Optimized thermoelectric properties of Mo 3Sb 7-xTe x with significant phonon scattering by electrons

Xiaoya Shi, Yanzhong Pei, G. Jeffrey Snyder, Lidong Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

Abstract

Heavily doped compounds Mo 3Sb 7-xTe x (x = 0, 1.0, 1.4, 1.8) were synthesized by solid state reaction and sintered by spark plasma sintering. Both X-ray diffraction and electron probe microanalysis indicated the maximum solubility of Te was around x = 1.8. The trends in the electrical transport properties can generally be understood using a single parabolic band model, which predicts that the extremely high carrier concentration of Mo 3Sb 7 (∼10 22 cm -3) can be reduced to a nearly optimized level (∼2 × 10 21 cm -3) for thermoelectric figure of merit (zT) by Te-substitution with x = 1.8. The increased lattice thermal conductivity by Te-doping was found to be due to the decreased Umklapp and electron-phonon scattering, according to a Debye model fitting. The thermoelectric figure of merit (zT) monotonously increased with increasing temperature and reached its highest value of about 0.51 at 850 K for the sample with x = 1.8, making these materials competitive with the state-of-the-art thermoelectric SiGe alloys. Evidence of significant electron-phonon scattering is found in the thermal conductivity.

Original languageEnglish (US)
Pages (from-to)4086-4095
Number of pages10
JournalEnergy and Environmental Science
Volume4
Issue number10
DOIs
StatePublished - Oct 2011

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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