Wang Lijun, Hong Min, Sun Qiang, Wang Yuan, Yue Luo, Zheng Shuqi, Zou Jin, Chen Zhi-Gang
State Key Laboratory of Heavy Oil Processing, College of New Energy and Materials, China University of Petroleum, Beijing 102249, PR China.
School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
ACS Appl Mater Interfaces. 2020 Aug 12;12(32):36370-36379. doi: 10.1021/acsami.0c09781. Epub 2020 Jul 29.
Minimizing lattice thermal conductivity, , of thermoelectric materials is an effective strategy to enhance their figure-of-merit, . However, the amorphous limit of affects the ceiling of the attainable . Herein, we fabricate hierarchical structures by using an microwave synthesis to break the amorphous limit of for achieving a high in (SnInTe)(AgCl) alloys. Our results from detailed electron microscopy characterizations suggest that the as-sintered (SnInTe)(AgCl) alloys contain a range of lattice imperfections, including microsized grains with dense grain boundaries, nanopores with sizes from several to hundreds of nanometers, and nanoscale precipitates, which result in strong phonon scatterings and in turn lead to a minimized of 0.245 W m K. Moreover, the calculated band structures reveal the introduction of resonance level by In doping, which dramatically enhances the electrical transport properties to ensure a high power factor of 26.4 μW cm K at 823 K and a maximum of 0.86 (823 K) in hierarchically structured (SnInTe)(AgCl). This work provides a new approach to modulate the hierarchical structures for optimizing thermal and electronic transport properties.
使热电材料的晶格热导率κ最小化是提高其优值ZT的有效策略。然而，κ的非晶极限影响了可达到的ZT的上限。在此，我们通过使用微波合成制备分级结构，以突破κ的非晶极限，从而在(SnInTe)(AgCl)合金中实现高ZT。我们详细的电子显微镜表征结果表明，烧结后的(SnInTe)(AgCl)合金包含一系列晶格缺陷，包括具有密集晶界的微米级晶粒、尺寸从几纳米到几百纳米的纳米孔以及纳米级析出物，这些导致强烈的声子散射，进而使κ最小化至0.245 W m⁻¹ K⁻¹。此外，计算得到的能带结构表明In掺杂引入了共振能级，这极大地增强了电输运性能，以确保分级结构的(SnInTe)(AgCl)在823 K时具有26.4 μW cm⁻¹ K⁻²的高功率因子以及0.86(823 K)的最大ZT。这项工作为调控分级结构以优化热输运和电子输运性能提供了一种新方法。
