Strained endotaxial nanostructures with high thermoelectric figure of merit
Strained endotaxial nanostructures with high thermoelectric figure of merit
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DOI：
10.1038/nchem.955
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发表时间：
2011-02-01
期刊：
影响因子：
21.8
通讯作者：
Kanatzidis, Mercouri G.
中科院分区：
文献类型：
--
作者：
Biswas, Kanishka;He, Jiaqing;Kanatzidis, Mercouri G.
热电材料可以直接利用废热发电，但挑战在于设计高效、稳定且廉价的系统。块体材料中的纳米结构极大地降低了热导率，但同时增加了载流子散射，这对载流子迁移率产生不利影响。我们通过在热电材料主体中纳米晶体的内轴放置，实验性地实现了声子阻挡和电荷传输的同时进行。将浓度低至 2% 的内轴排列 SrTe 纳米晶体掺入掺杂有 Na2Te 的 PbTe 基体中。这有效地抑制了系统中的热流，但不影响空穴迁移率，从而实现大功率因数。 SrTe 和 PbTe 晶格的晶体排列可解耦声子和电子传输，这使得系统在接近 800 K 时达到 1.7 的热电品质因数。
Thermoelectric materials can directly generate electrical power from waste heat but the challenge is in designing efficient, stable and inexpensive systems. Nanostructuring in bulk materials dramatically reduces the thermal conductivity but simultaneously increases the charge carrier scattering, which has a detrimental effect on the carrier mobility. We have experimentally achieved concurrent phonon blocking and charge transmitting via the endotaxial placement of nanocrystals in a thermoelectric material host. Endotaxially arranged SrTe nanocrystals at concentrations as low as 2% were incorporated in a PbTe matrix doped with Na2Te. This effectively inhibits the heat flow in the system but does not affect the hole mobility, allowing a large power factor to be achieved. The crystallographic alignment of SrTe and PbTe lattices decouples phonon and electron transport and this allows the system to reach a thermoelectric figure of merit of 1.7 at similar to 800 K.