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Antisite defect manipulation enables the high thermoelectric performance of p-type Bi2-xSbxTe3 alloys for solid-state refrigeration
Materials Today Physics ( IF 11.5 ) Pub Date : 2022-06-18 , DOI: 10.1016/j.mtphys.2022.100764
Shan Li , Xingce Fang , Tu Lyu , Jiahui Cheng , Weiqin Ao , Chaohua Zhang , Fusheng Liu , Junqin Li , Lipeng Hu

In thermoelectrics, carrier concentration, carrier mobility, density-of-state effective mass, and lattice thermal conductivity are all intimately associated with native point defects. Taking p-type Bi0.4Sb1.6Te3 polycrystal as an example, the excessive antisite defects results in too high carrier concentration and inferior carrier mobility. Herein the constructive role of antisite defect manipulation for enhancing thermoelectric performance of Bi0.4Sb1.6Te3 is reported. We explored the thermoelectric study of sole Gallium or Indium-doped p-type Bi0.4Sb1.6Te3 in two distinct compositional series: Bi0.4Sb1.6-xGaxTe3 and Bi0.4Sb1.6-yInyTe3, aka the x-series and y-series. In x-series, the fine-tuning of antisite defects is achieved for the first time via the reciprocal variation of electronegativity difference and atomic size difference between cations and anions on the grounds of chemical composition-regulated (χ, r) model. Compared to the dramatic reduction of antisite defect concentration for y-series, the slightly declined antisite defect concentration for x-series contributes to a more optimized carrier concentration and superior material parameter. In addition, the generated multiscale microstructures induced by Ga doping and hot deformation substantially diminish the lattice thermal conductivity through broad wavelength phonon scattering. As a result, a state-of-the-art zT = 1.47 at 350 K is attained in p-type Bi0.4Sb1.59Ga0.01Te3, indicating the potential advantages in solid-state refrigeration field. These results not only attest to the efficacy of native point defect engineering in V2VI3 and other thermoelectric materials, but also bring out the understanding and manipulation of native point defect to a new level.



中文翻译:

反位缺陷操纵使 p 型 Bi2-xSbxTe3 合金具有高热电性能,用于固态制冷

在热电中,载流子浓度、载流子迁移率、状态密度有效质量和晶格热导率都与自然点缺陷密切相关。以p型Bi 0.4 Sb 1.6 Te 3多晶为例,过多的反位缺陷导致载流子浓度过高,载流子迁移率变差。本文报道了反位缺陷操作对提高 Bi 0.4 Sb 1.6 Te 3热电性能的建设性作用。我们探索了单独的镓或铟掺杂p型Bi 0.4 Sb 1.6 Te 3的热电研究在两个不同的组成系列中:Bi 0.4 Sb 1.6- x Ga x Te 3和 Bi 0.4 Sb 1.6- y In y Te 3,又名x系列和y系列。在x系列中,首次基于化学成分调节( χ , r )模型,通过阳离子和阴离子之间的电负性差和原子尺寸差的倒数变化实现了反位缺陷的微调。与y的反位缺陷浓度显着降低相比- 系列, x系列略微下降的反位缺陷浓度有助于更优化的载流子浓度和优越的材料参数。此外,由 Ga 掺杂和热变形引起的多尺度微结构通过宽波长声子散射显着降低了晶格热导率。结果,p型Bi 0.4 Sb 1.59 Ga 0.01 Te 3 在350 K时达到了最先进的zT = 1.47 ,表明了在固态制冷领域的潜在优势。这些结果不仅证明了 V 2 VI 3中原生点缺陷工程的功效等热电材料,也将本征点缺陷的认识和操纵提升到了一个新的水平。

更新日期:2022-06-23
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