A magnetic thermoelectric multilayer film with enhanced thermoelectric properties and a preparation method thereof
By introducing a thin magnetic layer between the thermoelectric films and adopting empty-panel printing and leveling operations, alternately arranged thermoelectric films and magnetic film multi-layer structures are prepared, which solves the problem of improving the performance of low-cost thermoelectric films and achieves a thermoelectric multi-layer film with high electrical transport performance and density.
Patent Information
- Application Number
- CN202211040488.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-29
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2042-08-29
AI Technical Summary
The prior art is difficult to significantly improve the thermoelectric performance of flexible thermoelectric films at low cost, especially the electric transport performance, and cannot meet the efficient heat dissipation needs of micro electronic devices.
By introducing a thin magnetic layer between the thermoelectric films, using the interlayer coupling between magneto-layers/non-magnetic layers, a new effect of thermoelectric coupling is induced, and problems such as uneven film surfaces and large internal porosity between multilayer films are solved through empty-sheet printing and flattening operations, and multi-layer structures of thermoelectric films and magnetic films that are alternately arranged are prepared.
It significantly improves the electrical transport performance and density of thermoelectric films, improves the surface flatness, and improves the comprehensive use performance of thermoelectric multilayer films.
Smart Images
Figure CN115360289B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of energy materials, and particularly relates to a magnetic thermoelectric multilayer film with enhanced thermoelectric performance and a preparation method thereof. Background Art
[0002] The high integration, high power and flexibility of microelectronic devices urgently require the development of efficient flexible thermal management solutions. The in-plane heat dissipation technology based on thin-film thermoelectric refrigeration has attracted extensive attention from researchers at home and abroad due to its high theoretical power density and small volume. However, the development of high-performance and low-cost flexible thermoelectric thin films is extremely difficult, which greatly limits the application of thin-film thermoelectric refrigeration technology in the thermal management of microelectronic devices: The superlattice thin films prepared by foreign research scholars using metal-organic chemical vapor deposition technology have very high thermoelectric performance and refrigeration power density, but the preparation cost is too high; while the thermoelectric conversion performance, especially the electrical transport performance, of the low-cost thermoelectric thin films prepared by traditional processes (such as chemical vapor deposition, pulsed laser deposition, molecular beam epitaxy, etc.) deteriorates severely. Therefore, how to greatly improve the thermoelectric performance of low-cost thermoelectric thin films is a challenging problem facing their application.
[0003] At present, the widely studied low-cost flexible thermoelectric thin films mainly focus on organic thermoelectric thin films and organic / inorganic composite thermoelectric thin films. Among them, organic thermoelectric thin films have excellent flexibility but usually very low thermoelectric performance, and organic / inorganic composite thermoelectric thin films have received increasing attention due to their advantages of both organic and inorganic thin films. At the same time, various means such as hot pressing sintering, interface modification, conductive polymer composite, and modulation doping are used to further improve the electrothermal transport performance of organic / inorganic composite thermoelectric thin films, but still cannot meet the requirements of efficient heat dissipation of electronic devices. Summary of the Invention
[0004] The main purpose of the present invention is to provide a magnetic thermoelectric multilayer film with enhanced thermoelectric performance and a preparation method thereof in view of the problems or deficiencies existing in the prior art. By introducing a thin magnetic layer between two thermoelectric thin films and utilizing the interlayer coupling effect between the magnetic layer and the non-magnetic layer, a new thermomagnetic coupling effect is induced, endowing the obtained thermoelectric thin film with certain magnetic properties and significantly enhanced thermoelectric conversion performance; at the same time, problems such as uneven film surface and large internal porosity between multilayer films are solved through a flat-plate printing and flattening operation, further effectively improving the comprehensive service performance of the obtained magnetic thermoelectric multilayer film.
[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:
[0006] A magnetic thermoelectric multilayer film with enhanced thermoelectric properties, which comprises a plurality of alternately arranged thermoelectric thin film layers and magnetic thin film layers; wherein, the thermoelectric thin film layers and the magnetic thin film layers are respectively obtained by printing and leveling on the surface of a wet film obtained from the corresponding slurry, drying, and finally performing hot pressing and sintering treatment on the obtained composite multilayer film.
[0007] In the above solution, the slurry used for the thermoelectric thin film layer is thermoelectric slurry A, which is obtained by uniformly mixing (mechanically stirring and ultrasonically dispersing) thermoelectric powder in a binder solution.
[0008] In the above solution, the thermoelectric powder is a p-type or n-type Bi2Te3-based thermoelectric material or Sb2Te3-based thermoelectric material; the particle size of the thermoelectric powder is below 120 μm; the concentration of the thermoelectric powder in the thermoelectric slurry A is 40-80 wt%.
[0009] Further, the thermoelectric powder in the thermoelectric slurry is p-type or n-type Bi 3-x Se x or Bi 2-x Sb x Te3-based thermoelectric material.
[0010] In the above solution, the slurry used for the magnetic thin film layer is magnetic slurry B, which is obtained by uniformly mixing ferromagnetic metal nanopowder in a binder solution (mechanically stirring and ultrasonically dispersing).
[0011] Further, the ferromagnetic metal is one or several of Fe, Co, Ni, etc.; the particle size of the ferromagnetic metal does not exceed 1000 nm; the concentration of the ferromagnetic metal in the magnetic slurry B is 30-70 wt%.
[0012] In the above solution, the binder solution is composed of epoxy resin, curing agent, catalyst and solvent; the curing agent is selected from at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, pyromellitic dianhydride, etc.; the catalyst is selected from at least one of 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, etc.; the solvent is selected from at least one of N-methylpyrrolidone, ethanol, butyl glycidyl ether, terpineol, dimethyl ester, etc.
[0013] Further, the components and their weight parts in the binder solution include: epoxy resin above 20 parts, methylhexahydrophthalic anhydride below 17 parts, 2-ethyl-4-methylimidazole below 4 parts, and butyl glycidyl ether below 59 parts.
[0014] In the above solution, in the magnetic thermoelectric multilayer film with enhanced thermoelectric properties, the magnetic thin film layers are all arranged between two thermoelectric thin film layers.
[0015] In the above solution, the number of magnetic thin film layers is 0 - 10 layers.
[0016] Preferably, the number of magnetic thin film layers is 1 - 10 layers.
[0017] In the above solution, the printing and flattening step is to perform one or more printings on the surface of the wet film using a screen plate without paste.
[0018] In the above solution, the mesh number of the screen plate used for the printing and flattening operation is higher than that of the screen plates used for printing the thermoelectric thin film and the magnetic thin film.
[0019] Furthermore, the mesh number of the printing plate for the screen printing paste is 40 - 350, and specifically, one or more of 40, 60, 120, 200, 250, and 350 meshes can be selected.
[0020] Furthermore, the mesh number of the printing plate for flattening the wet film surface by screen printing is 120 - 800, and specifically, one or more of 120, 200, 350, 500, and 800 meshes can be selected.
[0021] In the above solution, the wet film is formed by respectively setting the thermoelectric paste A or the magnetic paste B on the surface of the substrate, or on the surface of the dried thermoelectric thin film layer or magnetic thin film layer by means of screen printing, spin coating, brushing, dispensing printing, inkjet printing, gravure printing, etc.
[0022] Preferably, the wet film is set by means of screen printing.
[0023] Furthermore, the speed of the screen printing process used for the wet film is 2000 - 4000 m / h.
[0024] The above method for preparing a magnetic thermoelectric multi-layer film with enhanced thermoelectric performance includes the following steps:
[0025] 1) Respectively prepare the thermoelectric paste A and the magnetic paste B that can be used for printing the thermoelectric thin film and the magnetic thin film;
[0026] 2) Print a thermoelectric wet film on the surface of the substrate using the thermoelectric paste A, perform printing and flattening on the surface of the thermoelectric wet film using a high-mesh screen plate without paste, and dry (preferably vacuum drying) to obtain the thermoelectric thin film A;
[0027] 3) Print a magnetic wet film on the surface of the thermoelectric thin film A using the magnetic paste B, perform printing and flattening on the surface of the magnetic wet film using a high-mesh screen plate without paste, and dry (preferably vacuum drying) to obtain the magnetic thin film B (obtaining a thermoelectric magnetic double-layer film in the form of AB);
[0028] Print a thermoelectric wet film on the surface of the magnetic thin film B using the thermoelectric paste A, print and level the surface of the thermoelectric wet film with a high-mesh screen plate without paste, and perform vacuum drying to obtain the thermoelectric thin film A (obtain a thermoelectric-magnetic three-layer film in the ABA form);
[0029] 4) Repeat the steps described in step 3) to obtain a multi-layer composite film in which the thermoelectric thin film and the magnetic thin film are alternately arranged;
[0030] 5) Thermally press and sinter the obtained multi-layer composite film to obtain the magnetic thermoelectric multi-layer film with significantly enhanced thermoelectric performance.
[0031] Furthermore, the mesh number of the screen plate used in the printing and leveling operation is higher than that of the screen plate used for printing the thermoelectric thin film and the magnetic thin film.
[0032] Furthermore, the mesh number of the high-mesh screen plate is 120 - 800.
[0033] In the above solution, the temperature of the vacuum drying is 50 - 150 °C.
[0034] Furthermore, the vacuum degree of the vacuum drying is less than 133 Pa.
[0035] In the above solution, the temperature used for the thermal press sintering is 200 - 450 °C, the thermal press pressure is 1 - 20 MPa, and the time is 1 - 8 h.
[0036] Furthermore, the substrate of the magnetic thermoelectric multi-layer film is selected from any one of polyimide, polyethylene terephthalate, polyethylene naphthalate, or glass cloth.
[0037] In the above solution, the number of repetitions in step 4) is 0 - 6 times.
[0038] The magnetic thermoelectric multi-layer film with enhanced thermoelectric performance prepared according to the above solution has high density, high electro-thermal conversion performance, and refrigeration performance.
[0039] Compared with the prior art, the beneficial effects of the present invention are:
[0040] 1) The present invention realizes a significant improvement in the electrical transport performance of the thermoelectric thin film by constructing an alternating overlapping structure of the thermoelectric thin film and the magnetic thin film;
[0041] 2) The surface flatness of each layer of functional thin film is effectively improved through the flat printing operation with an empty plate, effectively solving the problems such as poor surface flatness when printing thin films with a high-mesh screen plate;
[0042] 3) By repeating the printing multiple times, the pores in the thin film are effectively reduced, a dense magnetic thermoelectric multi-layer film is obtained, and the problem of deterioration of the thermoelectric performance of the screen-printed thermoelectric thin film is improved. Description of the Drawings
[0043] Figure 1 a, b, c, and d are Bi prepared in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 respectively 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Backscattered electron image of the cross-section of the Bi
[0044] Figure 2 For Bi prepared in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Relationship curve of conductivity (a), Seebeck coefficient (b), and power factor (c) of the Bi Detailed implementation manners
[0045] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention
[0046] In the following embodiments, the preparation method of the Bi 0.5 Sb 1.5 Te3 powder includes the following steps: After the p-type bismuth telluride BST crystal bar is crushed and screened by a sieve, BST thermoelectric powder with a particle size less than 120 μm is obtained. Accurately weigh 10 g of BST thermoelectric powder and add it to a 200 mL ball milling tank, mix it evenly with 50 mL of cyclohexane, introduce argon for protection, and ball mill it at a speed of 200 rpm for 2 h to obtain flat BST thermoelectric powder
[0047] The particle size of the Fe nanoparticles used is below 100 nm
[0048] Example 1
[0049] A magnetic thermoelectric multilayer film with enhanced thermoelectric performance, which is a Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 magnetic thermoelectric trilayer film, and the specific preparation steps are as follows
[0050] 1) Accurately weigh 10 g of Bi 0.5 Sb 1.5Te3(BST) thermoelectric powder, 0.612 g of bisphenol F diglycidyl ether epoxy resin (16 parts), 0.521 g of methylhexahydrophthalic anhydride (14 parts), 0.123 g of 2-ethyl-4-methylimidazole (3 parts), 1.8 g of butyl glycidyl ether (47 parts), and after mechanical stirring, ultrasonic dispersion is carried out to obtain thermoelectric slurry A;
[0051] Accurately weigh 3.0 g of Fe nanoparticles, 0.612 g of bisphenol F diglycidyl ether epoxy resin, 0.521 g of methylhexahydrophthalic anhydride, 0.123 g of 2-ethyl-4-methylimidazole, 1.8 g of butyl glycidyl ether, and after mechanical stirring, ultrasonic dispersion is carried out to obtain magnetic slurry B;
[0052] 2) Place the polyimide substrate in absolute ethanol, ultrasonically clean it for 15 min and then dry it. Then, use a screen printing machine and a 60-mesh screen plate to print the above thermoelectric slurry A on the polyimide substrate. After that, use a 500-mesh screen plate without slurry to perform a single printing and leveling on the obtained BST wet film (when the mesh of the screen plate used for leveling is the same as that in the printing step, the flatness of the slurry after printing cannot be guaranteed; the same below) to level the surface of the BST wet film and fill the pores, and vacuum dry it at 80 °C for 1 h to obtain Bi 0.5 Sb 1.5 Te3 thermoelectric thin film;
[0053] Then, use a screen printing machine and a 350-mesh screen plate to print the above magnetic slurry B on the above thermoelectric thin film. After that, use a 500-mesh screen plate without slurry to perform a single printing and leveling on the obtained wet film (when the mesh of the screen plate used for leveling is the same as that in the printing step, the flatness of the slurry after printing cannot be guaranteed; the same below) to level the surface of the wet film and fill the pores, and vacuum dry it at 80 °C for 1 h to obtain Bi 0.5 Sb 1.5 Te3 / Fe thermomagnetic thin film;
[0054] After that, use the 60-mesh screen plate again to print the above thermoelectric slurry A on the above thermomagnetic thin film. After that, use a 500-mesh screen plate without slurry to perform a single printing on the obtained wet film to level the surface of the wet film and fill the pores, and vacuum dry it at 100 °C for 3 h to obtain Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 composite thin film;
[0055] 3) Thermally press and sinter the obtained Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 composite thin film at 300 °C and 8 MPa for 4 h to obtain the said Bi0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 A Te3 magnetic thermoelectric trilayer film.
[0056] The Bi obtained in this example 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 The cross-sectional micrograph of the Te3 magnetic thermoelectric trilayer film is as shown in Figure 1 c, and the electrical transport properties are as shown in Figure 2 as follows.
[0057] Example 2
[0058] A magnetic thermoelectric multilayer film with enhanced thermoelectric properties, which is a Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 magnetic thermoelectric nonalayer film, and the specific preparation steps are as follows:
[0059] 1) Accurately weigh 10 g of Bi 0.5 Sb 1.5 Te3 (BST) thermoelectric powder, 0.612 g of bisphenol F diglycidyl ether epoxy resin, 0.521 g of methylhexahydrophthalic anhydride, 0.123 g of 2-ethyl-4-methylimidazole, and 1.8 g of butyl glycidyl ether, and ultrasonically disperse them after mechanical stirring to obtain thermoelectric slurry A;
[0060] Accurately weigh 3.0 g of Fe nanoparticles, 0.612 g of bisphenol F diglycidyl ether epoxy resin, 0.521 g of methylhexahydrophthalic anhydride, 0.123 g of 2-ethyl-4-methylimidazole, and 1.8 g of butyl glycidyl ether, and ultrasonically disperse them after mechanical stirring to obtain magnetic slurry B;
[0061] 2) Place the polyimide substrate in anhydrous ethanol and ultrasonically clean it for 15 min, then dry it. Then, use a screen printing machine and a 60-mesh screen plate to print the above thermoelectric slurry A on the polyimide substrate. After that, use a 500-mesh screen plate without slurry to perform a single printing on the obtained BST wet film to flatten the surface of the BST wet film and fill the pores, and vacuum dry it at 80 °C for 1 h to obtain a Bi 0.5 Sb 1.5 Te3 thermoelectric film;
[0062] Then, the above magnetic paste B was printed on the above thermoelectric thin film using a screen printing machine and a 350-mesh screen plate. After that, a 500-mesh screen plate without paste was used to perform a single printing on the obtained wet film to flatten the surface of the wet film and fill the pores, and it was vacuum dried at 80 °C for 1 h to obtain Bi 0.5 Sb 1.5 Te3 / Fe thermomagnetic thin film;
[0063] After that, the above thermoelectric paste A was printed on the above thermomagnetic thin film using a 60-mesh screen plate again. After that, a 500-mesh screen plate without paste was used to perform a single printing on the obtained BST wet film to flatten the surface of the BST wet film and fill the pores, and it was vacuum dried at 100 °C for 3 h to obtain Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 thermomagnetic thin film;
[0064] The above steps of printing the magnetic layer - printing the thermoelectric layer - flattening with an empty plate were repeated three times to obtain a nine-layer structure of Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 composite thin film;
[0065] 3) The composite thin film obtained in step 2) was hot-pressed and sintered at 300 °C and 8 MPa for 4 h to obtain the Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 magnetic thermoelectric nine-layer film.
[0066] The Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 The cross-sectional micrograph of the Te3 magnetic thermoelectric nine-layer film is as shown in Figure 1 d, and the electrical transport properties are as shown in Figure 2 shown.
[0067] Comparative Example 1
[0068] A Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 magnetic thermoelectric three-layer film, without using the flattening operation of printing with an empty plate, and the specific preparation steps are as follows:
[0069] 1) Accurately weigh 10 g of Bi 0.5 Sb 1.5Te3(BST) thermoelectric powder, 0.612 g of bisphenol F diglycidyl ether epoxy resin, 0.521 g of methylhexahydrophthalic anhydride, 0.123 g of 2-ethyl-4-methylimidazole, 1.8 g of butyl glycidyl ether, and after mechanical stirring, ultrasonic dispersion was carried out to obtain thermoelectric slurry A;
[0070] Accurately weigh 3.0 g of Fe nanoparticles, 0.612 g of bisphenol F diglycidyl ether epoxy resin, 0.521 g of methylhexahydrophthalic anhydride, 0.123 g of 2-ethyl-4-methylimidazole, 1.8 g of butyl glycidyl ether, and after mechanical stirring, ultrasonic dispersion was carried out to obtain magnetic slurry B;
[0071] 2) Place the polyimide substrate in absolute ethanol and ultrasonically clean it for 15 min, then dry it. Then, use a screen printing machine and a 60-mesh screen plate to print the above thermoelectric slurry A on the polyimide substrate, and vacuum dry it at 80 °C for 1 h to obtain Bi 0.5 Sb 1.5 Te3 thermoelectric thin film;
[0072] Then, use a screen printing machine and a 60-mesh screen plate to print the above slurry B on the above thermoelectric thin film, and vacuum dry it at 80 °C for 1 h to obtain Bi 0.5 Sb 1.5 Te3 / Fe thermomagnetic thin film;
[0073] After that, use the 60-mesh screen plate again to print the above slurry A on the above thermomagnetic thin film, and vacuum dry it at 100 °C for 3 h to obtain Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 composite thin film;
[0074] 3) Subject the obtained Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 composite thin film to hot pressing sintering at 300 °C and 8 MPa for 4 h to obtain the Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 magnetic thermoelectric three-layer film.
[0075] The cross-sectional microstructural diagram of the Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 magnetic thermoelectric three-layer film obtained in this comparative example is as shown in Figure 1 a, and its electrical transport properties are as shown in Figure 2 shown.
[0076] Comparative Example 2
[0077] A kind of Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 magnetic thermoelectric three-layer film, without using the flat printing operation of the empty plate. The specific preparation steps are as follows:
[0078] 1) Accurately weigh 10 g of Bi 0.5 Sb 1.5 Te3 (BST) BST thermoelectric powder, 0.612 g of bisphenol F diglycidyl ether epoxy resin, 0.521 g of methylhexahydrophthalic anhydride, 0.123 g of 2-ethyl-4-methylimidazole, 1.8 g of butyl glycidyl ether. After mechanical stirring, ultrasonic dispersion is carried out to obtain thermoelectric slurry A;
[0079] Accurately weigh 3.0 g of Fe nanoparticles, 0.612 g of bisphenol F diglycidyl ether epoxy resin, 0.521 g of methylhexahydrophthalic anhydride, 0.123 g of 2-ethyl-4-methylimidazole, 1.8 g of butyl glycidyl ether. After mechanical stirring, ultrasonic dispersion is carried out to obtain magnetic slurry B;
[0080] 2) Place the polyimide substrate in anhydrous ethanol and ultrasonically clean it for 15 min, then dry it. Then, use a screen printing machine and a 200-mesh screen plate to print the above thermoelectric slurry A on the polyimide substrate, and vacuum dry it at 80 °C for 1 h to obtain Bi 0.5 Sb 1.5 Te3 thermoelectric film;
[0081] Then, use a screen printing machine and a 500-mesh screen plate to print the above magnetic slurry B on the above thermoelectric film, and vacuum dry it at 80 °C for 1 h to obtain Bi 0.5 Sb 1.5 Te3 / Fe composite film;
[0082] After that, use the 200-mesh screen plate again to print the above slurry A on the above thermomagnetic film, and vacuum dry it at 100 °C for 3 h to obtain Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 thermomagnetic film;
[0083] 3) Heat press and sinter the obtained Bi 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 Te3 composite film at 300 °C and 8 MPa for 4 h to obtain the Bi 0.5 Sb 1.5Te3 / Fe / Bi 0.5 Sb 1.5 Te3 magnetic thermoelectric triple-layer film.
[0084] The Bi obtained in this comparative example 0.5 Sb 1.5 Te3 / Fe / Bi 0.5 Sb 1.5 The cross-sectional microstructural diagram of the Te3 magnetic thermoelectric triple-layer film is as Figure 1 shown in b, and the electrical transport properties are as Figure 2 shown.
[0085] Comparison Figure 1 (a) and Figure 1 (b) shows that the interface flatness of the multilayer film obtained by using a low-mesh screen printing plate (Comparative Example 1) is very poor, and changing to a high-mesh screen printing plate (Comparative Example 2) can only slightly improve the interface flatness; combined with Figure 1 (c) shows that adding an empty plate printing and flattening operation (Example 1) after printing the thermoelectric layer can significantly improve the interface flatness of the multilayer film. At the same time, it can be seen from Figure 2 that the electrical transport properties of the magnetic thermoelectric triple-layer film prepared by the method of Example 1 are increased by 351.90% and 43.12% respectively compared with Comparative Example 1 and Comparative Example 2.
[0086] From Figure 1 (d) shows that the interface of the magnetic thermoelectric nine-layer film obtained by using the preparation method of Example 2 is still flat, the combination is very tight, and it has excellent electrical transport properties.
[0087] The above embodiments are only for clearly illustrating the examples made, rather than limiting the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation manners here. Therefore, the obvious changes or modifications derived therefrom are still within the protection scope of this invention.
Claims
1. A magnetic thermoelectric multi-layer film with enhanced thermoelectric properties, characterized in that It includes a plurality of thermoelectric thin film layers and magnetic thin film layers which are alternately arranged in sequence; among them, the thermoelectric thin film layers and the magnetic thin film layers are respectively obtained by printing and leveling on the surface of the wet film obtained by using the corresponding slurry, drying, and finally performing hot pressing and sintering treatment on the obtained composite multi-layer film; The mesh number of the screen plate used in the printing and leveling operation is higher than that of the screen plate used for printing the thermoelectric thin film and the magnetic thin film.
2. The magnetic thermoelectric multilayer film according to claim 1, wherein The slurry used for the thermoelectric thin film layer is thermoelectric slurry A, which is obtained by uniformly mixing thermoelectric powder into a binder solution.
3. The magnetic thermoelectric multilayer film according to claim 2, wherein The thermoelectric powder is p type or n type of Bi2Te3-based thermoelectric material or Sb2Te3-based thermoelectric material; the particle size of the thermoelectric powder is 120 μm or less; the concentration of the thermoelectric powder in the thermoelectric slurry A is 40-80 wt%.
4. The magnetic thermoelectric multi-layer film according to claim 1, characterized in that The slurry used for the magnetic thin film layer is magnetic slurry B, which is obtained by uniformly mixing ferromagnetic metal nano-powder into a binder solution.
5. The magnetic thermoelectric multi-layer film according to claim 4, characterized in that, The ferromagnetic metal is one or more of Fe, Co, and Ni; the particle size of the ferromagnetic metal does not exceed 1000 nm; the concentration of the ferromagnetic metal in the magnetic slurry B is 30-70 wt%.
6. The magnetic thermoelectric multilayer film according to claim 1, wherein In the magnetic thermoelectric multi-layer film with enhanced thermoelectric performance, the magnetic thin film layers are all arranged between two thermoelectric thin film layers.
7. The magnetic thermoelectric multilayer film according to claim 1, wherein The number of the magnetic thin film layers is 0-10 layers.
8. The preparation method of a magnetic thermoelectric multi-layer film with enhanced thermoelectric performance according to any one of claims 1 to 7, comprising the following steps: 1) Respectively prepare thermoelectric slurry A and magnetic slurry B for printing the thermoelectric thin film and the magnetic thin film; 2) Print a thermoelectric wet film on the surface of the substrate by using the thermoelectric slurry A, and perform printing and leveling on the surface of the thermoelectric wet film by using a high-mesh screen plate without adding slurry, and dry to obtain a thermoelectric thin film A; 3) Print a magnetic wet film on the surface of the thermoelectric thin film A by using the magnetic slurry B, and perform printing and leveling on the surface of the magnetic wet film by using a low-mesh screen plate without adding slurry, and dry to obtain a magnetic thin film B; Print a thermoelectric wet film on the surface of the magnetic thin film B by using the thermoelectric slurry A, and perform printing and leveling on the surface of the thermoelectric wet film by using a high-mesh screen plate without adding slurry, and vacuum dry to obtain a thermoelectric thin film A; 4) Repeat the steps in step 3) to obtain a multi-layer composite film with thermoelectric thin films and magnetic thin films alternately arranged; 5) Perform hot pressing and sintering on the obtained multi-layer composite film to obtain the magnetic thermoelectric multi-layer film with significantly enhanced thermoelectric performance.
9. The preparation method according to claim 8, wherein, The temperature used for the hot pressing and sintering is 200-450 °C, the hot pressing pressure is 1-20 MPa, and the time is 1-8 h.