Combination of large nanostructures and complex band structure for high performance thermoelectric lead telluride
Combination of large nanostructures and complex band structure for high performance thermoelectric lead telluride
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DOI：
10.1039/c1ee01928g
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发表时间：
2011-09-01
影响因子：
32.5
通讯作者：
Snyder, G. Jeffrey
中科院分区：
文献类型：
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作者：
Pei, Yanzhong;Heinz, Nicholas A.;Snyder, G. Jeffrey
p型PbTe中价带结构的复杂性已被证明能够在重掺杂Na时显著增强平均热电优值（zT）。研究还表明，当PbTe是纳米结构的，具有大的纳米尺寸的Ag（2）Te沉淀物时，由于界面处的声子散射，zT增强。由这两种机制引起的zT的增强具有相似的幅度，但原则上彼此解耦。这项工作通过实验证明了价带结构的复杂性与纳米结构的成功结合，以创建高性能的热电材料。这些效应导致Na掺杂的PbTe/Ag（2）Te在宽的温度范围内具有高的zT，在T > 650 K时zT > 1.5。由于纳米结构，该高平均zT产生比纯Na掺杂的PbTe高30%的效率（300-750 K），而复杂的价带结构导致效率是相关n型La掺杂的PbTe/Ag（2）Te的两倍，而没有这种能带结构复杂性。
The complexity of the valence band structure in p-type PbTe has been shown to enable a significant enhancement of the average thermoelectric figure of merit (zT) when heavily doped with Na. It has also been shown that when PbTe is nanostructured with large nanometer sized Ag(2)Te precipitates there is an enhancement of zT due to phonon scattering at the interfaces. The enhancement in zT resulting from these two mechanisms is of similar magnitude but, in principle, decoupled from one another. This work experimentally demonstrates a successful combination of the complexity in the valence band structure with the addition of nanostructuring to create a high performance thermoelectric material. These effects lead to a high zT over a wide temperature range with peak zT > 1.5 at T > 650 K in Na-doped PbTe/Ag(2)Te. This high average zT produces 30% higher efficiency (300-750 K) than pure Na-doped PbTe because of the nanostructures, while the complex valence band structure leads to twice the efficiency as the related n-type La-doped PbTe/Ag(2)Te without such band structure complexity.