The Thermoelectric Properties of Bismuth Telluride
The Thermoelectric Properties of Bismuth Telluride
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DOI：
10.1002/aelm.201800904
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发表时间：
2019-06-01
影响因子：
6.2
通讯作者：
Snyder, G. Jeffrey
中科院分区：
文献类型：
--
作者：
Witting, Ian T.;Chasapis, Thomas C.;Snyder, G. Jeffrey
碲化铋是大多数珀尔帖冷却装置和热电发电机的工作材料。这是因为Bi₂Te₃（更准确地说，其与Sb₂Te₃形成的p型合金以及与Bi₂Se₃形成的n型材料合金）在室温附近的所有材料中具有最高的热电优值zT。由于通过改进Bi₂Te₃或找到一种更优的材料，热电技术将得到极大提升，本文旨在确定并量化使Bi₂Te₃成为如此优良热电材料的关键材料特性。较大的zT可归因于高的能带简并度、低的有效质量、高的载流子迁移率以及相对较低的晶格热导率，这些都对其极高的热电品质因数有贡献。利用文献数据并结合新的研究结果，对这些材料参数进行了量化，从而清晰地了解通过合金化来调整Bi₂Te₃的电子能带结构，或通过纳米结构化来降低热导率。例如，该分析清楚地表明，即使在室温下，跨越小带隙的少数载流子激发也显著限制了Bi₂Te₃的热电性能，这表明在更高温度下工作需要更大带隙的合金。这些有效的材料参数也可用于对Bi₂Te₃未来的改进或新的替代材料进行基准测试。
Bismuth telluride is the working material for most Peltier cooling devices and thermoelectric generators. This is because Bi2Te3 (or more precisely its alloys with Sb2Te3 for p-type and Bi2Se3 for n-type material) has the highest thermoelectric figure of merit, zT, of any material around room temperature. Since thermoelectric technology will be greatly enhanced by improving Bi2Te3 or finding a superior material, this review aims to identify and quantify the key material properties that make Bi2Te3 such a good thermoelectric. The large zT can be traced to the high band degeneracy, low effective mass, high carrier mobility, and relatively low lattice thermal conductivity, which all contribute to its remarkably high thermoelectric quality factor. Using literature data augmented with newer results, these material parameters are quantified, giving clear insight into the tailoring of the electronic band structure of Bi2Te3 by alloying, or reducing thermal conductivity by nanostructuring. For example, this analysis clearly shows that the minority carrier excitation across the small bandgap significantly limits the thermoelectric performance of Bi2Te3, even at room temperature, showing that larger bandgap alloys are needed for higher temperature operation. Such effective material parameters can also be used for benchmarking future improvements in Bi2Te3 or new replacement materials.