Enhanced thermoelectric performance in GeTe-Sb2Te3 pseudo-binary via lattice symmetry regulation and microstructure stabilization

Qi, Xia1,2,3; Yu, Yong3; Xu, Xiao3; Wang, Jicheng1,2; Zhang, Fudong1,2; Zhu, Bin3; He, Jiaqing3; Chao, Xiaolian1,2; Yang, Zupei1,2; Wu, Di1,2

2021-11-01

10.1016/j.mtphys.2021.100507

Materials Today Physics   影响因子和分区

2542-5293

Pseudo-binary GeTe-rich Sb2Te3(GeTe)(n) materials recently exhibited promising thermoelectric performance at intermediate temperatures (500-800 K), largely due to the intrinsically low lattice thermal conductivity coming from the discrete van der Waals gaps dispersed in a rhombohedral matrix. In this work, by alloying Ge with Pb and adjusting the molar ratio of GeTe/Sb2Te3 in the binary, we successfully modulated the crystal structure from rhombohedral Sb2Te3(GeTe)(17) to pseudo-cubic (Sb2Te3)(0.5)(-Ge0.91Pb0.09Te)(17.5) at room temperature, thus achieved higher electronic band degeneracy and electrical performance. High-resolution scanning transmission electron microscope (STEM) characterizations revealed the existence of high-density discrete van der Waals gaps (length similar to 10-40 nm) along {111} equivalent planes in GeTe matrix; surprisingly, these planar defects appear quite stable in following annealing processes at 873 K unlike what literatures reported. Further elemental mapping suggests that the enrichment of Pb element around van der Waals gaps are possibly responsible to the formation and stabilization of these planar defects. Eventually, a figure of merit ZT(max) similar to 2.4 at 773 K and average ZT(avg) similar to 1.5 at 323-773 K were simultaneously realized in the (Sb2Te3)(0.5)(Ge0.91Pb0.09Te)(17.5 )sample after 4 days annealing at 873 K. (C) 2021 Elsevier Ltd. All rights reserved.

Thermoelectric Lattice symmetry van der Waals gap DOS effective mass Sb2Te3(GeTe)n

SCI ; EI

英语

通讯

Natural Science Foundation of Shaanxi Province[2021JM-201] ; National Natural Science Foundation of China[51872177,52002167,11874194,11934007,51632005] ; Guangdong-Hong Kong-Macao Joint Laboratory[2019B121205001] ; Fundamental Research Funds for the Central Universities["GK202002014","2020CBLZ010"] ; Science and Technology Play Project in Xi'an[2020KJRC0014]

Materials Science ; Physics

Materials Science, Multidisciplinary ; Physics, Applied

WOS:000701925300014

ELSEVIER

20220311467255

Crystal lattices ; Defects ; High resolution transmission electron microscopy ; Molar ratio ; Stabilization ; Thermal conductivity ; Van der Waals forces

Nonferrous Metals and Alloys excluding Alkali and Alkaline Earth Metals:549.3 ; Thermodynamics:641.1 ; Optical Devices and Systems:741.3 ; Physical Chemistry:801.4 ; Atomic and Molecular Physics:931.3 ; Crystal Lattice:933.1.1 ; Materials Science:951

Web of Science

1.Shaanxi Normal Univ, Sch Mat & Engn, Key Lab Macromol Sci Shaanxi Prov, Xian 710062, Peoples R China
2.Shaanxi Normal Univ, Sch Mat & Engn, Shaanxi Key Lab Adv Energy Devices, Xian 710062, Peoples R China
3.Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China

Qi, Xia,Yu, Yong,Xu, Xiao,et al. Enhanced thermoelectric performance in GeTe-Sb2Te3 pseudo-binary via lattice symmetry regulation and microstructure stabilization[J]. Materials Today Physics,2021,21.

Qi, Xia.,Yu, Yong.,Xu, Xiao.,Wang, Jicheng.,Zhang, Fudong.,...&Wu, Di.(2021).Enhanced thermoelectric performance in GeTe-Sb2Te3 pseudo-binary via lattice symmetry regulation and microstructure stabilization.Materials Today Physics,21.

Qi, Xia,et al."Enhanced thermoelectric performance in GeTe-Sb2Te3 pseudo-binary via lattice symmetry regulation and microstructure stabilization".Materials Today Physics 21(2021).