Grain Boundaries Softening Thermoelectric Oxide BiCuSeO

Guodong Li*, Shiqiang Hao, Sergey I. Morozov, Pengcheng Zhai, Qingjie Zhang, William A. Goddard, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Engineering grain boundaries (GBs) are effective in tuning the thermoelectric (TE) properties of TE materials, but the role of GB on mechanical properties, which is important for their commercial applications, remains unexplored. In this paper, we apply ab initio method to examine the ideal shear strength and failure mechanism of GBs in TE oxide BiCuSeO. We find that the ideal shear strength of the GB is much lower than that of the ideal single crystal. The atomic rearrangements accommodating the lattice and neighbor structure mismatch between different grains leads to the much weaker GB stiffness compared with grains. Failure of the GBs arises from either the distortion of the Cu-Se layers or the relative slip between Bi-O and Cu-Se layers. This work is crucial to illustrate the deformation of GBs, laying the basis for the development and design of mechanically robust polycrystalline TE materials.

Original languageEnglish (US)
Pages (from-to)6772-6777
Number of pages6
JournalACS Applied Materials and Interfaces
Volume10
Issue number7
DOIs
StatePublished - Feb 21 2018

Keywords

  • atomistic modeling
  • grain boundary softening
  • micromechanics
  • thermoelectric oxide BiCuSeO

ASJC Scopus subject areas

  • Materials Science(all)

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