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Published October 2011 | Published
Journal Article Open

Optimized thermoelectric properties of Mo_3Sb_(7-x)Te_x with significant phonon scattering by electrons

Abstract

Heavily doped compounds Mo_3Sb_(7−x)Te_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.

Additional Information

© 2011 Royal Society of Chemistry. Received 03 Apr 2011, Accepted 07 Jul 2011. First published on the web 17 Aug 2011. This work was partially supported by The Program of Shanghai Subject Chief Scientist (09XD1404400) and The National High Technology Research and Development Program of China (2009AA03Z210).

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August 19, 2023
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