Condensed point defects enhance thermoelectric performance of rare-earth Lu-doped GeTe  

作　　者：Wan-Yu Lyu Wei-Di Liu Meng Li Xiao-Lei Shi Min Hong Tianyi Cao Kai Guo Jun Luo Jin Zou Zhi-Gang Chen 

机构地区：[1]Centre for Future Materials,University of Southern Queensland,Springfield,Queensland 4300,Australia [2]School of Chemistry and Physics,Queensland University of Technology,Brisbane,Queensland 4000,Australia [3]Australian Institute for Bioengineering and Nanotechnology,The University of Queensland,Brisbane,Queensland 4072,Australia [4]School of Physics and Materials Science,Guangzhou University,Guangzhou 510006,China [5]School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China [6]School of Mechanical and Mining Engineering,The University of Queensland,Brisbane,Queensland 4072,Australia [7]Centre for Microscopy and Microanalysis,The University of Queensland,Brisbane,Queensland 4072,Australia

出　　处：《Journal of Materials Science & Technology》2023年第20期227-233,共7页材料科学技术（英文版）

基　　金：supported by the Australian Research Council,the Innovation centre for Sustainable Steel project,and the QUT capacity building professor program.K.Guo thanks the support of the National Key Research and Development Program of China(No.2018YFA0702100)。

摘　　要：Heavy rare-earth element doping can effectively strengthen phonon scattering,suppress the lattice thermal conductivity,and enhance the overall thermoelectric performance of GeTe.However,the large electronegativity difference between rare-earth elements(such as La,Eu,and Gd)and Ge refrains the doping limit of rare-earth elements below 1 mol.%in GeTe.Here,compared with other rare earth elements,Lu was found to have a relatively small radius and electronegativity difference with Ge,which can induce a high doping level in GeTe.The result shows that Lu doping effectively reduces the lattice thermal conductivity from 0.77 W^(−1) m K^(−1) of GeTe to 0.35 W m^(−1) K^(−1) of Ge_(0.98)Lu_(0.02)Te at 673 K,and further induces a high zT value of 1.5 in Ge_(0.98)Lu_(0.02)Te at 673 K.Extra Sb alloying optimizes the carrier concentration from 1.02×10^(21) cm^(−3) of Ge_(0.98)Lu_(0.02)Te to 1.77×10^(20) cm^(−3) of Ge0.90Lu0.02Sb0.08Te,which results in a reasonable power factor of 33.82μW cm^(−1) K^(−2) and a low electrical thermal conductivity of 0.75 W m^(−1) K^(−1) at 673 K in Ge_(0.90)Lu_(0.02)Sb_(0.08)Te.Correspondingly,a peak zT of 1.75 at 673 K and an average zT of 0.92 within the temperature range of 303–723 K are obtained in Ge_(0.9)Lu_(0.02)Sb_(0.08)Te.This study indicates that Lu and Sb co-doping can effectively boost the thermoelectric performance of GeTe-based thermoelectric materials.

关 键 词：THERMOELECTRIC RARE-EARTH Thermal conductivity Carrier concentration 

分 类 号：TB34[一般工业技术—材料科学与工程]