Enhancement of Thermoelectric Figure of Merit by the Insertion of MgTe Nanostructures in p-type PbTe Doped with Na2Te

Authors

  • Michihiro Ohta,

    1. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
    2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
    3. Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, JAPAN
    Current affiliation:
    1. These authors contributed equally to this work.
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  • Kanishka Biswas,

    1. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
    Current affiliation:
    1. These authors contributed equally to this work.
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  • Shih-Han Lo,

    1. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
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  • Jiaqing He,

    1. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
    2. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
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  • Duck Young Chung,

    1. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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  • Vinayak P. Dravid,

    1. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
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  • Mercouri G. Kanatzidis

    Corresponding author
    1. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
    2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
    • Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
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Abstract

The thermoelectric properties of crystalline melt-grown ingots of p-type PbTe–xMgTe (x = 1–3 mol%) doped with Na2Te (1–2 mol%) were investigated over the temperature range of 300 K to 810 K. While the powder X-ray diffraction patterns show that all samples crystallize in the NaCl-type structure with no MgTe or other phases present, transmission electron microscopy reveals ubiquitous MgTe nanoprecipitates in the PbTe. The very small amounts of MgTe in PbTe have only a small effect on the electrical transport properties of the system, while they have a large effect on thermal transport significantly reducing the lattice thermal conductivity. A ZT of 1.6 at 780 K is achieved for the PbTe containing 2% MgTe doped with 2% Na2Te.

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