Enhancement in thermoelectric performance of SiGe nanoalloys dispersed with SiC nanoparticles,Physical Chemistry Chemical Physics

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Enhancement in thermoelectric performance of SiGe nanoalloys dispersed with SiC nanoparticles
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2017-08-31 00:00:00 , DOI: 10.1039/c7cp04240j
Sivaiah Bathula _{1,

2,

3,

4,

5} , M. Jayasimhadri _{5,

6,

7,

8} , Bhasker Gahtori _{1,

2,

3,

4,

5} , Anil Kumar _{1,

2,

3,

4,

5} , A. K. Srivastava _{1,

2,

3,

4,

5} , Ajay Dhar _{1,

2,

3,

4,

5}

Affiliation

SiGe is one of the most widely used thermoelectric materials for radioisotope thermoelectric generator applications for harnessing waste-heat at high temperatures. In the present study, we report a simple experimental strategy for enhancing the thermoelectric and mechanical properties of n-type SiGe nanoalloys by dispersing SiC nanoparticles in a SiGe nanoalloy matrix. This strategy yielded a high value of figure-of-merit (ZT) of ∼1.7 at 900 °C in the SiGe/SiC nanocomposite, which is nearly twice that reported for its pristine bulk counterpart and ∼15% higher than that of pristine SiGe nanoalloys. This significant enhancement in the ZT primarily originates from a reduction in the lattice thermal conductivity, owing to a high density of nano-scale interfaces, lattice-scale modulations and mass fluctuations, which lead to extensive scattering of heat-carrying phonons. The dispersion of SiC nanoparticles also significantly enhances the mechanical properties of the resulting SiGe/SiC nanocomposite, including fracture toughness and hardness. The enhancement in the thermoelectric and mechanical properties of the SiGe/SiC nanocomposites has been correlated with their microstructural features, elucidated employing X-ray diffraction, and scanning and transmission electron microscopy.

中文翻译：

分散有SiC纳米颗粒的SiGe纳米合金的热电性能增强

SiGe是用于放射性同位素热电发生器应用的最广泛使用的热电材料之一，用于利用高温下的余热。在本研究中，我们报告了一种简单的实验策略，通过将SiC纳米颗粒分散在SiGe纳米合金基体中来增强n型SiGe纳米合金的热电和机械性能。此策略在900°C的SiGe / SiC纳米复合材料中产生的高品质因数（ZT）约为1.7，是其原始大块对应物的近两倍，比原始SiGe的高约15％。纳米合金。ZT的显着增强主要是由于高密度的纳米级界面，晶格级调制和质量波动导致晶格热导率降低，从而导致载热声子的大量散布。SiC纳米颗粒的分散还显着增强了所得SiGe / SiC纳米复合材料的机械性能，包括断裂韧性和硬度。SiGe / SiC纳米复合材料的热电和机械性能的增强与其微结构特征相关联，已通过X射线衍射以及扫描和透射电子显微镜进行了阐明。

更新日期：2017-09-20

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