Extraordinary Thermoelectric Performance Realized in Hierarchically Structured AgSbSe2 with Ultralow Thermal Conductivity
Extraordinary Thermoelectric Performance Realized in Hierarchically Structured AgSbSe2 with Ultralow Thermal Conductivity
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具有超低导热率的分级结构 AgSbSe2 实现非凡的热电性能
DOI：
10.1021/acsami.8b03243
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发表时间：
2018-06-06
影响因子：
9.5
通讯作者：
Liu, Zihang
中科院分区：
文献类型：
--
作者：
Gao, Weihong;Wang, Zhenyou;Liu, Zihang
从低级热量到电的热电转换被认为是能源收获区中高度可靠且环保的技术。但是，如何使用简单制造方法开发有效的热电材料仍然是热电社区的关键挑战。在这里，我们首先使用既定的方法，即机械合金（仅30分钟）和快速的热压方法，首先使用层次微观结构制造Ca掺杂的AGSBSE2的高热电性能。分层微观结构，包括点缺陷（原子量表），位错和纳米沉淀物（纳米级）以及晶界（显微镜），强烈散射的声子具有相当的大小，而不会降低载流子迁移率。由于纳米结构的AGSBSE2的载体浓度高于粗粒AGSBSE2，因此纳米结构后也可以稍微提高功率因数。 CA掺杂进一步优化了载体浓度，并创建了声子的点缺陷散射，从而导致超级晶格的热导率与673 K时的0.27 w m（-1）K-1相似，从而在很大程度上提高了高达1.2的峰值ZT。高电离性能与便捷的制造方法结合使用，突出显示基于AGSBSE2的材料作为能量收集的强大热电候选者。
Thermoelectric conversion from low-grade heat to electricity is regarded as the highly reliable and environmentally friendly technology in energy-harvesting area. However, how to develop efficient thermoelectric materials using a simple fabrication method is still a critical challenge in thermoelectric community. Here, we first fabricate the high thermoelectric performance of Ca-doped AgSbSe2 with a hierarchical microstructure using a facile approach, namely, mechanical alloying (for only 30 min) and a quick hot-pressing method. The hierarchical microstructure, including point defects (atomic scale), dislocations, and nanoprecipitates (nanoscale) as well as grain boundaries (microscale), strongly scatters phonons with comparable sizes without deterioration of carrier mobility. Because of the higher carrier concentration of nanostructured AgSbSe2 than that of coarse-grain AgSbSe2, power factor can also be improved slightly after nanostructuring. Ca doping further optimizes the carrier concentration and creates the point-defect scattering of phonons, leading to the ultralow lattice thermal conductivity similar to 0.27 W m(-1) K-1 at 673 K and thus largely improving the peak ZT up to 1.2. The high thermoelectric performance in combination with a facile fabrication method highlights AgSbSe2-based materials as robust thermoelectric candidates for energy harvesting.