Thermoelectric Property Studies on Cu-Doped n-type CuxBi2Te2.7Se0.3 Nanocomposites
Thermoelectric Property Studies on Cu-Doped n-type CuxBi2Te2.7Se0.3 Nanocomposites
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DOI：
10.1002/aenm.201100149
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发表时间：
2011-07-01
影响因子：
27.8
通讯作者：
Ren, Zhifeng
中科院分区：
文献类型：
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作者：
Liu, Wei-Shu;Zhang, Qinyong;Ren, Zhifeng
高能球磨和热压相结合，显著提高了p型Bi0.4Sb1.6Te3纳米复合材料的热电优值。然而，将同样的技术应用于n型Bi2Te2.7Se0.3，由于n型Bi2Te2.7Se0.3的热电性质的各向异性，对ZT值没有改善。尽管织构能有效地将Bi2Te2.7Se0.3的ZT峰从0.85提高到1.04，但各批次的重现性仍然不能令人满意。在这里，我们表明，通过在每Bi2Te2.7Se0.3中引入0.01铜(Cu)的最佳浓度来制备Cu0.01Bi2Te2.7Se0.3样品，可以获得良好的重复性。未经织构处理的Cu0.01Bi2Te2.7Se0.3样品的ZT值为0.99。经复压织构后，ZT峰值增加到1.06。在空气中老化5个月以上没有恶化，但进一步提高了峰值ZT至1.10。文中还讨论了铜改善重复性、提高载流子迁移率、降低晶格热导率的机理。
Combining high energy ball-milling and hot-pressing, significant enhancements of the thermoelectric figure-of-merit (ZT) have been reported for p-type Bi0.4Sb1.6Te3 nanocomposites. However, applying the same technique to n-type Bi2Te2.7Se0.3 showed no improvement on ZT values, due to the anisotropic nature of the thermoelectric properties of n-type Bi2Te2.7Se0.3. Even though texturing was effective in improving peak ZT of Bi2Te2.7Se0.3 from 0.85 to 1.04, reproducibility from batch to batch remains unsatisfactory. Here, we show that good reproducibility can be achieved by introducing an optimal concentration of 0.01 copper (Cu) per Bi2Te2.7Se0.3 to make Cu0.01Bi2Te2.7Se0.3 samples. A peak ZT value of 0.99 was achieved in Cu0.01Bi2Te2.7Se0.3 samples without texturing. With texturing by re-pressing, the peak ZT was increased to 1.06. Aging in air for over 5 months did not deteriorate but further improved the peak ZT to 1.10. The mechanism by which copper improves the reproducibility, enhances the carrier mobility, and reduces the lattice thermal conductivity is also discussed.