Li Song, Zhang Jingwen, Liu Dawei, Wang Yan, Zhang Jiuxing
School of Materials Science and Engineering, Hefei University of Technology Hefei 230009 China
School of Physics and Materials Engineering, Hefei Normal University Hefei 230061 China.
RSC Adv. 2022 Aug 18;12(36):23074-23082. doi: 10.1039/d2ra04255j. eCollection 2022 Aug 16.
SnTe is becoming a new research focus as an intermediate temperature thermoelectric material for its environment-friendly property. Herein, the SnTe/ZnO core-shell structure prepared by a facile hydrothermal method is firstly constructed to enhance the thermoelectric performance. The characterization results demonstrate that ZnO nanosheets are coated on the surface of SnTe particles by synthesis and converted into ZnO nano-dots by spark plasma sintering. The energy barriers built by the SnTe/ZnO core-shell structure improve the Seebeck coefficient effectively. Additionally, the increased density of interfaces induced by ZnO can effectively scatter low/medium frequency phonons, reducing the lattice thermal conductivity in the low/medium temperature region. Further, the point defects caused by CuTe-alloying strengthen the scattering of high frequency phonons. The lattice thermal conductivity reaches 0.48 W m K, which is close to the amorphous limit of pristine SnTe. As a result, a peak value of 0.94 is achieved at 823 K for SnTe(CuTe)-1.5% ZnO, benefiting from the synergistic optimization of thermal and electrical properties. This provides a new idea for exploring an optimization strategy of thermoelectric performance.
碲化锡（SnTe）作为一种具有环境友好特性的中温热电材料，正成为新的研究热点。在此，首次构建了通过简便水热法制备的SnTe/ZnO核壳结构，以提高热电性能。表征结果表明，通过合成在SnTe颗粒表面包覆了氧化锌纳米片，并通过放电等离子烧结将其转化为氧化锌纳米点。SnTe/ZnO核壳结构构建的能垒有效地提高了塞贝克系数。此外，氧化锌诱导增加的界面密度可有效散射低/中频声子，降低低/中温区域的晶格热导率。进一步地，碲化铜合金化引起的点缺陷增强了高频声子的散射。晶格热导率达到0.48 W m K，接近原始SnTe的非晶极限。结果，得益于热学和电学性能的协同优化，SnTe（CuTe）-1.5% ZnO在823 K时实现了0.94的峰值。这为探索热电性能的优化策略提供了新思路。
