Optimization of high efficiency thermoelectrics based on Tl5Te3
Optimization of high efficiency thermoelectrics based on Tl5Te3
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基于Tl5Te3的高效热电优化
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
J. Teubner
中科院分区：
文献类型：
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作者：
J. Teubner
Tl 5 Te 3相关化合物最近被发现是用于热电应用的非常有效的材料[Wolfing 00]。在这项工作中，技术已被调查，以进一步优化这组材料。化合物T19 SbTe 6被表征并发现表现出非常好的热电性能，尽管它落后于T19 BiTe 6，T19 BiTe 6仍然被认为是T15 Te 3组中最好的三元化合物。为了优化Tl 9 SbTe 6-Tl 9 BiTe 6合金的电子性能和降低晶格热导率，对该合金体系进行了研究。测量和理论估计表明，优化的材料必须在或接近系统的Tl 9 BiTe 6端。然而，没有观察到由于合金散射导致的热导率降低而导致的预期改善。对Tl 9 BiTe 6的掺杂效应进行了研究。通过掺杂铋，可以制备n型Tl 9 BiTe 6，这对于仅基于Tl 9 BiTe 6的热电器件是必需的。不幸的是，发现n型Tl 9 BiTe 6具有比其p型对应物弱得多的热电性能。HgTe的掺杂实验表明，p型掺杂可以改善Tl 9 BiTe 6的性能。然而，在该材料上观察到显著的脆化，这限制了其在实际装置中的使用。掺杂技术和/或掺杂剂本身的进一步优化有望解决这些问题并提高Tl 9 BiTe 6的性能。在另外的调查YNiSband Zr 3 Ni 3Sb 4相关的化合物已被筛选其热电性能。这两组的成员都表现出高的热电势和低的热导率。然而，高电阻率限制了热电性能。然而，相关系统的进一步研究似乎很有希望。
The Tl5Te3 related compounds have recently been discovered as very efficient materials for thermoelectric applications [Wolfing00]. In this work, techniques have been investigated to further optimize materials in this group. The compound Tl9SbTe6 was characterized and found to exhibit very good thermoelectric performance, although it stays behind Tl9BiTe6, which still has to be considered as the best ternary compound in the Tl5Te3 group. Investigations on the Tl9SbTe6–Tl9BiTe6 alloy system have been carried out in order to optimize the electronic properties and lower the lattice thermal conductivity. Measurements and theoretical estimations show that an optimized material must be at or close to the Tl9BiTe6 end of the system. The expected improvement due to a reduction of the thermal conductivity by alloy scattering, however, was not observed. A study on the effect of doping in Tl9BiTe6 was carried out. By doping with bismuth n-type Tl9BiTe6 could be prepared, which would be necessary for a thermoelectric device that is solely based on Tl9BiTe6. Unfortunately, n-type Tl9BiTe6 was found to have much weaker thermoelectric performance than its p-type counterpart. Doping experiments with HgTe showed that p-type doping can improve the performance of Tl9BiTe6. However, a significant embrittlement has been observed on this material, that limits its use in actual devices. Further optimization of the doping technique and/or the dopant itself are expected to solve these problems and enhance the performance of Tl9BiTe6. In additional investigations YNiSband Zr3Ni3Sb4-related compounds have been screened for their thermoelectric properties. The members of both groups exhibit high thermopowers and have low thermal conductivities. The high electrical resistivity, however, limits the thermoelectric performance. Nevertheless, further research in related systems seems promising.