High-quality flexible n-type cu-doped bismuth antimony thermoelectric thin film and preparation method thereof

Abstract

The application discloses a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film and a preparation method thereof. The preparation method comprises the following steps: firstly, a Bi / Cu mixed film is prepared on a flexible substrate by adopting a Bi and Cu target material and a magnetron co-sputtering technology, and the content of Bi and Cu is adjusted by adjusting the sputtering power and sputtering time of the elemental metal Bi and elemental metal Cu target material; then, a Te single-element film is prepared by adopting a Te single-element target material and a magnetron sputtering technology; finally, the prepared Bi / Cu mixed film and the Te single-element film are laminated, and heating is performed at the bottom, so that a flexible n-type Cu-doped Bi2Te3 thermoelectric film with high preferred orientation is finally prepared. The method is simple and convenient for preparing the film, greatly simplifies the film preparation process, has low preparation cost, and can realize industrialized production. The film prepared by the method has high quality, good repeatability, and is easy to control the film composition and film growth orientation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermoelectric materials, in particular to a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film and a preparation method thereof. BACKGROUND

[0002] Thermoelectric materials are a kind of functional materials capable of directly converting thermal energy and electrical energy, and thermoelectric devices prepared therefrom can be widely applied in the fields of semiconductor power generation, refrigeration, etc. In recent years, due to the rapid development of micro semiconductor devices and wearable electronic products, thermoelectric materials and devices have been transformed towards miniaturization, microminiaturization and flexibility. Among them, thermoelectric films prepared on the basis of inorganic materials have more application prospects in the field of portable / wearable devices due to their small size, light weight and easy realization of miniaturization, and thus have gradually become one of the frontiers of current research in the field of thermoelectric technology.

[0003] n-type Bi2Te3-based thermoelectric materials are one of the best thermoelectric material systems at room temperature, but their flexible film performance is still poor, which restricts their practical application. Therefore, obtaining a flexible n-type Bi2Te3-based thermoelectric film is one of the frontiers of research in this field. In addition, Bi and Te are easily oxidized, and the prepared film material has poor density and many microstructure defects, resulting in that the thermoelectric performance of the current n-type Bi2Te3-based flexible film is still lower than that of its bulk material.

[0004] Therefore, the prior art still needs to be improved and developed. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a high-quality flexible n-type Cu-doped bismuth antimony (Bi2Te3) thermoelectric film and a preparation method thereof, aiming to solve the problem of low thermoelectric performance of the existing n-type Bi2Te3-based flexible film.

[0006] The technical scheme of the present application is as follows:

[0007] In a first aspect of the present application, a preparation method of a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film is provided, wherein the method comprises the following steps:

[0008] Bi target material and Cu target material are used as co-sputtering targets, and a Bi / Cu mixed film is prepared on a flexible substrate by using a magnetron co-sputtering technology;

[0009] A Te target material is used as a sputtering target, and a Te single-element film is prepared on a flexible substrate by using a magnetron sputtering technology;

[0010] The Bi / Cu mixed film is bonded with the Te single-element film, and heat treatment is performed, to obtain a flexible n-type Cu-doped Bi2Te3 thermoelectric film.

[0011] Optionally, the flexible substrate is a polyimide flexible substrate.

[0012] Optionally, the content of Bi and Cu in the Bi / Cu mixed film is adjusted by adjusting the sputtering power and sputtering time of the Bi target and the Cu target.

[0013] Optionally, in the magnetic co-sputtering, the sputtering power of the Bi target is 5-30 W, and the sputtering time of the Bi target is 5-100 minutes; the sputtering power of the Cu target is 5-10 W, and the sputtering time of the Cu target is 10 seconds-10 minutes.

[0014] Optionally, in the magnetic sputtering, the sputtering power of the Te target is 10-40 W, and the sputtering time of the Te target is 5-100 minutes.

[0015] Optionally, the heat treatment is performed at a temperature of 300-400 DEG C.

[0016] Optionally, the heat treatment is performed for a time of 10-200 minutes.

[0017] In a second aspect, the application provides a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film, which is prepared by the method of the application.

[0018] Beneficial effects: The application provides a method for preparing a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film. First, Bi and Cu targets are used to prepare a Bi / Cu mixed film on a flexible substrate by using a magnetic co-sputtering technique, and the content of Bi and Cu is adjusted by adjusting the sputtering power and sputtering time of the single-element metal Bi and single-element metal Cu targets; then, a Te single-element film is prepared by using a Te single-element target and a magnetic sputtering technique; finally, the prepared Bi / Cu mixed film is bonded with the Te single-element film, and heating is performed at the bottom, to finally prepare a flexible n-type Cu-doped Bi2Te3 thermoelectric film with high preferred orientation. The thermoelectric film has (00l) preferred orientation, which is beneficial to the transmission of in-plane electrons and improves the electrical transmission performance, thereby improving the thermoelectric performance of the thermoelectric film. In addition, the method for preparing the film is simple and convenient, greatly simplifies the film preparation process, has low preparation cost, and can realize industrialized production. The film prepared by the method has high quality, good repeatability, and is easy to control the film composition and film growth orientation. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1A flowchart of a preparation method of a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film is provided in the embodiments of the present application.

[0020] Figure 2 A crystal structure diagram of the film prepared in specific embodiments 1-4 and a control example 1.

[0021] Figure 3 A comprehensive thermoelectric performance of the film prepared in specific embodiments 1-4 and a control example 1. DETAILED DESCRIPTION

[0022] The present application provides a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film and a preparation method thereof. To make the purpose, technical scheme and effects of the present application clearer and more explicit, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0023] Please refer to Figure 1 The embodiments of the present application provide a preparation method of a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film, which comprises the following steps:

[0024] Bi target material and Cu target material are used as co-sputtering target materials, and a Bi / Cu mixed film is prepared on a flexible substrate by using a magnetron co-sputtering technology.

[0025] A Te target material is used as a sputtering target material, and a Te single-element film is prepared on a flexible substrate by using a magnetron sputtering technology.

[0026] The Bi / Cu mixed film and the Te single-element film are laminated and heat treated to obtain a flexible n-type Cu-doped Bi2Te3 thermoelectric film.

[0027] In the embodiments, a flexible n-type Cu-doped Bi2Te3 thermoelectric film with high preferred orientation is prepared by the above method. The method for preparing the film is simple and convenient, greatly simplifies the film preparation process, has low preparation cost, and can realize industrialized production. The film prepared by the method has high quality, good repeatability, and is easy to control the film composition and film growth orientation.

[0028] In the embodiments, Cu doping is used to first control the carrier concentration of the material, thereby adjusting the electrical transmission performance. In addition, co-sputtering doping is used, and the microstructure of the film changes, having (00l) preferred orientation, which is beneficial to the transmission of in-plane electrons, improves the electrical transmission performance, and further improves the thermoelectric performance of the thermoelectric film.

[0029] In the embodiments, the content of Bi and Cu in the Bi / Cu mixed film can be adjusted by adjusting the sputtering power and sputtering time of the Bi target material and the Cu target material.

[0030] In one embodiment, the sputtering power of the Bi target is 5-30 W, and the sputtering time of the Bi target is 5-100 minutes; the sputtering power of the Cu target is 5-10 W, and the sputtering time of the Cu target is 10 seconds-10 minutes.

[0031] In one embodiment, the sputtering power of the Te target is 10-40 W, and the sputtering time of the Te target is 5-100 minutes.

[0032] In one embodiment, the temperature of the heat treatment is 300-400 ℃.

[0033] In one embodiment, the time of the heat treatment is 10-200 minutes.

[0034] In one embodiment, the flexible substrate is a polyimide flexible substrate, but is not limited thereto.

[0035] The embodiment of the present application provides a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film, wherein the high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film is prepared by using the preparation method of the high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film.

[0036] The present application is further described below through specific examples.

[0037] Example 1

[0038] First, Bi target and Cu target are used as co-sputtering targets, polyimide substrate is used as a flexible substrate, and Bi / Cu mixed film is prepared on the polyimide flexible substrate by using the magnetron co-sputtering technology, the Bi sputtering power is 15 W, and the sputtering time is 30 minutes; the Cu sputtering power is 5 W, and the sputtering time is 15 s. Subsequently, Te target is used as a sputtering target, polyimide substrate is used as a flexible substrate, and Te single-element film is prepared by using the magnetron sputtering technology, the Te sputtering power is 25 W, and the sputtering time is 50 minutes. Finally, the prepared Bi / Cu mixed film and Te single-element film are laminated, and heating is performed at the bottom, the heating temperature is 350 ℃, and finally a flexible n-type Cu-doped Bi2Te3 thermoelectric film with high preferred orientation is prepared.

[0039] Example 2

[0040] The other conditions are the same as those in Example 1, except that the Cu sputtering time is 30 s.

[0041] Example 3

[0042] The other conditions are the same as those in Example 1, except that the Cu sputtering time is 45 s.

[0043] Example 4

[0044] Other conditions are the same as Example 1, except that the Cu sputtering time is 60s.

[0045] Comparative Example 1

[0046] Bi target is used as the co-sputtering target, and polyimide substrate is used as the flexible substrate, and Bi film is prepared on the polyimide flexible substrate by using the magnetron co-sputtering technology, the Bi sputtering power is 15W, and the sputtering time is 30 minutes; then, Te target is used as the sputtering target, and polyimide substrate is used as the flexible substrate, and Te single-element film is prepared by using the magnetron sputtering technology, the Te sputtering power is 25W, and the sputtering time is 50 minutes. Finally, the prepared Bi film and the Te single-element film are laminated, and heating is performed at the bottom, the heating temperature is 350 DEG C, and finally, undoped Bi2Te3 thermoelectric film is prepared.

[0047] Figure 2 The crystal structure diagram of the film prepared in specific examples 1-4 and comparative example 1 is shown. The film crystal structure result shows that by controlling the co-sputtering time of Cu, the preferred orientation of the prepared film is significantly changed.

[0048] Figure 3 The comprehensive thermoelectric performance of the film prepared in specific examples 1-4 and comparative example 1 is shown. The film thermoelectric performance result shows that the thermoelectric performance of different copper sputtering time is quite different, and the thermoelectric performance is optimal when the Cu sputtering time is 30s.

[0049] In summary, the application provides a high-quality flexible n-type Cu-doped Bi2Te3 thermoelectric film and a preparation method thereof. First, Bi and Cu targets are used, and Bi / Cu mixed film is prepared on the flexible substrate by using the magnetron co-sputtering technology, the content of Bi and Cu is adjusted by adjusting the sputtering power and sputtering time of the single-element metal Bi and single-element metal Cu target; then, Te single-element target is used, and Te single-element film is prepared by using the magnetron sputtering technology; finally, the prepared Bi / Cu mixed film and the Te single-element film are laminated, and heating is performed at the bottom, and finally, a flexible n-type Cu-doped Bi2Te3 thermoelectric film with high preferred orientation is prepared. The method for preparing the film is simple and convenient, greatly simplifies the film preparation process, has low preparation cost, and can realize industrialized production. The film prepared by the method has high quality, good repeatability, and is easy to control the film composition and film growth orientation.

[0050] It should be understood that the application of the application is not limited to the above examples, and those skilled in the art can make improvements or changes according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the application.

Claims

1. A method for preparing a flexible n-type Cu-doped Bi2Te3 thermoelectric thin film, characterized in that, The method comprises the steps of: Bi target and Cu target are used as co-sputtering targets, and a Bi / Cu mixed film is prepared on a flexible substrate by a magnetron co-sputtering technology, wherein the sputtering power of the Bi target is 5-30 W, and the sputtering time of the Bi target is 5-100 minutes; the sputtering power of the Cu target is 5-10 W, and the sputtering time of the Cu target is 10 seconds-10 minutes; A Te target is used as a sputtering target, and a Te single-element film is prepared on a flexible substrate by a magnetron sputtering technology, wherein the sputtering power of the Te target is 10-40 W, and the sputtering time of the Te target is 5-100 minutes; The Bi / Cu mixed film and the Te single-element film are laminated, and heat treatment is performed to obtain a flexible n-type Cu-doped Bi2Te3 thermoelectric film with (001) preferred orientation.

2. The method of claim 1, wherein the method further comprises: The flexible substrate is a polyimide flexible substrate.

3. The method for preparing a flexible n-type Cu-doped Bi₂Te₃ thermoelectric thin film according to claim 1, characterized in that, The content of Bi and Cu in the Bi / Cu mixed film is adjusted by adjusting the sputtering power and sputtering time of the Bi target and the Cu target.

4. The method for preparing a flexible n-type Cu-doped Bi₂Te₃ thermoelectric thin film according to claim 1, characterized in that, The heat treatment temperature is 300-400 DEG C.

5. The method for preparing a flexible n-type Cu-doped Bi₂Te₃ thermoelectric thin film according to claim 1, characterized in that, The heat treatment time is 10-200 minutes.

6. A flexible n-type Cu-doped Bi2Te3 thermoelectric thin film, characterized in that, The flexible n-type Cu-doped Bi2Te3 thermoelectric film is prepared by the method of any one of claims 1-5.

Images