Microstructure-lattice thermal conductivity correlation in nanostructured PbTe{sub 0.7}S{sub 0.3} thermoelectric materials.
- Materials Science Division
The reduction of thermal conductivity, and a comprehensive understanding of the microstructural constituents that cause this reduction, represent some of the important challenges for the further development of thermoelectric materials with improved figure of merit. Model PbTe-based thermoelectric materials that exhibit very low lattice thermal conductivity have been chosen for this microstructure-thermal conductivity correlation study. The nominal PbTe{sub 0.7}S{sub 0.3} composition spinodally decomposes into two phases: PbTe and PbS. Orderly misfit dislocations, incomplete relaxed strain, and structure-modulated contrast rather than composition-modulated contrast are observed at the boundaries between the two phases. Furthermore, the samples also contain regularly shaped nanometer-scale precipitates. The theoretical calculations of the lattice thermal conductivity of the PbTe{sub 0.7}S{sub 0.3} material, based on transmission electron microscopy observations, closely aligns with experimental measurements of the thermal conductivity of a very low value, {approx}0.8 W m{sup -1} K{sup -1} at room temperature, approximately 35% and 30% of the value of the lattice thermal conductivity of either PbTe and PbS, respectively. It is shown that phase boundaries, interfacial dislocations, and nanometer-scale precipitates play an important role in enhancing phonon scattering and, therefore, in reducing the lattice thermal conductivity.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC; ONR; NSF; State of Illinois; Norththwestern Univ.
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1014841
- Report Number(s):
- ANL/MSD/JA-69073
- Journal Information:
- Adv. Funct. Mater., Journal Name: Adv. Funct. Mater. Journal Issue: March 10, 2010 Vol. 20; ISSN 1616-301X
- Country of Publication:
- United States
- Language:
- ENGLISH
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