Design of lead telluride based thermoelectric materials through incorporation of lead sulfide inclusions or ligand stripping of nanosized building block

Derak James, Xu Lu, Alexander Chi Nguyen, Donald Morelli, Stephanie L. Brock

    Research output: Contribution to journalArticle

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    Abstract

    Design of thermoelectric materials focuses on the optimization of several unfavorably coupled factors: electrical conductivity, Seebeck coefficient, and thermal conductivity. Recent work in thermoelectrics has focused on decreasing lattice thermal conductivity by nanostructuring thermoelectric materials, while recent work in photovoltaics has demonstrated ligand stripping as a means to increased electron mobility in thin films of nanoparticles. In the present work, these two features are combined. A multigram scale synthesis of dispersible, lead telluride nanocrystals (25-50 nm) is developed using hot-injection methods in common organic solvents. These nanocrystals (NCs) are ligand stripped with sulfide (PbTe-S) or iodide (PbTe-I) sources to result in p-type or n-type materials with large Seebeck coefficients at room temperature of 520 or -540 μV·K-1, respectively. Sequential stripping with sulfide and then iodide (PbTe-SI) resulted in a small Seebeck due to counter doping. PbTe-S and PbTe-SI are found to generate nanostructured composites by growth of lead sulfide nanocrystals (∼50-60 nm) in situ upon annealing. However, the electrical conductivities are low (-1) due to excess doping during the ligand stripping. Intentional formation of a nanocomposite (PbTe-PbS) is achieved by combining PbTe NCs with 4-6 nm diameter lead sulfide particles via mixing by incipient wetness with a target of 8 mol % lead sulfide. The resulting nanocomposite is n-type with a Seebeck coefficient of -160 μV·K-1 and an electrical conductivity of 42 S·cm-1 at room temperature. The lattice thermal conductivities of all materials at room temperature are substantially lower than those of bulk lead telluride (2.0 W m-1·K-1). However, thermoelectric figure of merit (ZT) values are low for all samples (maximum ZT = 0.03 for PbTe-PbS), attributed primarily to the low electrical conductivities. This work underscores the importance of developing new methods for augmenting electrical conductivity if nanoparticle assemblies are to be practically employed in thermoelectrics.

    Original languageEnglish (US)
    Pages (from-to)4635-4644
    Number of pages10
    JournalJournal of Physical Chemistry C
    Volume119
    Issue number9
    DOIs
    StatePublished - Mar 5 2015

    Profile

    electrical resistivity
    Electric Conductivity
    Traffic Accidents
    lead sulfides
    stripping
    nanocrystals
    ligands
    Nicarbazin
    Nanocrystals
    Ligands
    lead tellurides
    thermoelectric materials
    Seebeck effect
    thermal conductivity
    room temperature
    Joint Loose Bodies
    Acetanilides
    Seebeck coefficient
    Thermal conductivity
    Temperature

    ASJC Scopus subject areas

    • Physical and Theoretical Chemistry
    • Electronic, Optical and Magnetic Materials
    • Surfaces, Coatings and Films
    • Energy(all)

    Cite this

    Design of lead telluride based thermoelectric materials through incorporation of lead sulfide inclusions or ligand stripping of nanosized building block. / James, Derak; Lu, Xu; Nguyen, Alexander Chi; Morelli, Donald; Brock, Stephanie L.

    In: Journal of Physical Chemistry C, Vol. 119, No. 9, 05.03.2015, p. 4635-4644.

    Research output: Contribution to journalArticle

    James, Derak; Lu, Xu; Nguyen, Alexander Chi; Morelli, Donald; Brock, Stephanie L. / Design of lead telluride based thermoelectric materials through incorporation of lead sulfide inclusions or ligand stripping of nanosized building block.

    In: Journal of Physical Chemistry C, Vol. 119, No. 9, 05.03.2015, p. 4635-4644.

    Research output: Contribution to journalArticle

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