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Title: High figure of merit and thermoelectric properties of Bi-doped Mg{sub 2}Si{sub 0.4}Sn{sub 0.6} solid solutions

The study of Mg{sub 2}Si{sub 1−x}Sn{sub x}-based thermoelectric materials has received widespread attention due to a potentially high thermoelectric performance, abundant raw materials, relatively low cost of modules, and non-toxic character of compounds. In this research, Mg{sub 2.16}(Si{sub 0.4}Sn{sub 0.6}){sub 1−y}Bi{sub y} solid solutions with the nominal Bi content of 0≤y≤0.03 are prepared using a two-step solid state reaction followed by spark plasma sintering consolidation. Within this range of Bi concentrations, no evidence of second phase segregation was found. Bi is confirmed to occupy the Si/Sn sites in the crystal lattice and behaves as an efficient n-type dopant in Mg{sub 2}Si{sub 0.4}Sn{sub 0.6}. Similar to the effect of Sb, Bi doping greatly increases the electron density and the power factor, and reduces the lattice thermal conductivity of Mg{sub 2.16}Si{sub 0.4}Sn{sub 0.6} solid solutions. Overall, the thermoelectric figure of merit of Bi-doped Mg{sub 2.16}Si{sub 0.4}Sn{sub 0.6} solid solutions is improved by about 10% in comparison to values obtained with Sb-doped materials of comparable dopant content. This improvement comes chiefly from a marginally higher Seebeck coefficient of Bi-doped solid solutions. The highest ZT∼1.4 is achieved for the y=0.03 composition at 800 K. - Graphical abstract: (a)The relationship between electrical conductivity and powermore » factor for Sb/Bi-doped Mg{sub 2.16}(Si{sub 0.4}Sn{sub 0.6}){sub 1−y}(Sb/Bi){sub y} (0« less
Authors:
 [1] ;  [2] ; ;  [1] ; ;  [3] ;  [1] ;  [4] ;  [3]
  1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)
  2. (United States)
  3. Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States)
  4. (China)
Publication Date:
OSTI Identifier:
22309055
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 203; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CRYSTAL LATTICES; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; ELECTRON DENSITY; MAGNESIUM SILICIDES; POINT DEFECTS; RAW MATERIALS; SCATTERING; SOLID SOLUTIONS; SOLIDS; TEMPERATURE DEPENDENCE; THERMAL CONDUCTIVITY; THERMOELECTRIC MATERIALS; THERMOELECTRIC PROPERTIES; TOXICITY