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采用高压烧结技术制备了稀土元素Tb掺杂的n型Bi2Te2.7Se0.3基纳米晶块体热电材料. 将高压烧结成型的样品于633 K真空退火36 h. 研究了Tb掺杂量对样品的晶体结构和热电性能的影响. 结果表明, 高压烧结制备的样品为纳米结构, Tb掺杂使样品的晶胞体积变大, 功率因子增大, 热导率降低, 从而使ZT值提高. Tb掺杂量为x = 0.004是最优的掺杂量, 该掺杂量的高压烧结样品经退火处理后, 于373 K时 ZT值达到最大为0.99, 并且在323—473 K范围内, ZT值均大于0.8, 这对用于温差发电领域具有重要意义.
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关键词:
- 高压烧结 /
- Tb掺杂 /
- n型Bi2Te2.7Se0.3 /
- 热电性能
Nanocrystalline bulk materials n-type (Bi1–xTbx)2(Te0.9Se0.1)3 (x = 0, 0.002, 0.004, 0.008) are fabricated by high pressure sintering (HPS) technique. The HPS samples are then annealed for 36 h in a vacuum at 633 K. The phase compositions and crystal structure of HPS sample are analyzed by X-ray diffraction. The microscopic morphology of HPS sample is observed by field-emission scanning electron microscopy. The electric conductivity, Seebeck coefficient, and thermal conductivity of the HPS sample and annealed sample are measured in a temperature range from room temperature to 473 K. The effects of Tb content on crystal structure and thermoelectric properties of the sample are systematically studied. The results show that HPS sample consists of nanoparticles. With the increase of content of Tb, the cell volume increases. Besides, the power factor increases but thermal conductivity decreases through doping Tb, thus the optimal figure of merit (ZT) value increases. The Tb doping amount of x = 0.004 is an optimal doping amount. At this doping amount, the maximum ZT of 0.29 is achieved, which is enhanced by 32% compared with the ZT value of undoped sample. The thermoelectric performance can be improved significantly by annealing. The thermal conductivity of the annealed sample with x = 0.004 is 0.9 W·m–1·K–1 at 373 K, decreased by 23% compared with the thermal conductivity of HPS sample. Consequently, the ZT value of annealed sample is significantly higher than that of HPS sample. The maximum thermoelectric ZT of 0.99 is achieved for annealed sample with x =0.004 at 373 K. Furthermore, it is worthwhile to note that this annealed sample possesses a ZT value larger than 0.8 when the temperature is higher than 323 K.-
Keywords:
- high pressure sintering /
- Tb-doped /
- n-type Bi2Te2.7Se0.3 /
- thermoelectric properties
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[10] 王善禹, 谢文杰, 李涵, 唐新峰 2010 物理学报 59 8927Google Scholar
Wang S Y, Xie W J, Li H, Tang X F 2010 Acta Phys. Sin. 59 8927Google Scholar
[11] Rong Z Z, Fan X A, Yang F, Cai X Z, Han X W, Li G Q 2016 Mater. Res. Bull. 83 122Google Scholar
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[13] Yu F R, Xu B, Zhang J J, Yu D L, He J L, Liu Z Y, Tian Y J 2012 Mater. Res. Bull. 47 1432Google Scholar
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[16] 徐桂英, 邹平, 王松, 张艳华 2015 稀有金属材料与工程 44 950
Xu G Y, Zou P, Wang S, Zhang Y H 2015 Rare Metal Mat. Eng. 44 950
[17] Sharp J W, Poon S J, Goldsmid H J 2001 Phys. Status Solidi A 187 507Google Scholar
[18] Kim DH, MitaniT 2005 J. Alloys Compd. 399 14Google Scholar
[19] Slack GA, Hussain MA 1991 J. Appl. Phys. 70 2694Google Scholar
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表 1 (Bi1–xTbx)2(Te0.9Se0.1)3 (x = 0, 0.002, 0.004, 0.008)样品的晶格常数
Table 1. Lattice constants of (Bi1–xTbx)2(Te0.9Se0.1)3 (x = 0, 0.002, 0.004, 0.008).
Sample x = 0 x = 0.002 x = 0.004 x = 0.008 a/Å 4.3748 4.38086 4.38205 4.38468 c/Å 30.3456 30.34931 30.35013 30.35389 V/Å3 502.96 504.41 504.70 505.37 表 2 (Bi1–xTbx)2(Te0.9Se0.1)3样品的载流子浓度和迁移率
Table 2. Carrier concentrations and mobility of (Bi1–xTbx)2(Te0.9Se0.1)3 samples.
Samples Carrier concentrationn/1019 cm–3 Carrier mobility μ/cm2·V–1·s–1 x = 0 (HPS) 1.92 197.98 x = 0.002 (HPS) 3.95 133.53 x = 0.004 (HPS) 6.51 95.31 x = 0.008 (HPS) 7.17 92.39 x = 0.004 (Annealed) 1.36 599.34 x = 0.008 (Annealed) 1.77 491.17 -
[1] DiSalvo F J 1999 Science 285 703Google Scholar
[2] Bell L E 2008 Science 321 1457Google Scholar
[3] Wu D, Zhao L D, Hao SQ, Jiang Q K, Zheng F S, Doak J W, Wu H J, Chi H, Gelbstein Y, Uher C, Wolverton C, Kanatzidis M, He J Q 2014 J. Am. Chem. Soc. 136 11412Google Scholar
[4] Zhou Y M, Zhao L D 2017 Adv. Mater. 29 1702676Google Scholar
[5] Chang C, Wu M H, He D S, Pei Y L, Wu C F, Wu X F, Yu H L, Zhu F Y, Wang K D, Chen Y, Wang K D, Huang L, Li J F, He J Q, Zhao L D 2018 Science 360 778Google Scholar
[6] Snyder G J, Toberer E S 2008 Nat. Mater. 7 105Google Scholar
[7] Wang Z L, Akao T, Onda T, Chen Z C 2017 Scripta Mater. 136 111Google Scholar
[8] Pan Y, Wei T R, Cao Q, Li J F 2015 Mater. Sci. Eng. B 197 75Google Scholar
[9] Jiang C P, Fan X A, Feng B, Hu J, Xiang Q S, Li G Q, Li Y W, He Z 2017 J. Alloys Compd. 692 885Google Scholar
[10] 王善禹, 谢文杰, 李涵, 唐新峰 2010 物理学报 59 8927Google Scholar
Wang S Y, Xie W J, Li H, Tang X F 2010 Acta Phys. Sin. 59 8927Google Scholar
[11] Rong Z Z, Fan X A, Yang F, Cai X Z, Han X W, Li G Q 2016 Mater. Res. Bull. 83 122Google Scholar
[12] Xu GY, Niu ST, Wu XF 2012 J. Appl. Phys. 112 073708Google Scholar
[13] Yu F R, Xu B, Zhang J J, Yu D L, He J L, Liu Z Y, Tian Y J 2012 Mater. Res. Bull. 47 1432Google Scholar
[14] May A F, Singh D J, Snyder G J 2009 Phys. Rev. B 79 153101Google Scholar
[15] Zhang Y H, Zhu T J, Tu J P, Zhao X B 2007 Mater. Chem. Phys. 103 484Google Scholar
[16] 徐桂英, 邹平, 王松, 张艳华 2015 稀有金属材料与工程 44 950
Xu G Y, Zou P, Wang S, Zhang Y H 2015 Rare Metal Mat. Eng. 44 950
[17] Sharp J W, Poon S J, Goldsmid H J 2001 Phys. Status Solidi A 187 507Google Scholar
[18] Kim DH, MitaniT 2005 J. Alloys Compd. 399 14Google Scholar
[19] Slack GA, Hussain MA 1991 J. Appl. Phys. 70 2694Google Scholar
[20] Wang SY, Xie WJ, Li H, Tang X F 2011 Intermetallics 19 1024Google Scholar
[21] Wu F, Song H Z, Jia J F, Gao F, Zhang Y J, Hu X 2013 Phys. Status Solidi A 210 1183Google Scholar
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