Theory-Guided Synthesis of an Eco-Friendly and Low-Cost Copper Based Sulfide Thermoelectric Material
Theory-Guided Synthesis of an Eco-Friendly and Low-Cost Copper Based Sulfide Thermoelectric Material
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DOI：
10.1021/acs.jpcc.6b09379
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发表时间：
2016-12-08
影响因子：
3.7
通讯作者：
Reece, Mike J.
中科院分区：
文献类型：
--
作者：
Chen, Kan;Du, Baoli;Reece, Mike J.
Cu3SbS4是一种富含稀土元素的铜基硫化物。我们对掺Ge的Cu3SbS4的热电性能进行了理论和实验相结合的研究。在密度泛函理论的基础上，我们发现原始化合物是一种具有大的态密度的半导体，其有效质量与空穴的2.2m(E)相近。Ge被认为是一种有效的p型掺杂剂，只会轻微地改变Cu3SbS4的能带结构。在高温(700K)下(n=(6-9)×10(20)cm(-3))，当Sb位掺入10-15mol%Ge时，功率因数达到最大值。用理论指导了最佳掺杂Cu3SbS4块体样品的合成。实验上，采用机械合金化和放电等离子烧结法制备了Cu3SbS4块体样品。样品具有非常精细的微观结构，其晶粒度接近100-300 nm，这使得其晶格热导率比文献报道的要低得多。最大功率因数接近1.08 mW K~(-2)m~(-1)，最佳载流子浓度接近4.79×10~(20)cm~(-3)，与理论预测一致，在623K下获得接近0.63的zT。
Cu3SbS4 is a copper-based sulfide composed of earth abundant elements. We present a combined theoretical and experimental study of the thermoelectric properties of Ge-doped Cu3SbS4. On the basis of density functional theory, we found that the pristine compound is a semiconductor with a large density-of-state effective mass of similar to 2.2 m(e) for holes. Ge was predicted to be an effective p-type dopant that only slightly shifts the band structure of Cu3SbS4. The power factor was predicted to reach a maximum value with 10-15 mol % Ge-doping on the Sb site (n = (6-9) x 10(20) cm(-3)) at high temperature (up to 700 K). Theory was used to guide the synthesis of optimally doped Cu3SbS4 bulk samples. Experimentally, Cu3SbS4 bulk samples were prepared by mechanical alloying and spark plasma sintering. The samples had very fine microstructures, with a grain size of similar to 100-300 nm, which contributed to a much lower lattice thermal conductivity than reported in the literature. A maximum power factor of similar to 1.08 mW K-2 m(-1) was achieved with an optimized carrier concentration of similar to 4.79 x10(20) cm(-3) which is in good agreement with theoretical prediction, and a zT of similar to 0.63 was obtained at 623 K.