Qiu Pengfei, Qin Yuting, Zhang Qihao, Li Ruoxi, Yang Jiong, Song Qingfeng, Tang Yunshan, Bai Shengqiang, Shi Xun, Chen Lidong
State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China.
University of Chinese Academy of Sciences Beijing 100049 China.
Adv Sci (Weinh). 2017 Dec 18;5(3):1700727. doi: 10.1002/advs.201700727. eCollection 2018 Mar.
Diamond-like compounds are a promising class of thermoelectric materials, very suitable for real applications. However, almost all high-performance diamond-like thermoelectric materials are p-type semiconductors. The lack of high-performance n-type diamond-like thermoelectric materials greatly restricts the fabrication of diamond-like material-based modules and their real applications. In this work, it is revealed that n-type AgInSe diamond-like compound has intrinsically high thermoelectric performance with a figure of merit () of 1.1 at 900 K, comparable to the best p-type diamond-like thermoelectric materials reported before. Such high is mainly due to the ultralow lattice thermal conductivity, which is fundamentally limited by the low-frequency Ag-Se "cluster vibrations," as confirmed by ab initio lattice dynamic calculations. Doping Cd at Ag sites significantly improves the thermoelectric performance in the low and medium temperature ranges. By using such high-performance n-type AgInSe-based compounds, the diamond-like thermoelectric module has been fabricated for the first time. An output power of 0.06 W under a temperature difference of 520 K between the two ends of the module is obtained. This work opens a new window for the applications using the diamond-like thermoelectric materials.
类金刚石化合物是一类很有前景的热电材料，非常适合实际应用。然而，几乎所有高性能的类金刚石热电材料都是p型半导体。缺乏高性能的n型类金刚石热电材料极大地限制了基于类金刚石材料的模块的制造及其实际应用。在这项工作中，发现n型AgInSe类金刚石化合物具有本征的高热电性能，在900 K时优值（）为1.1，与之前报道的最佳p型类金刚石热电材料相当。如此高的主要归因于超低的晶格热导率，这从根本上受到低频Ag-Se“团簇振动”的限制，这一点通过第一性原理晶格动力学计算得到了证实。在Ag位点掺杂Cd显著提高了中低温范围内的热电性能。通过使用这种高性能的基于n型AgInSe的化合物，首次制造出了类金刚石热电模块。在模块两端温差为520 K的情况下，获得了0.06 W的输出功率。这项工作为使用类金刚石热电材料的应用打开了一扇新窗口。
