Extraordinary role of Hg in enhancing the thermoelectric performance of p-type SnTe

Gangjian Tan, Fengyuan Shi, Jeff W. Doak, Hui Sun, Li Dong Zhao, Pengli Wang, Ctirad Uher, Chris Wolverton, Vinayak P. Dravid, Mercouri G. Kanatzidis

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190 Citations (Scopus)

Abstract

We report several synergistic effects in Hg alloying of SnTe to enhance the power factor and overall figure of merit ZT. Hg alloying decreases the energy separation between the two valence bands, leading to pronounced band convergence that improves the Seebeck coefficient. Hg alloying of SnTe also significantly enlarges the band gap thereby effectively suppressing the bipolar diffusion. Collectively, this results in high ZT of ∼1.35 at 910 K for 2% Bi-doped SnTe with 3%HgTe. The solubility limit of Hg in SnTe is less than 3 mol%, and above this level we observe HgTe precipitates in the SnTe matrix, typically trapped at grain boundary triple junctions. The strong point defect scattering of phonons caused by Hg alloying coupled with mesoscale scattering via grain boundaries contributes to a great reduction of lattice thermal conductivity. The multiple synergistic roles that Hg plays in regulating the electron and phonon transport in SnTe provide important new insights into continued optimization of SnTe-based and related materials.

Original languageEnglish
Pages (from-to)267-277
Number of pages11
JournalEnergy and Environmental Science
Volume8
Issue number1
DOIs
Publication statusPublished - Jan 1 2015

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ASJC Scopus subject areas

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

Cite this

Tan, G., Shi, F., Doak, J. W., Sun, H., Zhao, L. D., Wang, P., Uher, C., Wolverton, C., Dravid, V. P., & Kanatzidis, M. G. (2015). Extraordinary role of Hg in enhancing the thermoelectric performance of p-type SnTe. Energy and Environmental Science, 8(1), 267-277. https://doi.org/10.1039/c4ee01463d