Enhancing the Thermoelectric Performance of Mg2Sn Single Crystals via Point Defect Engineering and Sb Doping

Wataru Saito, Kei Hayashi, Zhicheng Huang, Jinfeng Dong, Jing Feng Li, Yuzuru Miyazaki

Research output: Contribution to journalArticlepeer-review

Abstract

Mg2Sn is a potential thermoelectric (TE) material that exhibits environmental compatibility. In this study, we fabricated Sb-doped Mg2Sn (Mg2Sn1-xSbx) single-crystal ingots and demonstrated the enhancement of TE performance via point defect engineering and Sb doping. The Mg2Sn1-xSbx single-crystal ingots exhibited considerably enhanced electrical conductivity because of the donor-doping effect in addition to high carrier mobility. Moreover, the Mg2Sn1-xSbx single-crystal ingots contained Mg vacancy (VMg) as a point defect. The introduced VMg and doped Sb atoms formed nanostructures, both acting as phonon-scattering centers. Consequently, lower lattice thermal conductivity was achieved for the Mg2Sn1-xSbx single-crystal ingots compared with polycrystalline counterparts. Owing to the significant enhancement in the electrical conductivity and the reduction in the lattice thermal conductivity, the maximum power factor of 5.1(4) × 10-3 W/(K2 m) and the maximum dimensionless figure of merit of 0.72(5) were achieved for the Mg2Sn0.99Sb0.01 single-crystal ingot, which are higher than those of single-phase Mg2Sn1-xSb polycrystals.

Original languageEnglish
Pages (from-to)57888-57897
Number of pages10
JournalACS Applied Materials and Interfaces
Volume12
Issue number52
DOIs
Publication statusPublished - 2020 Dec 30

Keywords

  • Mg vacancy
  • MgSn
  • Sb doping
  • nanostructure
  • point defect
  • single crystal
  • thermoelectric properties

ASJC Scopus subject areas

  • Materials Science(all)

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