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Issue 11, 2013
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All-scale hierarchical thermoelectrics: MgTe in PbTe facilitates valence band convergence and suppresses bipolar thermal transport for high performance

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Abstract

We report a high ZT of ∼2.0 at 823 K for 2% Na-doped PbTe with 6% MgTe with excellent thermal stability. We attribute the high thermoelectric performance to a synergistic combination of enhanced power factor, reduction of the lattice thermal conductivity and simultaneous suppression of bipolar thermal conductivity. MgTe inclusion in PbTe owns triple functions: the Mg alloying within the solubility limit in PbTe modifies the valence band structure by pushing the two valence bands (L and Σ bands) closer in energy, thereby facilitating charge carrier injection. When the solubility limit of Mg is exceeded, ubiquitous endotaxial nanostructures form, which when coupled with mesoscale microstructuring results in a very low (lattice) thermal conductivity through all-scaled length phonon scattering. Meanwhile, most significantly, the Mg alloying enlarges the energy gap of conduction band (C band) and light valence band (L band), thereby suppresses the bipolar thermal conductivity through an increase in band gap.

Graphical abstract: All-scale hierarchical thermoelectrics: MgTe in PbTe facilitates valence band convergence and suppresses bipolar thermal transport for high performance

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Publication details

The article was received on 29 Jun 2013, accepted on 11 Sep 2013 and first published on 24 Sep 2013


Article type: Paper
DOI: 10.1039/C3EE42187B
Citation: Energy Environ. Sci., 2013,6, 3346-3355
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    All-scale hierarchical thermoelectrics: MgTe in PbTe facilitates valence band convergence and suppresses bipolar thermal transport for high performance

    L. D. Zhao, H. J. Wu, S. Q. Hao, C. I. Wu, X. Y. Zhou, K. Biswas, J. Q. He, T. P. Hogan, C. Uher, C. Wolverton, V. P. Dravid and M. G. Kanatzidis, Energy Environ. Sci., 2013, 6, 3346
    DOI: 10.1039/C3EE42187B

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