Synthesis and Characterization of Telluride Aerogels: Effect of Gelation on Thermoelectric Performance of Bi2Te3 and Bi2-xSbxTe3 Nanostructures
Synthesis and Characterization of Telluride Aerogels: Effect of Gelation on Thermoelectric Performance of Bi2Te3 and Bi2-xSbxTe3 Nanostructures
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DOI：
10.1021/jp3055608
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发表时间：
2012-08-23
影响因子：
3.7
通讯作者：
Brock, Stephanie L.
中科院分区：
文献类型：
--
作者：
Ganguly, Shreyashi;Zhou, Chen;Brock, Stephanie L.
本文报道了Bi_2Te_3和Bi_2-xSb_xTe_3气凝胶材料的合成和表征，以及凝胶化对热电相关性能的影响。气凝胶是通过氧化离散的硫醇盐封端的纳米颗粒以产生湿凝胶，然后通过超临界CO2干燥来制备的。所得气凝胶的表面积为36 - 45 m2/g。热压粒料的Bi 2 Te 3气凝胶的热电性能的表征表明相对于散装材料的晶格热导率的降低，归因于纳米结构化的效果，但功率因数（S-2西格玛）也降低了由于偶然掺杂的效果。在Bi 2-xSbxTe 3气凝胶的情况下，在纳米结构化后晶格热导率没有变化，但是功率因数相对于块体材料再次降低。这归因于过量碲的存在，其导致多数电荷载流子的补偿。如果硫属化物气凝胶材料要在热电中被利用，则需要这些材料的适当载流子浓度优化。
The synthesis and characterization of Bi2Te3 and Bi2-xSbxTe3 aerogel materials, and the effect of gelation on thermoelectrically relevant properties, is reported. Aerogels are prepared from oxidation of discrete thiolate-capped nanoparticles to yield a wet gel, followed by supercritical CO2 drying. The resultant aerogels have surface areas between 36 and 45 m(2)/g. Characterization of the thermoelectric properties of hot pressed pellets of Bi2Te3 aerogels suggested a decrease in lattice thermal conductivity with respect to the bulk materials, attributed to the effect of nanostructuring, but the power factor (S-2 sigma) was also reduced due to the effect of adventitious doping. In the case of Bi2-xSbxTe3 aerogels, there was no change in the lattice thermal conductivity upon nanostructuring, but again the power factor was reduced with respect to bulk materials. This is attributed to the presence of excess tellurium, which led to compensation of the majority charge carriers Proper carrier concentration optimization of the chalcogenide aerogel materials is needed if these materials are to be exploited in thermoelectrics.