KR101983626B1 - Thermoelectric module including thermoelectric material having ordered 3-dimensional nano structure and method for manufacturing the same - Google Patents

Abstract

The thermoelectric module includes a first electrode, a second electrode spaced apart from the first electrode, and a thermoelectric element disposed between the first and second electrodes and electrically connected to the first and second electrodes. . The thermoelectric element includes an insulating material portion having an aligned three-dimensional network shape and a thermoelectric material portion surrounding the insulating material portion to have an inverse opal shape.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-efficiency thermoelectric module using an aligned thermoelectric material having a three-dimensional nano structure, and a method of manufacturing the same. BACKGROUND ART < RTI ID = 0.0 >

The present invention relates to a thermoelectric module. More particularly, the present invention relates to a high-efficiency thermoelectric module using a highly efficient thermoelectric material having aligned three-dimensional nanostructures, and a method of manufacturing the same.

The use of explosive fossil fuels in modern society is recognized as a social issue due to the problem of depletion of the energy source and environmental pollution inevitably occurring in the process of energy use. Accordingly, new technologies utilizing abundant energy sources and utilizing solar energy, wind power, and tidal power that do not cause environmental pollution problems are being invented. In addition, there are many ways to utilize abandoned heat in the process of using energy.

In particular, thermoelectric technology is a technology that can convert waste heat to direct electricity by utilizing the electromotive force generated by the temperature difference at both ends. It is a very high added value in that it uses as an electric energy what is not economically valuable.

The thermoelectric performance of a thermoelectric material is represented by a dimensionless figure of merits (ZT) related to the energy conversion efficiency, where ZT = σS ² T / κ. σ, S, κ, and T are physical performances related to thermoelectric materials, which are electrical conductivity, whiteness index, thermal conductivity, and absolute temperature, respectively. Therefore, improving the electrical conductivity and the whiteness index and lowering the thermal conductivity can improve the performance of the thermoelectric material.

Techniques that improve the performance of thermoelectric materials that have been developed in the past can not be controlled by different physical factors by changing the composition of the material or by using additional process techniques such as heat treatment, . In recent years, the development of nanotechnology has made it possible to control the physical properties related to thermoelectric materials independently using nanotechnology, and technologies that dramatically improve the performance of thermoelectric materials have been developed. However, the previously reported methods are related to the method of using 0D, 1D and 2D nanostructures, and even if the thermoelectric material manufactured is improved, it is difficult to actually use the thermoelectric material because of its size limit.

 Nature, 451, 163, 2008  Nano Letters, 10 (10), 4279, 2010

An object of the present invention is to provide a thermoelectric module capable of commercialization and improving thermoelectric conversion efficiency by using a thermoelectric material having a nano bulk structure.

Another object of the present invention is to provide a method of manufacturing the thermoelectric module.

According to an aspect of the present invention, there is provided a thermoelectric module including a first electrode, a second electrode spaced apart from the first electrode, and a second electrode disposed between the first electrode and the second electrode. And a thermoelectric element electrically connected to the first electrode and the second electrode. The thermoelectric element includes an insulating material portion having an aligned three-dimensional network shape and a thermoelectric material portion surrounding the insulating material portion to have an inverse opal shape.

According to an embodiment, the period of the thermoelectric part is from 100 nm to 2,000 nm, and the thickness of the thermoelectric part is from 50 nm to 300 nm.

According to one embodiment, the insulating material portion comprises air.

According to one embodiment, the insulating material portion includes a polymer resin.

According to one embodiment, the thermoelectric material portion may include a chalcogenide-based material, a skutterudite-based material, a silicide-based material, a clathrate-based material, a Half heusler- And a tellurium (Bi-Te) -based thermoelectric material.

A method of manufacturing a thermoelectric module according to an embodiment of the present invention includes the steps of forming a three-dimensional porous template aligned in three dimensions, filling a thermoelectric material in pores of the three-dimensional porous template to form an inverse opal shape Connecting the first electrode to one end of the thermoelectric element including the thermoelectric material portion, and connecting the second electrode to the other end of the thermoelectric element, wherein the thermoelectric material portion surrounds the three- .

According to one embodiment, the three-dimensional porous mold is formed on a metal layer disposed on a base substrate, the thermoelectric material portion is formed by performing electroplating using the metal layer as a cathode, and after performing the electroplating , Separating the base substrate from the metal layer, separating the base substrate, and removing the metal layer from the thermoelectric material portion.

As described above, according to exemplary embodiments of the present invention, a thermoelectric material having a nanostructure aligned in three dimensions can be obtained, and the thermoelectric material can have substantially the same electrical conductivity , The thermal conductivity can be greatly reduced. Therefore, the thermoelectric performance can be improved.

In addition, the thermoelectric material of the nanostructure arranged in three dimensions is easier to form in bulk than the conventional nanostructure such as nanowire. Therefore, a high performance thermoelectric module that can be used for commercialization can be provided.

1 is a cross-sectional view illustrating a thermoelectric module according to an embodiment of the present invention.
2 is an enlarged perspective view of an aligned three-dimensional nanostructure of thermoelectric elements of a thermoelectric module according to an embodiment of the present invention.
3 is a flowchart schematically showing a method of manufacturing a thermoelectric material according to an embodiment of the present invention.
4 is a scanning electron micrograph of the three-dimensional nanostructured thermoelectric material obtained in Example 2. Fig.
FIG. 5A is a graph showing changes in electrical conductivity of a 3D nanostructured BT film obtained in Example 1 and a Bi-Te film obtained in Comparative Example 1 according to temperature. FIG.
FIG. 5B is a graph showing changes in the whitening index according to the temperatures of the 3D nanostructured BT film obtained in Example 1 and the Bi-Te film obtained in Comparative Example 1. FIG.
FIG. 5C is a graph showing changes in power factor according to temperature of the 3D nanostructured BT film obtained in Example 1 and the Bi-Te film obtained in Comparative Example 1 (normal BT film). FIG.
6 is a graph showing XRD analysis results of the 3D nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2. FIG.
7 is an EDS mapping image of the three-dimensional nanostructured thermoelectric material obtained in Example 2. Fig.
8A is a graph showing changes in electrical conductivity of a 3-dimensional nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and a Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2 according to temperature.
FIG. 8B is a graph showing changes in the whitening index according to the temperature of the 3D nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2. FIG.
8C is a graph showing a change in power factor according to temperature of the 3D nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2. FIG.
9 is a graph showing changes in thermal conductivity of the 3D nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2 according to the temperature.
10 is a graph showing the thermoelectric performance index (Figure of Merit, ZT) of the 3-dimensional nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) ) In the second embodiment.

Hereinafter, a high-efficiency thermoelectric module using an aligned thermoelectric material having a three-dimensional nanostructure according to an embodiment of the present invention and a method of manufacturing the same will be described in detail with reference to the accompanying drawings. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. In the accompanying drawings, the dimensions of the structures are enlarged to illustrate the present invention in order to clarify the present invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms " comprises ", or " having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, or combinations thereof, , Steps, operations, elements, or combinations thereof, as a matter of principle, without departing from the spirit and scope of the invention.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

1 is a cross-sectional view illustrating a thermoelectric module according to an embodiment of the present invention. 2 is an enlarged perspective view of an aligned three-dimensional nanostructure of thermoelectric elements of a thermoelectric module according to an embodiment of the present invention.

1, a thermoelectric module according to an embodiment of the present invention includes a first substrate 10, a second substrate 20 spaced apart from the first substrate 10, a first substrate 10, A first electrode (12) and a second electrode (22, 24) disposed between the substrates (20) and spaced apart from each other, a first electrode (12) disposed between the first electrode (12) And devices 32 and 34. FIG.

For example, high temperature and low temperature may be applied to the first substrate 10 and the second substrate 20, respectively, so that both ends of the thermoelectric elements 32 and 34 have a temperature difference. The first electrode 12 and the second electrode 22 may be disposed on the first substrate 10 and the second substrate 20, respectively. Hereinafter, the first electrode 12 and the second electrode 22 may be referred to as a high-temperature electrode and a low-temperature electrode, respectively.

A barrier layer 40 may be disposed between the first electrode 12 and the thermoelectric elements 32 and 34. The barrier layer 40 can protect the thermoelectric elements 32 and 34. Although not shown, the barrier layer 40 may be additionally disposed between the second electrode 22 and the thermoelectric elements 32 and 34.

The first substrate 10 and the second substrate 20 may each include an electrically insulating material. For example, the first substrate 10 and the second substrate 20 may include alumina, sapphire, silicon, silicon nitride, silicon carbide, silicon carbide aluminum, quartz, polymer, and the like. The polymer may include polyimide, polyamide, polycarbonate, polyethylene terephthalate, polyacrylic resin, and the like. The first substrate 10 and the second substrate 20 may be made of the same material or may be made of different materials.

The thermoelectric elements 32 and 34 may include a first thermoelectric element 32 and a second thermoelectric element 34 which are spaced apart from each other. One end of the first thermoelectric element 32 and one end of the second thermoelectric element 34 are electrically connected in common to the first electrode 12 and the first thermoelectric element 32 and the second thermoelectric element 34 34 may be electrically connected to the second electrode pair 22, 24, which are spaced apart from each other.

In one embodiment, the first thermoelectric element 32 and the second thermoelectric element 34 may be doped with different types. For example, the first thermoelectric element 32 may be doped with n-type and the second thermoelectric element 34 may be doped with a p-type.

For example, the first electrode 12 may include a metal such as nickel (Ni), titanium (Ti), copper (Cu), platinum (Pt), gold (Au), silver . The first electrode 12 may further include a metal compound such as NiP, TiN, ZnO, or the like. These may be used alone or in combination. According to one embodiment, the first electrode 12 may include copper. The second electrode 22 may include the same material or another material as the first electrode.

The barrier layer 40 includes a material different from that of the first electrode 12. For example, the barrier layer 40 may be formed of a metal such as nickel (Ni), titanium (Ti), copper (Cu), platinum (Pt), gold (Au), silver (Ag), molybdenum ), Zirconium (Zr), niobium (Nb), tungsten (W) and the like, alloys thereof, and metal compounds thereof. The metal compound may further include a metal compound such as NiP, TiN, ZnO, and the like. According to one embodiment, the barrier layer 40 may include a material having a thermal expansion coefficient lower than that of the first electrode 12. For example, when the first electrode 12 includes copper, the barrier layer 40 may include a material other than copper. Specifically, the barrier layer 40 may include nickel, titanium, tin, zirconium, Or a metal compound thereof.

The second electrodes 22 and 24 may include the same material as the first electrode 12 or other materials.

The first thermoelectric element 32 or the second thermoelectric element 34 includes an aligned thermoelectric material of a three-dimensional nanostructure. Specifically, the thermoelectric material includes an insulating material portion 135 having an aligned three-dimensional network shape and a thermoelectric material portion 140 surrounding the insulating material portion to have an inverse opal shape. That is, the thermoelectric part 140 has a reverse phase of the insulating material part 135.

For example, the insulating material portion 135 may have an interval of 100 nm to 2,000 nm, and the thickness of the thermoelectric material 140 may be 50 nm to 300 nm. Preferably, the thickness of the thermoelectric material 140 is 100 nm to 200 nm.

The insulating material portion 135 may include an insulating material having low thermal conductivity and low electrical conductivity, for example, a polymer resin such as an epoxy resin, an acrylic resin, a phenol resin, or the like. Preferably, the thermoelectric material may include an insulating material portion defined by pores having an aligned three-dimensional network shape and a thermoelectric material portion 140 surrounding it, as shown by the right side of FIG.

Generally, the mean free path of a phonon that transfers heat is greater than the mean free path of electrons. Therefore, by appropriately controlling the thickness of the nanostructure constituting the thermoelectric material, for example, by making the phonon scattering smaller than the average free path of phonons and having a larger range than the average free path of electrons, , The thermal conductivity can be greatly reduced.

In addition, although the thickness of the nanostructure constituting the thermoelectric material is larger than the mean free path of electrons, in the irregular structure, the electric conductivity may be largely reduced by the scattering of electrons. In the present invention, however, It is possible to prevent or minimize deterioration of electrical conductivity and whitening index.

According to one embodiment, the thermoelectric part 140 may be formed of a material selected from the group consisting of a chalcogenide-based material, a skutterudite-based material, a silicide-based material, a clathrate-based material, a Half heusler- ), Bismuth-tellurium (Bi-Te), and the like. For example, the bismuth-tellurium-based thermoelectric material may be selected from the group consisting of bismuth-tellurium (Bi-Te), bismuth-tellurium-selenium (Bi-Te-Se), bismuth-tellurium- Bi-Te-Sb), bismuth-antimony-tellurium-selenium (Bi-Sb-Te-Se), and the like.

In another embodiment, the thermoelectric portion 140 may comprise a metal oxide or silicon. For example, the metal oxide may include zinc oxide, indium oxide, tin oxide, titanium oxide, gallium oxide, combinations thereof, and the like.

Method for manufacturing thermoelectric material and thermoelectric module

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

Referring to FIG. 3, first, a three-dimensional porous mold 135 is formed.

For example, the three-dimensional porous mold 135 may be a multi-beam interference lithography, proximity field nano-patterning (PnP), direct laser writing, (2-photon lithography), and physical methods such as colloidal self-assembly and block-copolymer may be used.

In one embodiment, a photoresist film may be formed on the substrate, and then the photoresist film may be patterned by the PnP method.

In the PnP method, a periodic three-dimensional distribution generated from an interference phenomenon of light transmitted through a phase mask including an elastomer material may be utilized to pattern a polymer material such as a photoresist. For example, if a flexible, elastomer-based phase mask having a concavo-convex lattice structure on its surface is brought into contact with the photoresist, the phase mask is naturally contacted to the photoresist surface (e.g., based on Van der Waals forces) For example, conformal contact).

When a laser having a wavelength in a range similar to the lattice period of the phase mask is irradiated on the phase mask surface, a three-dimensional light distribution can be formed by the Talbot effect. When a negative tone photoresist is used, crosslinking of the photoresist selectively occurs only in a part where light is strongly formed due to constructive interference, and the remaining part where light is weak is insufficient in exposure dose for crosslinking it can be dissolved and removed in the developing process. When a drying process is finally performed, a porous polymer material having a periodic three-dimensional structure of several hundred nanometers (nm) to several micrometers (m) is connected to the network by the wavelength of the laser and the design of the phase mask .

According to the exemplary embodiments, the pore size and periodicity of the three-dimensional porous mold 135 can be controlled by controlling the pattern period of the phase mask and the wavelength of the incident light used in the PnP method.

Using the above-described PnP method, the photoresist film formed on the substrate may be patterned to form a three-dimensional porous mold 135 having, for example, a periodic three-dimensional porous nanostructured pattern.

A more detailed description of the PnP method can be found in Korean Patent Laid-Open Publication No. 2006-0109477 (published on October 20, 2006).

In one embodiment, the phase mask used in the PnP process may be a material such as polydimethyl siloxane (PDMS), polyurethane acrylate (PUA), perfluoropolyether (PFPE) . ≪ / RTI >

For example, a silicon master can be manufactured by spin coating a photoresist on a silicon wafer, and then patterning the photoresist pattern through an exposure and development process. The silicon master surface can be surface treated, for example, through perfluorinated trichlorosilane vapor.

The elastomer phase mask can then be prepared by coating the PDMS layer on the silicon master, curing and then separating. In one embodiment, the PDMS layer is formed by spin-coating a first PDMS layer of high modulus (e.g., greater than 10 Mpa) onto the silicon master and depositing a low modulus (e.g., 2 Mpa or less) of the second PDMS layer may be spin-coated to form a multi-layer structure.

After the elastomer phase mask is conformally contacted with the photoresist film, an ultraviolet laser, for example, can be vertically irradiated on the elastomer phase mask. The irradiated light may form a periodic three-dimensional distribution in accordance with the constructive interference and destructive interference generated by the step structure included in the elastomer phase mask.

In one embodiment, when the photoresist film is formed of a negative tone photoresist, the non-exposed portion may be removed by the developer and the exposed portion may remain. Accordingly, a three-dimensional porous mold 135 including three-dimensional nanopores can be formed on the substrate. As the developer, for example, propylene glycol monomethyl ether acetate (PGMEA) may be used.

In one embodiment, after the photoresist film is patterned using the PnP method, an additional patterning process, such as a photolithography process, may be performed to form the three-dimensional porous mold 135. Therefore, the material of the three-dimensional porous mold 135 may be determined by the photoresist to be used. For example, the three-dimensional porous mold 135 may be a polymer resin such as an epoxy resin, an acrylic resin, a phenol resin, . ≪ / RTI >

For example, the three-dimensional porous mold 135 may have an aligned three-dimensional network shape, and the alignment period may be from 100 nm to 2,000 nm. In addition, a pore network connected with a three-dimensional network structure is formed in the three-dimensional porous mold 135.

The three-dimensional porous mold 135 may then be formed on the metal layer 132 for performing a plating process to fill the pore network. The metal layer 132 may be disposed on the base substrate 130.

For example, the metal layer 132 may include a metal such as nickel (Ni), titanium (Ti), copper (Cu), platinum (Pt), gold (Au), silver (Ag) can do.

The base substrate 130 may include silicon oxide, sapphire, or the like. The base substrate 130 may include silicon oxide so that releasing from the metal layer 132 can proceed easily.

Next, the thermoelectric material 140 is formed by filling the pores included in the three-dimensional porous mold 135.

The thermoelectric material 140 may substantially completely fill the pores so as to have a reversed phase of the three-dimensional porous mold 135. Electroplating, electroless plating, solution processing, chemical vapor deposition (CVD), or the like can be used to form the thermoelectric part 140. Hereinafter, a method using electroplating will be exemplarily described.

According to one embodiment, the thermoelectric part 140 may be formed using an electroplating process. For performing the electroplating process, an electrolytic cell including an anode, an electrolyte solution and a cathode is used, and a metal layer 132 on which a three-dimensional porous mold 135 is formed may be provided as the cathode, for example. The electrolyte solution may include cations of metals constituting the thermoelectric part 140. For example, when the thermoelectric material 140 includes Bi-Te, the electrolyte solution may include cations of Bi and Te. When the electrolyte solution is impregnated with the three-dimensional porous mold 135 and the metal layer 132 and a predetermined voltage is supplied through a power source, the metal cations contained in the electrolyte solution are injected into the three- .

According to one embodiment, the surface of the three-dimensional porous mold 135 may be plasma treated prior to performing the electroplating. Accordingly, the surface of the three-dimensional porous mold 135 can be converted from hydrophobic to hydrophilic, and the accessibility of the metal cation of the electrolyte solution can be improved.

In performing the electroplating, the pores in the three-dimensional porous mold 135 can be sufficiently filled by adjusting the electrolyte concentration, the voltage and / or the current magnitude and the supply time.

The thermoelectric material part 140 has a reversed phase of the three-dimensional porous mold 135. For example, the thickness of the thermoelectric material part 140 may be 50 nm to 300 nm.

Thereby, a thermoelectric composite including the thermoelectric part 140 and the three-dimensional porous mold 135 is obtained.

Next, the metal layer 132 and the base substrate 130 are separated. The thermocompression complex associated with the metal layer 132 may function as a freestanding membrane. For example, when the base substrate 130 includes silicon oxide, the base substrate 130 may be removed by providing a solution such as a hydrofluoric acid solution.

Next, the metal layer 132 is removed from the thermoelectric composite. The method for removing the metal layer 132 is not particularly limited. For example, a method such as ion-milling may be used.

In another embodiment, the metal layer 132 may not be removed, but may be used as an electrode or barrier layer of a thermoelectric module.

The thermoelectric composite itself can be used as a thermoelectric material. The three-dimensional porous mold 135 may be removed, and a three-dimensional nanostructure formed of the thermoelectric material 140 and the pore array may be used as a thermoelectric material.

For example, the three-dimensional porous mold 135 may be removed through heat treatment, wet etching, plasma treatment, or the like.

The heat treatment may be performed at a temperature of about 400 ^° C to about 1,000 ^° C, for example, in an air or oxygen atmosphere. An inert gas such as argon (Ar) may be added to the atmosphere for the heat treatment.

The plasma treatment may include an oxygen plasma treatment or a reactive ion etching (RIE) process.

When the three-dimensional porous mold 135 is removed, the thermoelectric material 140 may be subjected to a reduction process. The reduction process may improve the electrical characteristics of the thermoelectric part 140 by removing generated oxygen during the process of removing the three-dimensional porous mold 135 by heat treatment or plasma treatment.

The reduction process may be performed by performing heat treatment in a mixed gas atmosphere of hydrogen and an inert gas such as argon (Ar), for example, at a temperature of about 400 ^° C to about 1,000 ^° C.

Through this, a thermoelectric material including an insulating material portion having an aligned three-dimensional network shape and a thermoelectric material portion surrounding the insulating material portion to have an inverse opal shape can be obtained.

The thermoelectric material can be used in the manufacture of a thermoelectric module. For example, a thermoelectric module can be manufactured by coupling the first electrode to one end of the thermoelectric material and the second electrode to the other end. In another embodiment, as shown in FIG. 1, functional layers such as a barrier layer may be provided between the first electrode or the second electrode of the thermoelectric material.

According to the embodiment of the present invention, it is possible to obtain a thermoelectric material having a nanostructure aligned in three dimensions, and the thermoelectric material has a high thermal conductivity due to the phonon scattering effect by the insulating material portion, . Therefore, the thermoelectric performance can be improved.

In addition, the thermoelectric material of the nanostructure arranged in three dimensions is easier to form in bulk than the conventional nanostructure such as nanowire. Therefore, a high performance thermoelectric module that can be used for commercialization can be provided.

Hereinafter, a process of a method of manufacturing a thermoelectric module and a module according to the present invention will be described in detail with reference to specific experimental examples. The following examples are provided by way of illustration only and are not intended to limit the scope of the present invention.

Example 1

≪ Formation of a three-dimensional porous mold &

A photoresist (trade name: SU-8 2, manufactured by Micro Chem) was spin-coated on the Au (50 nm) / Cr (5 nm) / SiO ₂ substrate manufactured using an E-beam evaporation apparatus at 3000 rpm, It was heated on a hot plate at 65 ^° C for 2 minutes and at 95 ^° C for 3 minutes. Then exposed to a 365 nm UV lamp for 2 minutes and heated at 180 ^° C for 3 minutes to completely crosslink the photoresist. A photoresist (trade name: SU-8 2, manufactured by Micro Chem) was spin-coated thereon at 2000 rpm and then heated on a hot plate at 65 ^° C for 10 minutes and 95 ^° C for 15 minutes.

The substrate coated with the photoresist was brought into contact with a phase mask made of PDMS having a periodic concavo-convex structure. The phase mask had apertures arranged in a square grid with a period of 600 nm. The phase mask was irradiated with a laser having a wavelength of 355 nm of 15 mJ / cm ² , developed and dried to obtain a three-dimensional porous mold having pores having a period of 600 nm in the x and y axes and a period of 1 μm in the z axis.

≪ Formation of three-dimensional thermoelectric material part &

The Au / Cr / SiO ₂ substrate on which the 3-dimensional porous template was formed was used as a negative electrode, and 2 mM Bi (NO ₃ ) ₃ , 4 mM TeO ₂ , 0.35 M HNO ₃ and 40 mM L - (+) - Tartaric acid Using the electrolyte solution, a voltage of 0.05 V for 4 seconds and a voltage of +0.017 V for 6 seconds were alternately applied to form a thermoelectric material portion having Bi-Te and having a reversed phase with respect to the 3-dimensional porous template.

Next, after the SiO ₂ substrate was removed from the hydrofluoric acid solution, the Au / Cr layer was removed by ion-milling equipment to obtain a three-dimensional nanostructured thermoelectric material having a thickness of about 8.2 μm.

Example 2

≪ Formation of a three-dimensional porous mold &

A three-dimensional porous template was obtained in the same manner as in Example 1.

≪ Formation of three-dimensional thermoelectric material part &

The 3D porous mold, and using the Au / Cr / SiO ₂ substrate is formed as a _{cathode, 2 mM Bi (NO 3)} 3, 2 mM SbO 2, 4 mM TeO 2, 0.35 M HNO 3 , and 40 mM L - (+ ) -Tartaric acid electrolyte solution, Bi-Sb-Te is applied by alternately applying a voltage of 0.05 V for 4 seconds and a voltage of +0.017 V for 6 seconds using a voltage, and a thermoelectric Thereby forming a material portion.

Next, after the SiO ₂ substrate was removed from the hydrofluoric acid solution, the Au / Cr layer was removed by ion-milling equipment to obtain a three-dimensional nanostructured thermoelectric material having a thickness of about 8.2 μm.

Comparative Example 1

Using the electrolyte solution of Tartaric acid, Bi - using a Au / Cr / SiO ₂ substrate with a cathode _{and, 2 mM Bi (NO 3)} 3, 4 mM TeO 2, 0.35 M HNO 3 , and 40 mM L - (+) -Te film.

Comparative Example 1

Using a Au / Cr / SiO ₂ substrate with a cathode _{and, 2 mM Bi (NO 3)} 3, 2 mM SbO 2, 4 mM TeO 2, 0.35 M HNO 3 , and 40 mM L - electrolyte solution of Tartaric acid - (+) , A Bi-Sb-Te film was obtained.

4 is a scanning electron micrograph of the three-dimensional nanostructured thermoelectric material obtained in Example 2. Fig.

Referring to FIG. 4, it can be confirmed that a thermoelectric material (Bi-Sb-Te) is filled between insulating material (PR) arrays periodically arranged in three dimensions.

FIG. 5A is a graph showing changes in electrical conductivity of a 3D nanostructured BT film obtained in Example 1 and a Bi-Te film obtained in Comparative Example 1 according to temperature. FIG. FIG. 5B is a graph showing changes in the whitening index according to the temperatures of the 3D nanostructured BT film obtained in Example 1 and the Bi-Te film obtained in Comparative Example 1. FIG. FIG. 5C is a graph showing changes in power factor according to temperature of the 3D nanostructured BT film obtained in Example 1 and the Bi-Te film obtained in Comparative Example 1 (normal BT film). FIG.

5A to 5C, the electrical conductivity and the thermoelectric conversion index (whiteness index and power factor) associated therewith show that when comparing the Bi-Te three-dimensional nanostructure obtained in Example 1 with the general type Bi-Te film, .

6 is a graph showing XRD analysis results of the 3D nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2. FIG. 7 is an EDS mapping image of the three-dimensional nanostructured thermoelectric material obtained in Example 2. Fig.

6 and 7, the Bi-Sb-Te three-dimensional nanostructure obtained in Example 2 is composed of an alloy in which Bi, Sb and Te are uniformly dispersed and is compared with a Bi-Sb-Te film of a general shape , It can be confirmed that they have substantially the same crystal structure.

8A is a graph showing changes in electrical conductivity of a 3-dimensional nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and a Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2 according to temperature. FIG. 8B is a graph showing changes in the whitening index according to the temperature of the 3D nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2. FIG. 8C is a graph showing a change in power factor according to temperature of the 3D nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2. FIG. 9 is a graph showing changes in thermal conductivity of the 3D nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) obtained in Comparative Example 2 according to the temperature. 10 is a graph showing the thermoelectric performance index (Figure of Merit, ZT) of the 3-dimensional nanostructured thermoelectric material (3D nanostructured BST film) obtained in Example 2 and the Bi-Sb-Te film (Normal BST film) ) In the second embodiment. In the graph of FIG. 9, in order to obtain the thermal conductivity of only the thermoelectric part except the three-dimensional porous mold, the thermal conductivity of the three-dimensional porous mold was separately calculated and removed.

Referring to FIGS. 8A to 8C, 9 and 10, the electrical conductivity and the thermoelectric performance index (whiteness index and power factor) associated therewith are compared with the Bi-Sb-Te three-dimensional nanostructure obtained in Example 2 and the Bi- When the Sb-Te films are compared, there is no significant difference, but the thermal conductivity is greatly reduced and the thermoelectric performance index is greatly increased.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It will be understood that the invention may be modified and varied without departing from the scope of the invention.

INDUSTRIAL APPLICABILITY The present invention can be used for manufacturing a thermoelectric module and a power generator using a thermoelectric module.

Claims (10)

delete delete delete delete delete Forming a three-dimensional porous mold including a polymer and three-dimensionally arranged pores on a metal layer disposed on the base substrate;
Plasma processing the surface of the three-dimensional porous mold;
Forming a thermoelectric material portion surrounding the three-dimensional porous mold so as to have an inverse opal shape by filling the pores of the three-dimensional porous mold with thermoelectric material by performing electroplating using the metal layer as a negative electrode, ;
Separating the base substrate from the metal layer;
Removing the three-dimensional porous template through plasma treatment;
Performing a reduction process in a mixed gas atmosphere of hydrogen and an inert gas at 400 ° C. to 1,000 ° C. after removing the three-dimensional porous mold;
Connecting a first electrode to one end of the thermoelectric element including the thermoelectric part; And
And connecting a second electrode to the other end of the thermoelectric module. [7] The method of claim 6, wherein the thermoelectric part has an alignment period of 100 nm to 2,000 nm and the thermoelectric part has a thickness of 50 nm to 300 nm. 7. The method of claim 6, wherein the thermoelectric material is selected from the group consisting of chalcogenide, skutterudite, silicide, clathrate, half-heusler, and bismuth- And at least one thermoelectric material selected from the group consisting of tellurium (Bi-Te). delete delete

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