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Medientyp:
E-Artikel
Titel:
Time-dependent investigation of a mechanochemical synthesis of bismuth telluride-based materials and their structural and thermoelectric properties
Beteiligte:
Groeneveld, Dennis;
Koenig, Jan D.;
Poschmann, Michael;
Groß, Hendrik;
Bensch, Wolfgang;
Kienle, Lorenz;
Wöllenstein, Jürgen
Beschreibung:
<jats:p>Here, we report on the time dependence of a synthesis procedure for generation of both n- and p-type bismuth telluride-based materials. To initiate the reaction, the starting materials were first mechanical pre-reacted. The Rietveld refinements of X-ray diffraction (XRD) data collected after different milling times demonstrate that Bi<jats:sub>2</jats:sub>Te<jats:sub>3</jats:sub>was formed after only 10 min, and longer milling times do not alter the composition. To complete the phase formation, the powders were treated by field-assisted sintering and heat treatment afterwards. The effect of this fast procedure on the structural and thermoelectric properties was investigated. Samples were obtained with relative densities above 99%. A clear preferred orientation of the crystallites in the samples is evidenced by Rietveld refinements of XRD data. The thermoelectric characteristics demonstrate a good performance despite the short milling time. Further, it was demonstrated for this fast synthesis that the physical transport properties can be varied with well-known n- and p-type dopants like CHI<jats:sub>3</jats:sub>or Pb. For these non-optimized materials, a<jats:italic>ZT</jats:italic>value of 0.7 (n-type) and 0.9 (p-type) between 400 and 450 K was achieved. The long-term stability is demonstrated by repeated measurements up to 523 K showing no significant alteration of the thermoelectric performance.</jats:p>