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Enhancement in Thermoelectric Figure of Merit in Nanostructured Bi2Te3 with Semimetal Nanoinclusions

Authors

  • S. Sumithra,

    1. Dept. of Physics and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA-70148, USA
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  • Nathan J. Takas,

    1. Dept. of Chemistry and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA-70148, USA
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  • Dinesh K. Misra,

    1. Dept. of Chemistry and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA-70148, USA
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  • Westly M. Nolting,

    1. Dept. of Physics and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA-70148, USA
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  • P.F.P. Poudeu,

    1. Dept. of Chemistry and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA-70148, USA
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  • Kevin L. Stokes

    Corresponding author
    1. Dept. of Physics and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA-70148, USA
    • Dept. of Physics and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA-70148, USA.
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Abstract

The effect of Bi (semimetal) nanoinclusions in nanostructured Bi2Te3 matrices is investigated. Bismuth nanoparticles synthesized by a low temperature solvothermal method are incorporated into Bi2Te3 matrix phases, synthesized by planetary ball milling. High density pellets of the Bi nanoparticle/Bi2Te3 nanocomposites are created by hot pressing the powders at 200 °C and 100 MPa. The effect of different volume fractions (0–7%) of Bi semimetal nanoparticles on the Seebeck coefficient, electrical conductivity, thermal conductivity and carrier concentration is reported. Our results show that the incorporation of semimetal nanoparticles results in a reduction in the lattice thermal conductivity in all the samples. A significant enhancement in power factor is observed for Bi nanoparticle volume fraction of 5% and 7%. We show that it is possible to reduce the lattice thermal conductivity and increase the power factor resulting in an increase in figure of merit by a factor of 2 (from ZT = 0.2 to 0.4). Seebeck coefficient and electrical conductivity as a function of carrier concentration data are consistent with the electron filtering effect, where low-energy electrons are preferentially scattered by the barrier potentials set up at the semimetal nanoparticle/semiconductor interfaces.

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