WO2015057000A1 - Thermoelectric material and method for manufacturing same - Google Patents

Abstract

Disclosed is a thermoelectric material having excellent thermoelectric performance. The thermoelectric material, according to the present invention, can be represented by chemical formula 1 as follows. <Chemical formula 1> Cu_xSe_1-yQ_y, wherein, in chemical formula 1, Q is S and/or Te, and 2<x≤2.6, 0<y<1.

Description

Thermoelectric material and its manufacturing method

The present invention relates to a thermoelectric conversion technology, and more particularly, to a thermoelectric conversion material having excellent thermoelectric conversion characteristics, a method of manufacturing the same, and a use thereof.

This application is a priority claim application for Korean Patent Application No. 10-2013-0124024, filed October 17, 2013, and Korean Patent Application No. 10-2014-0131791, filed September 30, 2014. All the contents disclosed in the specification and drawings of this application are incorporated in this application by reference.

Compound A semiconductor is a compound which acts as a semiconductor by combining two or more elements rather than a single element such as silicon or germanium. Various kinds of such compound semiconductors are currently developed and used in various fields. Typically, a compound semiconductor may be used in a thermoelectric conversion element using a Peltier effect, a light emitting element such as a light emitting diode or a laser diode using the photoelectric conversion effect, and a solar cell.

In particular, the thermoelectric conversion element may be applied to thermoelectric power generation, thermoelectric conversion cooling, or the like, and is generally configured in such a manner that an N-type thermoelectric semiconductor and a P-type thermoelectric semiconductor are electrically connected in series and thermally in parallel. Among these, thermoelectric conversion power generation is a form of power generation that converts thermal energy into electrical energy by using thermoelectric power generated by providing a temperature difference to a thermoelectric conversion element. And thermoelectric conversion cooling is a form of cooling which converts electrical energy into thermal energy by taking advantage of the effect that a temperature difference occurs at both ends when a direct current flows through both ends of the thermoelectric conversion element.

The energy conversion efficiency of such a thermoelectric conversion element is largely dependent on ZT which is a figure of merit of a thermoelectric conversion material. Here, ZT may be determined according to Seebeck coefficient, electrical conductivity, thermal conductivity, and the like, and the higher the ZT value, the better the thermoelectric conversion material.

Although many thermoelectric conversion materials have been proposed so far, there is no situation that sufficient thermoelectric conversion materials having high thermoelectric conversion performance are provided. In particular, in recent years, the field of application for thermoelectric conversion materials is gradually expanding, and the temperature conditions may vary depending on the application field. However, since thermoelectric conversion performance may vary depending on temperature, each thermoelectric conversion material needs to be optimized for thermoelectric conversion performance in a field in which the thermoelectric conversion material is applied. However, it is not yet seen that thermoelectric conversion materials with optimized performance over a wide and wide temperature range are well prepared.

Accordingly, an object of the present invention is to provide a thermoelectric material having excellent thermoelectric conversion performance in a wide temperature range, a method of manufacturing the same, and an apparatus using the same.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

In order to achieve the above object, the present inventors have succeeded in synthesizing the thermoelectric material represented by the following Chemical Formula 1 after repeated studies on the thermoelectric material, and confirmed that the novel thermoelectric conversion material may have excellent thermoelectric conversion performance. The present invention was completed.

<Formula 1>

Cu _x Se _1-y Q _y

In Formula 1, Q is at least one or more of S and Te, 2 <x≤2.6, 0 <y <1.

Here, x in Chemical Formula 1 may be x ≦ 2.2.

In addition, x in Chemical Formula 1 may be x ≦ 2.1.

In addition, x in Chemical Formula 1 may be 2.025 ≦ x.

In addition, y in Formula 1 may be y <0.1.

In addition, y in Formula 1 may be y ≦ 0.05.

In addition, the thermoelectric material manufacturing method according to the present invention for achieving the above object comprises the steps of forming a mixture by weighing and mixing Cu, Se and Q to correspond to the formula (1); And synthesizing the compound represented by Chemical Formula 1 by heat treating the mixture.

Here, the method of manufacturing a thermoelectric material according to the present invention may further include a step of sintering the composite after the composite forming step.

In addition, the pressure sintering step may be performed by a hot press method or a discharge plasma sintering method.

In addition, the thermoelectric conversion element according to the present invention for achieving the above object includes the thermoelectric material according to the present invention.

In addition, the thermoelectric generator according to the present invention for achieving the above object includes the thermoelectric material according to the present invention.

According to the present invention, a thermoelectric material excellent in thermoelectric conversion performance can be provided.

In particular, in the thermoelectric material according to an aspect of the present invention, a low thermal diffusivity, a low lattice thermal conductivity, a high Seebeck coefficient and a high ZT value may be ensured in a wide temperature range of 50 ° C to 500 ° C.

Thus, the thermoelectric material according to the present invention can be used as another material in place of or in addition to the conventional thermoelectric material.

Furthermore, the thermoelectric material according to the present invention can maintain a higher ZT value than the conventional thermoelectric material even at a temperature of 500 ° C. or lower, and even at a low temperature near 200 ° C. Therefore, when the thermoelectric material according to the present invention is used in a thermoelectric device for power generation or the like, stable thermoelectric conversion performance can be ensured even when a material is exposed to a relatively low temperature.

In addition, the thermoelectric material according to the present invention may be used in solar cells, infrared windows (IR windows), infrared sensors, magnetic elements, memories, and the like.

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to.

1 is a flowchart schematically showing a compound semiconductor manufacturing method according to an aspect of the present invention.

2 is a graph showing an XRD analysis result for thermoelectric materials according to various embodiments of the present disclosure.

3 is an enlarged graph of portion A of FIG. 2.

4 is a graph illustrating a comparison of thermal diffusivity measurement results according to temperatures of thermoelectric materials according to examples and comparative examples of the present invention.

5 is a graph illustrating a comparison of Seebeck coefficient measurement results according to temperatures of thermoelectric materials according to examples and comparative examples of the present disclosure.

6 is a graph illustrating a comparison of lattice thermal conductivity measurement results according to temperatures of thermoelectric materials according to examples and comparative examples of the present disclosure.

7 is a graph illustrating a comparison of ZT value measurement results according to temperatures of thermoelectric materials according to examples and comparative examples of the present disclosure.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

The thermoelectric material according to an aspect of the present invention may be represented by the following Chemical Formula 1.

<Formula 1>

Cu _x Se _1-y Q _y

In Formula 1, Q is at least one or more of S and Te, 2 <x≤2.6, 0 <y <1.

First, the thermoelectric material according to the present invention is configured in a form in which a part of Se is substituted with Cu and / or Se. That is, the thermoelectric material according to the present invention is composed of a form in which a part of Se site is deficient in Cu-Se based thermoelectric material and S and / or Te are substituted in such deficient site. And, due to such a constitutional feature, the thermoelectric material according to the present invention, the thermoelectric conversion performance can be improved compared to the conventional Cu-Se-based thermoelectric material.

Moreover, the thermoelectric material which concerns on this invention is Cu-Se type thermoelectric material containing Cu and Se, and x is larger than two.

Preferably, in Chemical Formula 1, it may be preferable to satisfy the condition of x≤2.2. In particular, in Formula 1, x <2.2 may be.

More preferably, in Chemical Formula 1, the thermoelectric material according to the present invention may satisfy the condition of x ≦ 2.15.

In particular, Formula 1 may be configured to satisfy the condition of x≤2.1.

In addition, Chemical Formula 1 may satisfy a condition of 2.01 ≦ x. In particular, in Chemical Formula 1, x may be 2.01 <x.

Furthermore, in Chemical Formula 1, x may satisfy a condition of 2.025 ≦ x. Under such conditions, the thermoelectric conversion performance of the thermoelectric material according to the present invention may be further improved.

In particular, in Chemical Formula 1, x may be configured to satisfy a condition of 2.04 <x.

Furthermore, in Chemical Formula 1, x may satisfy a condition of 2.05 ≦ x.

In addition, in Chemical Formula 1, x may be 2.075 ≦ x.

In addition, in Formula 1, y <0.1 may be. In particular, in Chemical Formula 1, y ≦ 0.075. Furthermore, in Chemical Formula 1, y ≦ 0.05.

On the other hand, the thermoelectric material represented by the formula (1), may include a part of the secondary phase, the amount may vary depending on the heat treatment conditions.

Thus, in the thermoelectric material according to the present invention, when the content of Se is 1 with respect to the Cu-Se-based thermoelectric material, the content of Cu exceeds 2, and a part of Se is replaced with S and / or Te It can be formed as. Therefore, the thermoelectric material according to the present invention, due to such a constitutional feature, compared with the conventional Cu-Se-based thermoelectric material, the Seebeck coefficient is increased, the thermal diffusivity is reduced, ZT value is increased, the thermoelectric conversion performance can be improved. have.

1 is a flowchart schematically showing a method of manufacturing a thermoelectric material according to an aspect of the present invention.

Referring to FIG. 1, the method of manufacturing a thermoelectric material according to the present disclosure may include a mixture forming step S110 and a compound forming step S120.

In the mixture forming step (S110), to correspond to the formula (1), it is possible to form a mixture by mixing S and / or Te in addition to Cu and Se as a raw material.

Here, in step S110, each raw material may be mixed in powder form. In this case, the mixing between each raw material is made better, the reactivity between each raw material can be improved, the compound synthesis can be made well in step S120.

In addition, in the mixture forming step (S110), the mixing of each raw material, may be performed in the manner of hand milling (ball milling), ball milling (planetary ball mill), etc. using mortar (mortar) However, the present invention is not limited by this specific mixing method.

The compound forming step (S120) is a step of forming a compound according to Chemical Formula 1 by heat-treating the mixture formed in the step S110, that is, Cu _x Se _1-y Q _y (Q is at least one of S and Te, 2 <x≤2.6, 0 <y <1) A step of synthesizing the compound. Here, in step S120, the mixture produced in step S110 may be put into a furnace and heated at a predetermined temperature for a predetermined time to allow the compound of Formula 1 to be synthesized.

Preferably, step S120 may be performed by a solid phase reaction method. In the case of the synthesis by the solid phase reaction method, the raw material, that is, the mixture used in the synthesis, does not change into a completely liquid state in the synthesis process, and the reaction may occur in the solid state.

For example, the step S120 may be performed for 1 hour to 24 hours in the temperature range of 200 ℃ to 650 ℃. Since this temperature range is lower than the melting point of Cu, Cu _x Se _1-y Q _y may be synthesized when Cu is not melted when heated in this temperature range. For example, the step S120 may be performed for 15 hours under a temperature condition of 450 ° C.

In the step S120, a mixture of Cu, Se and S and / or Te is put into a cemented carbide mold to form a pellet for the synthesis of Cu _x Se _1-y Q _y , and the mixture of pellets is fused. It can be enclosed in a fused silica tube and vacuum sealed. The vacuum-sealed first mixture may be charged into a furnace and heat treated.

Preferably, the thermoelectric material manufacturing method according to the present invention, as shown in Figure 1, after the compound forming step (S120), may further comprise a step (S130) of pressure sintering the compound.

Here, step S130 may be performed by a hot press (Hot Press) method or a discharge plasma sintering (Spark Plasma Sintering) method. In the case of the thermoelectric material according to the present invention, when sintered by the pressure sintering method, it is easy to obtain a high sintered density and an effect of improving thermoelectric performance.

For example, the pressure sintering step may be performed under a pressure condition of 30MPa to 200MPa. In addition, the pressure sintering step may be performed under a temperature condition of 300 ℃ to 800 ℃. In addition, the pressure sintering step may be performed for 1 minute to 12 hours under the pressure and temperature conditions.

In addition, the step S130 may be performed while flowing a gas, such as Ar, He, N ₂ , which contains a part of hydrogen or does not contain hydrogen in a vacuum state.

Also preferably, the step S130 may be performed by pulverizing the composite formed in the step S120 into a powder form, followed by pressure sintering. In this case, while improving convenience in the sintering and measuring process, the sintered density can be further increased.

The thermoelectric conversion element according to the present invention may include the above-mentioned thermoelectric material. In particular, the thermoelectric material according to the present invention can effectively improve the ZT value in a wide temperature range compared to conventional thermoelectric materials, especially Cu-Se-based thermoelectric materials. Therefore, the thermoelectric material according to the present invention can be usefully used in thermoelectric conversion elements in place of or in addition to conventional thermoelectric conversion materials.

Moreover, the thermoelectric material according to the present invention can be used in a thermoelectric power generation device that performs thermoelectric power generation using a waste heat source or the like. That is, the thermoelectric generator according to the present invention includes the thermoelectric material according to the present invention described above. In the case of the thermoelectric material according to the present invention, since it shows a high ZT value in a wide temperature range, such as a temperature range of 50 ° C. to 500 ° C., the thermoelectric material may be more usefully applied to thermoelectric power generation.

In addition, the thermoelectric material according to the present invention may be manufactured in the form of a bulk type thermoelectric material.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the embodiment according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Example 1

Cu, Se and S in powder form were weighed to conform to the chemical formula of Cu _2.025 Se _0.99 S _0.01 , and then mixed in alumina mortar. The mixed material was placed in a cemented carbide mold to make pellets and placed in a fused silica tube and vacuum sealed. Then, the mixture was heated in a box furnace for 1 hour and then heated for 15 hours at 500 ° C., and then slowly cooled to room temperature to obtain a Cu _2.025 Se _0.99 S _0.01 compound.

Then, after filling the composite in the graphite mold, discharge plasma sintering (SPS) for 10 minutes in a vacuum state at 500 ℃, 50MPa conditions to obtain a sample of Example 1. At this time, the sintered density was 98% or more compared with the theoretical value.

Example 2

Cu, Se and S in powder form were weighed to conform to the chemical formula of Cu _2.025 Se _0.95 S _0.05 , and then mixed and synthesized in the same manner as in Example 1 to obtain a Cu _2.025 Se _0.95 S _0.05 composite. Then, a sample of Example 2 was obtained through a sintering process in the same manner as in Example 1 above.

Example 3

Cu, Se and S in powder form were weighed to conform to the chemical formula of Cu _2.05 Se _0.99 S _0.01 , and then mixed and synthesized in the same manner as in Example 1 to obtain a Cu _2.05 Se _0.99 S _0.01 composite. Then, a sample of Example 3 was obtained through a sintering process in the same manner as in Example 1.

Example 4

Cu, Se and S in powder form were weighed to conform to the chemical formula of Cu _2.05 Se _0.95 S _0.05 , and then mixed and synthesized in the same manner as in Example 1 to obtain a Cu _2.05 Se _0.95 S _0.05 composite. Then, a sample of Example 4 was obtained through a sintering process in the same manner as in Example 1.

Example 5

Cu, Se and S in powder form were weighed to conform to the chemical formula of Cu _2.1 Se _0.99 S _0.01 , and then mixed and synthesized in the same manner as in Example 1 to obtain a Cu _2.1 Se _0.99 S _0.01 composite. Then, a sample of Example 5 was obtained through a sintering process in the same manner as in Example 1.

Example 6

Cu, Se, and S in powder form were weighed according to the chemical formula of Cu _2.1 Se _0.95 S _0.05 , and then mixed and synthesized in the same manner as in Example 1 to obtain a Cu _2.1 Se _0.95 S _0.05 composite. Then, a sample of Example 6 was obtained through a sintering process in the same manner as in Example 1.

Comparative example

Cu and Se in powder form were weighed to conform to the chemical formula of Cu ₂ Se, and then mixed and synthesized in the same manner as in Example 1 to obtain a Cu ₂ Se composite. Then, a comparative example sample was obtained through a sintering process in the same manner as in Example 1.

For the thermoelectric materials of Examples 1 to 6, the XRD pattern was analyzed and shown in FIG. 2. In addition, the portion A of FIG. 2 is enlarged and illustrated in FIG. 3, and in FIG. 3, a Cu peak appearing when Cu is present in a single composition is indicated by B. FIG.

1 and 2, it can be seen that the samples of Examples 1 to 6 form the Cu ₂ Se monoclinic main phase, and the Cu peak grows according to the tendency of the excess of Cu. have. In addition, other secondary phases are not observed.

Therefore, according to these measurement results, the samples of Examples 1 to 6 all are formed from the material of the Cu _x Se in the form of a portion S is substituted Cu _x Se _1-y S _y on Se sites, Cu ₂ S It can be seen that it is not formed in the form of.

In addition, for the Examples 1 to 6 samples and the Comparative Example samples, the thermal diffusivity (TD) was measured at predetermined temperature intervals using LFA457 (Netzsch), and the results are shown as Examples 1 to 6 and Comparative Examples 4. Shown in

In addition, for each of the other portions of the Examples 1 to 6 samples and the Comparative Example samples, the electrical conductivity and the Seebeck coefficient of the samples were measured at predetermined temperature intervals using ZEM-3 (Ulvac-Riko, Inc), among which The Seebeck coefficient S measurement results are shown in FIG. 5 as Examples 1 to 6 and Comparative Examples.

In addition, the lattice thermal conductivity (κ _L ) and ZT values of the samples of Examples 1 to 6 and Comparative Examples were calculated and the results are shown in FIGS. 6 and 7, respectively. In particular, the lattice thermal conductivity was obtained using the Wiedenmann-Franz Law, and the Lorentz constant used at that time was 1.86 * 10 ^-8 . More specifically, the lattice thermal conductivity may be calculated using the following equation.

κ _L = κ _total -κ _e

Here, it can be said that κ _L represents lattice thermal conductivity, κ _total is thermal conductivity, and κ _e represents thermal conductivity by electrical conductivity. Κ _e can be expressed as follows.

κ _e = σLT

Is the electrical conductivity, and L is the Lorentz constant, representing 1.86 E-8. In addition, T means temperature (K).

First, referring to the result of FIG. 4, the thermoelectric materials of Examples 1 to 6 represented by Cu _x Se _1-y S _y (2 < _x ≦ 2.6, 0 <y <1) are compared with the thermoelectric materials of the comparative example. It can be seen that thermal diffusivity is remarkably low over the entire temperature measurement interval of 100 ° C to 500 ° C.

More specifically, the thermoelectric material of the comparative example has a thermal diffusivity of more than 0.4 mm ² / s, while all of the thermoelectric materials of the examples do not exceed 0.4 mm ² / s. Moreover, the thermoelectric material of the comparative example shows the thermal diffusivity more than twice compared with the thermoelectric materials of Examples 1-6. In particular, the thermoelectric materials of Examples 2 to 6 have a thermal diffusivity of 0.2 mm ² / s or less in the temperature range of 100 ° C. to 500 ° C., and thermal diffusion at a level of about one third to one quarter compared to the comparative example. It can be seen that the degree is greatly reduced.

Next, referring to the results of FIG. 5, the Seebeck coefficient S is remarkable in the thermoelectric materials of Examples 1 to 6 according to the present invention over the entire temperature measurement section of 50 ° C. to 500 ° C., compared to the thermoelectric material of the comparative example. It can be seen that high.

Typically, the thermoelectric material of the comparative example has only a Seebeck coefficient of 120 kW / K or less in the temperature range of 500 ° C, whereas the thermoelectric materials of Examples 1 to 6 all have a Seebeck coefficient of 175 kW / K or more at a temperature of 500 ° C. Is showing. In particular, in Examples 2 to 6, the Seebeck coefficient is at least 220 Pa / K at a temperature of 500 ° C. Furthermore, in Examples 3 to 6, the Seebeck coefficient is at least 260 Pa / K.

In addition, referring to the results of FIG. 6, in the thermoelectric material of the comparative example, the lattice thermal conductivity is greater than 0.4 W / mK in the temperature range of 200 ° C. to 500 ° C., whereas in the thermoelectric material of Examples 1 to 6, the same The lattice thermal conductivity is less than 0.4 W / mK over the temperature range.

In particular, the thermoelectric material of the comparative example at a temperature of 200 ℃ shows a lattice thermal conductivity of approximately 0.65 W / mK, whereas the thermoelectric material of Examples 1 to 6 shows a lattice thermal conductivity of 0.4 W / mK, a large difference It is shown. Furthermore, it can be seen that the thermoelectric material of Example 2 has a lattice thermal conductivity of about 0.25 W / mK at a temperature of 200 ° C., which has a very low lattice thermal conductivity compared to the comparative example.

Next, referring to the results of FIG. 7, it can be seen that the thermoelectric material of the example exhibits a ZT value improvement effect of about 2 to 3 times in the temperature range of 200 ° C. to 500 ° C. as compared to the thermoelectric material of the comparative example. Can be.

For example, at a temperature of 200 ° C., the ZT value of the comparative example is only about 0.15, while the ZT values of Examples 1 to 6 show values of 0.35 or more, and in particular, the ZT values of Examples 2 to 6 are 0.5 or more. The value is shown. Moreover, in Examples 2 and 3, the ZT value is approximately 0.6, which is about 4 times that of the comparative example.

In addition, at a temperature of 300 ° C., the ZT value of the comparative example is about 0.25 or less, whereas the ZT values of Examples 1 to 6 show a larger value than 0.5, and particularly, in Examples 2 to 6, the ZT value is 0.7 or more. It is shown. Moreover, in Examples 2 and 3, the ZT value has a value larger than 0.8, which shows a great difference from the comparative example.

In addition, at a temperature of 400 ° C., the ZT value of the comparative example was about 0.35 or less, while the ZT values of Examples 1 to 6 showed values of 0.8 or more and more than 1.0, showing a difference of two or more times. Moreover, in the case of Example 2, the ZT value showed a value close to 1.1, which shows a big difference from the comparative example.

And at the temperature of 500, the ZT value of the comparative example is about 0.5, while the ZT values of Examples 1 to 6 show values of 0.9 or more, more than 1.0. In particular, in the case of Example 2, ZT value has shown the value of 1.25 or more.

In summary, the thermoelectric material according to each embodiment of the present invention, compared with the thermoelectric material of the comparative example, the thermal diffusivity is significantly lowered and the Seebeck coefficient is increased over the entire temperature range of 100 ℃ to 500 ℃, ZT value It can be seen that the back is significantly improved. Therefore, it can be said that the thermoelectric material according to the present invention is excellent in thermoelectric conversion performance.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

Claims (11)

1. A thermoelectric material represented by the following formula (1).

   <Formula 1>

   Cu _x Se _1-y Q _y

   In Formula 1, Q is at least one or more of S and Te, 2 <x≤2.6, 0 <y <1.
2. The method of claim 1,

   X in the formula (1), x≤2.2, characterized in that the thermoelectric material.
3. The method of claim 1,

   X in the formula (1), x≤2.1, characterized in that the thermoelectric material.
4. The method of claim 1,

   X in the formula (1) is 2.025≤x characterized in that the thermoelectric material.
5. The method of claim 1,

   Y in the general formula (1), y <0.1, characterized in that the thermoelectric material.
6. The method of claim 1,

   Y in the formula (1), y≤0.05, characterized in that the thermoelectric material.
7. Forming a mixture by weighing and mixing Cu, Se, and Q so as to correspond to Formula 1 of claim 1; And

   Heat-treating the mixture to synthesize a compound represented by Chemical Formula 1

   The thermoelectric material manufacturing method of claim 1 comprising a.
8. The method of claim 7, wherein

   After the compound forming step, the thermoelectric material manufacturing method further comprising the step of sintering the compound.
9. The method of claim 8,

   The pressure sintering step is a thermoelectric material manufacturing method, characterized in that carried out by hot press method or discharge plasma sintering method.
10. A thermoelectric conversion element comprising the thermoelectric material according to any one of claims 1 to 6.
11. A thermoelectric power generation device comprising the thermoelectric material according to any one of claims 1 to 6.

Images