JP2002305330A - Element for thermoelectromotive force amplification - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element for thermoelectromotive force amplification that is formed by polyanilines film having a high dimensionless thermoelectric performance index (ZT) that is not provided in the conventional organic material, can be miniaturized and thinned, and generates large thermoelectromotive force. SOLUTION: In the element for thermoelectromotive force amplification, plural thermocouples made of a laminate should be connected in series. The laminate comprises the slender polyanilines film-like object, and a semiconductor film-like object. In the polyanilines film-like object (A), the thickness, length, and width are set to 0.42 to 2×10<7> nm, 300 to 14×10<7> nm, and 300 to 2×10<7> nm, respectively. The semiconductor film-like object (B) is set to the film-like object of a p- or an n-type semiconductor (1) or (2) where the Seebeck coefficient is different from that of the polyanilines film-like object. In the semiconductor film-like object, the length and width are nearly the same as the polyanilines film-like object, and at the same time the thickness is set to 0.42 to 2×10<7> nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel thermo-electromotive force amplifying element.

[0002]

2. Description of the Related Art The present inventors have previously described Japanese Patent Application Laid-Open No. 2000-32.
No. 3758 proposes an organic thermoelectric material in which a high conductive layer made of doped polyaniline and a low conductive layer made of undoped polyaniline are alternately laminated, and a method of manufacturing the same.
No. 140831 proposed a doped emeraldine-type conductive polyaniline having a physical internal factor (TPF) with high thermoelectric properties and a method for producing the same. Japanese Patent Application No. 2000-290208 discloses a doped emeraldine-type conductive polyaniline film having an elongated molecular conformation, a film thickness of 0.42 to 1000 nm, and a conductivity of 15,000 Ω ^{- 1} m ⁻¹ or more. Article and its manufacturing method were proposed.

However, it has been found that in order to put a polyaniline film having lower thermoelectric properties into practical use as a thermoelectric material than a general-purpose inorganic thermoelectric material, it is necessary to make it into a device.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high dimensionless thermoelectric figure of merit (Z) which has not been obtained in conventional organic materials.
The present invention relates to a thermoelectromotive force amplifying element which is formed from a polyaniline film having T), can be reduced in size and thickness, and generates a large thermoelectromotive force.

[0005]

Means for Solving the Problems A first aspect of the present invention is that (A)
The film thickness is 0.42 nm to 2 × 10 ⁷ nm, preferably 0.1 nm.
42 nm to 2 × 10 ⁵ nm, particularly preferably 0.42
nm to 2 × 10 ³ nm, length 300 nm to 14 × 10
⁷ nm, preferably 300 nm to 14 × 10 ⁵ nm, particularly preferably 300 nm to 14 × 10 ³ nm, and a width of ³ nm.
00 nm to 2 × 10 ⁷ nm, preferably 300 nm to 2
× 10 ⁶ nm, particularly preferably 300 nm to 2 × 10
⁴ nm elongated polyaniline film, (B) (a)
A p-type semiconductor having a Seebeck coefficient different from that of a polyaniline film, or (b) an n-type semiconductor having a Seebeck coefficient different from a polyaniline film, wherein the length and width of the semiconductor film are: It is almost the same as the polyaniline film, and has a thickness of 0.42 nm to 2 × 10 ^7.
The present invention relates to an element for amplifying a thermoelectromotive force, characterized in that a plurality of thermocouples composed of a laminate of a semiconductor film having a thickness of nm and a laminate thereof are connected in series. A second aspect of the present invention is that the polyaniline film has a sufficient conductivity of 5000 Ω ⁻¹ m ⁻¹ or more and a Seebeck coefficient of 2 × 10 ⁻⁵ VK ⁻¹ or more. 1. A thermoelectric power amplifying element according to item 1. A third aspect of the present invention is that the polyaniline film-like substance is
At 00K, the dimensionless thermoelectric figure of merit (ZT) is 0.01 or more,
The thermoelectric power amplifying element according to claim 1 or 2, wherein the dimensionless thermoelectric figure of merit (ZT) at 427K is 0.03 or more. A fourth aspect of the present invention is that the thermocouple is 5 × 10 ^{−3 to} 3 × 10 ^−3.
The thermoelectric power amplifying device according to any one of claims 1 to 3, wherein a sufficient number of the layers are stacked at a stacking density of × 10 ⁴ / mm ³ and the thermoelectromotive force is 6 × 10 ⁻⁵ VK ⁻¹ or more. Related to the element.

The polyaniline film in the present invention is a p-type emeraldine-type conductive polyaniline film (N-substituted aniline) obtained by doping a polyaniline represented by the following formula with a usual doping agent. ), And its molecular weight is usually 10,000 to 1,000,000.
Such polyaniline film-like materials are basically disclosed in Japanese Patent Application Laid-Open No. 2000-323758 and Japanese Patent Application No. 2000-323758.
No. 0-290208.

Embedded image (Wherein, R ¹ , R ² , R ³ , and R ⁴ are each independently selected from the group consisting of hydrogen, an alkyl group, an aryl group, a halogen, a sulfonic acid group, a carboxyl group, and a nitrile group. , A is an acid group as a doping agent, and y
Represents the ratio of the quinoid structure in all polyanilines, and n represents the number of aniline units. )

The doping agent used in the present invention is a functional acid for polyanilines, particularly camphorsulfonic acid (CSA), dodecylbenzenesulfonic acid (DBS),
Examples thereof include 2-naphthalenesulfonic acid and phosphoric acid.

Although the solvent used in the present invention is not particularly limited, N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), m-cresol, dimethylfuran (DMF), N, N'-dimethylpropylene urea (DM
PU), chloroform, toluene, xylene and the like.

The ratio of the polyaniline and the dopant in the mixed solution for preparing the doped emeraldine-type polyaniline film-forming material is usually 0.2 to 2.0, preferably 0.2 to 2.0, preferably in a molar ratio of the polyaniline to the aniline unit. 0.3
The weight content of the total amount of the polyaniline and the dopant with respect to the solvent is usually 1 to 10% by weight, preferably 3 to 8%.
%, Particularly preferably 4 to 5% by weight.

It is desirable that the mixed solution of the polyaniline, the dopant and the solvent is subjected to ultrasonic treatment for the purpose of improving the dissolution state. The output of the ultrasonic processor is 110-930W, the liquid temperature is 20-55 ° C, and the processing time is 1
The liquid temperature varies depending on the dopant and the boiling point of the solvent. It is preferable that the solution thus obtained is completely removed of insoluble components by means such as centrifugation.

The polyaniline solution from which the insolubles have been removed is
It is formed into a thin film by means such as casting and spin coating.
If the solution concentration is reduced, the film thickness can be considerably reduced even in casting.

The coating density is as follows:

## EQU1 ## Coating density = (weight of applied solution) / (area of applied substrate) Unit: (gcm ⁻² )

The film forming means in the present invention is not particularly limited, but a spin coating method, a spray method or the like can be used.

The definition of the length of the polyaniline film in the present invention indicates the upper limit and the lower limit of the length of the polyaniline molecule, and the width of the polyaniline film is determined by the width of the molecule and the tunnel current. The thickness of the polyaniline film is a range that covers the range of the molecular spacing that does not flow, and the thickness of the polyaniline film covers the range of the molecular spacing that prevents the tunnel current from flowing. However, a feature of the present invention is that a small thermocouple is integrated with a high volume density.

The polyaniline used in the present invention has a p-type Seebeck coefficient. Examples of the p-type semiconductor having a different Seebeck coefficient include polypyrrole, polythiophene, polyparaphenylene, polyvinylenephenylene, and polyacene. it can. Examples of the n-type semiconductor exhibiting a Seebeck coefficient different from that of polyanilines include a platinum-rhodium alloy, platinum, gold, copper, graphite, and the like, but are not limited thereto.

The p-type or n-type semiconductor of (B) is laminated with the polyaniline-like film of (A) (including the so-called film-like to linear-like appearance). Although the length and width are almost the same as those of the above-mentioned polyaniline film-like material (A), the thickness is not necessarily required to be the same, and the same lamination gives the highest lamination density. It is preferred. The dimensions of the semiconductor film (B) can be set from the following ranges so as to satisfy these conditions. That is, the semiconductor film-like material (B) has a thickness of 0.42 nm to 2 × 10 ⁷ nm, preferably 0.42 nm to 2 × 10 ⁵ nm, and particularly preferably 0.42 nm to 2 × 10 ³ nm. Thin and 300 in length
nm to 14 × 10 ⁷ nm, preferably 300 nm to 14
× 10 ⁵ nm, particularly preferably 300 nm to 14 × 10
^It is as short as ³ nm, and has a narrow width of 300 nm to 2 × 10 ⁷ nm, preferably 300 nm to 2 × 10 ⁶ nm, particularly preferably 300 nm to 2 × 10 ⁴ nm.

The thermoelectromotive force amplifying element of the present invention is characterized in that (A)
A plurality of thermocouples composed of a laminate of the polyaniline film and the semiconductor film of the above (B) are connected in series, and the cross section of the laminate which is the basis of the present invention may be square or rectangular. It may be a circle, and a rectangular case is described in Example 1 described later.
The case of a circle is Example 2 described later. From the viewpoint of the lamination density and the manufacturing method, a rectangle having a width larger than the height (film thickness) is preferable.

The thermoelectromotive force amplifying device using the polyaniline film of the present invention has a dimensionless thermoelectric figure of merit (Z) at 300K.
T) is 0.01 or 427 K, and the dimensionless thermoelectric figure of merit (Z
T) is 0.03, which is formed from a polyaniline film showing the largest value among the conductive organic polymers reported so far and another thermoelectric material film having a different Seebeck coefficient,
It is characteristic that it shows a value larger than the thermoelectric property ZT of the conductive organic polymer reported hitherto. In addition, ZT

ZT = T × (S ² σ / k) S is Seebeck coefficient (VK ⁻¹ ) (electromotive force per 1 ° C. absolute temperature difference) σ is conductivity (Ω ⁻¹ m ⁻¹ ) k is heat Conductivity (Wm ^-1 K ^-1 ) T can be expressed in absolute temperature.

Further, the thermoelectric power amplifying element of the present invention is a thermoelectric material of any one of the polyaniline film material according to any one of claims 1 to 3 and another p-type or n-type semiconductor film material having a different Seebeck coefficient. It is a characteristic that it shows a value larger than both the Seebeck coefficient and ZT.

The lamination density in the present invention is:

## EQU3 ## Stacking density = (number of stacked thermocouples) / (volume of thermoelectromotive force amplifying element) Unit: (number / nm ³ ) [see FIG. 2 (b)].

[0021]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited in any way by this.

Example 1 Weight average molecular weight (Mw) 9900 obtained by subjecting aniline to chemical oxidation polymerization at a polymerization temperature of -8 ° C to -6 ° C.
0, 1.0 g of polyaniline having a dispersity (Mw / Mn) of 3.20 was added to (±) -10-camphorsulfonic acid 1.2.
g and m-cresol in a mixed solution of 24.9 g, and at a liquid temperature of 20 to 55 ° C., 110 to 930 W and 38 KHz.
Was carried out for 4 hours to sufficiently advance dissolution and doping, and then centrifuged to remove insoluble components.
The thus obtained doped emeraldine-type conductive polyaniline solution was placed on a silicon wafer substrate at 2 × 1
Spin coating at a coating density of 0 ⁻³ gcm ⁻² , 80 ° C.
For 10 minutes, and 1 × 10 ⁵ nm as shown in FIG.
Emeraldine-type conductive polyaniline film [conductivity = 10000Ω ⁻¹ m ⁻¹ , ZT = 10 ^−2]
(300K)]. Apply this film at 20 Torr to 10
^The sample was dried at 60 ° C. for 24 hours under a reduced pressure of ⁻⁴ Torr to obtain a thermoelectric property measurement sample.

From this polyaniline film and a 1 mm-thick graphite film (HOPG), as shown in FIG. 2, a thermoelectric power amplifying element having a lamination density of 5 × 10 ⁻³ pieces / mm ³ was prepared and the heat generation was performed. 2.5 × 10 at 300K when measuring power
^-4 VK ^-1 or more. This value was nearly 20 times larger than the Seebeck coefficient of a conductive organic polymer reported hitherto.

Example 2 A linear thermocouple formed by coating a platinum alloy wire using the polyaniline film of Example 1 was connected in the same manner as in FIG. A thermoelectric power amplifying element of No. ³ was produced. In this case, the platinum alloy wire serves as both a thermoelectric material having a different Seebeck coefficient and a connection wire corresponding to the above (B) of the present invention. When the thermoelectromotive force of this thermoelectric power amplification element was measured, it showed a large value of 6.0 × 10 ⁻⁵ VK ⁻¹ or more at 300K. This value is nearly four times larger than the Seebeck coefficient of a conductive organic polymer reported in the past.

COMPARATIVE EXAMPLE 1 The thermoelectric properties of only the polyaniline film of Example 1 were measured, and the thermoelectromotive force was found to be 1.3 × 10 ⁻⁵ VK ^−1.
2 and 1 to 20 times lower than those of the thermopile trains 2 and 2.

[0026]

The element for amplifying a thermoelectromotive force according to the present invention comprises:
It is easy to be small and thin, and it is an element that directly converts a temperature difference into electric power, or conversely, directly converts electric power into a temperature difference. Specifically, a clock that moves at body temperature, a refrigerator without vibration (for cooling and storing wine), power generation using a laser, power generation using cold waste heat such as liquefied natural gas, and a device that cannot avoid generating heat, such as an EL element It can be used as an electronic coolant (utilizing the Peltier effect) such as an LSI and an LSI.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph of a cross section of a polyaniline film obtained in Example 1.

FIG. 2 is a conceptual diagram of a thermoelectromotive force amplifying element manufactured in Example 1. (A) is a circuit diagram showing that they are connected in series. (B) is a three-dimensional conceptual diagram of the laminated state of (a).

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Naohiko Fukuoka 1-3-3 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Inside Chemipro Kasei Co., Ltd.

Claims (4)

[Claims] (A) a thickness of 0.42 nm to 2 × 10 ⁷
nm, length between 300 nm and 14 × 10 ⁷ nm, width 30
An elongated polyaniline film having a thickness of 0 nm to 2 × 10 ⁷ nm, and (B) a (a) p-type semiconductor having a Seebeck coefficient different from that of a polyaniline film or (b) a polyaniline film having a Seebeck coefficient. A film of a different n-type semiconductor, wherein the length and width of the semiconductor film are substantially the same as those of the polyaniline film, and the thickness thereof is 0.42.
A thermo-electromotive force amplifying element comprising a plurality of thermocouples, each of which is formed by laminating a semiconductor film having a thickness of 2 nm to 2 × 10 ⁷ nm. 2. The method according to claim 1, wherein the polyaniline film has a conductivity of 5.
The element for amplifying a thermoelectromotive force according to claim 1, wherein the element has sufficient conductivity of 000 Ω ⁻¹ m ⁻¹ or more and has a Seebeck coefficient of 2 × 10 ⁻⁵ VK ⁻¹ or more. 3. The polyaniline film material is 300K.
Dimensionless thermoelectric figure of merit (ZT) is 0.01 or more, 427
The thermoelectric power amplifying element according to claim 1 or 2, wherein a dimensionless thermoelectric figure of merit (ZT) in K is 0.03 or more. 4. The thermocouple according to claim 1, wherein said thermocouple is 5 × 10 ^{−3 to} 3 × 10 ^4.
The thermoelectromotive force amplifying element according to any one of claims 1 to 3, wherein a sufficient number of the thermoelectromotive force elements are stacked at a stacking density of ³ pieces / mm3, and the thermoelectromotive force is 6 x ^10-5 VK- ¹ or more.