Analysis and Implications of Structural Complexity in Low Lattice Thermal Conductivity High Thermoelectric Performance PbTe–PbSnS ₂ Composites

Journal Article · Tue Jun 14 00:00:00 EDT 2016 · Chemistry of Materials

DOI:https://doi.org/10.1021/acs.chemmater.6B00710· OSTI ID:1352613

Ioannidou, Chrysoula; Lioutas, Christos B.; Frangis, Nikolaos; Girard, Steven N.; Kanatzidis, Mercouri G.

The high-performance PbTe-SnTe-PbS-thermoelectric system forms a completely new composite PbTe PbSnS2 with high n-type figure of merit. Electron diffraction and high-resolution electron microscopy characterization of the thermoelectric composite PbTe + 25% PbSnS2 reveals that the system is nanostructured, with PbSnS(2)nanocrystals in the range Of 80 to 500 nm in size. In most of the cases, they are endotaxially grown within the PbTe matrix. Three independent crystal superstructures were observed for the PbSnS2 inclusions, originating from the same parent SnS-type structure. The presence of the parent structure is not excluded. Modified structural models for two of the superstructures observed in the PbSnS2 precipitates are proposed: Often, more than one of the structural phases am observed In the same nanocrystal, providing one extra phonon scattering factor in the system. Evidence was also found for the growth process of the nanocrystals, starting from PbS and followed by gradual dissolving of SnS. Our findings suggest that this nanostructured thermoelectric composite exhibits unique structural complexity, which Contributes to the low lattice thermal :conductivity reported for these nanocomposite materials.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1352613
• Journal Information: Chemistry of Materials, Vol. 28, Issue 11; ISSN 0897-4756
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English