semiconductor composition in which N-methylpyrrolidone, solid content concentration: 18% by mass) 3.2% by mass (solid content), and 1-butylpyridinium bromide 14.3% by mass as an ionic liquid are mixed and dispersed. Was prepared.
  • thermoelectric conversion material layer On an alumina substrate (manufactured by Kyocera Corporation, trade name: alumina substrate A0476T, 100 mm ⁇ 100 mm, thickness: 1 mm), the coating liquid prepared in (1) above is applied.
  • the film was printed as a solid film using an applicator and dried at a temperature of 140 ° C. for 40 minutes in an argon atmosphere to form a thin film (thermoelectric conversion material layer before annealing treatment) having a thickness of 37 ⁇ m.
  • the dried thermoelectric conversion material layer was cooled to room temperature, and the alumina substrate on which the thermoelectric conversion material layer was printed was cut out to a size of 5 mm ⁇ 15 mm.
  • thermoelectric conversion material layer was uniformly applied at 40.0 MPa.
  • thermoelectric conversion material layer was prepared in the same manner as in Example 1 except that the entire upper surface of the thermoelectric conversion material layer was uniformly pressurized at 30.0 MPa in Example 1. The obtained thermoelectric conversion material layer was evaluated for filling rate and electric conductivity. The results are shown in Table 1.
  • thermoelectric conversion material layer was prepared in the same manner as in Example 1 except that the pressure treatment was not performed, and the obtained thermoelectric conversion material layer was evaluated for filling rate and electric conductivity. .. The results are shown in Table 1.
  • thermoelectric conversion material layer of the present invention in which the filling rate of the thermoelectric conversion material in the thermoelectric conversion material layer composed of the coating film of the thermoelectric semiconductor composition satisfies the specification of the present invention
  • Comparative Example 1 in which the filling rate is outside the range of the specification of the present invention. It can be seen that the electrical conductivity is increased by 50 to 118%. Therefore, by applying the thermoelectric conversion material layer of the present invention and the manufacturing method thereof to the thermoelectric conversion module, the thermoelectric performance of the thermoelectric conversion module can be improved.
  • thermoelectric conversion material layer composed of the coating film of the thermoelectric semiconductor composition of the present invention and the method for producing the same, the electric conductivity of the thermoelectric conversion material layer is increased. Therefore, the thermoelectric conversion material layer of the present invention is incorporated into the thermoelectric conversion module. This can be expected to improve thermoelectric performance.
  • the obtained thermoelectric conversion module has the possibility of being more flexible and thinner (smaller and lighter) than the thermoelectric conversion module using a sintered body of a conventional thermoelectric semiconductor material.
  • the thermoelectric conversion module using the above thermoelectric conversion material layer converts exhaust heat from various combustion furnaces such as factories, waste combustion furnaces, cement combustion furnaces, automobile combustion gas exhaust heat, and electronic equipment exhaust heat into electricity. It is conceivable to apply it to power generation applications.
  • As a cooling application in the field of electronic equipment, for example, it can be considered to be applied to temperature control of various sensors such as CCD (Charge Coupled Device), MEMS (Micro Electro Mechanical Systems), and light receiving element, which are semiconductor elements. ..
  • Substrate 1b Alumina substrate 2,2s, 2t: Thermoelectric conversion material layer 3: Void portion 3a, 4a: Void portion 3b: Void portion (Comparative Example 1) 4b: Void portion (Example 1) 5: Press pressurizing part X: Length (width direction) Y: Length (depth direction) D: Thickness (thickness direction) Dmax: Maximum value of thickness in the thickness direction (longitudinal section) Dmin: Minimum value of thickness in the thickness direction (longitudinal section) C: Central part of thermoelectric conversion material layer

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Abstract

Provided are: a high performance thermoelectric material layer comprising a coating film of a thermoelectric semiconductor composition and being configured such that the electrical conductivity of the thermoelectric material in the thermoelectric material layer is improved; and a method for producing the thermoelectric material layer. The thermoelectric material layer comprises a coating film of a thermoelectric semiconductor composition, the thermoelectric material layer has void portions, and the filling rate is equal to or greater than 0.800 and less than 1.000 when the filling rate is defined to be the ratio of the area of the thermoelectric semiconductor composition relative to the area of a longitudinal cross section including the center portion of the thermoelectric material layer.

Description

熱電変換材料層及びその製造方法Thermoelectric conversion material layer and its manufacturing method
 本発明は、熱電変換材料層及びその製造方法に関する。 The present invention relates to a thermoelectric conversion material layer and a method for producing the same.
 従来から、エネルギーの有効利用手段の一つとして、ゼーベック効果やペルチェ効果などの熱電効果を有する熱電変換モジュールにより、熱エネルギーと電気エネルギーとを直接相互変換するようにした装置がある。
 前記熱電変換モジュールとして、いわゆるπ型の熱電変換素子の使用が知られている。π型は、互いに離間するー対の電極を基板上に設け、例えば、―方の電極の上にP型熱電素子を、他方の電極の上にN型熱電素子を、同じく互いに離間して設け、両方の熱電材料の上面を対向する基板の電極に接続することで構成されている。また、いわゆるインプレーン型の熱電変換素子の使用が知られている。インプレーン型は、P型熱電素子とN型熱電素子とが基板の面内方向に交互に設けられ、例えば、両熱電素子間の接合部の下部を電極を介在し直列に接続することで構成されている。
 このような中、熱電変換モジュールの屈曲性向上、薄型化及び熱電性能の向上等の要求がある。これらの要求を満足するために、例えば、熱電変換モジュールに用いる基板として、ポリイミド等の樹脂基板が耐熱性及び屈曲性の観点から使用されている。また、N型の熱電半導体材料、P型の熱電半導体材料としては、熱電性能の観点から、ビスマステルライド系材料が用いられ、例えば、屈曲性、薄型化の観点から、樹脂及び熱電半導体材料を含む熱電半導体組成物としてスクリーン印刷法等を用い塗布膜の態様で形成している。(特許文献1等)。
Conventionally, as one of the effective utilization means of energy, there is a device in which thermal energy and electric energy are directly converted into each other by a thermoelectric conversion module having a thermoelectric effect such as the Seebeck effect and the Peltier effect.
As the thermoelectric conversion module, the use of a so-called π-type thermoelectric conversion element is known. In the π-type, a pair of electrodes separated from each other are provided on the substrate, for example, a P-type thermoelectric element is provided on the-one electrode and an N-type thermoelectric element is provided on the other electrode, also separated from each other. , It is configured by connecting the top surfaces of both thermoelectric materials to the electrodes of the opposing substrates. Further, the use of a so-called in-plane type thermoelectric conversion element is known. In the in-plane type, P-type thermoelectric elements and N-type thermoelectric elements are alternately provided in the in-plane direction of the substrate. For example, the lower part of the joint between the two thermoelectric elements is connected in series via electrodes. Has been done.
Under these circumstances, there are demands for improving the flexibility of the thermoelectric conversion module, making it thinner, and improving the thermoelectric performance. In order to satisfy these requirements, for example, as a substrate used for a thermoelectric conversion module, a resin substrate such as polyimide is used from the viewpoint of heat resistance and flexibility. Further, as the N-type thermoelectric semiconductor material and the P-type thermoelectric semiconductor material, a bismasterlide-based material is used from the viewpoint of thermoelectric performance, and for example, a resin and a thermoelectric semiconductor material are included from the viewpoint of flexibility and thinning. The thermoelectric semiconductor composition is formed in the form of a coating film by using a screen printing method or the like. (Patent Document 1 etc.).
国際公開2016/104615号公報International Publication No. 2016/10461
 しかしながら、熱電変換モジュールに用いる熱電半導体材料が、樹脂及び熱電半導体材料等を含む熱電半導体組成物から塗布膜の態様で熱電変換材料層として形成されるため、得られる熱電変換材料層にあっては、高い電気伝導率を十分に得ることができず、熱電性能が十分でなかった。 However, since the thermoelectric semiconductor material used for the thermoelectric conversion module is formed as a thermoelectric conversion material layer in the form of a coating film from a thermoelectric semiconductor composition containing a resin, a thermoelectric semiconductor material, etc., the obtained thermoelectric conversion material layer is not available. , High electrical conductivity could not be obtained sufficiently, and thermoelectric performance was not sufficient.
 本発明は、上記を鑑み、熱電半導体組成物の塗布膜からなる熱電変換材料層中の熱電変換材料の電気伝導率が向上された、熱電性能の高い熱電変換材料層及びその製造方法を提供することを課題とする。 In view of the above, the present invention provides a thermoelectric conversion material layer having high thermoelectric performance and a method for producing the same, in which the electric conductivity of the thermoelectric conversion material in the thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition is improved. That is the issue.
 本発明者らは上記課題を解決すべく鋭意研究した結果、熱電半導体組成物の塗布膜には空隙が多く内包されており、これらの体積を減少させることで、熱電変換材料の充填率が高い熱電変換材料層が、高い電気伝導率を与えることを見出し、本発明を完成するに至った。
 すなわち、本発明は、以下の(1)~(10)を提供するものである。
(1)熱電半導体組成物の塗布膜からなる熱電変換材料層であって、前記熱電変換材料層は空隙を有し、前記熱電変換材料層の中央部を含む縦断面の面積における前記熱電半導体組成物の面積の占める割合を充填率としたときに、前記充填率が、0.800以上1.000未満である、熱電変換材料層。
(2)前記熱電半導体組成物は熱電半導体材料を含み、該熱電半導体材料がビスマス-テルル系熱電半導体材料、テルライド系熱電半導体材料、アンチモン-テルル系熱電半導体材料、又はビスマスセレナイド系熱電半導体材料である、上記(1)に記載の熱電変換材料層。
(3)前記熱電半導体組成物が、さらに、耐熱性樹脂を含む、上記(1)又は(2)に記載の熱電変換材料層。
(4)前記耐熱性樹脂が、ポリイミド樹脂、ポリアミド樹脂、ポリアミドイミド樹脂、又はエポキシ樹脂である、上記(1)~(3)のいずれかに記載の熱電変換材料層。
(5)前記熱電半導体組成物が、さらに、イオン液体及び/又は無機イオン性化合物を含む、上記(1)~(4)のいずれかに記載の熱電変換材料層。
(6)前記熱電変換材料層の厚さが、1~1000μmである、上記(1)~(5)のいずれかに記載の熱電変換材料層。
(7)前記充填率が、0.850~0.999である、上記(1)~(6)のいずれかに記載の熱電変換材料層。
(8)熱電半導体組成物の塗布膜からなる熱電変換材料層を製造する方法であって、(A)熱電変換材料層を形成する工程、(B)前記(A)の工程で得られた前記熱電変換材料層を乾燥する工程、(C)前記(B)の工程で得られた乾燥後の前記熱電変換材料層を加圧する工程、及び(D)前記(C)の工程で得られた加圧された熱電変換材料層をアニール処理する工程、を含む、熱電変換材料層の製造方法。
(9)前記アニール処理の温度が、250~600℃で行われる、上記(8)に記載の熱電変換材料層の製造方法。
(10)前記加圧が、1.0~60MPaで行われる、上記(8)又は(9)に記載の熱電変換材料層の製造方法。
As a result of diligent research to solve the above problems, the present inventors have included many voids in the coating film of the thermoelectric semiconductor composition, and by reducing these volumes, the filling rate of the thermoelectric conversion material is high. We have found that the thermoelectric conversion material layer gives high electrical conductivity, and have completed the present invention.
That is, the present invention provides the following (1) to (10).
(1) A thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition, wherein the thermoelectric conversion material layer has voids, and the thermoelectric semiconductor composition in a vertical cross-sectional area including a central portion of the thermoelectric conversion material layer. A thermoelectric conversion material layer having a filling rate of 0.800 or more and less than 1.000, where the filling rate is taken as a proportion of the area of an object.
(2) The thermoelectric semiconductor composition contains a thermoelectric semiconductor material, and the thermoelectric semiconductor material is a bismuth-tellu-based thermoelectric semiconductor material, a telluride-based thermoelectric semiconductor material, an antimony-tellu-based thermoelectric semiconductor material, or a bismuth selenide-based thermoelectric semiconductor material. The thermoelectric conversion material layer according to (1) above.
(3) The thermoelectric conversion material layer according to (1) or (2) above, wherein the thermoelectric semiconductor composition further contains a heat-resistant resin.
(4) The thermoelectric conversion material layer according to any one of (1) to (3) above, wherein the heat-resistant resin is a polyimide resin, a polyamide resin, a polyamide-imide resin, or an epoxy resin.
(5) The thermoelectric conversion material layer according to any one of (1) to (4) above, wherein the thermoelectric semiconductor composition further contains an ionic liquid and / or an inorganic ionic compound.
(6) The thermoelectric conversion material layer according to any one of (1) to (5) above, wherein the thermoelectric conversion material layer has a thickness of 1 to 1000 μm.
(7) The thermoelectric conversion material layer according to any one of (1) to (6) above, wherein the filling rate is 0.850 to 0.999.
(8) A method for producing a thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition, wherein (A) a step of forming a thermoelectric conversion material layer, and (B) the step obtained in the step (A). The step of drying the thermoelectric conversion material layer, (C) the step of pressurizing the thermoelectric conversion material layer after drying obtained in the step (B), and (D) the addition obtained in the step (C). A method for producing a thermoelectric conversion material layer, which comprises a step of annealing a compressed thermoelectric conversion material layer.
(9) The method for producing a thermoelectric conversion material layer according to (8) above, wherein the annealing treatment is performed at a temperature of 250 to 600 ° C.
(10) The method for producing a thermoelectric conversion material layer according to (8) or (9) above, wherein the pressurization is performed at 1.0 to 60 MPa.
 本発明によれば、熱電半導体組成物の塗布膜からなる熱電変換材料層中の熱電変換材料の電気伝導率が向上された、熱電性能の高い熱電変換材料層及びその製造方法を提供することができる。 According to the present invention, it is possible to provide a thermoelectric conversion material layer having high thermoelectric performance and a method for producing the same, in which the electric conductivity of the thermoelectric conversion material in the thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition is improved. it can.
本発明の熱電変換材料層の縦断面の定義を説明するための図である。It is a figure for demonstrating the definition of the longitudinal section of the thermoelectric conversion material layer of this invention. 本発明の実施例又は比較例で得られた熱電変換素子層の縦断面を説明するための断面模式図である。It is sectional drawing for demonstrating the vertical cross section of the thermoelectric conversion element layer obtained in the Example or the comparative example of this invention. 本発明の熱電変換材料層の製造方法の一例を工程順に示す説明図である。It is explanatory drawing which shows an example of the manufacturing method of the thermoelectric conversion material layer of this invention in process order.
[熱電変換材料層]
 本発明の熱電変換材料層は、熱電半導体組成物の塗布膜からなる熱電変換材料層であって、前記熱電変換材料層は空隙を有し、前記熱電変換材料層の中央部を含む縦断面の面積における前記熱電半導体組成物の面積の占める割合を充填率としたときに、前記充填率が、0.800以上1.000未満であることを特徴としている。
[Thermoelectric conversion material layer]
The thermoelectric conversion material layer of the present invention is a thermoelectric conversion material layer made of a coating film of a thermoelectric semiconductor composition, and the thermoelectric conversion material layer has voids and has a vertical cross section including a central portion of the thermoelectric conversion material layer. When the ratio of the area of the thermoelectric semiconductor composition to the area is taken as the filling rate, the filling rate is 0.800 or more and less than 1.000.
〈熱電変換材料層の縦断面〉
 本明細書における、「熱電変換材料層の中央部を含む縦断面」の定義を、図を用いて説明する。
 図1は、本発明の熱電変換材料層の縦断面の定義を説明するための図であり、(a)は、熱電変換材料層2の平面図であり、熱電変換材料層2は、幅方向に長さX、奥行き方向に長さYを有し、(b)は、基板1a上に形成された、空隙部3を含む熱電変換材料層2の縦断面であり、縦断面は、前記(a)の中央部Cを含み、幅方向にA-A’間で切断した時に得られる長さX、厚さDからなる(図では長方形としている)。
<Vertical section of thermoelectric conversion material layer>
The definition of "longitudinal section including the central portion of the thermoelectric conversion material layer" in the present specification will be described with reference to the drawings.
FIG. 1 is a diagram for explaining the definition of a vertical cross section of the thermoelectric conversion material layer of the present invention, FIG. 1A is a plan view of the thermoelectric conversion material layer 2, and the thermoelectric conversion material layer 2 is in the width direction. Has a length X and a length Y in the depth direction, and (b) is a vertical cross section of the thermoelectric conversion material layer 2 including the voids 3 formed on the substrate 1a, and the vertical cross section is the above-mentioned ( It includes the central portion C of a), and is composed of a length X and a thickness D obtained when cutting between A and A'in the width direction (rectangular in the figure).
 本発明の熱電変換材料層の縦断面について、図を用いて説明する。
 図2は、本発明の実施例又は比較例の熱電変換材料層の縦断面を説明するための断面模式図であり、(a)は、比較例1で得られた、アルミナ基板1b上に形成した熱電変換材料層2sの縦断面であり、熱電変換材料層2sは、幅方向に長さX、厚さ方向は、Dmin及び、Dmaxの値を取る曲線からなる縦断面を有し、縦断面の上部は凹部と凸部を備え、縦断面内には、空隙部3bが存在する。また、(b)は、実施例1で得られた、アルミナ基板1b上に形成した熱電変換材料層2tの縦断面であり、熱電変換材料層2tの縦断面は、幅方向に長さX、厚さ方向に厚さがD[図2の(a)におけるDminとDmaxの値が僅差の場合]からなり、縦断面の上部は、略直線状になっており、縦断面内には、空隙数、及び体積が抑制された空隙部4bが存在する。なお、Dminは縦断面の厚さ方向の厚さの最小値、Dmaxは縦断面の厚さ方向の厚さの最大値を意味する。
The vertical cross section of the thermoelectric conversion material layer of the present invention will be described with reference to the drawings.
FIG. 2 is a schematic cross-sectional view for explaining a vertical cross section of the thermoelectric conversion material layer of the example or comparative example of the present invention, and FIG. 2A is formed on the alumina substrate 1b obtained in Comparative Example 1. It is a vertical cross section of the thermoelectric conversion material layer 2s, and the thermoelectric conversion material layer 2s has a vertical cross section consisting of a curve having a length X in the width direction and Dmin and Dmax values in the thickness direction. The upper part of the is provided with a concave portion and a convex portion, and a gap portion 3b exists in the vertical cross section. Further, (b) is a vertical cross section of the thermoelectric conversion material layer 2t formed on the alumina substrate 1b obtained in Example 1, and the vertical cross section of the thermoelectric conversion material layer 2t has a length X in the width direction. The thickness in the thickness direction is D [when the values of Dmin and Dmax in (a) of FIG. 2 are small], the upper part of the vertical cross section is substantially linear, and there are voids in the vertical cross section. There are voids 4b in which the number and volume are suppressed. Note that Dmin means the minimum value of the thickness in the thickness direction of the vertical cross section, and Dmax means the maximum value of the thickness in the thickness direction of the vertical cross section.
 本発明の熱電変換材料層では、熱電変換材料層の中央部を含む縦断面の面積における前記熱電半導体組成物の面積の占める割合で定義される、前記熱電変換材料層中の前記熱電半導体組成物の充填率が、0.800以上1.000未満であり、熱電変換材料層中の空隙が少ない。
 熱電変換材料層中の前記熱電半導体組成物の充填率が0.800未満であると、熱電変換材料層中の空隙が多くなり、優れた電気伝導率が得られにくくなり、高い熱電性能が得られない。充填率は、好ましくは0.810~0.999、より好ましくは0.850~0.999、さらに好ましくは0.900~0.999、特に好ましくは0.950~0.999であり、充填率がこの範囲にあると、優れた電気伝導率が得られ、高い熱電性能を有する熱電変換材料層となる。
In the thermoelectric conversion material layer of the present invention, the thermoelectric semiconductor composition in the thermoelectric conversion material layer is defined by the ratio of the area of the thermoelectric semiconductor composition to the area of the longitudinal section including the central portion of the thermoelectric conversion material layer. The filling rate of is 0.800 or more and less than 1.000, and there are few voids in the thermoelectric conversion material layer.
When the filling rate of the thermoelectric semiconductor composition in the thermoelectric conversion material layer is less than 0.800, the number of voids in the thermoelectric conversion material layer increases, it becomes difficult to obtain excellent electric conductivity, and high thermoelectric performance can be obtained. I can't. The filling rate is preferably 0.810 to 0.999, more preferably 0.850 to 0.999, still more preferably 0.900 to 0.999, and particularly preferably 0.950 to 0.999. When the rate is in this range, excellent electrical conductivity is obtained, and the thermoelectric conversion material layer has high thermoelectric performance.
 本発明の熱電変換材料層(以下、「熱電変換材料層からなる薄膜」ということがある。)は、熱電半導体組成物の塗布膜からなる。熱電半導体組成物は、熱電半導体材料、また、熱電変換材料層の形状安定性の観点から耐熱性樹脂を含むことが好ましく、熱電性能の観点から、熱電半導体材料、耐熱性樹脂、並びにイオン液体及び/又は無機イオン性化合物を含む熱電半導体組成物からなることがより好ましい。
 前記熱電半導体材料は、熱電性能の観点から、熱電半導体粒子として用いることが好ましい(以下、熱電半導体材料を「熱電半導体粒子」ということがある。)。
The thermoelectric conversion material layer of the present invention (hereinafter, may be referred to as “thin film composed of a thermoelectric conversion material layer”) is made of a coating film of a thermoelectric semiconductor composition. The thermoelectric semiconductor composition preferably contains a thermoelectric semiconductor material and a heat-resistant resin from the viewpoint of shape stability of the thermoelectric conversion material layer, and from the viewpoint of thermoelectric performance, the thermoelectric semiconductor material, the heat-resistant resin, and an ionic liquid and / Or more preferably it consists of a thermoelectric semiconductor composition containing an inorganic ionic compound.
From the viewpoint of thermoelectric performance, the thermoelectric semiconductor material is preferably used as thermoelectric semiconductor particles (hereinafter, the thermoelectric semiconductor material may be referred to as "thermoelectric semiconductor particles").
 前記熱電変換材料層の厚さは、特に制限はないが、フレキシブル性、熱電性能と皮膜強度の点から、好ましくは1nm~1000μm、より好ましくは3~600μm、さらに好ましくは5~400μmである。 The thickness of the thermoelectric conversion material layer is not particularly limited, but is preferably 1 nm to 1000 μm, more preferably 3 to 600 μm, and further preferably 5 to 400 μm from the viewpoint of flexibility, thermoelectric performance, and film strength.
(熱電半導体材料)
 本発明に用いる熱電半導体材料は、温度差を付与することにより、熱起電力を発生させることができる材料であれば特に制限されず、例えば、P型ビスマステルライド、N型ビスマステルライド等のビスマス-テルル系熱電半導体材料;GeTe、PbTe等のテルライド系熱電半導体材料;アンチモン-テルル系熱電半導体材料;ZnSb、ZnSb2、ZnSb等の亜鉛-アンチモン系熱電半導体材料;SiGe等のシリコン-ゲルマニウム系熱電半導体材料;BiSe等のビスマスセレナイド系熱電半導体材料;β―FeSi、CrSi、MnSi1.73、MgSi等のシリサイド系熱電半導体材料;酸化物系熱電半導体材料;FeVAl、FeVAlSi、FeVTiAl等のホイスラー材料、TiS等の硫化物系熱電半導体材料等が用いられる。
 これらの中で、ビスマス-テルル系熱電半導体材料、テルライド系熱電半導体材料、アンチモン-テルル系熱電半導体材料、又はビスマスセレナイド系熱電半導体材料が好ましい。
(Thermoelectric semiconductor material)
The thermoelectric semiconductor material used in the present invention is not particularly limited as long as it is a material capable of generating thermoelectromotive force by applying a temperature difference. For example, bismuth such as P-type bismasterlide and N-type bismasterlide. Tellur-based thermoelectric semiconductor material; Telluride-based thermoelectric semiconductor material such as GeTe, PbTe; Antimon-Teruru-based thermoelectric semiconductor material; Zinc-antimon-based thermoelectric semiconductor material such as ZnSb, Zn 3 Sb 2, Zn 4 Sb 3 ; Silicon such as SiGe -Germanium-based thermoelectric semiconductor material; Bismus selenide-based thermoelectric semiconductor material such as Bi 2 Se 3 ; VDD-based thermoelectric semiconductor material such as β-FeSi 2 , CrSi 2 , MnSi 1.73 , Mg 2 Si; Oxide-based thermoelectric semiconductor Materials: Whistler materials such as FeVAl, FeVALSi, and FeVTiAl, sulfide-based thermoelectric semiconductor materials such as TiS 2 , and the like are used.
Among these, bismuth-tellu-based thermoelectric semiconductor materials, telluride-based thermoelectric semiconductor materials, antimony-tellu-based thermoelectric semiconductor materials, or bismuth selenide-based thermoelectric semiconductor materials are preferable.
 さらに、熱電性能の観点から、P型ビスマステルライド又はN型ビスマステルライド等のビスマス-テルル系熱電半導体材料であることがより好ましい。
 前記P型ビスマステルライドは、キャリアが正孔で、ゼーベック係数が正値であり、例えば、BiTeSb2-Xで表わされるものが好ましく用いられる。この場合、Xは、好ましくは0<X≦0.8であり、より好ましくは0.4≦X≦0.6である。Xが0より大きく0.8以下であるとゼーベック係数と電気伝導率が大きくなり、P型熱電素子としての特性が維持されるので好ましい。
 また、前記N型ビスマステルライドは、キャリアが電子で、ゼーベック係数が負値であり、例えば、BiTe3-YSeで表わされるものが好ましく用いられる。この場合、Yは、好ましくは0≦Y≦3(Y=0の時:BiTe)であり、より好ましくは0<Y≦2.7である。Yが0以上3以下であるとゼーベック係数と電気伝導率が大きくなり、N型熱電素子としての特性が維持されるので好ましい。
Further, from the viewpoint of thermoelectric performance, a bismuth-tellurium-based thermoelectric semiconductor material such as P-type bismuthellide or N-type bismuthellide is more preferable.
As the P-type bismuth telluride, those having holes as carriers and a positive Seebeck coefficient, for example, represented by Bi X Te 3 Sb 2-X , are preferably used. In this case, X is preferably 0 <X ≦ 0.8, more preferably 0.4 ≦ X ≦ 0.6. When X is larger than 0 and 0.8 or less, the Seebeck coefficient and the electric conductivity become large, and the characteristics as a P-type thermoelectric element are maintained, which is preferable.
Further, as the N-type bismuth telluride, one having an electron carrier and a negative Seebeck coefficient, for example, represented by Bi 2 Te 3-Y Se Y is preferably used. In this case, Y is preferably 0 ≦ Y ≦ 3 (when Y = 0: Bi 2 Te 3 ), and more preferably 0 <Y ≦ 2.7. When Y is 0 or more and 3 or less, the Seebeck coefficient and the electric conductivity become large, and the characteristics as an N-type thermoelectric element are maintained, which is preferable.
 熱電半導体組成物に用いる熱電半導体粒子は、前述した熱電半導体材料を、微粉砕装置等により、所定のサイズまで粉砕したものである。 The thermoelectric semiconductor particles used in the thermoelectric semiconductor composition are obtained by pulverizing the above-mentioned thermoelectric semiconductor material to a predetermined size by a fine pulverizer or the like.
 熱電半導体粒子の前記熱電半導体組成物中の配合量は、好ましくは、30~99質量%である。より好ましくは、50~96質量%であり、さらに好ましくは、70~95質量%である。熱電半導体粒子の配合量が、上記範囲内であれば、ゼーベック係数(ペルチェ係数の絶対値)が大きく、また電気伝導率の低下が抑制され、熱伝導率のみが低下するため高い熱電性能を示すとともに、十分な皮膜強度、屈曲性を有する膜が得られ好ましい。 The blending amount of the thermoelectric semiconductor particles in the thermoelectric semiconductor composition is preferably 30 to 99% by mass. It is more preferably 50 to 96% by mass, and even more preferably 70 to 95% by mass. When the blending amount of the thermoelectric semiconductor particles is within the above range, the Seebeck coefficient (absolute value of the Peltier coefficient) is large, the decrease in the electric conductivity is suppressed, and only the thermal conductivity is decreased, so that high thermoelectric performance is exhibited. At the same time, a film having sufficient film strength and flexibility can be obtained, which is preferable.
 熱電半導体粒子の平均粒径は、好ましくは、10nm~200μm、より好ましくは、10nm~30μm、さらに好ましくは、50nm~10μm、特に好ましくは、1~6μmである。上記範囲内であれば、均一分散が容易になり、電気伝導率を高くすることができる。
 前記熱電半導体材料を粉砕して熱電半導体粒子を得る方法は特に限定されず、ジェットミル、ボールミル、ビーズミル、コロイドミル、ローラーミル等の公知の微粉砕装置等により、所定のサイズまで粉砕すればよい。
 なお、熱電半導体粒子の平均粒径は、レーザー回折式粒度分析装置(Malvern社製、マスターサイザー3000)にて測定することにより得られ、粒径分布の中央値とした。
The average particle size of the thermoelectric semiconductor particles is preferably 10 nm to 200 μm, more preferably 10 nm to 30 μm, still more preferably 50 nm to 10 μm, and particularly preferably 1 to 6 μm. Within the above range, uniform dispersion can be facilitated and the electric conductivity can be increased.
The method of pulverizing the thermoelectric semiconductor material to obtain thermoelectric semiconductor particles is not particularly limited, and it may be pulverized to a predetermined size by a known pulverizer such as a jet mill, a ball mill, a bead mill, a colloid mill, a roller mill or the like. ..
The average particle size of the thermoelectric semiconductor particles was obtained by measuring with a laser diffraction type particle size analyzer (Mastersizer 3000 manufactured by Malvern), and was used as the median value of the particle size distribution.
 また、熱電半導体粒子は、事前に熱処理されたものであることが好ましい(ここでいう「熱処理」とは、後述する本発明の熱電変換材料層の製造方法におけるアニール処理工程で行う「アニール処理」とは異なる)。熱処理を行うことにより、熱電半導体粒子は、結晶性が向上し、さらに、熱電半導体粒子の表面酸化膜が除去されるため、熱電変換材料のゼーベック係数又はペルチェ係数が増大し、熱電性能指数をさらに向上させることができる。熱処理は、特に限定されないが、熱電半導体組成物を調製する前に、熱電半導体粒子に悪影響を及ぼすことがないように、ガス流量が制御された、窒素、アルゴン等の不活性ガス雰囲気下、同じく水素等の還元ガス雰囲気下、または真空条件下で行うことが好ましく、不活性ガス及び還元ガスの混合ガス雰囲気下で行うことがより好ましい。具体的な温度条件は、用いる熱電半導体粒子に依存するが、通常、粒子の融点以下の温度で、かつ100~1500℃で、数分~数十時間行うことが好ましい。 Further, the thermoelectric semiconductor particles are preferably heat-treated in advance (the "heat treatment" referred to here is the "annealing treatment" performed in the annealing treatment step in the method for producing a thermoelectric conversion material layer of the present invention described later. Is different). By performing the heat treatment, the crystallinity of the thermoelectric semiconductor particles is improved, and the surface oxide film of the thermoelectric semiconductor particles is removed, so that the Seebeck coefficient or the Peltier coefficient of the thermoelectric conversion material is increased, and the thermoelectric performance index is further increased. Can be improved. The heat treatment is not particularly limited, but before preparing the thermoelectric semiconductor composition, the gas flow rate is controlled so as not to adversely affect the thermoelectric semiconductor particles under an atmosphere of an inert gas such as nitrogen or argon. It is preferably performed in a reducing gas atmosphere such as hydrogen or under vacuum conditions, and more preferably in a mixed gas atmosphere of an inert gas and a reducing gas. The specific temperature condition depends on the thermoelectric semiconductor particles used, but it is usually preferable to carry out the temperature at a temperature equal to or lower than the melting point of the particles and at 100 to 1500 ° C. for several minutes to several tens of hours.
(耐熱性樹脂)
 本発明に用いる熱電半導体組成物には、熱電半導体材料を高温度でアニール処理を行う観点から、耐熱性樹脂が好ましく用いられる。熱電半導体材料(熱電半導体粒子)間のバインダーとして働き、熱電変換モジュールの屈曲性を高めることができるとともに、塗布等による薄膜の形成が容易になる。該耐熱性樹脂は、特に制限されるものではないが、熱電半導体組成物からなる薄膜をアニール処理等により熱電半導体粒子を結晶成長させる際に、樹脂としての機械的強度及び熱伝導率等の諸物性が損なわれず維持される耐熱性樹脂が好ましい。
 前記耐熱性樹脂は、耐熱性がより高く、且つ薄膜中の熱電半導体粒子の結晶成長に悪影響を及ぼさないという点から、ポリアミド樹脂、ポリアミドイミド樹脂、ポリイミド樹脂、エポキシ樹脂が好ましく、屈曲性に優れるという点からポリアミド樹脂、ポリアミドイミド樹脂、ポリイミド樹脂がより好ましい。なお、本発明においてポリイミド樹脂とは、ポリイミド及びその前駆体を総称する。
(Heat resistant resin)
As the thermoelectric semiconductor composition used in the present invention, a heat-resistant resin is preferably used from the viewpoint of annealing the thermoelectric semiconductor material at a high temperature. It acts as a binder between thermoelectric semiconductor materials (thermoelectric semiconductor particles), can increase the flexibility of the thermoelectric conversion module, and facilitates the formation of a thin film by coating or the like. The heat-resistant resin is not particularly limited, but when a thin film made of a thermoelectric semiconductor composition is subjected to crystal growth of thermoelectric semiconductor particles by annealing or the like, various factors such as mechanical strength and thermal conductivity as the resin are obtained. A heat-resistant resin that maintains its physical properties without being impaired is preferable.
The heat-resistant resin is preferably a polyamide resin, a polyamideimide resin, a polyimide resin, or an epoxy resin, and has excellent flexibility, because it has higher heat resistance and does not adversely affect the crystal growth of thermoelectric semiconductor particles in the thin film. From this point of view, polyamide resin, polyamideimide resin and polyimide resin are more preferable. In the present invention, the polyimide resin is a general term for polyimide and its precursor.
 前記耐熱性樹脂は、分解温度が300℃以上であることが好ましい。分解温度が上記範囲であれば、後述するように、熱電半導体組成物からなる薄膜をアニール処理した場合でも、バインダーとして機能が失われることなく、屈曲性を維持することができる。 The heat-resistant resin preferably has a decomposition temperature of 300 ° C. or higher. As long as the decomposition temperature is within the above range, the flexibility can be maintained without losing the function as a binder even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
 また、前記耐熱性樹脂は、熱重量測定(TG)による300℃における質量減少率が10%以下であることが好ましく、5%以下であることがより好ましく、1%以下であることがさらに好ましい。質量減少率が上記範囲であれば、後述するように、熱電半導体組成物からなる薄膜をアニール処理した場合でも、バインダーとして機能が失われることなく、熱電変換材料層の屈曲性を維持することができる。 Further, the heat-resistant resin preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and further preferably 1% or less at 300 ° C. by thermogravimetric analysis (TG). .. As long as the mass reduction rate is within the above range, the flexibility of the thermoelectric conversion material layer can be maintained without losing the function as a binder even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later. it can.
 前記耐熱性樹脂の前記熱電半導体組成物中の配合量は、0.1~40質量%、好ましくは0.5~20質量%、より好ましくは、1~20質量%、さらに好ましくは2~15質量%である。前記耐熱性樹脂の配合量が、上記範囲内であると、熱電半導体材料のバインダーとし機能し、薄膜の形成がしやすくなり、しかも高い熱電性能と皮膜強度が両立した膜が得られる。 The blending amount of the heat-resistant resin in the thermoelectric semiconductor composition is 0.1 to 40% by mass, preferably 0.5 to 20% by mass, more preferably 1 to 20% by mass, still more preferably 2 to 15. It is mass%. When the blending amount of the heat-resistant resin is within the above range, it functions as a binder for the thermoelectric semiconductor material, facilitates the formation of a thin film, and provides a film having both high thermoelectric performance and film strength.
(イオン液体)
 本発明で用いるイオン液体は、カチオンとアニオンとを組み合わせてなる溶融塩であり、-50~400℃の温度領域のいずれかの温度領域において、液体で存在し得る塩をいう。換言すれば、イオン液体は、融点が-50℃以上400℃未満の範囲にあるイオン性化合物である。イオン液体の融点は、好ましくは-25℃以上200℃以下、より好ましくは0℃以上150℃以下である。イオン液体は、蒸気圧が極めて低く不揮発性であること、優れた熱安定性及び電気化学安定性を有していること、粘度が低いこと、かつイオン伝導度が高いこと等の特徴を有しているため、導電補助剤として、熱電半導体粒子間の電気伝導率の低減を効果的に抑制することができる。また、イオン液体は、非プロトン性のイオン構造に基づく高い極性を示し、耐熱性樹脂との相溶性に優れるため、熱電変換材料層の電気伝導率を均一にすることができる。
(Ionic liquid)
The ionic liquid used in the present invention is a molten salt formed by combining a cation and an anion, and refers to a salt that can exist as a liquid in any temperature range of −50 to 400 ° C. In other words, the ionic liquid is an ionic compound having a melting point in the range of −50 ° C. or higher and lower than 400 ° C. The melting point of the ionic liquid is preferably −25 ° C. or higher and 200 ° C. or lower, and more preferably 0 ° C. or higher and 150 ° C. or lower. Ionic liquids have features such as extremely low vapor pressure, non-volatility, excellent thermostability and electrochemical stability, low viscosity, and high ionic conductivity. Therefore, as a conductive auxiliary agent, it is possible to effectively suppress the reduction of the electric conductivity between the thermoelectric semiconductor particles. Further, since the ionic liquid exhibits high polarity based on the aprotic ionic structure and has excellent compatibility with the heat-resistant resin, the electric conductivity of the thermoelectric conversion material layer can be made uniform.
 イオン液体は、公知または市販のものが使用できる。例えば、ピリジニウム、ピリミジニウム、ピラゾリウム、ピロリジニウム、ピペリジニウム、イミダゾリウム等の窒素含有環状カチオン化合物及びそれらの誘導体;テトラアルキルアンモニウムのアミン系カチオン及びそれらの誘導体;ホスホニウム、トリアルキルスルホニウム、テトラアルキルホスホニウム等のホスフィン系カチオン及びそれらの誘導体;リチウムカチオン及びその誘導体等のカチオン成分と、Cl、AlCl 、AlCl 、ClO 等の塩化物イオン、Br等の臭化物イオン、I等のヨウ化物イオン、BF 、PF 等のフッ化物イオン、F(HF) 等のハロゲン化物アニオン、NO 、CHCOO、CFCOO、CHSO 、CFSO 、(FSO、(CFSO、(CFSO、AsF 、SbF 、NbF 、TaF 、F(HF)n、(CN)、CSO 、(CSO、CCOO、(CFSO)(CFCO)N等のアニオン成分とから構成されるものが挙げられる。 As the ionic liquid, known or commercially available ones can be used. For example, nitrogen-containing cyclic cation compounds such as pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, imidazolium and their derivatives; amine-based cations of tetraalkylammonium and their derivatives; phosphine such as phosphonium, trialkylsulfonium, tetraalkylphosphonium. systems cations and their derivatives; and cationic components, such as lithium cations and derivatives thereof, Cl -, AlCl 4 -, Al 2 Cl 7 -, ClO 4 - chloride or ion, Br -, etc. of bromide ion, I -, etc. of iodide ion, BF 4 -, PF 6 - fluoride such as ions, F (HF) n - such as halide anions of, NO 3 -, CH 3 COO -, CF 3 COO -, CH 3 SO 3 -, CF 3 SO 3 -, (FSO 2) 2 N -, (CF 3 SO 2) 2 N -, (CF 3 SO 2) 3 C -, AsF 6 -, SbF 6 -, NbF 6 -, TaF 6 -, F (HF) n -, ( CN) 2 n -, C 4 F 9 SO 3 -, (C 2 F 5 SO 2) 2 n -, C 3 F 7 COO -, (CF 3 SO 2) (CF 3 Examples thereof include those composed of anionic components such as CO) N .
 上記のイオン液体の中で、高温安定性、熱電半導体粒子及び樹脂との相溶性、熱電半導体粒子間隙の電気伝導率の低下抑制等の観点から、イオン液体のカチオン成分が、ピリジニウムカチオン及びその誘導体、イミダゾリウムカチオン及びその誘導体から選ばれる少なくとも1種を含むことが好ましい。イオン液体のアニオン成分が、ハロゲン化物アニオンを含むことが好ましく、Cl、Br及びIから選ばれる少なくとも1種を含むことがさらに好ましい。 Among the above ionic liquids, the cation component of the ionic liquid is a pyridinium cation and its derivatives from the viewpoints of high temperature stability, compatibility with thermoelectric semiconductor particles and resins, and suppression of decrease in electrical conductivity between thermoelectric semiconductor particle gaps. , At least one selected from imidazolium cations and derivatives thereof is preferably contained. Anionic component of the ionic liquid preferably contains a halide anion, Cl -, Br - and I - is more preferably contains at least one selected from.
 カチオン成分が、ピリジニウムカチオン及びその誘導体を含むイオン液体の具体的な例として、4-メチル-ブチルピリジニウムクロライド、3-メチル-ブチルピリジニウムクロライド、4-メチル-ヘキシルピリジニウムクロライド、3-メチル-ヘキシルピリジニウムクロライド、4-メチル-オクチルピリジニウムクロライド、3-メチル-オクチルピリジニウムクロライド、3、4-ジメチル-ブチルピリジニウムクロライド、3、5-ジメチル-ブチルピリジニウムクロライド、4-メチル-ブチルピリジニウムテトラフルオロボレート、4-メチル-ブチルピリジニウムヘキサフルオロホスフェート、1-ブチルピリジニウムブロミド、1-ブチル-4-メチルピリジニウムブロミド、1-ブチル-4-メチルピリジニウムヘキサフルオロホスファート、1-ブチル-4-メチルピリジニウムヨージド等が挙げられる。この中で、1-ブチルピリジニウムブロミド、1-ブチル-4-メチルピリジニウムブロミド、1-ブチル-4-メチルピリジニウムヘキサフルオロホスファート、1-ブチル-4-メチルピリジニウムヨージドが好ましい。 Specific examples of an ionic liquid in which the cation component contains a pyridinium cation and a derivative thereof include 4-methyl-butylpyridinium chloride, 3-methyl-butylpyridinium chloride, 4-methyl-hexylpyridinium chloride, and 3-methyl-hexylpyridinium. Chloride, 4-methyl-octylpyridinium chloride, 3-methyl-octylpyridinium chloride, 3,4-dimethyl-butylpyridinium chloride, 3,5-dimethyl-butylpyridinium chloride, 4-methyl-butylpyridinium tetrafluoroborate, 4- Methyl-butylpyridinium hexafluorophosphate, 1-butylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium hexafluorophosphate, 1-butyl-4-methylpyridinium iodide and the like. Be done. Of these, 1-butylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium hexafluorophosphate, and 1-butyl-4-methylpyridinium iodide are preferable.
 また、カチオン成分が、イミダゾリウムカチオン及びその誘導体を含むイオン液体の具体的な例として、[1-ブチル-3-(2-ヒドロキシエチル)イミダゾリウムブロミド]、[1-ブチル-3-(2-ヒドロキシエチル)イミダゾリウムテトラフルオロボレイト]、1-エチル-3-メチルイミダゾリウムクロライド、1-エチル-3-メチルイミダゾリウムブロミド、1-ブチル-3-メチルイミダゾリウムクロライド、1-ヘキシル-3-メチルイミダゾリウムクロライド、1-オクチル-3-メチルイミダゾリウムクロライド、1-デシル-3-メチルイミダゾリウムクロライド、1-デシル-3-メチルイミダゾリウムブロミド、1-ドデシル-3-メチルイミダゾリウムクロライド、1-テトラデシル-3-メチルイミダゾリウムクロライド、1-エチル-3-メチルイミダゾリウムテトラフロオロボレート、1-ブチル-3-メチルイミダゾリウムテトラフロオロボレート、1-ヘキシル-3-メチルイミダゾリウムテトラフロオロボレート、1-エチル-3-メチルイミダゾリウムヘキサフルオロホスフェート、1-ブチル-3-メチルイミダゾリウムヘキサフルオロホスフェート、1-メチル-3-ブチルイミダゾリウムメチルスルフェート、1、3-ジブチルイミダゾリウムメチルスルフェート等が挙げられる。この中で、[1-ブチル-3-(2-ヒドロキシエチル)イミダゾリウムブロミド]、[1-ブチル-3-(2-ヒドロキシエチル)イミダゾリウムテトラフルオロボレイト]が好ましい。 Further, as specific examples of the ionic liquid in which the cation component contains an imidazolium cation and a derivative thereof, [1-butyl-3- (2-hydroxyethyl) imidazolium bromide] and [1-butyl-3- (2) -Hydroxyethyl) imidazolium tetrafluoroborate], 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3 -Methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium bromide, 1-dodecyl-3-methylimidazolium chloride, 1-Tetradecyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium tetrafurobolate, 1-butyl-3-methylimidazolium tetrafuroborobolate, 1-hexyl-3-methylimidazolium tetraflolate Orobolate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-methyl-3-butylimidazolium methylsulfate, 1,3-dibutylimidazolium methyl Sulfate and the like can be mentioned. Of these, [1-butyl-3- (2-hydroxyethyl) imidazolium bromide] and [1-butyl-3- (2-hydroxyethyl) imidazolium tetrafluoroborate] are preferable.
 上記のイオン液体は、電気伝導率が10-7S/cm以上であることが好ましく、10-6S/cm以上であることがより好ましい。電気伝導率が上記の範囲であれば、導電補助剤として、熱電半導体粒子間の電気伝導率の低減を効果的に抑制することができる。 The above-mentioned ionic liquid preferably has an electric conductivity of 10-7 S / cm or more, and more preferably 10-6 S / cm or more. When the electric conductivity is in the above range, the reduction of the electric conductivity between the thermoelectric semiconductor particles can be effectively suppressed as a conductivity auxiliary agent.
 また、上記のイオン液体は、分解温度が300℃以上であることが好ましい。分解温度が上記範囲であれば、後述するように、熱電半導体組成物からなる薄膜をアニール処理した場合でも、導電補助剤としての効果を維持することができる。 Further, the above-mentioned ionic liquid preferably has a decomposition temperature of 300 ° C. or higher. As long as the decomposition temperature is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
 さらに、上記のイオン液体は、熱重量測定(TG)による300℃における質量減少率が10%以下であることが好ましく、5%以下であることがより好ましく、1%以下であることがさらに好ましい。質量減少率が上記範囲であれば、後述するように、熱電半導体組成物からなる薄膜をアニール処理した場合でも、導電補助剤としての効果を維持することができる。 Further, the above-mentioned ionic liquid preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and further preferably 1% or less at 300 ° C. by thermogravimetric analysis (TG). .. As long as the mass reduction rate is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
 前記イオン液体の前記熱電半導体組成物中の配合量は、好ましくは0.01~50質量%、より好ましくは0.5~30質量%、さらに好ましくは1.0~20質量%である。前記イオン液体の配合量が、上記の範囲内であれば、電気伝導率の低下が効果的に抑制され、高い熱電性能を有する膜が得られる。 The blending amount of the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 20% by mass. When the blending amount of the ionic liquid is within the above range, the decrease in electrical conductivity is effectively suppressed, and a film having high thermoelectric performance can be obtained.
(無機イオン性化合物)
 本発明で用いる無機イオン性化合物は、少なくともカチオンとアニオンから構成される化合物である。無機イオン性化合物は室温において固体であり、400~900℃の温度領域のいずれかの温度に融点を有し、イオン伝導度が高いこと等の特徴を有しているため、導電補助剤として、熱電半導体粒子間の電気伝導率の低減を抑制することができる。
(Inorganic ionic compound)
The inorganic ionic compound used in the present invention is a compound composed of at least cations and anions. The inorganic ionic compound is solid at room temperature, has a melting point in any temperature in the temperature range of 400 to 900 ° C., and has characteristics such as high ionic conductivity. Therefore, it can be used as a conductive auxiliary agent. It is possible to suppress a decrease in electrical conductivity between thermoelectric semiconductor particles.
 カチオンとしては、金属カチオンを用いる。
 金属カチオンとしては、例えば、アルカリ金属カチオン、アルカリ土類金属カチオン、典型金属カチオン及び遷移金属カチオンが挙げられ、アルカリ金属カチオン又はアルカリ土類金属カチオンがより好ましい。
 アルカリ金属カチオンとしては、例えば、Li、Na、K、Rb、Cs及びFr等が挙げられる。
 アルカリ土類金属カチオンとしては、例えば、Mg2+、Ca2+、Sr2+及びBa2+等が挙げられる。
As the cation, a metal cation is used.
Examples of the metal cation include alkali metal cations, alkaline earth metal cations, typical metal cations and transition metal cations, and alkali metal cations or alkaline earth metal cations are more preferable.
Examples of the alkali metal cation include Li + , Na + , K + , Rb + , Cs +, Fr + and the like.
Examples of the alkaline earth metal cation include Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ .
 アニオンとしては、例えば、F、Cl、Br、I、OH、CN、NO 、NO 、ClO、ClO 、ClO 、ClO 、CrO 2-、HSO 、SCN、BF 、PF 等が挙げられる。 The anion such as, F -, Cl -, Br -, I -, OH -, CN -, NO 3 -, NO 2 -, ClO -, ClO 2 -, ClO 3 -, ClO 4 -, CrO 4 2 -, HSO 4 -, SCN - , BF 4 -, PF 6 - , and the like.
 無機イオン性化合物は、公知または市販のものが使用できる。例えば、カリウムカチオン、ナトリウムカチオン、又はリチウムカチオン等のカチオン成分と、Cl、AlCl 、AlCl 、ClO 等の塩化物イオン、Br等の臭化物イオン、I等のヨウ化物イオン、BF 、PF 等のフッ化物イオン、F(HF) 等のハロゲン化物アニオン、NO 、OH、CN等のアニオン成分とから構成されるものが挙げられる。 As the inorganic ionic compound, known or commercially available ones can be used. For example, a cation component such as potassium cation, sodium cation, or lithium cations, Cl -, AlCl 4 -, Al 2 Cl 7 -, ClO 4 - chloride or ion, Br -, etc. of bromide ion, I -, etc. iodide ion, BF 4 -, PF 6 - fluoride ions, F (HF) n, such as - such as halide anions of, NO 3 -, OH -, CN - and the ones mentioned consists the anion component of such Be done.
 上記の無機イオン性化合物の中で、高温安定性、熱電半導体粒子及び樹脂との相溶性、熱電半導体粒子間隙の電気伝導率の低下抑制等の観点から、無機イオン性化合物のカチオン成分が、カリウム、ナトリウム、及びリチウムから選ばれる少なくとも1種を含むことが好ましい。また、無機イオン性化合物のアニオン成分が、ハロゲン化物アニオンを含むことが好ましく、Cl、Br、及びIから選ばれる少なくとも1種を含むことがさらに好ましい。 Among the above-mentioned inorganic ionic compounds, the cationic component of the inorganic ionic compound is potassium from the viewpoints of high temperature stability, compatibility with thermoelectric semiconductor particles and resins, and suppression of decrease in electrical conductivity between thermoelectric semiconductor particle gaps. , Sodium, and lithium are preferably included. Further, the anion component of the inorganic ionic compound preferably contains a halide anion, and more preferably contains at least one selected from Cl , Br , and I .
 カチオン成分が、カリウムカチオンを含む無機イオン性化合物の具体的な例として、KBr、KI、KCl、KF、KOH、KCO等が挙げられる。この中で、KBr、KIが好ましい。
 カチオン成分が、ナトリウムカチオンを含む無機イオン性化合物の具体的な例として、NaBr、NaI、NaOH、NaF、NaCO等が挙げられる。この中で、NaBr、NaIが好ましい。
 カチオン成分が、リチウムカチオンを含む無機イオン性化合物の具体的な例として、LiF、LiOH、LiNO等が挙げられる。この中で、LiF、LiOHが好ましい。
Cationic component is, as a specific example of the inorganic ionic compound containing a potassium cation, KBr, KI, KCl, KF , KOH, K 2 CO 3 and the like. Of these, KBr and KI are preferable.
Specific examples of the inorganic ionic compound whose cation component contains a sodium cation include NaBr, NaI, NaOH, NaF, Na 2 CO 3 and the like. Of these, NaBr and NaI are preferable.
Specific examples of the inorganic ionic compound whose cation component contains a lithium cation include LiF, LiOH, and LiNO 3 . Of these, LiF and LiOH are preferable.
 上記の無機イオン性化合物は、電気伝導率が10-7S/cm以上であることが好ましく、10-6S/cm以上であることがより好ましい。電気伝導率が上記範囲であれば、導電補助剤として、熱電半導体粒子間の電気伝導率の低減を効果的に抑制することができる。 The above-mentioned inorganic ionic compound preferably has an electric conductivity of 10-7 S / cm or more, and more preferably 10-6 S / cm or more. When the electric conductivity is within the above range, the reduction of the electric conductivity between the thermoelectric semiconductor particles can be effectively suppressed as a conductivity auxiliary agent.
 また、上記の無機イオン性化合物は、分解温度が400℃以上であることが好ましい。分解温度が上記範囲であれば、後述するように、熱電半導体組成物からなる薄膜をアニール処理した場合でも、導電補助剤としての効果を維持することができる。 Further, the decomposition temperature of the above-mentioned inorganic ionic compound is preferably 400 ° C. or higher. As long as the decomposition temperature is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
 さらに、上記の無機イオン性化合物は、熱重量測定(TG)による400℃における質量減少率が10%以下であることが好ましく、5%以下であることがより好ましく、1%以下であることがさらに好ましい。質量減少率が上記範囲であれば、後述するように、熱電半導体組成物からなる薄膜をアニール処理した場合でも、導電補助剤としての効果を維持することができる。 Further, the above-mentioned inorganic ionic compound preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and preferably 1% or less at 400 ° C. by thermogravimetric analysis (TG). More preferred. As long as the mass reduction rate is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.
 前記無機イオン性化合物の前記熱電半導体組成物中の配合量は、好ましくは0.01~50質量%、より好ましくは0.5~30質量%、さらに好ましくは1.0~10質量%である。前記無機イオン性化合物の配合量が、上記範囲内であれば、電気伝導率の低下を効果的に抑制でき、結果として熱電性能が向上した膜が得られる。
 なお、無機イオン性化合物とイオン液体とを併用する場合においては、前記熱電半導体組成物中における、無機イオン性化合物及びイオン液体の含有量の総量は、好ましくは0.01~50質量%、より好ましくは0.5~30質量%、さらに好ましくは1.0~10質量%である。
The blending amount of the inorganic ionic compound in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 10% by mass. .. When the blending amount of the inorganic ionic compound is within the above range, the decrease in electrical conductivity can be effectively suppressed, and as a result, a film having improved thermoelectric performance can be obtained.
When the inorganic ionic compound and the ionic liquid are used in combination, the total content of the inorganic ionic compound and the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass. It is preferably 0.5 to 30% by mass, more preferably 1.0 to 10% by mass.
(その他の添加剤)
 本発明で用いる熱電半導体組成物には、上記以外の成分以外に、必要に応じて、さらに分散剤、造膜助剤、光安定剤、酸化防止剤、粘着付与剤、可塑剤、着色剤、樹脂安定剤、充てん剤、顔料、導電性フィラー、導電性高分子、硬化剤等の他の添加剤を含んでいてもよい。これらの添加剤は、1種単独で、あるいは2種以上を組み合わせて用いることができる。
(Other additives)
In addition to the components other than the above, the thermoelectric semiconductor composition used in the present invention further contains, if necessary, a dispersant, a film-forming aid, a light stabilizer, an antioxidant, a tackifier, a plasticizer, a colorant, and the like. It may contain other additives such as resin stabilizers, fillers, pigments, conductive fillers, conductive polymers and hardeners. These additives can be used alone or in combination of two or more.
 本発明の熱電変換材料層は、電気伝導率が向上されたものであり、熱電変換モジュールの熱電変換材料層として適用することにより、熱電性能が高い熱電変換モジュールを得ることができる。 The thermoelectric conversion material layer of the present invention has improved electrical conductivity, and by applying it as a thermoelectric conversion material layer of a thermoelectric conversion module, a thermoelectric conversion module having high thermoelectric performance can be obtained.
[熱電変換材料層の製造方法]       
 本発明の熱電変換材料層の製造方法は、熱電半導体組成物の塗布膜からなる熱電変換材料層を製造する方法であって、(A)熱電変換材料層を形成する工程、(B)前記(A)の工程で得られた前記熱電変換材料層を乾燥する工程、(C)前記(B)の工程で得られた乾燥後の前記熱電変換材料層を加圧する工程、及び(D)前記(C)の工程で得られた加圧された熱電変換材料層をアニール処理する工程を含むことを特徴とする。
 本発明の熱電変換材料層の製造方法においては、熱電変換材料層を形成後、所定の温度で乾燥し、次いで、熱電変換材料層の上面を所定の圧力で加圧し、熱電変換材料層中の空隙の体積を減少させ、その後、アニール処理することにより、電気伝導率が向上した熱電変換材料層が得られる。
[Manufacturing method of thermoelectric conversion material layer]
The method for producing a thermoelectric conversion material layer of the present invention is a method for producing a thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition, wherein (A) a step of forming a thermoelectric conversion material layer, (B) the above-mentioned (). A step of drying the thermoelectric conversion material layer obtained in the step A, (C) a step of pressurizing the dried thermoelectric conversion material layer obtained in the step (B), and (D) the step (D). It is characterized by including a step of annealing the pressurized thermoelectric conversion material layer obtained in the step of C).
In the method for producing a thermoelectric conversion material layer of the present invention, after forming the thermoelectric conversion material layer, it is dried at a predetermined temperature, and then the upper surface of the thermoelectric conversion material layer is pressed with a predetermined pressure to form the thermoelectric conversion material layer. By reducing the volume of the voids and then annealing, a thermoelectric conversion material layer with improved electrical conductivity can be obtained.
 図3は、本発明の熱電変換材料層の製造方法の一例を工程順に示す説明図であり、(a)は基板1a上に熱電変換材料層2sを形成した態様を示す断面図であり、基板1a上に熱電変換材料層2sを塗布膜(空隙部3aを含む)として形成し、所定の温度で乾燥させる;
(b)は熱電変換材料層2sの上面にプレス加圧部5を対向させた後の態様を示す断面図であり、(a)で得られた乾燥後の熱電変換材料層2sを常温まで冷却した後、熱電変換材料層2sとプレス加圧部5とを対向させる;
(c)はプレス加圧部5により熱電変換材料層2sの上面を加圧した後、熱電変換材料層2sからプレス加圧部5をリリースした後の態様を示す断面図である。
その後、アニール処理を行うことにより、本発明の熱電変換材料層2t(空隙数及び体積が減少した空隙部4aを含む)を得ることができる。
FIG. 3 is an explanatory view showing an example of a method for manufacturing a thermoelectric conversion material layer of the present invention in order of steps, and FIG. 3A is a cross-sectional view showing an embodiment in which a thermoelectric conversion material layer 2s is formed on a substrate 1a. A thermoelectric conversion material layer 2s is formed on 1a as a coating film (including a gap 3a) and dried at a predetermined temperature;
(B) is a cross-sectional view showing an aspect after the press pressurizing portion 5 is opposed to the upper surface of the thermoelectric conversion material layer 2s, and the dried thermoelectric conversion material layer 2s obtained in (a) is cooled to room temperature. After that, the thermoelectric conversion material layer 2s and the press pressurizing section 5 face each other;
(C) is a cross-sectional view showing an aspect after pressurizing the upper surface of the thermoelectric conversion material layer 2s by the press pressurizing section 5 and then releasing the press pressurizing section 5 from the thermoelectric conversion material layer 2s.
Then, by performing an annealing treatment, the thermoelectric conversion material layer 2t of the present invention (including the void portion 4a in which the number of voids and the volume are reduced) can be obtained.
 熱電変換材料層は、好ましい態様として、基板上にベタ膜状に作製し、その後、目的とするチップサイズに個片化してもよい。また、好ましい他の態様として、基板上に前述の熱電変換材料のチップの大きさに塗布膜を形成してもよい。さらに、熱電変換材料層の形状制御性の観点から、より好ましい態様として、熱電変換材料のチップ形状を有する離間した開口部を含む、格子状のパターン枠部材を用いて作製してもよい。
 チップサイズとしては、例えば、短辺0.1~20mm、長辺0.2~25mm程度である。
As a preferred embodiment, the thermoelectric conversion material layer may be formed on a substrate in the form of a solid film, and then individualized into a desired chip size. Further, as another preferred embodiment, a coating film may be formed on the substrate in the size of the chip of the thermoelectric conversion material described above. Further, from the viewpoint of shape controllability of the thermoelectric conversion material layer, as a more preferable embodiment, a grid-like pattern frame member including a separated opening having a chip shape of the thermoelectric conversion material may be used.
The chip size is, for example, about 0.1 to 20 mm on the short side and 0.2 to 25 mm on the long side.
 前記熱電変換材料のチップ形状を有する離間した開口部を含む、格子状のパターン枠部材を使用する場合の熱電変換材料層の製造方法は、例えば、以下のようである。
(p)基板上に、熱電変換材料のチップ形状を有する離間した開口部を含む、格子状のパターン枠部材を静置する;
(q)パターン枠部材の開口部に、熱電変換材料層の塗布膜を形成し、所定の温度で乾燥させる;
(r)(q)で得られた乾燥後の熱電変換材料層を常温まで冷却した後、熱電変換材料層とプレス加圧部(図3におけるプレス加圧部5に相当)とを対向させる;
(t)プレス加圧部で熱電変換材料層の上面を加圧し、熱電変換材料層の空隙数及び体積を減少させ、プレス加圧部を熱電変換材料層からリリースし、さらにパターン枠部材をリリースする;
(u)その後、基板上に得られたパターン枠部材の開口部の形状が反映された熱電変換材料層に対しアニール処理を行うことにより、本発明のチップ状の熱電変換材料層を得る。
 前記開口部は、特に制限されないが、パターン枠部材をリリースした後、熱電変換材料のチップの形状に反映される形状を有するものであればよく、長方形状、正方形状、又は円形状であることが好ましく、長方形状、正方形状であることがさらに好ましい。
 また、前記パターン枠部材として、形成の容易さの観点から、ステンレス鋼、銅等を用いることができる。
The method for manufacturing the thermoelectric conversion material layer when the grid-like pattern frame member including the separated openings having the chip shape of the thermoelectric conversion material is used is as follows, for example.
(P) A grid-like pattern frame member including a separated opening having a chip shape of a thermoelectric conversion material is placed on the substrate;
(Q) A coating film of a thermoelectric conversion material layer is formed in the opening of the pattern frame member and dried at a predetermined temperature;
(R) After cooling the dried thermoelectric conversion material layer obtained in (q) to room temperature, the thermoelectric conversion material layer and the press pressurizing section (corresponding to the press pressurizing section 5 in FIG. 3) are opposed to each other;
(T) The upper surface of the thermoelectric conversion material layer is pressurized by the press pressurizing part to reduce the number of voids and the volume of the thermoelectric conversion material layer, the press pressurizing part is released from the thermoelectric conversion material layer, and the pattern frame member is further released. Do;
(U) After that, the chip-shaped thermoelectric conversion material layer of the present invention is obtained by subjecting the thermoelectric conversion material layer reflecting the shape of the opening of the pattern frame member obtained on the substrate to an annealing treatment.
The opening is not particularly limited, but may be rectangular, square, or circular as long as it has a shape that is reflected in the shape of the chip of the thermoelectric conversion material after the pattern frame member is released. Is preferable, and it is more preferable that the shape is rectangular or square.
Further, as the pattern frame member, stainless steel, copper or the like can be used from the viewpoint of ease of formation.
(A)熱電変換材料層形成工程
 熱電変換材料層形成工程は、基板上に熱電変換材料層を形成する工程であり、例えば、図3(a)においては、基板1a上に熱電半導体組成物を塗布し、熱電変換材料層2sを形成する工程である。
(A) Thermoelectric conversion material layer forming step The thermoelectric conversion material layer forming step is a step of forming a thermoelectric conversion material layer on a substrate. For example, in FIG. 3A, a thermoelectric semiconductor composition is formed on a substrate 1a. This is a step of coating and forming a thermoelectric conversion material layer 2s.
(基板)
 基板としては、特に制限はなく、ガラス、シリコン、セラミック、金属、又はプラスチック等が挙げられる。アニール処理を高温度下で行う観点から、ガラス、シリコン、セラミック、金属が好ましく、熱処理後の寸法安定性の観点から、ガラス、シリコン、セラミックを用いることがより好ましい。
 前記基板の厚さは、プロセス及び寸法安定性の観点から、100~10000μmのものが使用できる。
(substrate)
The substrate is not particularly limited, and examples thereof include glass, silicon, ceramic, metal, and plastic. Glass, silicon, ceramic and metal are preferable from the viewpoint of performing the annealing treatment at a high temperature, and glass, silicon and ceramic are more preferable from the viewpoint of dimensional stability after heat treatment.
From the viewpoint of process and dimensional stability, the thickness of the substrate can be 100 to 10000 μm.
(熱電半導体組成物)
 本発明に用いる熱電半導体組成物は、前述したものと同様のものを用いることができる。熱電半導体材料、耐熱性樹脂、イオン液体、無機イオン性化合物等に関する、好ましい材料、配合量等も同様である。
(Thermoelectric semiconductor composition)
As the thermoelectric semiconductor composition used in the present invention, the same thermoelectric semiconductor composition as described above can be used. The same applies to preferable materials, blending amounts, etc. for thermoelectric semiconductor materials, heat-resistant resins, ionic liquids, inorganic ionic compounds, and the like.
(熱電半導体組成物の調製方法)
 本発明で用いる熱電半導体組成物の調製方法は、特に制限はなく、超音波ホモジナイザー、スパイラルミキサー、プラネタリーミキサー、ディスパーサー、ハイブリッドミキサー等の公知の方法により、前記熱電半導体粒子、前記耐熱性樹脂、前記イオン液体及び無機イオン性化合物の一方又は双方、必要に応じて前記その他の添加剤、さらに溶媒を加えて、混合分散させ、当該熱電半導体組成物を調製すればよい。
 前記溶媒としては、例えば、トルエン、酢酸エチル、メチルエチルケトン、アルコール、テトラヒドロフラン、メチルピロリドン、エチルセロソルブ等の溶媒などが挙げられる。これらの溶媒は、1種を単独で用いてもよく、2種以上を混合して用いてもよい。熱電半導体組成物の固形分濃度としては、該組成物が塗工に適した粘度であればよく、特に制限はない。
(Method for preparing thermoelectric semiconductor composition)
The method for preparing the thermoelectric semiconductor composition used in the present invention is not particularly limited, and the thermoelectric semiconductor particles and the heat-resistant resin are prepared by a known method such as an ultrasonic homogenizer, a spiral mixer, a planetary mixer, a disperser, and a hybrid mixer. , One or both of the ionic liquid and the inorganic ionic compound, and if necessary, the other additive and a solvent may be added and mixed and dispersed to prepare the thermoelectric semiconductor composition.
Examples of the solvent include solvents such as toluene, ethyl acetate, methyl ethyl ketone, alcohol, tetrahydrofuran, methylpyrrolidone, and ethyl cellosolve. One of these solvents may be used alone, or two or more of these solvents may be mixed and used. The solid content concentration of the thermoelectric semiconductor composition is not particularly limited as long as the composition has a viscosity suitable for coating.
 前記熱電半導体組成物からなる薄膜は、例えば、前記基板上に、前記熱電半導体組成物を塗布し、乾燥することで形成することができる。 The thin film made of the thermoelectric semiconductor composition can be formed, for example, by applying the thermoelectric semiconductor composition on the substrate and drying it.
 熱電半導体組成物を、基板上に塗布する方法としては、スクリーン印刷法、フレキソ印刷法、グラビア印刷法、スピンコート法、ディップコート法、ダイコート法、スプレーコート法、バーコート法、ドクターブレード法、アプリケーター法等の公知の方法が挙げられ、特に制限されない。塗膜をパターン状に形成する場合は、所望のパターンを有するスクリーン版を用いて簡便にパターン形成が可能なスクリーン印刷、ステンシル印刷、スロットダイコート等が好ましく用いられる。 As a method of applying the thermoelectric semiconductor composition on a substrate, a screen printing method, a flexographic printing method, a gravure printing method, a spin coating method, a dip coating method, a die coating method, a spray coating method, a bar coating method, a doctor blade method, etc. Known methods such as the applicator method can be mentioned and are not particularly limited. When the coating film is formed into a pattern, screen printing, stencil printing, slot die coating, etc., which can easily form a pattern using a screen plate having a desired pattern, are preferably used.
(B)熱電変換材料層乾燥工程
 熱電変換材料層乾燥工程は、(A)の工程で得られた熱電変換材料層を乾燥する工程であり、例えば、図3(a)においては、基板1a上の熱電変換材料層2sを乾燥する工程である。
 乾燥方法としては、熱風乾燥法、熱ロール乾燥法、赤外線照射法等、従来公知の乾燥方法が採用できる。加熱温度は、通常、80~170℃であり、好ましくは100~150℃であり、より好ましくは110~145℃であり、さらに好ましくは120~140℃である。
 加熱時間は、加熱方法により異なるが、通常30秒~5時間、好ましくは1分~3時間、より好ましくは5分~2時間、さらに好ましくは10分~50分である。
 加熱温度及び加熱時間がこの範囲であれば、加圧後及びアニール処理後の熱電変換材料層の電気伝導率の向上につながりやすくなる。
 また、熱電半導体組成物の調製において溶媒を使用した場合、加熱温度は、使用した溶媒が乾燥できる温度範囲であっても、それ以下の温度範囲であってもよい。
(B) Thermoelectric conversion material layer drying step The thermoelectric conversion material layer drying step is a step of drying the thermoelectric conversion material layer obtained in the step (A). For example, in FIG. 3A, on the substrate 1a. This is a step of drying the thermoelectric conversion material layer 2s.
As the drying method, conventionally known drying methods such as a hot air drying method, a hot roll drying method, and an infrared irradiation method can be adopted. The heating temperature is usually 80 to 170 ° C., preferably 100 to 150 ° C., more preferably 110 to 145 ° C., still more preferably 120 to 140 ° C.
The heating time varies depending on the heating method, but is usually 30 seconds to 5 hours, preferably 1 minute to 3 hours, more preferably 5 minutes to 2 hours, and further preferably 10 minutes to 50 minutes.
When the heating temperature and the heating time are within this range, it is easy to improve the electric conductivity of the thermoelectric conversion material layer after pressurization and annealing treatment.
When a solvent is used in the preparation of the thermoelectric semiconductor composition, the heating temperature may be in a temperature range in which the solvent used can be dried or in a temperature range lower than that.
(C)熱電変換材料層加圧工程
 熱電変換材料層加圧工程は、(B)の工程で得られた乾燥後の熱電変換材料層を加圧する工程であり、例えば、図3(b)においては、熱電変換材料層2sの上面をプレス加圧部5で加圧する工程である。
(C) Thermoelectric conversion material layer pressurizing step The thermoelectric conversion material layer pressurizing step is a step of pressurizing the dried thermoelectric conversion material layer obtained in the step (B), for example, in FIG. 3 (b). Is a step of pressurizing the upper surface of the thermoelectric conversion material layer 2s with the press pressurizing section 5.
 加圧は、一態様として、(B)の工程で得られた乾燥後の熱電変換材料層を常温まで冷却してから大気圧雰囲気下で行うことが好ましい。また、他の態様として、加圧は、(B)の工程で得られた乾燥後の熱電変換材料層を常温まで冷却せずに乾燥温度を維持し行い、次工程となる後述するアニール処理工程に投入することが好ましい。
 加圧方法としては、例えば、油圧式プレス、真空プレス機、重り等、物理的加圧手段を用いる方法が挙げられる。加圧量は、熱電変換材料層の粘度、空隙の量等により異なるが、通常0.1~80MPaであり、好ましくは1.0~60MPaであり、より好ましくは5~50MPaであり、さらに好ましくは10~42MPaである。なお、加圧は、所定の加圧量まで一気に上げて行ってもよいが、熱電変換材料層の形状安定性の維持及び熱電変換材料層内の空隙をより多く減少させ熱電変換材料の充填率を向上させる観点から、適宜調整するが、通常0.1~50MPa/分、好ましくは0.5~30MPa/分、さらに好ましくは1.0~10MPa/分で所定の加圧量まで加圧量を増加させる。
 加圧時間は、加圧方法により異なるが、通常5秒~5時間、好ましくは30秒~3時間、より好ましくは5分~2時間、さらに好ましくは10分~1時間である。
 加圧量及び加圧時間がこの範囲であれば、充填率が増大し、アニール処理後の熱電変換材料層の電気伝導率が向上しやすくなる。
As one aspect, the pressurization is preferably performed in an atmospheric pressure atmosphere after the dried thermoelectric conversion material layer obtained in the step (B) is cooled to room temperature. Further, as another embodiment, the pressurization is performed by maintaining the drying temperature without cooling the thermoelectric conversion material layer after drying obtained in the step (B) to room temperature, and an annealing treatment step described later, which is a next step. It is preferable to put it in.
Examples of the pressurizing method include a method using a physical pressurizing means such as a hydraulic press, a vacuum press, and a weight. The amount of pressurization varies depending on the viscosity of the thermoelectric conversion material layer, the amount of voids, etc., but is usually 0.1 to 80 MPa, preferably 1.0 to 60 MPa, more preferably 5 to 50 MPa, still more preferable. Is 10 to 42 MPa. The pressurization may be performed by increasing the pressurization amount to a predetermined amount at once, but the shape stability of the thermoelectric conversion material layer is maintained and the voids in the thermoelectric conversion material layer are further reduced to reduce the filling rate of the thermoelectric conversion material. The pressure is adjusted as appropriate from the viewpoint of improving the above pressure, but is usually 0.1 to 50 MPa / min, preferably 0.5 to 30 MPa / min, and more preferably 1.0 to 10 MPa / min to a predetermined pressurization amount. To increase.
The pressurization time varies depending on the pressurization method, but is usually 5 seconds to 5 hours, preferably 30 seconds to 3 hours, more preferably 5 minutes to 2 hours, and further preferably 10 minutes to 1 hour.
When the pressurization amount and the pressurization time are within this range, the filling rate increases, and the electric conductivity of the thermoelectric conversion material layer after the annealing treatment tends to improve.
(D)アニール処理工程
 アニール処理工程は、前記(C)の工程で得られた加圧された熱電変換材料層をアニール処理する工程であり、例えば、図3(c)においては、加圧後の熱電変換材料層2sをアニール処理の温度でアニールする工程である(アニール処理後、熱電変換材料層2tが得られる)。
 熱電変換材料層は、薄膜として形成、乾燥後、アニール処理を行うことで、熱電性能を安定化させるとともに、薄膜中の熱電半導体粒子を結晶成長させることができ、熱電性能をさらに向上させることができる。
(D) Annealing Treatment Step The annealing treatment step is a step of annealing the pressurized thermoelectric conversion material layer obtained in the step (C) above. For example, in FIG. 3C, after pressurization. This is a step of annealing the thermoelectric conversion material layer 2s of No. 2 at the temperature of the annealing treatment (after the annealing treatment, the thermoelectric conversion material layer 2t is obtained).
The thermoelectric conversion material layer is formed as a thin film, dried, and then annealed to stabilize the thermoelectric performance, and the thermoelectric semiconductor particles in the thin film can be crystal-grown to further improve the thermoelectric performance. it can.
 アニール処理は、熱電変換材料層を加圧した状態、又は加圧しない状態で行われる。加圧する場合の加圧量は、通常0.1~80MPaであり、好ましくは1.0~60MPaであり、より好ましくは5~50MPaであり、さらに好ましくは10~42MPaである。
 また、特に限定されないが、通常、ガス流量が制御された、窒素、アルゴン等の不活性ガス雰囲気下、還元ガス雰囲気下、または真空条件下で行われ、熱電半導体組成物に用いる熱電半導体材料、耐熱性樹脂、イオン液体、無機イオン性化合物等に依存するが、アニール処理の温度は、通常100~600℃で、数分~数十時間、好ましくは250~450℃で、数分~数十時間行う。
The annealing treatment is performed with or without pressurizing the thermoelectric conversion material layer. The amount of pressurization in the case of pressurization is usually 0.1 to 80 MPa, preferably 1.0 to 60 MPa, more preferably 5 to 50 MPa, still more preferably 10 to 42 MPa.
Further, although not particularly limited, a thermoelectric semiconductor material used in a thermoelectric semiconductor composition, which is usually carried out under an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere, or under vacuum conditions in which the gas flow rate is controlled. Although it depends on the heat-resistant resin, ionic liquid, inorganic ionic compound, etc., the temperature of the annealing treatment is usually 100 to 600 ° C. for several minutes to several tens of hours, preferably 250 to 450 ° C. for several minutes to several tens of hours. Do time.
 前記熱電変換材料層の厚さは、加圧により形状安定性及び熱電性能が損なわれなければ特に制限はなく、前述したとおりである。 The thickness of the thermoelectric conversion material layer is not particularly limited as long as the shape stability and thermoelectric performance are not impaired by pressurization, and are as described above.
 本発明の熱電変換材料層の製造方法によれば、簡便な方法で電気伝導率が向上された熱電変換材料層を製造することができる。 According to the method for producing a thermoelectric conversion material layer of the present invention, a thermoelectric conversion material layer having improved electrical conductivity can be produced by a simple method.
 次に、本発明を実施例によりさらに詳細に説明するが、本発明は、これらの例によってなんら限定されるものではない。 Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples.
 実施例、比較例で作製した熱電変換材料層中の熱電半導体組成物の充填率の評価及び電気伝導率の評価は、以下の方法で行った。
(a)充填率の評価
 実施例及び比較例で作製した熱電変換材料層に対し、研磨装置(リファインテック社製、型名:リファイン・ポリッシャーHV)によって熱電変換材料層の中央部を含む縦断面出しを行い、FE-SEM/EDX(FE-SEM:日立ハイテクノロジーズ社製、型名:S-4700)を用い、縦断面の観察を行い、次いで、Image J(画像処理ソフト、ver.1.44P)を用い、熱電変換材料層の縦断面の面積における熱電半導体組成物の面積の占める割合で定義される充填率を算出した。
 充填率の測定においては、倍率500倍のSEM画像(縦断面)を用いて、測定範囲を熱電変換材料層とアルミナ基板との境界を基準として幅方向に1280pixel、厚さ方向に220pixelで囲まれる範囲とし、画像として切り出した。切り出した画像を「Brightness/Contrast」からコントラストを最大値にして二値化処理を行い、二値化処理における暗部を空隙部、明部を熱電半導体組成物と見なし「Threshold」にて、熱電半導体組成物の充填率を算出した。充填率はSEM画像3枚について算出し、それらの平均値とした。
 なお、切り出す画像は、縦断面の領域部内で選択されるものであり、例えば、図2の(a)においては、熱電変換材料層の周囲の空隙部(空気層部)が取り込まれることが無いように、縦断面の幅方向にX、厚さ方向にDminを超えることがない領域を選択した。
(b)電気伝導率の評価
 実施例及び比較例で作製した熱電変換材料層について、低抵抗測定装置(日置社製、型名:RM3545)を用いて、25℃60%RHの環境下で、四端子法で表面抵抗値を測定し、電気伝導率を算出した。
The evaluation of the filling rate and the electric conductivity of the thermoelectric semiconductor composition in the thermoelectric conversion material layer produced in Examples and Comparative Examples was carried out by the following methods.
(A) Evaluation of filling rate A vertical cross section of the thermoelectric conversion material layer produced in Examples and Comparative Examples including the central portion of the thermoelectric conversion material layer by a polishing device (manufactured by Refine Tech, model name: Refine Polisher HV). After taking out, the vertical cross section was observed using FE-SEM / EDX (FE-SEM: manufactured by Hitachi High-Technologies Corporation, model name: S-4700), and then Image J (image processing software, ver.1. Using 44P), the filling rate defined by the ratio of the area of the thermoelectric semiconductor composition to the area of the longitudinal section of the thermoelectric conversion material layer was calculated.
In the measurement of the filling rate, an SEM image (longitudinal cross section) with a magnification of 500 times is used, and the measurement range is surrounded by 1280 pixels in the width direction and 220 pixels in the thickness direction with reference to the boundary between the thermoelectric conversion material layer and the alumina substrate. It was taken as a range and cut out as an image. The cut-out image is binarized from "Brightness / Contrast" with the maximum contrast value, and the dark part and the bright part in the binarization process are regarded as the thermoelectric semiconductor composition, and the thermoelectric semiconductor is used in "Throld". The filling rate of the composition was calculated. The filling rate was calculated for three SEM images and used as the average value thereof.
The image to be cut out is selected within the region portion of the vertical cross section. For example, in FIG. 2A, the void portion (air layer portion) around the thermoelectric conversion material layer is not captured. As described above, a region not exceeding X in the width direction and Dmin in the thickness direction of the vertical cross section was selected.
(B) Evaluation of Electrical Conductivity The thermoelectric conversion material layers produced in Examples and Comparative Examples were subjected to an environment of 25 ° C. and 60% RH using a low resistance measuring device (manufactured by Hioki Co., Ltd., model name: RM3545). The surface resistance value was measured by the four-terminal method, and the electric conductivity was calculated.
(実施例1)
<熱電変換材料層の作製>
(1)熱電半導体組成物の作製
(熱電半導体粒子の作製)
 ビスマス-テルル系熱電半導体材料であるP型ビスマステルライドBi0.4TeSb1.6(高純度化学研究所製、粒径:180μm)を、遊星型ボールミル(フリッチュジャパン社製、Premium line P-7)を使用し、窒素ガス雰囲気下で粉砕することで、平均粒径2.0μmの熱電半導体粒子を作製した。粉砕して得られた熱電半導体粒子に関して、レーザー回折式粒度分析装置(Malvern社製、マスターサイザー3000)により粒度分布測定を行った。
(熱電半導体組成物の塗工液の調製)
 上記で得られたP型ビスマステルライドBi0.4TeSb1.6粒子82.5質量%、耐熱性樹脂としてポリイミド前駆体であるポリアミック酸(宇部興産社製、U-ワニスA、溶媒:N-メチルピロリドン、固形分濃度:18質量%)3.2質量%(固形分)、及びイオン液体として1-ブチルピリジニウムブロミド14.3質量%を混合分散した熱電半導体組成物からなる塗工液を調製した。
(2)熱電変換材料層の形成及び加圧処理
 アルミナ基板(京セラ社製、商品名:アルミナ基板 A0476T、100mm×100mm、厚さ:1mm)上に、上記(1)で調製した塗工液を、アプリケーターを用いてベタ膜として印刷し、温度140℃で40分間アルゴン雰囲気下で乾燥し、厚さが37μmの薄膜(アニール処理前の熱電変換材料層)を形成した。
 次いで、乾燥後の熱電変換材料層を室温まで冷却し、熱電変換材料層を印刷したアルミナ基板を5mm×15mmサイズに切り出した。その後、油圧式プレス機(テスター産業社製、型名:SA-30卓上型テストプレス)を用いて、室温、大気雰囲気下において、熱電変換材料層の上面全体に対して均一に40.0MPaで1分間、加圧処理を行った。
 さらに、加圧処理をして得られた熱電変換材料層に対し、水素とアルゴンの混合ガス(水素:アルゴン=3体積%:97体積%)雰囲気下で、加温速度5K/minで昇温し、430℃で30分間保持し、前記熱電変換材料層をアニール処理し、熱電半導体材料の粒子を結晶成長させ、熱電変換材料層を作製した。得られた熱電変換材料層に対し、充填率の評価及び電気伝導率の評価を行った。結果を表1に示す。
(Example 1)
<Preparation of thermoelectric conversion material layer>
(1) Preparation of thermoelectric semiconductor composition (production of thermoelectric semiconductor particles)
P-type bismuth tellurium Bi 0.4 Te 3 Sb 1.6 (manufactured by High Purity Chemical Laboratory, particle size: 180 μm), which is a bismuth-tellurium thermoelectric semiconductor material, is used in a planetary ball mill (manufactured by Fritsch Japan, Premium line P). Thermoelectric semiconductor particles having an average particle size of 2.0 μm were produced by pulverizing in a nitrogen gas atmosphere using -7). The thermoelectric semiconductor particles obtained by pulverization were subjected to particle size distribution measurement with a laser diffraction type particle size analyzer (Mastersizer 3000 manufactured by Malvern).
(Preparation of coating liquid for thermoelectric semiconductor composition)
P-type bismuthellide Bi 0.4 Te 3 Sb 1.6 particles 82.5% by mass obtained above, polyamic acid which is a polyimide precursor as a heat-resistant resin (manufactured by Ube Kosan Co., Ltd., U-Wanis A, solvent: A coating liquid consisting of a thermoelectric semiconductor composition in which N-methylpyrrolidone, solid content concentration: 18% by mass) 3.2% by mass (solid content), and 1-butylpyridinium bromide 14.3% by mass as an ionic liquid are mixed and dispersed. Was prepared.
(2) Formation and pressure treatment of thermoelectric conversion material layer On an alumina substrate (manufactured by Kyocera Corporation, trade name: alumina substrate A0476T, 100 mm × 100 mm, thickness: 1 mm), the coating liquid prepared in (1) above is applied. The film was printed as a solid film using an applicator and dried at a temperature of 140 ° C. for 40 minutes in an argon atmosphere to form a thin film (thermoelectric conversion material layer before annealing treatment) having a thickness of 37 μm.
Next, the dried thermoelectric conversion material layer was cooled to room temperature, and the alumina substrate on which the thermoelectric conversion material layer was printed was cut out to a size of 5 mm × 15 mm. Then, using a hydraulic press (manufactured by Tester Sangyo Co., Ltd., model name: SA-30 tabletop test press), at room temperature and atmospheric atmosphere, the entire upper surface of the thermoelectric conversion material layer was uniformly applied at 40.0 MPa. The pressurization treatment was performed for 1 minute.
Further, the thermoelectric conversion material layer obtained by the pressurization treatment is heated at a heating rate of 5 K / min in an atmosphere of a mixed gas of hydrogen and argon (hydrogen: argon = 3% by volume: 97% by volume). Then, the mixture was held at 430 ° C. for 30 minutes, the thermoelectric conversion material layer was annealed, and particles of the thermoelectric semiconductor material were grown into crystals to prepare a thermoelectric conversion material layer. The obtained thermoelectric conversion material layer was evaluated for filling rate and electric conductivity. The results are shown in Table 1.
(実施例2)
 実施例1において、熱電変換材料層の上面全体に対して均一に30.0MPaで加圧処理を行った以外は、実施例1と同様に熱電変換材料層を作製した。得られた熱電変換材料層に対し、充填率の評価及び電気伝導率の評価を行った。結果を表1に示す。
(Example 2)
A thermoelectric conversion material layer was prepared in the same manner as in Example 1 except that the entire upper surface of the thermoelectric conversion material layer was uniformly pressurized at 30.0 MPa in Example 1. The obtained thermoelectric conversion material layer was evaluated for filling rate and electric conductivity. The results are shown in Table 1.
(比較例1)
 実施例1において、加圧処理をしない以外は、実施例1と同様に熱電変換材料層を作製し、得られた熱電変換材料層に対し、充填率の評価及び電気伝導率の評価を行った。結果を表1に示す。
(Comparative Example 1)
In Example 1, a thermoelectric conversion material layer was prepared in the same manner as in Example 1 except that the pressure treatment was not performed, and the obtained thermoelectric conversion material layer was evaluated for filling rate and electric conductivity. .. The results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
 熱電半導体組成物の塗布膜からなる熱電変換材料層中の熱電変換材料の充填率が本発明の規定を満たす実施例1~2では、充填率が本発明の規定の範囲外である比較例1と比べ、電気伝導率が50~118%増大することがわかる。このため、本発明の熱電変換材料層及びその製造方法を熱電変換モジュールに適用することにより、当該熱電変換モジュールの熱電性能の向上を図ることができる。 In Examples 1 and 2 in which the filling rate of the thermoelectric conversion material in the thermoelectric conversion material layer composed of the coating film of the thermoelectric semiconductor composition satisfies the specification of the present invention, Comparative Example 1 in which the filling rate is outside the range of the specification of the present invention. It can be seen that the electrical conductivity is increased by 50 to 118%. Therefore, by applying the thermoelectric conversion material layer of the present invention and the manufacturing method thereof to the thermoelectric conversion module, the thermoelectric performance of the thermoelectric conversion module can be improved.
 本発明の熱電半導体組成物の塗布膜からなる熱電変換材料層及びその製造方法によれば、熱電変換材料層の電気伝導率が増大するため、本発明の熱電変換材料層を熱電変換モジュールに組み込むことにより熱電性能の向上が期待できる。同時に、得られた熱電変換モジュールは、従来型の熱電半導体材料の焼結体を用いた熱電変換モジュールに比べ、屈曲性を有するとともに、薄型化(小型、軽量)が実現できる可能性を有する。
 上記の熱電変換材料層を用いた熱電変換モジュールは、工場や廃棄物燃焼炉、セメント燃焼炉等の各種燃焼炉からの排熱、自動車の燃焼ガス排熱及び電子機器の排熱を電気に変換する発電用途に適用することが考えられる。冷却用途としては、エレクトロニクス機器の分野において、例えば、半導体素子である、CCD(Charge Coupled Device)、MEMS(Micro Electro Mechanical Systems)、受光素子等の各種センサーの温度制御等に適用することが考えられる。
According to the thermoelectric conversion material layer composed of the coating film of the thermoelectric semiconductor composition of the present invention and the method for producing the same, the electric conductivity of the thermoelectric conversion material layer is increased. Therefore, the thermoelectric conversion material layer of the present invention is incorporated into the thermoelectric conversion module. This can be expected to improve thermoelectric performance. At the same time, the obtained thermoelectric conversion module has the possibility of being more flexible and thinner (smaller and lighter) than the thermoelectric conversion module using a sintered body of a conventional thermoelectric semiconductor material.
The thermoelectric conversion module using the above thermoelectric conversion material layer converts exhaust heat from various combustion furnaces such as factories, waste combustion furnaces, cement combustion furnaces, automobile combustion gas exhaust heat, and electronic equipment exhaust heat into electricity. It is conceivable to apply it to power generation applications. As a cooling application, in the field of electronic equipment, for example, it can be considered to be applied to temperature control of various sensors such as CCD (Charge Coupled Device), MEMS (Micro Electro Mechanical Systems), and light receiving element, which are semiconductor elements. ..
1a:基板
1b:アルミナ基板
2,2s,2t:熱電変換材料層
3:空隙部
3a,4a:空隙部
3b:空隙部(比較例1)
4b:空隙部(実施例1)
5:プレス加圧部
X:長さ(幅方向)
Y:長さ(奥行き方向)
D:厚さ(厚さ方向)
Dmax:厚さ方向の厚さの最大値(縦断面)
Dmin:厚さ方向の厚さの最小値(縦断面)
C:熱電変換材料層の中央部
1a: Substrate 1b: Alumina substrate 2,2s, 2t: Thermoelectric conversion material layer 3: Void portion 3a, 4a: Void portion 3b: Void portion (Comparative Example 1)
4b: Void portion (Example 1)
5: Press pressurizing part X: Length (width direction)
Y: Length (depth direction)
D: Thickness (thickness direction)
Dmax: Maximum value of thickness in the thickness direction (longitudinal section)
Dmin: Minimum value of thickness in the thickness direction (longitudinal section)
C: Central part of thermoelectric conversion material layer

Claims (10)

  1.  熱電半導体組成物の塗布膜からなる熱電変換材料層であって、
    前記熱電変換材料層は空隙を有し、
    前記熱電変換材料層の中央部を含む縦断面の面積における前記熱電半導体組成物の面積の占める割合を充填率としたときに、前記充填率が、0.800以上1.000未満である、熱電変換材料層。
    A thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition.
    The thermoelectric conversion material layer has voids and
    When the ratio of the area of the thermoelectric semiconductor composition to the area of the longitudinal section including the central portion of the thermoelectric conversion material layer is taken as the filling rate, the filling rate is 0.800 or more and less than 1.000. Conversion material layer.
  2.  前記熱電半導体組成物は熱電半導体材料を含み、該熱電半導体材料がビスマス-テルル系熱電半導体材料、テルライド系熱電半導体材料、アンチモン-テルル系熱電半導体材料、又はビスマスセレナイド系熱電半導体材料である、請求項1に記載の熱電変換材料層。 The thermoelectric semiconductor composition includes a thermoelectric semiconductor material, and the thermoelectric semiconductor material is a bismuth-tellu-based thermoelectric semiconductor material, a telluride-based thermoelectric semiconductor material, an antimony-tellu-based thermoelectric semiconductor material, or a bismuth selenide-based thermoelectric semiconductor material. The thermoelectric conversion material layer according to claim 1.
  3.  前記熱電半導体組成物が、さらに、耐熱性樹脂を含む、請求項1又は2に記載の熱電変換材料層。 The thermoelectric conversion material layer according to claim 1 or 2, wherein the thermoelectric semiconductor composition further contains a heat-resistant resin.
  4.  前記耐熱性樹脂が、ポリイミド樹脂、ポリアミド樹脂、ポリアミドイミド樹脂、又はエポキシ樹脂である、請求項1~3のいずれか1項に記載の熱電変換材料層。 The thermoelectric conversion material layer according to any one of claims 1 to 3, wherein the heat-resistant resin is a polyimide resin, a polyamide resin, a polyamide-imide resin, or an epoxy resin.
  5.  前記熱電半導体組成物が、さらに、イオン液体及び/又は無機イオン性化合物を含む、請求項1~4のいずれか1項に記載の熱電変換材料層。 The thermoelectric conversion material layer according to any one of claims 1 to 4, wherein the thermoelectric semiconductor composition further contains an ionic liquid and / or an inorganic ionic compound.
  6.  前記熱電変換材料層の厚さが、1~1000μmである、請求項1~5のいずれか1項に記載の熱電変換材料層。 The thermoelectric conversion material layer according to any one of claims 1 to 5, wherein the thermoelectric conversion material layer has a thickness of 1 to 1000 μm.
  7.  前記充填率が、0.850~0.999である、請求項1~6のいずれか1項に記載の熱電変換材料層。 The thermoelectric conversion material layer according to any one of claims 1 to 6, wherein the filling rate is 0.850 to 0.999.
  8.  熱電半導体組成物の塗布膜からなる熱電変換材料層を製造する方法であって、
    (A)熱電変換材料層を形成する工程、
    (B)前記(A)の工程で得られた前記熱電変換材料層を乾燥する工程、
    (C)前記(B)の工程で得られた乾燥後の前記熱電変換材料層を加圧する工程、及び
    (D)前記(C)の工程で得られた加圧された熱電変換材料層をアニール処理する工程、
    を含む、熱電変換材料層の製造方法。
    A method for producing a thermoelectric conversion material layer composed of a coating film of a thermoelectric semiconductor composition.
    (A) Step of forming thermoelectric conversion material layer,
    (B) A step of drying the thermoelectric conversion material layer obtained in the step (A).
    (C) The step of pressurizing the dried thermoelectric conversion material layer obtained in the step (B), and (D) annealing the pressurized thermoelectric conversion material layer obtained in the step (C). Process to process,
    A method for manufacturing a thermoelectric conversion material layer, including.
  9.  前記アニール処理の温度が、250~600℃で行われる、請求項8に記載の熱電変換材料層の製造方法。 The method for producing a thermoelectric conversion material layer according to claim 8, wherein the annealing treatment is performed at a temperature of 250 to 600 ° C.
  10.  前記加圧が、1.0~60MPaで行われる、請求項8又は9に記載の熱電変換材料層の製造方法。

     
    The method for producing a thermoelectric conversion material layer according to claim 8 or 9, wherein the pressurization is performed at 1.0 to 60 MPa.

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