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Enhanced thermoelectric performance through synergy of resonance levels and valence band convergence via Q/In (Q = Mg, Ag, Bi) co-doping

Journal Article


Abstract


  • The temperature-dependent evolution of heavy-hole valence band contribution to the Seebeck coefficients of SnTe-based thermoelectric materials is revealed in situ by neutron and synchrotron powder diffraction. The additional carriers with high effective mass are created in a heavy-hole valence band above 493 K, which contribute to the electrical transport, and lead to a significant enhancement of the Seebeck coefficient at high temperature. In addition, remarkably improved electrical transport properties are achieved through the synergetic effects of the resonance levels, the valence band convergence, and the carrier concentration optimization by co-doping with Mg & In, Ag & In and Bi & In. Significant reduction in the lattice thermal conductivity is obtained by multiscale phonon scattering over a wide spectrum via atomic point defects, nanoscale elongated screw dislocations with random directions, and the microscale grain boundaries caused by sintering. As a result, a high figure of merit, ZT, of ∼1 at 873 K is obtained for the Mg0.015In0.015Sn0.97Te sample.

Publication Date


  • 2018

Citation


  • Zhang, L., Qin, P., Han, C., Wang, J., Ge, Z., Sun, Q., Cheng, Z., Li, Z. & Dou, S. Xue. (2018). Enhanced thermoelectric performance through synergy of resonance levels and valence band convergence via Q/In (Q = Mg, Ag, Bi) co-doping. Journal of Materials Chemistry A, 6 (6), 2507-2516.

Scopus Eid


  • 2-s2.0-85041952320

Number Of Pages


  • 9

Start Page


  • 2507

End Page


  • 2516

Volume


  • 6

Issue


  • 6

Place Of Publication


  • United Kingdom

Abstract


  • The temperature-dependent evolution of heavy-hole valence band contribution to the Seebeck coefficients of SnTe-based thermoelectric materials is revealed in situ by neutron and synchrotron powder diffraction. The additional carriers with high effective mass are created in a heavy-hole valence band above 493 K, which contribute to the electrical transport, and lead to a significant enhancement of the Seebeck coefficient at high temperature. In addition, remarkably improved electrical transport properties are achieved through the synergetic effects of the resonance levels, the valence band convergence, and the carrier concentration optimization by co-doping with Mg & In, Ag & In and Bi & In. Significant reduction in the lattice thermal conductivity is obtained by multiscale phonon scattering over a wide spectrum via atomic point defects, nanoscale elongated screw dislocations with random directions, and the microscale grain boundaries caused by sintering. As a result, a high figure of merit, ZT, of ∼1 at 873 K is obtained for the Mg0.015In0.015Sn0.97Te sample.

Publication Date


  • 2018

Citation


  • Zhang, L., Qin, P., Han, C., Wang, J., Ge, Z., Sun, Q., Cheng, Z., Li, Z. & Dou, S. Xue. (2018). Enhanced thermoelectric performance through synergy of resonance levels and valence band convergence via Q/In (Q = Mg, Ag, Bi) co-doping. Journal of Materials Chemistry A, 6 (6), 2507-2516.

Scopus Eid


  • 2-s2.0-85041952320

Number Of Pages


  • 9

Start Page


  • 2507

End Page


  • 2516

Volume


  • 6

Issue


  • 6

Place Of Publication


  • United Kingdom