Enhanced average thermoelectric figure of merit of n-type PbTe1-xIx-MgTe
Enhanced average thermoelectric figure of merit of n-type PbTe1-xIx-MgTe
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DOI：
10.1039/c5tc01652e
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发表时间：
2015-01-01
影响因子：
6.4
通讯作者：
Kanatzidis, Mercouri G.
中科院分区：
文献类型：
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作者：
Jood, Priyanka;Ohta, Michihiro;Kanatzidis, Mercouri G.
研究了n型PbTe_（1-x）Ix-yMgTe（x = 0.0012-0.006; y = 0和1%）烧结样品在300 ~ 900 K温度范围内的热电性能。扫描电子显微镜显示两个不同的长度尺度的晶粒在样品中具有较高的I和MgTe含量，而一个均匀的微观结构的样品具有较低的掺杂剂含量。透射电子显微镜发现无处不在的球形纳米沉淀物在PbTe 1-xIx与MgTe和纳米级盘状沉淀物，PbTe 1-xIx与和没有MgTe。纳米结构的PbTe显示出比预期值更高的塞贝克系数。我们还观察到一个缓慢的速度增加的电阻率与温度上升PbTe 1-xIx-yMgTe低于B550 K，导致更高的热电功率因数。纳米结构和混合微结构散射声子，在600 K下将晶格热导率降低至0.4 W K-1 m（-1）。在PbTe 0.996I 0.004 -1 mol% MgTe中，当冷端温度为303 K，热端温度为873 K时，在700 K时获得了1.2的高ZT，平均ZT为0.8。
The thermoelectric properties of sintered samples of n-type PbTe1-xIx-yMgTe (x = 0.0012-0.006; y = 0 and 1%) were investigated over the temperature range of 300 K to 900 K. Scanning electron microscopy revealed two different length scales of grains in samples with higher I and MgTe contents, while a homogenous microstructure for samples with a lower dopant content. Transmission electron microscopy revealed ubiquitous spherical nanoprecipitates in PbTe1-xIx with MgTe and nanoscale disk like precipitates in both, PbTe1-xIx with and without MgTe. The nanostructured PbTe showed higher Seebeck coefficients than expected values. We also observed a slower rate of increase in the electrical resistivity with rising temperature in PbTe1-xIx-yMgTe below B550 K, leading to a higher thermoelectric power factor. The nanostructures and mixed microstructures scatter phonons, reducing the lattice thermal conductivity as low as 0.4 W K-1 m(-1) at 600 K. A high ZT of 1.2 at 700 K was achieved as well as a high average ZT of 0.8 was observed in PbTe0.996I0.004-1 mol% MgTe for a cold-side temperature of 303 K and a hot-side temperature of 873 K.