The influence of Dy concentration on the thermoelectric properties of n-type Dy-doped Bi2Te3 pellets prepared by hydrothermal and carbon burial sintering

Tony Kristiantoro, Dedi, Vivi Fauzia

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1 Citation (Scopus)

Abstract

Dy-doped Bi2Te3 pellets with three different molar ratios between the precursors BiCl3 and DyCl3∙6H2O (x = 0.05, 0.1, and 0.25) were prepared by hydrothermal and carbon burial sintering. The excess of Dy ions in the highly doped samples (x = 0.25) remarkably increased the Seebeck coefficient, reduced the thermal conductivity, and increased ZT more than twofold in the temperature range of 323–375 K compared to pristine Bi2Te3. At low Dy concentrations (x = 0.05 and 0.1), the Dy ions substituted the TeBi antisites and then intercalated between the Bi2Te3 interlayers at higher concentration. The Dy ions act as both the phonon and charge carrier scattering centers which increase the scattering factor and decrease the point defect scattering relaxation time γ. The increase in the number of Te vacancies and the higher sound velocity of Dy (2710 m/s at 20 °C) compared to that of Bi (1790 m/s) considerably contribute to the improvement of the thermoelectric performance of pristine Bi2Te3.

Original languageEnglish
Article number110241
JournalJournal of Physics and Chemistry of Solids
Volume158
DOIs
Publication statusPublished - Nov 2021

Keywords

  • Intercalation
  • point defect
  • scattering
  • Seebeck coefficient
  • sound velocity

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