Thermoelectric Ag2Se: Imperfection, Homogeneity, and Reproducibility
Thermoelectric Ag2Se: Imperfection, Homogeneity, and Reproducibility
复制标题
热电 Ag2Se：不完美性、均匀性和再现性
DOI：
10.1021/acsami.1c18483
复制
发表时间：
2021-12-22
影响因子：
9.5
通讯作者：
Shi, Xun
中科院分区：
文献类型：
--
作者：
Huang, Shaoji;Wei, Tian-Ran;Shi, Xun
Ag 2Se是一种窄带隙n型半导体，具有高载流子迁移率和低晶格热导率。它在室温附近具有很高的热电性能。然而，在文献研究中，热电性能的数据存在明显的差异，这极大地阻碍了对这种材料的合理理解和潜在应用。在这项工作中，我们全面研究了均匀性，再现性和热稳定性的大块Ag 2Se制备的熔融和机械合金化方法，然后放电等离子烧结。凭借的原子探针拓扑技术，我们发现纳米级的银或硒丰富的沉淀物和微孔与硒聚集的接口，以前没有检测到。采用熔融法和放电等离子烧结法制备的样品，尽管含有大量的纳米沉淀物，但其热电性能的均匀性和重复性最好。此外，通过引入少量过量的硒，Ag_2Se的热电性能大大提高。在300-380 K的范围内，平均zT可以稳定地达到0.8-0.9，这是Ag 2Se基材料报道的最高值之一。这项工作将合理化的热电性能的Ag 2Se的评价。
Ag2Se is a narrow band gap n-type semiconductor with high carrier mobility and low lattice thermal conductivity. It has high thermoelectric performance near room temperature. However, there is a noticeable data discrepancy for thermoelectric performance in the reported literature studies, which greatly hinders the rational understanding and potential application of this material. In this work, we comprehensively studied the homogeneity, reproducibility, and thermal stability of bulk Ag2Se prepared by melting and mechanical alloying methods followed by spark plasma sintering. By virtue of the atom probe topology technique, we revealed nanosized Ag- or Se-rich precipitates and micropores with Se-aggregated interfaces that have not been detected previously. The samples prepared by melting and spark plasma sintering exhibit the best homogeneity and repeatability in thermoelectric properties despite abundant nanoprecipitates. Moreover, the thermoelectric performance of Ag2Se is greatly improved by introducing a slight amount of excess selenium. The average zT can steadily reach 0.8-0.9 in the range of 300-380 K, which is among the highest values reported for Ag2Se-based materials. This work will rationalize the evaluation of the thermoelectric performance of Ag2Se.