High thermoelectric performance of GeTe–Ag8GeTe6 eutectic composites
High thermoelectric performance of GeTe–Ag8GeTe6 eutectic composites
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DOI：
10.1016/j.jallcom.2013.02.149
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发表时间：
2013-07
影响因子：
6.2
通讯作者：
Junqing Li;Ling-Feng Li;S. Song;F. S. Liu;W. Ao
中科院分区：
文献类型：
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作者：
Junqing Li;Ling-Feng Li;S. Song;F. S. Liu;W. Ao
采用熔炼、球磨和放电等离子烧结技术制备了x=0.02、0.05、0.08和0.11的(GeTe)1−x(Ag8GeTe6)x复合材料。研究了复合材料的热电性能。实验结果表明，所有样品都是由初凝相GeTe和含有GeTe和Ag8GeTe6相的共晶组织组成的复合材料。这种复合材料是p型半导体。与纯化合物GeTe相比，GeTe相中Ag8GeTe6化合物的存在提高了其低温电阻率，但降低了高温电阻率。由于Ag8GeTe6化合物的加入，复合材料的Seebeck系数略有降低，但导热系数显著降低。因此，可以提高材料的品质因数ZT。在673K时，样品(GeTe)0.89(Ag8GeTe6)0.11的优值系数ZT达到最大值1.15。这一值比纯GETE的高得多，导致材料的热电性能有了实质性的改善。
The (GeTe)1−x(Ag8GeTe6)xcomposites with x=0.02, 0.05, 0.08 and 0.11 were prepared by melting, ball milling and spark plasma sintering techniques. The thermoelectric properties of the composites were investigated. The experimental results show that all samples are composites consisting of the primary solidification phase GeTe and eutectic microstructures with GeTe and Ag8GeTe6phases. The composites are p-type semiconductors. As compared to the pure compound GeTe, the existence of Ag8GeTe6compound in the GeTe phase enhances its electrical resistivity at low temperatures while reduces its electrical resistivity at high temperatures. Also, the Seebeck coefficient of the composite is slightly decreased due to the Ag8GeTe6compound, but its thermal conductivities are reduced significantly. As a result, the figure of merit ZT for the materials can be enhanced. The maximum figure of merit ZT was obtained as 1.15 in the sample (GeTe)0.89(Ag8GeTe6)0.11at 673K. This value is much higher than that for the pure GeTe, leading to a substantial improvement in the thermoelectric performance of the material.