Rare earth element Ce enables high thermoelectric performance in n-type SnSe polycrystals  

作　　者：Shan Li Li Yin Yijie Liu Xiaodong Wang Chen Chen Qian Zhang 

机构地区：[1]School of Civil Aviation,Northwestern Polytechnical University,Xi’an 710072,China [2]School of Materials Science and Engineering,and Institute of Materials Genome&Big Data,Harbin Institute of Technology,Shenzhen 518055,China [3]State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China

出　　处：《Journal of Materials Science & Technology》2023年第12期234-241,共8页材料科学技术（英文版）

基　　金：supported by the Fundamental Research Funds for the Central Universities (No.G2022WD01007);the National Natural Science Foundation of China (Nos.11874313,51971081,and 52172194);the Shenzhen Science and Technology Innovation Plan (No.KQTD20200820113045081);State Key Lab of Advanced Welding and Joining,Harbin Institute of Technology.

摘　　要：SnSe exhibits excellent thermoelectric performance in both n-and p-type single crystals,but its n-type polycrystals are restricted because of the lower electrical conductivity.Here,we dually introduced rare earth element Ce and PbTe to optimize the thermoelectric properties of n-type SnSe polycrystals.It is demonstrated that Ce is an effective cationic dopant to convert SnSe from p-to n-type conductor,and an enhanced peak zT value of∼0.9 at 823 K was obtained in Sn 0.97 Ce 0.03 Se due to the improved power factor.Furthermore,PbTe alloying not only reduced the band gap to increase the carrier concentration,but also enhanced the density-of-states effective mass,and hence further increased the power factor in the whole measured temperature range.Meanwhile,the lattice thermal conductivity was significantly reduced owing to the enhanced phonon scattering by the mass and strain fluctuations.As a result,the peak zT value was increased to∼1.3 for Sn 0.9 Pb 0.07 Ce 0.03 Se 0.93 Te 0.07 together with a high average zT value of∼0.52 in the temperature range of 300 to 823 K.

关 键 词：THERMOELECTRIC N-type SnSe Ce doping PbTe alloying 

分 类 号：TB34[一般工业技术—材料科学与工程]