State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics , Chinese Academy of Sciences , Shanghai 200050 , China.
Center of Materials Science and Optoelectronics Engineering , University of Chinese Academy of Sciences , Beijing 100049 , China.
ACS Appl Mater Interfaces. 2019 Apr 3;11(13):12632-12638. doi: 10.1021/acsami.8b22741. Epub 2019 Mar 25.
AgSSe, named as aguilarite in mineralogy, belongs to the family of liquid-like superionic compounds at middle temperature, but its thermoelectric (TE) properties are rarely investigated so far. In this study, a series of Ag-deficient AgSSe samples have been synthesized by the melting-annealing method. Their crystal structures, phase transition features, and electrical and thermal transport properties have been systematically investigated. It is found that AgSSe allows a small amount of Ag deficiency inside the lattice without altering the initial crystal structure and phase transition feature. The stoichiometric AgSSe has a low TE figure of merit ( zT) of 0.24 at 613 K because of the overhigh carrier concentration. Introducing Ag deficiency in AgSSe significantly lowers the carrier concentration, yielding a greatly enhanced Seebeck coefficient and suppressed carrier thermal conductivity throughout the entire measured temperature range. A maximum TE zT of 0.53 is achieved at 493 K for AgSSe, about two times that for the stoichiometric AgSSe. The present study suggests that aguilarite AgSSe is a promising TE material applied at the middle temperature range.
AgSSe，在矿物学中称为阿瓜拉莱特，属于中温液态类超离子化合物家族，但迄今为止，其热电（TE）性质很少被研究。在本研究中，通过熔融-退火法合成了一系列 Ag 缺乏的 AgSSe 样品。系统研究了它们的晶体结构、相变特征以及电输运和热输运性能。结果发现，AgSSe 允许晶格内存在少量的 Ag 缺乏，而不会改变初始晶体结构和相变特征。化学计量的 AgSSe 的 TE 优值（zT）在 613 K 时仅为 0.24，因为载流子浓度过高。在 AgSSe 中引入 Ag 缺乏会显著降低载流子浓度，从而在整个测量温度范围内产生大幅增强的 Seebeck 系数和抑制的载流子热导率。对于 AgSSe，在 493 K 时获得了最大的 TE zT 为 0.53，大约是化学计量的 AgSSe 的两倍。本研究表明，阿瓜拉莱特 AgSSe 是一种很有前途的中温应用 TE 材料。
