Micro- and Macromechanical Properties of Thermoelectric Lead Chalcogenides

Guodong Li, Umut Aydemir, Bo Duan, Matthias T. Agne, Hongtao Wang, Max Wood, Qingjie Zhang*, Pengcheng Zhai, William A. Goddard, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Both n- and p-type lead telluride (PbTe)-based thermoelectric (TE) materials display high TE efficiency, but the low fracture strength may limit their commercial applications. To find ways to improve these macroscopic mechanical properties, we report here the ideal strength and deformation mechanism of PbTe using density functional theory calculations. This provides structure-property relationships at the atomic scale that can be applied to estimate macroscopic mechanical properties such as fracture toughness. Among all the shear and tensile paths that are examined here, we find that the lowest ideal strength of PbTe is 3.46 GPa along the (001)/«100» slip system. This leads to an estimated fracture toughness of 0.28 MPa m1/2 based on its ideal stress-strain relation, which is in good agreement with our experimental measurement of 0.59 MPa m1/2. We find that softening and breaking of the ionic Pb-Te bond leads to the structural collapse. To improve the mechanical strength of PbTe, we suggest strengthening the structural stiffness of the ionic Pb-Te framework through an alloying strategy, such as alloying PbTe with isotypic PbSe or PbS. This point defect strategy has a great potential to develop high-performance PbTe-based materials with robust mechanical properties, which may also be applied to other materials and applications.

Original languageEnglish (US)
Pages (from-to)40488-40496
Number of pages9
JournalACS Applied Materials and Interfaces
Volume9
Issue number46
DOIs
StatePublished - Nov 22 2017

Keywords

  • PbTe-based thermoelectric materials
  • macroscopic mechanical properties

ASJC Scopus subject areas

  • Materials Science(all)

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