Nanostructures in high-performance (GeTe)x(AgSbTe2)100−x thermoelectric materials
Nanostructures in high-performance (GeTe)x(AgSbTe2)100−x thermoelectric materials
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DOI：
10.1088/0957-4484/19/24/245707
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发表时间：
2008-06
期刊：
影响因子：
3.5
通讯作者：
S. H. Yang;T. Zhu;T. Sun;J. He;S. N. Zhang;X. Zhao
中科院分区：
文献类型：
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作者：
S. H. Yang;T. Zhu;T. Sun;J. He;S. N. Zhang;X. Zhao
研究了（GeTe）x（AgSbTe 2）100-x化合物（x = 75、80、85和90; TAGS-x）的热电性能与300至720 K温度的函数关系。在720 K时，TAGS-75样品的无量纲优值ZT达到最新值1.53，TAGS-80和TAGS-85样品的无量纲优值ZT分别达到最新值1.50。而TAGS-90样品由于载流子浓度高，在720 K时的ZT值仅为0.50。利用高分辨率透射电子显微镜和选区电子衍射技术，我们确定了相当数量的纳米级域与典型的尺寸<$10 nm的样品中，显示高ZT值。有人建议，纳米结构域的存在下，如在PbTe-AgSbTe 2化合物的情况下，应作出轻微的贡献，由于增强的中频声子散射的低晶格热导率的TAGS化合物。
The thermoelectric properties of (GeTe)x(AgSbTe2)100−x compounds (x = 75, 80, 85 and 90; TAGS-x) have been studied as a function of temperature from 300 to 720 K. At 720 K the dimensionless figure of merit ZT reaches the state-of-the-art value of 1.53 for TAGS-75 and 1.50 for TAGS-80 and TAGS-85 samples, respectively. But the ZT value of the TAGS-90 sample is only 0.50 at 720 K due to the high carrier concentration. Utilizing high-resolution transmission electron microscope and selected area electron diffraction techniques, we identify a considerable number of nanoscale domains with typical size ∼10 nm in the samples that show high ZT values. It is suggested that the presence of nanoscale domains, like the situation in PbTe–AgSbTe2 compounds, should make a slight contribution to the low lattice thermal conductivity of TAGS compounds due to the enhanced mid-frequency phonon scattering.