Band modification towards high thermoelectric performance of SnSb_(2)Te_(4) with strong anharmonicity driven by cation disorder  

作　　者：Hong Wu Peng Chen Zizhen Zhou De Zhang Xiangnan Gong Bin Zhang Yang Zhou Kunling Peng Yanci Yan Guiwen Wang Jun Liu Dengfeng Li Guang Han Guoyu Wang Xu Lu Xiaoyuan Zhou 

机构地区：[1]School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China [2]College of Physics and Center for Quantum Materials & Devices, Chongqing University, Chongqing 401331, China [3]College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China [4]Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China [5]Analytical and Testing Center of Chongqing University, Chongqing 401331, China [6]Interdisciplinary Center for Fundamental and Frontier Sciences, Nanjing University of Science and Technology, Jiangyin 214443, China

出　　处：《Journal of Materials Science & Technology》2023年第23期140-148,共9页材料科学技术（英文版）

基　　金：financially supported in part by the National Natural Science Foundation of China(Grant Nos.52125103,52071041,U21A2054,12204080,11904039,and 12004060);supported in part by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(GrantNo.KJQN202200623);the Natural Science Foundation of Chongqing(Grant No.CSTB2022NSCQ-MSX0382)。

摘　　要：As a typical (IV–VI)_(x)(V_(2)VI_(3))_(y) compound, the tetradymite-like layered SnSb_(2)Te_(4) -based compounds have attracted increasing attention in the thermoelectric community owing to the intrinsically low lattice thermal conductivity. Nevertheless, the effect of cations disorder on the inherent physical characteristics remains puzzling, and its inferior Seebeck coefficient is the bottleneck to achieving high thermoelectric performance. In this work, the thermoelectric properties of polycrystalline In_(x)Sn_(1−x)Sb_(2)(Te_(1−y)Se_(y))_(4) (0≤x≤0.1,0≤y≤0.15) samples are comprehensively investigated. In conjunction with the calculated band structure and experimental results, the Seebeck coefficient and power factor are markedly improved after the introduction of indium and selenium, which originates from the combined effects of the emergent resonant states and converged valence bands along with optimal carrier concentration. Additionally, compared with the ordered lattice structure, the disordered cations occupancy in SnSb_(2)Te_(4) further strengthens lattice anharmonicity and reduces phonon group velocity verified by first-principles calculations, securing intrinsically low lattice thermal conductivity. Finally, a record zT value of ∼0.6 at 670 K and an average zT of ∼0.4 between 320 and 720 K are obtained in the In0.1 Sn0.9 Sb2 Te3.4 Se0.6 sample, being one of the highest zT values among SnSb2 Te4 -based materials. This work not only demonstrates that SnSb2 Te4 -based compounds are promising thermoelectric candidates, but also provides guidance for the promotion of thermoelectric performance in a broad temperature range.

关 键 词：THERMOELECTRIC SnSb_(2)Te_(4) Lattice anharmonicity Resonant level Band Convergence 

分 类 号：TB34[一般工业技术—材料科学与工程]