Improvement of thermoelectric properties of SnTe by Mn Bi codoping
Improvement of thermoelectric properties of SnTe by Mn Bi codoping
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DOI：
10.1016/j.cej.2020.127795
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发表时间：
2020-11
影响因子：
15.1
通讯作者：
Qiang Zhang;X. Tan;Zhe Guo;Hongxiang Wang;Chenglong Xiong;Na Man;Fanfan Shi;Hao-yang Hu
中科院分区：
文献类型：
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作者：
Qiang Zhang;X. Tan;Zhe Guo;Hongxiang Wang;Chenglong Xiong;Na Man;Fanfan Shi;Hao-yang Hu
SnTe是一种受吸引的无铅热电材料，但其高空穴浓度、不理想的价带结构和高热导率严重限制了其热电性能。在本工作中，我们研究了Mn单键Bi共掺杂SnTe的多重效应，以协同提高总功率因数和ZT值。发现Mn单键Bi共掺杂有效地将空穴浓度降低到最佳范围。正如预期的那样，Mn和Bi掺杂明显地减小了两个价带最大值之间的能量分离，使得能够实现显著的能带会聚和改进的塞贝克系数。此外，Mn单键Bi共掺杂引入了各种声子散射中心，以散射宽光谱的声子，从而在850 K下抑制了0.67 W m-1 K-1的晶格热导率。这些效应的协同作用使Sn_（0.90）Mn_（0.07）Bi_（0.03）Te在850 K时的峰值Z_T为1.3，平均Z_T为0.68（300-850 K），表明SnTe基材料是一种有希望的中温热电材料。
SnTe is an attracted lead-free thermoelectric material, but the thermoelectric performance is severely limited by the high hole concentration, undesirable valence band structure and high thermal conductivity. In this work, we study the multiple effects of Mnsingle bondBi codoping in SnTe to synergistically improve the overall power factor andZTvalues. It is found that the Mnsingle bondBi codoping effectively reduces the hole concentration to an optimal range. As expected, Mn and Bi doping obviously decreases the energy separation between the two valence band maxima, enabling pronounced band convergence and improved Seebeck coefficient. Moreover, Mnsingle bondBi codoping introduces various phonon scattering centers to scatter a wide spectrum of phonons for a suppressed lattice thermal conductivity of 0.67 W m−1K−1at 850 K. The synergy of these effects yields a peakZTof 1.3 at 850 K and an averageZTof 0.68 (300–850 K) in Sn0.90Mn0.07Bi0.03Te, suggesting SnTe-based material a promising candidate for medium-temperature thermoelectric applications.