Thermoelectric and microstructural properties of Pb{sub 0.9-x}Sn{sub 0.1}Ge{sub x}Te compounds prepared by spinodal decomposition

Journal Article · Sun May 15 04:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.02.028· OSTI ID:21494272

Sondergaard, M; Christensen, M; Johnsen, S ^[1]; Stiewe, C; Dasgupta, T; Mueller, E ^[2]

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1. Center for Energy Materials, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C (Denmark)
2. German Aerospace Center (DLR), Linder Hoehe, DE-51147 Cologne (Germany)

Three samples of Pb{sub 0.9-x}Sn{sub 0.1}Ge{sub x}Te with x=0.25, 0.35, 0.6 were prepared by heating the mixtures above the melting point of the constituent elements followed by quenching in water. The x=0.6 sample is close to the center of the immiscibility region, while the x=0.25 and 0.35 samples are in the Pb rich region inside the spinodal miscibility gap. Microstructural investigations using Powder X-ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy revealed both GeTe-rich and PbTe-rich phases. The samples were uniaxially hot pressed and the thermoelectric properties were characterized in the temperature range 2-400 K using a commercial apparatus and from 300 to 650 K with a custom designed setup. The best sample (x=0.6) reached zT{approx}0.6 at 650 K, while the x=0.25 and 0.35 samples showed thermal instability at elevated temperatures. -- Graphical abstract: Spinodal decomposition in the GeTe-SnTe-PbTe system demonstrated by SEM and EXS images. Display Omitted Highlights: {yields} Investigation of Pb-rich part of the spinodal miscibility gap in PbTe-SnTe-GeTe. {yields} zT=0.6 at 650 K reproduced for Pb{sub 0.3}Sn{sub 0.1}Ge{sub 0.6}Te. {yields} Pb-rich phases shown to be thermally instable. {yields} Thermoelectric property characterization at low and high temperature. {yields} Microstructural investigations using PXRD, SEM, EDX and PSM.

• OSTI ID: 21494272
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 5 Vol. 184; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
DECOMPOSITION
DIFFRACTION
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
GERMANIUM COMPOUNDS
GERMANIUM TELLURIDES
HEATING
LEAD COMPOUNDS
LEAD TELLURIDES
MELTING POINTS
MICROSCOPY
MICROSTRUCTURE
PHYSICAL PROPERTIES
QUENCHING
SCANNING ELECTRON MICROSCOPY
SCATTERING
SOLUBILITY
SPECTROSCOPY
TELLURIDES
TELLURIUM COMPOUNDS
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
THERMODYNAMIC PROPERTIES
THERMOELECTRIC PROPERTIES
TIN COMPOUNDS
TIN TELLURIDES
TRANSITION TEMPERATURE
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY