Defect and Dopant Mediated Thermoelectric Power Factor Tuning in β-Zn4Sb3

Vaithinathan Karthikeyan, Tan Li, Bharat Medasani, Caiqin Luo, Dongliang Shi, Joseph C.K. Wong, Kwok Ho Lam, Francis C.C. Ling, Vellaisamy A.L. Roy

Research output: Journal article publicationJournal articleAcademic researchpeer-review

1 Citation (Scopus)

Abstract

The presence of defects in thermoelectric materials plays a significant role in the modification their properties by influencing the behavior of electrons and phonons. Dopants with a unique f-orbital can directly cause distortions in electronic density of states (eDOS) and phonon transport mechanism by intentionally inducing defects in their lattice. The theoretical and experimental outcomes of engineered vacancy defects are investigated by intentional doping of f-block rare earth elements in β-Zn4Sb3. Thermoelectric behavior breaks down the inverse relation and results in a parallel increase in Seebeck coefficient and electrical conductivity for β-(Zn0.997Ce0.003)4Sb3 and β-(Zn0.997Er0.003)4Sb3. This synergistic response triples the power factor of a thermoelectric β-Zn4Sb3 system realized by the impurity induced resonant distortion in eDOS. From first principle GGA + U calculations, the above-mentioned unconventional properties are attributed to the effect of doping induced vacancy formation and the formation of resonant impurity levels. Hence, it is postulated that defect engineering can be a broad strategy to improve the power factor of the system and can be extended to other thermoelectric materials.

Original languageEnglish
Article number1901284
JournalAdvanced Electronic Materials
Volume6
Issue number4
DOIs
Publication statusPublished - 1 Apr 2020

Keywords

  • extrinsic doping
  • intrinsic defects
  • power factor
  • thermoelectrics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this