Significant improvement in thermoelectric performance of SnSe/SnS via nano-heterostructures.
Significant improvement in thermoelectric performance of SnSe/SnS via nano-heterostructures.
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DOI：
10.1039/d0cp05548d
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发表时间：
2021-02
期刊：
影响因子：
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通讯作者：
Renqi Zhang;Zizhen Zhou;Qi Yao;N. Qi;Zhiquan Chen
中科院分区：
文献类型：
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作者：
Renqi Zhang;Zizhen Zhou;Qi Yao;N. Qi;Zhiquan Chen
本文从理论上研究了SnSe/SnS异质结、双层SnSe和SnS的电子和声子输运性质。SnSe/SnS中纳米异质结构引起的能量过滤效应引起Seebeck系数的增加，从而引起大的功率因数。我们计算了三种结构的声子弛豫时间和晶格热导率κL，异质纳米结构可以有效地降低κL，这是由于界面处声子边界散射的增强。在300 K时，平均κL从SnSe（SnS）双层的3.3（3.2）W m-1 K-1显著降低到SnSe/SnS的2.2 W m-1 K-1。结果表明，在300-800 K温度范围内，平均ZT（B和c方向的ZTave）达到1.63，比双层SnSe（SnS）提高了63%（25%）。我们的理论结果表明，异质纳米结构是一种创新的方法，提高塞贝克系数，显着降低κL，有效地提高热电性能。
In this work, we study theoretically the electronic and phonon transport properties of heterojunction SnSe/SnS, bilayer SnSe and SnS. The energy filtering effect caused by the nano heterostructure in SnSe/SnS induces an increase in the Seebeck coefficient, causing a large power factor. We calculate the phonon relaxation time and lattice thermal conductivity κL for the three structures; the heterogeneous nanostructure could effectively reduce κL due to the enhanced phonon boundary scattering at interfaces. The average κL notably reduces from around 3.3 (3.2) W m-1 K-1 for bilayer SnSe (SnS) to nearly 2.2 W m-1 K-1 for SnSe/SnS at 300 K. As a result, the average ZT (ZTave in b and c directions) reaches 1.63 with temperature range around 300-800 K, which is improved by 63% (25%) compared with that of bilayer SnSe (SnS). Our theoretical results show that the heterogeneous nanostructure is an innovative approach for improving the Seebeck coefficient and significantly reducing κL, effectively enhancing thermoelectric properties.