Optimizing the Dopant and Carrier Concentration of Ca5Al2Sb6 for High Thermoelectric Efficiency.
Optimizing the Dopant and Carrier Concentration of Ca5Al2Sb6 for High Thermoelectric Efficiency.
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优化 Ca5Al2Sb6 的掺杂剂和载流子浓度以获得高热电效率
DOI：
10.1038/srep29550
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发表时间：
2016-07-13
影响因子：
4.6
通讯作者：
Ren W
中科院分区：
文献类型：
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作者：
Yan Y;Zhang G;Wang C;Peng C;Zhang P;Wang Y;Ren W
采用第一性原理电子结构方法和玻尔兹曼输运理论研究了掺杂对Ca5Al2Sb6输运性质的影响。计算结果表明，在1000 K时，当载流子浓度达到最佳值时，ZT值最大，为1.45。然而，实验研究表明，在1000 K时，最大ZT值不大于1。通过计算得到的Seebeck系数与实验值的比较，我们发现该材料中较低的掺杂溶解度不利于实现最佳载流子浓度，导致最大ZT的实验值较小。有趣的是，计算出的掺杂剂形成能表明，最佳的载流子浓度时，可以实现掺杂剂和Sb原子具有相似的电子配置。因此，有可能在1000 K下用合适的掺杂剂实现1.45的最大ZT值。这些结果为通过掺杂剂优化合成高性能块体热电材料提供了有价值的理论指导。
The effects of doping on the transport properties of Ca5Al2Sb6 are investigated using first-principles electronic structure methods and Boltzmann transport theory. The calculated results show that a maximum ZT value of 1.45 is achieved with an optimum carrier concentration at 1000 K. However, experimental studies have shown that the maximum ZT value is no more than 1 at 1000 K. By comparing the calculated Seebeck coefficient with experimental values, we find that the low dopant solubility in this material is not conductive to achieve the optimum carrier concentration, leading a smaller experimental value of the maximum ZT. Interestingly, the calculated dopant formation energies suggest that optimum carrier concentrations can be achieved when the dopants and Sb atoms have similar electronic configurations. Therefore, it might be possible to achieve a maximum ZT value of 1.45 at 1000 K with suitable dopants. These results provide a valuable theoretical guidance for the synthesis of high-performance bulk thermoelectric materials through dopants optimization.