A strong texture N-type bismuth telluride material regulated by configuration entropy and a preparation method thereof

Abstract

The application discloses a strong-textured N-type bismuth telluride material regulated by configuration entropy and a preparation method thereof, and belongs to the technical field of thermoelectric materials. 1‑x (Sb2Se2S) x +y at.% BiBr3, wherein x=0.05-0.20 and y=0.18-0.24; the method comprises the following steps: firstly, weighing and mixing; secondly, introducing the mixed powder into a quartz ampoule and vacuum sealing; and thirdly, increasing temperature, keeping temperature and decreasing temperature.The application is used for regulating the strong-textured N-type bismuth telluride material induced by configuration entropy and preparing the same.

Description

Technical Field

[0001] This invention belongs to the field of thermoelectric materials technology. Background Technology

[0002] Thermoelectric materials are functional materials that utilize the Seebeck and Peltier effects to convert heat energy into electrical energy. Due to their small size, lack of noise, and zero greenhouse gas emissions, they have been widely used in emerging fields such as 5G optical communication, IC refrigeration, the Internet of Things, and self-powered wearable terminals. Among numerous thermoelectric material systems, bismuth telluride-based alloys and their solid solutions are currently the only commercially available thermoelectric materials due to their excellent thermoelectric properties near room temperature. However, the five-atom-layer structure of bismuth telluride determines its inherent anisotropy, while in N-type Bi₂Te… 3-x Se x In alloy systems, the electrical conductivity along the ab axis is 3 to 7 times that along the c axis, while the thermal conductivity along the ab axis is about twice that along the c axis. This results in a thermoelectric figure of merit along the ab axis being 1.5 to 2 times that along the c axis. Therefore, texturing along the ab axis can clearly define the direction of high thermoelectric figure of merit in the crystal, which is an essential requirement for optimizing the thermoelectric properties of N-type bismuth telluride. Among various texturing strategies, the zone melting method, with its advantages of no crucible contact, short preparation cycle, and high yield, has become one of the most commonly used methods in the industry to construct bismuth telluride textures. However, in the process of preparing bismuth telluride using the zone melting method, the uneven temperature gradient often leads to poor texture (texture degree F less than 0.2) in about one-third of the total amount of the ingot at the beginning and end, significantly deteriorating the thermoelectric properties and causing a large amount of waste in production.

[0003] CN114447201A discloses a method for synthesizing bismuth telluride-based semiconductor thermoelectric materials. The material processing steps are as follows: 1) an induction-coupled assisted zone melting-directional solidification vertical zone melting method; 2) a high-density nucleus rapid formation method; and 3) an argon pressure-modulated solid-liquid-vapor volume ratio control method. By controlling the nucleation and growth process of the crystal through modulation of the growth front temperature gradient, the supercooled melt temperature, and the volume ratio of the three aggregated states (solid, liquid, and vapor) at the crystallization front, a bismuth telluride-based rod-shaped thermoelectric material with nanocrystal inhomogeneity ≤5% along the crystal growth direction was obtained. However, its complex processing and insufficient texturing characteristics still largely limit the thermoelectric performance of N-type bismuth telluride. Summary of the Invention

[0004] This invention aims to solve the problems of complex processing and non-uniform texture of existing zone-melted bismuth telluride-based thermoelectric materials, and further provides a strongly textured N-type bismuth telluride material with controlled configuration entropy and its preparation method.

[0005] A strongly textured N-type bismuth telluride material with regulated configurational entropy-induced properties, its general chemical formula is (Bi₂Te₃). 1-x (Sb2Se2S) x +y at.%BiBr3;where x=0.05~0.20,y=0.18~0.24。

[0006] A method for preparing strongly textured N-type bismuth telluride materials with controlled configuration entropy-induced properties, comprising the following steps:

[0007] I. According to the general chemical formula (Bi2Te3) 1-x (Sb2Se2S) x The stoichiometric ratio of BiBr3 is as follows: Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder are weighed and mixed to obtain a mixed powder; where x = 0.05~0.20, y = 0.18~0.24;

[0008] 2. The mixed powder is introduced into a pointed-bottom quartz tube and vacuum sealed to obtain a sealed pointed-bottom quartz tube;

[0009] 3. Place the sealed pointed-bottom quartz tube in a muffle furnace and hold it at 700℃~1000℃ for 2h~20h. Then, cool it down to 400℃~650℃ at a cooling rate of 0.01℃ / min~10℃ / min. Then, cool it down to 400℃~600℃ at a cooling rate of 0.01℃ / min~10℃ / min. Finally, cool it down to room temperature with the furnace to obtain a strongly textured N-type bismuth telluride material with controlled configuration entropy.

[0010] The beneficial effects of this invention are:

[0011] 1. In terms of formulation, this invention effectively expands the band gap of the thermoelectric material by adjusting the content of (Sb₂Se₂S), while simultaneously increasing the configurational entropy of the material system. This results in a stable single-phase structure while significantly improving the high-temperature performance of the material. Furthermore, by adjusting the doping amount of BiBr₃ to control the carrier concentration, the thermoelectric figure of merit of the material is further improved.

[0012] 2. In terms of preparation process, the present invention adopts slow cooling directional solidification growth and prepares N-type bismuth telluride material with strong texture through configuration entropy induction.

[0013] 3. The preparation process adopted in this invention is simple and easy to implement, with low production cost and high single-tube output. It does not require complex and expensive equipment. The growth process of strongly textured N-type bismuth telluride material does not require human intervention. The preparation process has good repeatability and is suitable for mass production of large single crystals.

[0014] 4. The strongly textured N-type bismuth telluride material (Bi2Te3) prepared by this invention1-x (Sb2Se2S) x +y at.%BiBr3 (x=0.05~0.20,y=0.18~0.24), through adjustment, the thermoelectric figure of merit can be achieved to reach 1.15 at 323K, 1.05 at 373K, or 0.95 at 473K, respectively, thus broadening the application of bismuth telluride thermoelectric materials across the entire temperature range. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the heating-holding-cooling process in the muffle furnace during step three of Example 1.

[0016] Figure 2 The images show the XRD patterns of the strongly textured N-type bismuth telluride material with regulated configuration entropy induced by Example 1, along the direction perpendicular to the grain growth direction and along the direction parallel to the grain growth direction. 1 is along the direction parallel to the grain growth direction, and 2 is along the direction perpendicular to the grain growth direction.

[0017] Figure 3 The images show backscattered diffraction (EBSD) images of the strongly textured N-type bismuth telluride material with regulated configuration entropy induced by Example 1, along the direction perpendicular to the grain growth direction and along the direction parallel to the grain growth direction. 1 is the EBSD image along the direction parallel to the grain growth direction, and 2 is the EBSD image along the direction perpendicular to the grain growth direction.

[0018] Figure 4 The images show the macroscopic morphology of the strongly textured N-type bismuth telluride materials induced by controlled configuration entropy prepared in Examples 1 to 3, and the bismuth telluride materials prepared in the comparative experiment. a) is the top surface of the bismuth telluride material prepared in the comparative experiment; b) is the crystal cleavage along the van der Waals layer of the bismuth telluride material prepared in the comparative experiment; c) is the top surface of the strongly textured N-type bismuth telluride material induced by controlled configuration entropy prepared in Example 1; d) is the appearance of the strongly textured N-type bismuth telluride material induced by controlled configuration entropy prepared in Example 1; e) is the crystal cleavage surface along the van der Waals layer of the strongly textured N-type bismuth telluride material induced by controlled configuration entropy prepared in Example 1; f) is the cleavage surface of the bismuth telluride material prepared in Example 2. The top surface of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation, g is the appearance of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation prepared in Example 2, h is the crystal cleavage plane of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation prepared in Example 2 along the van der Waals layer, i is the top surface of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation prepared in Example 3, j is the longitudinal section (j-1) of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation prepared in Example 3, the sample obtained after cutting for thermal conductivity characterization (j-2), and the sample obtained after cutting for electrical conductivity and Seebeck coefficient characterization (j-3).

[0019] Figure 5The graphs show the relationship between the thermoelectric figure of merit and temperature for the strongly textured N-type bismuth telluride materials with regulated configuration entropy induced by Examples 1 to 3 and the bismuth telluride materials prepared by comparative experiments. Detailed Implementation

[0020] Specific Implementation Method 1: This implementation method describes a strongly textured N-type bismuth telluride material induced by controlled configuration entropy, with the general chemical formula (Bi₂Te₃). 1-x (Sb2Se2S) x +y at.%BiBr3;where x=0.05~0.20,y=0.18~0.24。

[0021] The beneficial effects of this embodiment are:

[0022] 1. Regarding the formulation, this embodiment effectively expands the band gap of the thermoelectric material by adjusting the content of (Sb2Se2S), while simultaneously increasing the configurational entropy of the material system. This results in a stable single-phase structure while significantly improving the high-temperature performance of the material. Furthermore, by adjusting the doping amount of BiBr3 to control the carrier concentration, the thermoelectric figure of merit of the material is further improved.

[0023] 2. In terms of preparation process, this embodiment adopts slow cooling directional solidification growth, and prepares N-type bismuth telluride material with strong texture through configuration entropy induction.

[0024] 3. The preparation process used in this embodiment is simple and easy to implement, with low production cost and high single-tube output. It does not require complex and expensive equipment. The growth process of strongly textured N-type bismuth telluride material does not require human intervention. The preparation process has good repeatability and is suitable for mass production of large single crystals.

[0025] 4. The strongly textured N-type bismuth telluride material (Bi2Te3) prepared in this embodiment. 1-x (Sb2Se2S) x +y at.%BiBr3 (x=0.05~0.20,y=0.18~0.24), through adjustment, the thermoelectric figure of merit can be achieved to reach 1.15 at 323K, 1.05 at 373K, or 0.95 at 473K, respectively, thus broadening the application of bismuth telluride thermoelectric materials across the entire temperature range.

[0026] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that its chemical formula is (Bi2Te3). 0.95 (Sb2Se2S) 0.05 +0.18 at.% BiBr3. Everything else is the same as in Specific Implementation Method 1.

[0027] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that its chemical formula is (Bi2Te3).0.9 (Sb2Se2S) 0.1 +0.21 at.% BiBr3. Other details are the same as in specific implementation method one or two.

[0028] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that its chemical formula is (Bi2Te3). 0.8 (Sb2Se2S) 0.2 +0.24 at.% BiBr3. Other details are the same as in embodiments one through three.

[0029] Specific Implementation Method 5: This implementation method provides a method for preparing strongly textured N-type bismuth telluride materials induced by controlled configuration entropy, which is carried out according to the following steps:

[0030] I. According to the general chemical formula (Bi2Te3) 1-x (Sb2Se2S) x The stoichiometric ratio of BiBr3 is as follows: Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder are weighed and mixed to obtain a mixed powder; where x = 0.05~0.20, y = 0.18~0.24;

[0031] 2. The mixed powder is introduced into a pointed-bottom quartz tube and vacuum sealed to obtain a sealed pointed-bottom quartz tube;

[0032] 3. Place the sealed pointed-bottom quartz tube in a muffle furnace and hold it at 700℃~1000℃ for 2h~20h. Then, cool it down to 400℃~650℃ at a cooling rate of 0.01℃ / min~10℃ / min. Then, cool it down to 400℃~600℃ at a cooling rate of 0.01℃ / min~10℃ / min. Finally, cool it down to room temperature with the furnace to obtain a strongly textured N-type bismuth telluride material with controlled configuration entropy.

[0033] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that the purity of the Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder mentioned in step one is all 99.999%. Everything else is the same as in Specific Implementation Method Five.

[0034] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Five or Six in that: the Bi particles in step one have a particle size of 0.01mm to 2mm; the Te blocks in step one have a particle size of 0.5mm to 5mm; the Se particles in step one have a particle size of 0.01mm to 2mm; the Sb blocks in step one have a particle size of 0.5mm to 5mm; the S powder in step one has a particle size of 0.005mm to 0.1mm; and the BiBr3 powder in step one has a particle size of 0.001mm to 0.1mm. Everything else is the same as in Specific Implementation Method Five or Six.

[0035] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods Five to Seven in that, in step three, the sealed pointed-bottom quartz tube is placed vertically into the muffle furnace. Everything else is the same as in Specific Implementation Methods Five to Seven.

[0036] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Five to Eight in that, in step three, the temperature is increased to 700℃ to 1000℃ at a heating rate of 0.1℃ / min to 10℃ / min. Everything else is the same as in Specific Implementation Methods Five to Eight.

[0037] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Five to Nine in that: in step three, the temperature is first increased to 800°C at a heating rate of 5°C / min, held at 800°C for 8 hours, then decreased to 620°C at a cooling rate of 5°C / min, and finally decreased to 550°C at a cooling rate of 0.02°C / min. Everything else is the same as in Specific Implementation Methods Five to Nine.

[0038] The beneficial effects of the present invention are verified using the following embodiments:

[0039] Example 1, combined with Figure 1 Detailed explanation:

[0040] A method for preparing strongly textured N-type bismuth telluride materials with controlled configuration entropy-induced properties, comprising the following steps:

[0041] I. Based on the chemical formula (Bi2Te3) 0.95 (Sb2Se2S) 0.05 Weigh out Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder in a stoichiometric ratio of +0.18 at.% to obtain a mixed powder;

[0042] 2. The mixed powder is introduced into a pointed-bottom quartz tube and vacuum sealed to obtain a sealed pointed-bottom quartz tube;

[0043] 3. The sealed pointed-bottom quartz tube is placed vertically in a muffle furnace. The temperature is first increased to 800℃ at a rate of 5℃ / min, and then held at 800℃ for 8 hours. The temperature is then decreased to 620℃ at a rate of 5℃ / min, and then decreased to 550℃ at a rate of 0.02℃ / min. Finally, the temperature is cooled to room temperature with the furnace to obtain a strongly textured N-type bismuth telluride material with controlled configuration entropy.

[0044] The purity of Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder mentioned in step one is all 99.999%.

[0045] The average particle size of Bi particles mentioned in step one is 2 mm; the average particle size of Te blocks mentioned in step one is 3 mm; the average particle size of Se particles mentioned in step one is 2 mm; the average particle size of Sb blocks mentioned in step one is 1 mm; the average particle size of S powder mentioned in step one is 0.1 mm; and the average particle size of BiBr3 powder mentioned in step one is 0.05 mm.

[0046] The vacuum sealing pressure in step two is 3 × 10⁻⁶. -3 Pa.

[0047] Example 2: This example differs from Example 1 in that: in step one, the chemical formula (Bi2Te3) is used. 0.9 (Sb2Se2S) 0.1 Weigh out Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder at a stoichiometric ratio of +0.21 at.% BiBr3 and mix them to obtain a mixed powder. Other steps are the same as in Example 1.

[0048] Example 3: This example differs from Example 1 in that: in step one, the chemical formula (Bi2Te3) is used. 0.8 (Sb2Se2S) 0.2 Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder were weighed and mixed at a stoichiometric ratio of +0.24 at.% BiBr3 to obtain a mixed powder. Other steps were the same as in Example 1.

[0049] Comparative experiment: This embodiment differs from Embodiment 1 in that: in step one, Bi particles and Te blocks are weighed and mixed according to the stoichiometric ratio of Bi₂Te₃ to obtain a mixed powder; in step three, bismuth telluride material is obtained. Everything else is the same as in Embodiment 1.

[0050] Figure 2The images show the XRD patterns of the strongly textured N-type bismuth telluride material prepared in Example 1, induced by controlled configuration entropy, along the direction perpendicular to and parallel to the grain growth direction. Image 1 shows the pattern parallel to the grain growth direction, and image 2 shows the pattern perpendicular to the grain growth direction. As can be seen from the image, the diffraction peaks in line 1 (006), (0012), (0015), and (0018) are all from the (00L) crystal plane family, with an orientation factor F of approximately 1. There are no other diffraction peaks from non-(00L) crystal plane families, indicating that the sample has a relatively uniform microstructure, approaching single-crystal level. Line 2 shows diffraction peaks such as (015) that are different from the (00L) crystal plane family, indicating that there may be orientation differences along the growth direction. Overall, the XRD results show that the N-type bismuth telluride material prepared by this method has a high degree of texture along the growth direction.

[0051] Figure 3 The images show backscattered electron diffraction (EBSD) images of the strongly textured N-type bismuth telluride material prepared in Example 1, induced by controlled configuration entropy, along the direction perpendicular to and parallel to the grain growth direction. Image 1 shows the EBSD image along the direction parallel to the grain growth direction, and image 2 shows the EBSD image along the direction perpendicular to the grain growth direction. The backscattered electron diffraction results along the direction parallel to the grain growth direction show that the plane completely exhibits a single orientation composed of (001) crystal planes, corresponding to the XRD results. The results along the direction perpendicular to the grain growth direction show that within a region, four indices (1-100) perpendicular to the (001) crystal plane can be observed. Considering the combined EBSD results, the N-type bismuth telluride material prepared by this method has a high texture along the growth direction, approaching the level of a single crystal.

[0052] Figure 4The images show the macroscopic morphology of the strongly textured N-type bismuth telluride materials induced by controlled configuration entropy prepared in Examples 1 to 3, and the bismuth telluride materials prepared in the comparative experiment. a) is the top surface of the bismuth telluride material prepared in the comparative experiment; b) is the crystal cleavage along the van der Waals layer of the bismuth telluride material prepared in the comparative experiment; c) is the top surface of the strongly textured N-type bismuth telluride material induced by controlled configuration entropy prepared in Example 1; d) is the appearance of the strongly textured N-type bismuth telluride material induced by controlled configuration entropy prepared in Example 1; e) is the crystal cleavage surface along the van der Waals layer of the strongly textured N-type bismuth telluride material induced by controlled configuration entropy prepared in Example 1; f) is the cleavage surface of the bismuth telluride material prepared in Example 2. The top surface of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation is shown in Figure 2. g represents the appearance of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation prepared in Example 2. h represents the crystal cleavage plane cleaved along the van der Waals layer of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation prepared in Example 2. i represents the top surface of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation prepared in Example 3. j represents the longitudinal section (j-1) of the strongly textured N-type bismuth telluride material induced by configurational entropy regulation prepared in Example 3, the sample obtained after cutting for thermal conductivity characterization (j-2), and the sample obtained after cutting for electrical conductivity and Seebeck coefficient characterization (j-3). As shown in Figure a, the comparative experiment, which did not undergo elemental doping and configurational entropy control according to the present invention, exhibits a relatively chaotic microstructure on the top surface of the sample. Figure b shows that while the bismuth telluride material prepared in the comparative experiment exhibits a layered structure along the van der Waals layers, it is difficult to obtain complete layered crystals of good quality and large size. The layered structures of some crystals are perpendicular to each other, exhibiting a large orientation difference angle. It can be considered that in crystals without elemental doping and configurational entropy control according to the present invention, the microstructure is relatively chaotic and the orientation is poor. Figure c, compared to Figure a, shows that the sample of Example 1 clearly obtained a layered structure concentrated in the same direction, with a significantly improved texture. Figure e clearly shows specular reflection, and this specular reflection extends from the top to the bottom of the sample, achieving full coverage. This indicates that the sample of Example 1, after elemental doping and configurational entropy control, obtained a high-quality layered structure with high texture. Figures f, g, and h show that the results of Example 2 are highly similar to those of Example 1. As can be seen from the cuboid in Figure j-3, it still has obvious mirror features, proving that Example 3 also retains strong texture.

[0053] Figure 5The graphs show the thermoelectric figure of merit (TGM) versus temperature for the strongly textured N-type bismuth telluride materials prepared in Examples 1-3 with controlled configuration entropy and the bismuth telluride materials prepared in the comparative experiment. The TGM results for all samples were characterized along the crystal growth direction. As shown in the graphs, the material prepared in the comparative experiment, due to the lack of bandgap control and microstructure optimization, has a TGM of only 0.64 at 300 K. In contrast, the strongly textured N-type bismuth telluride materials prepared through elemental doping and controlled configuration entropy in the examples exhibit excellent thermoelectric performance. Specifically, the sample in Example 1 achieves a TGM of 1.15 at 323 K; the sample in Example 2, due to further increasing the bandgap, shows a peak TGM shifting to 1.05 at 373 K; and the sample in Example 3, for the same reason, achieves a TGM of 0.95 at 473 K. The thermoelectric performance of the samples from all three examples is significantly higher than that of the material prepared in the comparative experiment without compositional control and microstructure optimization.

Claims

1. A strongly textured N-type bismuth telluride material with regulated configuration entropy-induced properties, characterized in that... Its general chemical formula is (Bi₂Te₃). 1-x (Sb2Se2S) x +y at.%BiBr3; where x = 0.05~0.20, y = 0.18~0.24; Furthermore, the strongly textured N-type bismuth telluride material induced by controlled configuration entropy is prepared according to the following steps: I. According to the general chemical formula (Bi2Te3) 1-x (Sb2Se2S) x The stoichiometric ratio of BiBr3 is as follows: Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder are weighed and mixed to obtain a mixed powder; where x = 0.05~0.20, y = 0.18~0.

24.

2. The mixed powder is introduced into a pointed-bottom quartz tube and vacuum sealed to obtain a sealed pointed-bottom quartz tube; 3. Place the sealed pointed-bottom quartz tube in a muffle furnace and heat it to 700℃~1000℃ at a heating rate of 0.1℃ / min~10℃ / min. Hold it at 700℃~1000℃ for 2h~20h, then cool it down to 400℃~650℃ at a cooling rate of 0.01℃ / min~10℃ / min, then cool it down to 400℃~600℃ at a cooling rate of 0.01℃ / min~10℃ / min, and finally cool it down to room temperature with the furnace to obtain a strongly textured N-type bismuth telluride material with controlled configuration entropy.

2. The strongly textured N-type bismuth telluride material with regulated configuration entropy-induced properties according to claim 1, characterized in that... Its chemical formula is (Bi₂Te₃). 0.95 (Sb2Se2S) 0.05 +0.18at.%BiBr3.

3. The strongly textured N-type bismuth telluride material with regulated configuration entropy-induced properties according to claim 1, characterized in that... Its chemical formula is (Bi₂Te₃). 0.9 (Sb2Se2S) 0.1 +0.21at.%BiBr3.

4. The strongly textured N-type bismuth telluride material with regulated configuration entropy-induced properties according to claim 1, characterized in that... Its chemical formula is (Bi₂Te₃). 0.8 (Sb2Se2S) 0.2 +0.24at.%BiBr3.

5. The strongly textured N-type bismuth telluride material with regulated configuration entropy-induced properties according to claim 1, characterized in that... The purity of Bi granules, Te blocks, Se granules, Sb blocks, S powder, and BiBr3 powder mentioned in step one is 99.999%.

6. The strongly textured N-type bismuth telluride material with regulated configuration entropy-induced properties according to claim 1, characterized in that... The Bi particles mentioned in step one have a particle size of 0.01mm~2mm; the Te blocks mentioned in step one have a particle size of 0.5mm~5mm; the Se particles mentioned in step one have a particle size of 0.01mm~2mm; the Sb blocks mentioned in step one have a particle size of 0.5mm~5mm; the S powder mentioned in step one has a particle size of 0.005mm~0.1mm; and the BiBr3 powder mentioned in step one has a particle size of 0.001mm~0.1mm.

7. The strongly textured N-type bismuth telluride material with regulated configuration entropy-induced properties according to claim 1, characterized in that... In step three, the sealed pointed-bottom quartz tube is placed vertically into the muffle furnace.

8. The strongly textured N-type bismuth telluride material with regulated configuration entropy-induced properties according to claim 1, characterized in that... In step three, the temperature is first increased to 800℃ at a rate of 5℃ / min, and then held at 800℃ for 8 hours. The temperature is then decreased to 620℃ at a rate of 5℃ / min, and finally decreased to 550℃ at a rate of 0.02℃ / min.

Images