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Title: From thermoelectric bulk to nanomaterials: Current progress for Bi 2 Te 3 and CoSb 3: From thermoelectric bulk to nanomaterials

We synthesized Bi2Te3 and CoSb3 based nanomaterials and their thermoelectric, structural, and vibrational properties analyzed to assess and reduce ZT-limiting mechanisms. The same preparation and/or characterization methods were applied in the different materials systems. Single-crystalline, ternary p-type Bi15Sb29Te56, and n-type Bi38Te55Se7 nanowires with power factors comparable to nanostructured bulkmaterialswere prepared by potential-pulsed electrochemical deposition in a nanostructured Al2O3 matrix. p-type Sb2Te3, n-type Bi2Te3, and n-type CoSb3 thin films were grown at room temperature using molecular beam epitaxy and were subsequently annealed at elevated temperatures. It yielded polycrystalline, single phase thin films with optimized charge carrier densities. In CoSb3 thin films the speed of sound could be reduced by filling the cage structure with Yb and alloying with Fe yielded p-type material. Bi2(Te0.91Se0.09)3/SiC and (Bi0.26Sb0.74)2Te3/SiC nanocomposites with low thermal conductivities and ZT values larger than 1 were prepared by spark plasma sintering. Nanostructure, texture, chemical composition, as well as electronic and phononic excitations were investigated by X-ray diffraction, nuclear resonance scattering, inelastic neutron scattering, M ossbauer spectroscopy, and transmission electron microscopy. Furthermore, for Bi2Te3 materials, ab-initio calculations together with equilibrium and non-equilibrium molecular dynamics simulations for point defects yielded their formation energies and their effect on lattice thermal conductivity, respectively. Currentmore » advances in thermoelectric Bi2Te3 and CoSb3 based nanomaterials are summarized. Advanced synthesis and characterization methods and theoreticalmodelingwere combined to assess and reduce ZT-limiting mechanisms in these materials.« less
Authors:
 [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [7] ;  [8] ;  [8] ;  [8]
  1. Eberhard Karls Univ. of Tubingen (Germany)
  2. Univ. of Hamburg (Germany)
  3. Julich Research Centre for Neutron Science JCNS (Germany). Peter Grunberg Inst. PGI
  4. Julich Research Centre for Neutron Science JCNS (Germany). Peter Grunberg Inst. PGI; Univ. of Liege, (Belgium); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Chemnitz University of Technology (Germany)
  6. Chemnitz University of Technology (Germany); Univ. of Augsburg (Germany)
  7. Fraunhofer Inst. for Manufacturing Technology and Advanced Materials IFAM, Dresden (Germany)
  8. Fraunhofer Institute for Mechanics of Materials IWM, Freiburg (Germany)
Publication Date:
OSTI Identifier:
1261324
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Physica Status Solidi. A, Applications and Materials Science
Additional Journal Information:
Journal Volume: 213; Journal Issue: 3; Journal ID: ISSN 1862-6300
Publisher:
Wiley
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE Bi2Te3; CoSb3; lattice dynamics; nanomaterials; point defects; thermoelectric effects; transmission electron microscopy