Optimized thermoelectric properties of Mo3Sb7-xTex with significant phonon scattering by electrons
Optimized thermoelectric properties of Mo3Sb7-xTex with significant phonon scattering by electrons
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DOI：
10.1039/c1ee01406d
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发表时间：
2011-10-01
影响因子：
32.5
通讯作者：
Chen, Lidong
中科院分区：
文献类型：
--
作者：
Shi, Xiaoya;Pei, Yanzhong;Chen, Lidong
采用固相反应法合成了重掺杂Mo_3Sb_7 Te_x（x）（x = 0，1.0，1.4，1.8）化合物，并采用放电等离子烧结法进行了烧结。X射线衍射和电子探针显微分析表明，Te的最大溶解度在x = 1.8附近。电输运性质的趋势通常可以使用单抛物线带模型来理解，该模型预测，对于热电优值（zT），通过Te取代（x = 1.8），Mo 3Sb 7的极高载流子浓度（类似于10（22）cm（-3））可以降低到接近优化的水平（类似于2 × 10（21）cm（-3））。根据德拜模型拟合，发现通过Te掺杂增加的晶格热导率是由于Umklapp和电子-声子散射的降低。热电优值（zT）随着温度的增加而单调增加，并且对于x = 1.8的样品在850 K时达到其最高值约0.51，使得这些材料与最先进的热电SiGe合金竞争。显着的电子-声子散射的证据中发现的热导率。
Heavily doped compounds Mo3Sb7 Te-x(x) (x = 0, 1.0, 1.4, 1.8) were synthesized by solid state reaction and sintered by spark plasma sintering. Both X-ray diffraction and electron probe microanalysis indicated the maximum solubility of Te was around x = 1.8. The trends in the electrical transport properties can generally be understood using a single parabolic band model, which predicts that the extremely high carrier concentration of Mo3Sb7 (similar to 10(22) cm(-3)) can be reduced to a nearly optimized level (similar to 2 x 10(21) cm(-3)) for thermoelectric figure of merit (zT) by Te-substitution with x = 1.8. The increased lattice thermal conductivity by Te-doping was found to be due to the decreased Umklapp and electron-phonon scattering, according to a Debye model fitting. The thermoelectric figure of merit (zT) monotonously increased with increasing temperature and reached its highest value of about 0.51 at 850 K for the sample with x = 1.8, making these materials competitive with the state-of-the-art thermoelectric SiGe alloys. Evidence of significant electron-phonon scattering is found in the thermal conductivity.