Air-stable n-type single-walled carbon nanotube thermoelectric thin films, methods of making, and uses thereof

Abstract

The application provides an air-stable N-type single-walled carbon nanotube thermoelectric film, a preparation method and application thereof, and the preparation method specifically comprises the following steps: S1, single-walled carbon nanotubes and poly(benzodifuran-diketone) are diluted to a certain concentration to obtain a single-walled carbon nanotube dispersion and a poly(benzodifuran-diketone) dispersion; S2, polyethyleneimine solution is added to the single-walled carbon nanotube dispersion, stirring is carried out at room temperature for 20-30 hours, vacuum filtration is carried out after uniform mixing to obtain a film A; S3, the poly(benzodifuran-diketone) dispersion is introduced into the film A and filtration is carried out to obtain a film B with a laminated structure; and S4, the film B is immersed in a post-treatment solution for post-treatment, and after being taken out, vacuum drying is carried out at 50-70 DEG C for 0.5-1.5 hours, and the film is obtained.

Description

Technical Field

[0001] This invention relates to the field of thermoelectric materials technology, specifically to an air-stabilized N-type single-walled carbon nanotube thermoelectric thin film, its preparation method, and its applications. Background Technology

[0002] Thermoelectric materials are key materials capable of converting heat energy into electrical energy or vice versa, and are widely used in renewable energy utilization and energy efficiency improvement. Flexible thermoelectric devices have attracted much attention due to their ability to adapt to various curved surfaces and their thin and flexible characteristics. Traditional thermoelectric materials such as lead sulfide and bismuth selenide have received widespread attention due to their excellent thermoelectric properties, but their application in flexible devices is limited by mechanical stability and fabrication complexity. Therefore, developing novel flexible thermoelectric materials that combine stability and high performance has become one of the current research priorities.

[0003] Carbon nanotubes (CNTs) have become a hot topic in thermoelectric materials research due to their excellent electron transport properties and unique structural characteristics. In particular, single-walled carbon nanotubes (SWCNTs) possess extremely high electrical conductivity and good solution processing capabilities, making them promising for wide applications in flexible electronic devices.

[0004] To enable single-walled carbon nanotubes to possess superior thermoelectric properties, we need to convert p-type SWCNTs into n-type SWCNTs. However, n-type SWCNTs readily undergo nucleophilic reactions with oxygen, water, and carbon dioxide in the air, causing them to revert back to p-type. This limits their widespread application in applications requiring high environmental stability.

[0005] Therefore, the urgent technical problem to be solved is how to convert P-type SWCNTs into N-type SWCNTs, while improving the stability of N-type single-walled carbon nanotube thermoelectric films in air, so as to give them excellent thermoelectric properties. Summary of the Invention

[0006] This invention is made to solve the above-mentioned problems, and aims to provide an air-stable N-type single-walled carbon nanotube thermoelectric thin film, its preparation method and its application.

[0007] This invention provides a method for preparing an air-stabilized N-type single-walled carbon nanotube thermoelectric thin film, characterized by the following steps: S1, diluting single-walled carbon nanotubes and poly(benzodifurandione) to a certain concentration to obtain a single-walled carbon nanotube dispersion and a poly(benzodifurandione) dispersion; S2, adding a polyethyleneimine solution to the single-walled carbon nanotube dispersion, stirring at room temperature for 20-30 hours, mixing evenly, and then vacuum filtering to obtain film A; S3, introducing the poly(benzodifurandione) dispersion into film A and filtering to obtain a multilayer film B; S4, immersing film B in a post-treatment solution for post-treatment, removing it, and then vacuum drying at 50-70°C for 0.5-1.5 hours to obtain the final product.

[0008] The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films provided by the present invention may also have the following feature: in step S1, the dispersion solvent of the single-walled carbon nanotube dispersion is a polar solvent.

[0009] The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films provided by the present invention may also have the following feature: wherein the polar solvent is water or N-methyl-2-pyrrolidone.

[0010] The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films provided by the present invention may also have the following characteristic: the concentrations of the single-walled carbon nanotube dispersion and the poly(benzodifurandione) dispersion are both 0.1-0.3 mg / mL.

[0011] The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films provided by the present invention may also have the following feature: in step S4, the post-treatment solution is a polyethyleneimine solution, and the dispersing solvent of the polyethyleneimine solution is at least one of N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, water and ethanol.

[0012] The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films provided by the present invention may also have the following features: in step S4, the specific post-treatment steps are as follows: the post-treatment solution without film B is heated to 15-200℃ and held for 8-24 hours.

[0013] The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films provided by the present invention may also have the following features: in step S2, the specific steps of vacuum filtration are as follows: the single-walled carbon nanotube dispersion is vacuum filtered through a microporous filter membrane.

[0014] The method for preparing air-stable N-type single-walled carbon nanotube thermoelectric thin films provided by the present invention may also have the following feature: the pore size of the microporous filter membrane is 0.4-0.5 μm.

[0015] The present invention also provides an air-stabilized N-type single-walled carbon nanotube thermoelectric thin film, which is prepared by the above-described method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin film.

[0016] This invention also provides the application of air-stabilized N-type single-walled carbon nanotube thermoelectric thin films in flexible electronic devices.

[0017] The role and effect of invention

[0018] According to the present invention, the air-stable N-type single-walled carbon nanotube thermoelectric thin film, its preparation method and its application, the present invention transforms the semiconductor behavior of the stacked thin film from P-type to N-type by adding polyethyleneimine. At the same time, based on the stacked structure of the present invention and the introduction of poly(benzodifurandione), N-type single-walled carbon nanotubes are prepared while also possessing good air stability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the chemical structure of single-walled carbon nanotubes, polyethyleneimine, and poly(benzodifurandione) in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the vacuum filtration and solvent post-treatment process in an embodiment of the present invention;

[0021] Figure 3 The thermoelectric properties of the laminated filtration membrane and the physically mixed membrane in Embodiment 1 of the present invention;

[0022] Figure 4 The thermoelectric properties of the polyethyleneimine laminated filtration membranes with and without the addition of polyethyleneimine in Examples 1-2 of the present invention;

[0023] Figure 5 The thermoelectric properties of the thin films post-treated at different temperatures in Examples 1 and 4 of the present invention; and

[0024] Figure 6 This refers to the long-term stability of the thin film in Example 1 of the present invention. Detailed Implementation

[0025] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the air-stable N-type single-walled carbon nanotube thermoelectric thin film, its preparation method and its application.

[0026] Figure 1 This is a schematic diagram of the chemical structure of single-walled carbon nanotubes, polyethyleneimine, and poly(benzodifurandione) in an embodiment of the present invention. Figure 2This is a schematic diagram of the vacuum filtration and solvent post-treatment process in an embodiment of the present invention.

[0027] Example 1

[0028] S1, the dispersion of single-walled carbon nanotubes and poly(benzodifurandione) was diluted to 0.2 mg / mL to obtain a single-walled carbon nanotube solution and a poly(benzodifurandione) dispersion.

[0029] S2, add 1 mL of polyethyleneimine solution to the single-walled carbon nanotube dispersion, stir at room temperature for 24 hours, and then vacuum filter the diluted single-walled carbon nanotube dispersion through a microporous membrane with a pore size of 0.45 μm to obtain film A.

[0030] S3, introduce poly(benzodifurandione) dispersion into film A, filter under vacuum and dry under vacuum at 60°C for 1 hour to obtain film B with a multilayer structure.

[0031] S4. Prepare a polyethyleneimine / dimethyl sulfoxide mixed solution with a mass concentration of 25 mg / mL as a post-treatment solution, place film B in it, heat to 100℃ and hold for 12 hours to obtain N-type single-walled carbon nanotube thermoelectric film.

[0032] Example 2

[0033] This embodiment omits step S4, based on embodiment 1.

[0034] Example 3

[0035] Based on Example 1, this embodiment omits step S4 and replaces step S2 with "vacuum filtration of the diluted single-walled carbon nanotube dispersion through a microporous membrane with a pore size of 0.45 μm to obtain film A".

[0036] Example 4

[0037] Based on Example 1, this embodiment replaces "place film B in it and heat to 100°C for 12 hours" in step 4 with "place film B in it and keep at room temperature for 12 hours".

[0038] Figure 3 The thermoelectric properties of the stacked filtration membrane and the physically mixed membrane in Embodiment 1 of the present invention are described.

[0039] like Figure 3 As shown, compared to direct physical mixing, the multilayered thin film exhibits better thermoelectric properties.

[0040] Figure 4 The thermoelectric properties of the polyethyleneimine laminated filtration membranes with and without the addition of polyethyleneimine are described in Examples 1-2 of the present invention.

[0041] like Figure 4 As shown, the addition of polyethyleneimine can better transform the semiconductor behavior of the multilayer film from P-type to N-type.

[0042] Figure 5 These are the thermoelectric properties of the thin films after different temperature post-treatments in Examples 1 and 4 of the present invention.

[0043] like Figure 5 As shown, post-treatment with increased temperature can further improve the thermoelectric properties of N-type multilayer films.

[0044] Figure 6 This refers to the long-term stability of the thin film in Example 1 of the present invention.

[0045] like Figure 6 As shown, the thermoelectric properties of the laminated thin film treated with heating exhibit better stability.

[0046] The role and effect of the embodiments

[0047] According to the present invention, the air-stable N-type single-walled carbon nanotube thermoelectric thin film, its preparation method and its application, the present invention transforms the semiconductor behavior of the stacked thin film from P-type to N-type by adding polyethyleneimine. At the same time, based on the stacked structure of the present invention and the introduction of poly(benzodifurandione), N-type single-walled carbon nanotubes are prepared while also possessing good air stability.

[0048] The thin film prepared by this invention has broad application prospects in the field of low-grade thermoelectric energy harvesting at room temperature.

[0049] In the post-processing stage, this invention combines polyethyleneimine and other solvents to effectively improve the stability and thermoelectric properties of single-walled carbon nanotube films, making them suitable for applications in flexible electronic devices and energy conversion.

[0050] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an air-stabilized N-type single-walled carbon nanotube thermoelectric thin film, characterized in that, Specifically, the steps include the following: S1, single-walled carbon nanotubes and poly(benzodifurandione) are diluted to a certain concentration to obtain a single-walled carbon nanotube dispersion and a poly(benzodifurandione) dispersion. S2, add polyethyleneimine solution to the single-walled carbon nanotube dispersion, stir at room temperature for 20-30 h, mix evenly and then filter under vacuum to obtain film A; S3, the poly(benzodifurandione) dispersion is introduced into film A and filtered to obtain film B with a multilayer structure; S4. Immerse the film B in the post-treatment solution for post-treatment, and then remove it and vacuum dry it at 50-70℃ for 0.5-1.5h to obtain the final product.

2. The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films according to claim 1, characterized in that: in, In step S1, the dispersion solvent of the single-walled carbon nanotube dispersion is a polar solvent.

3. The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films according to claim 2, characterized in that: in, The polar solvent is water or N-methyl-2-pyrrolidone.

4. The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films according to claim 1, characterized in that: in, The concentrations of the single-walled carbon nanotube dispersion and the poly(benzodifurandione) dispersion are both 0.1-0.3 mg / mL.

5. The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films according to claim 1, characterized in that: in, In step S4, the post-treatment solution is a polyethyleneimine solution, and the dispersing solvent of the polyethyleneimine solution is at least one of N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, water, and ethanol.

6. The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films according to claim 1, characterized in that: in, In step S4, the specific steps of the post-treatment are as follows: the post-treatment solution without film B is heated to 15-200℃ and maintained for 8-24 hours.

7. The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films according to claim 1, characterized in that: in, In step S2, the specific steps of vacuum filtration are as follows: the single-walled carbon nanotube dispersion is vacuum filtered through a microporous filter membrane.

8. The method for preparing air-stabilized N-type single-walled carbon nanotube thermoelectric thin films according to claim 7, characterized in that: in, The microporous filter membrane has a pore size of 0.4-0.5 μm.

9. The air-stabilized N-type single-walled carbon nanotube thermoelectric thin film according to claim 1, characterized in that: The air-stabilized N-type single-walled carbon nanotube thermoelectric thin film was prepared by the method described in any one of claims 1-8.

10. The application of an air-stabilized N-type single-walled carbon nanotube thermoelectric thin film as described in claim 9 in flexible electronic devices.

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