Realizing high thermoelectric performance in hot-pressed polycrystalline Al_(x)Sn_(1-x) Se through band engineering tuning  

作　　者：Nan Xin Yifei Li Hao Shen Longyun Shen Guihua Tang 

机构地区：[1]MOE Key Laboratory of ThermoeFluid Science and Engineering,School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an,Shaanxi,710049,China [2]State Key Laboratory for Mechanical Behavior of Materials,School of Materials Science and Engineering,Xi'an Jiaotong University,Xi'an,Shaanxi,710049,China

出　　处：《Journal of Materiomics》2022年第2期475-488,共14页无机材料学学报（英文）

基　　金：For financial support,the authors are grateful to the funding support from the China Postdoctoral Science Foundation under grant number of 2019M653619;the National Natural Science Foundation of China under grant numbers of 52006167,51825604 and 51721004;the 111 Project under grant number of B16038.

摘　　要：SnSe-based thermoelectric materials are being explored since they have potential high thermoelectric figure of merit.We synthesized polycrystalline Al_(x)Sn_(1-x)Se(x=0.01,0.02,0.03 and 0.04)by hot-pressing method,and combined theoretical estimation with experimental measurement to investigate the in-fluence of Al doping on thermoelectric properties of SnSe.It was found that dopant Al can effectively adjust the band structure of SnSe by introducing intermediate band.Al doping with low content(x=0.01 and 0.02)can introduce a single intermediate band close to the valence band maximum or conduction band minimum,achieving band engineering optimization.In high temperature region(498 K<T<823 K),the electronic transport properties significantly enhance with thermal excitation.The lattice thermal conductivity reduces with the Al atomic point defect scattering,leading to a low thermal conductivity of 0.47 W m^(-1) K^(-1) in Al_(0.04)Sn_(0.96)Se at 823 K.As a result,a high ZT of 0.84 at 823 K is obtained from the Al_(0.04)Sn_(0.96) Se perpendicular to the pressing direction,which is 58.5%larger than that of SnSe.In addition,dopant Al can adjust the anisotropy of polycrystalline SnSe.The anisotropy of electronic properties are enhanced with low doping level(x=0.01,0.02)and suppressed with high doping level(x=0.03,0.04).

关 键 词：Thermoelectric materials SnSe doped HOT-PRESSING Thermoelectric performance Band engineering 

分 类 号：O61[理学—无机化学]