Synergistic Compositional–Mechanical–Thermal Effects Leading to a Record High zT in n‐Type V2VI3 Alloys Through Progressive Hot Deformation,Advanced Functional Materials

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Synergistic Compositional–Mechanical–Thermal Effects Leading to a Record High zT in n‐Type V2VI3 Alloys Through Progressive Hot Deformation
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2018-07-13 , DOI: 10.1002/adfm.201803617
Lipeng Hu _{1,

2} , Yang Zhang ₃ , Haijun Wu ₃ , Yamei Liu ₄ , Junqin Li ₁ , Jian He ₄ , Weiqin Ao ₁ , Fusheng Liu ₁ , Stephen John Pennycook ₃ , Xierong Zeng _{1,

2}

Affiliation

Here a progressive hot deformation procedure that endows the benchmark n‐type V₂VI₃ thermoelectric materials with short range disorder (multiple defects), long range order (crystallinity), and strong texture (nearly orientation order) is reported. Not only it is rare for these structural features to coexist but also these structural features elicit the synergistic compositional–mechanical–thermal effects, i.e., a profound interplay among the counts, magnitude, and temperature of hot deformation in relation to the as formed point defects, dislocations, textures, strain clusters, and distortions. Using progressively larger die sets and relatively low hot deformation temperature, rich multiscale microstructures concurrently with a high level of texture comparable to that of zone melted ingot are obtained. The strong donor‐like effect significantly increases the majority carrier concentration, suppressing the detrimental bipolar effect. In addition, the multiscale microstructures yield an ultralow lattice thermal conductivity ≈0.31 W m⁻¹ K⁻¹ at 405 K. A record zT ≈ 1.3 at 450 K are attained in progressively hot deformed n‐type Bi_1.95Sb_0.05Te_2.3Se_0.7 through the synergistic effects. These results not only promise a better pairing between n‐type and p‐type legs in device fabrication but also bring our understanding of n‐type V₂VI₃ alloys and hot deformation technique to a new level.

中文翻译：

通过渐进热变形在n型V2VI3合金中产生协同的成分-机械-热效应，从而导致创纪录的高ZT

这是一种渐进的热变形过程，赋予基准n型V ₂ VI ₃据报道，具有短程无序（多个缺陷），长程有序（结晶度）和强织构（接近取向序）的热电材料。这些结构特征不仅很少共存，而且这些结构特征会引起成分-机械-热效应的协同作用，即热变形的数量，大小和温度与所形成的点缺陷之间存在深刻的相互作用。，位错，纹理，应变簇和变形。使用逐渐增大的模具组和相对较低的热变形温度，可获得与区域熔融锭相当的丰富的多尺度微结构，同时具有高织构水平。强烈的类似供体的作用显着增加了多数载流子的浓度，抑制有害的双极效应。此外，多尺度微结构可产生≈0.31W m的超低晶格热导率在405 K时^-1 K ^-1。通过协同效应，在逐渐热变形的n型Bi _1.95 Sb _0.05 Te _2.3 Se _0.7中获得450 K时的zT≈1.3的记录。这些结果不仅保证了器件制造中n型和p型支脚之间更好的配对，而且使我们对n型V ₂ VI ₃合金和热变形技术的理解达到了一个新的水平。

更新日期：2018-07-13

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