PbTe–PbSnS2 thermoelectric composites: low lattice thermal conductivity from large microstructures

• DOI: 10.1039/c2ee22495j
• Publication Date: 2012-08-07T11:00:20Z
• Authors: Steven N. Girard; Thomas C. Chasapis; Jiaqing He; Xiaoyuan Zhou; Euripides Hatzikr...; Ctirad Uher; Konstantinos M. P...; Vinayak P. Dravid; Mercouri G. Kanat...
• Keywords: Ingot

Recent advances in the field of thermoelectrics have shown embedding appropriate nanostructures can significantly suppress lattice thermal conductivity and therefore enhance ZT. Here we report a new class thermoelectric composites PbTe–PbSnS2. PbSnS2 is naturally layered material (space group Pnma) comprised Sn–Pb bilayers approximately 0.6 nm thickness. High resolution transmission electron microscopy reveals segregates into coherent lamellar structures 50–100 thickness that extend 100 to 15 μm length. Despite relatively large size precipitates, find incorporation PbTe results significant reduction 0.4–0.65 W m−1 K−1 over temperature range 300–700 K, 50–70% bulk PbTe. As result, maximum ZT 1.1 obtained for ingot samples PbTe–PbSnS2 6% composition. We provide extensive characterization physical, structural, chemical properties this materials system including powder X-ray diffraction, infrared reflectivity, scanning microscopy, measurements. The synthesis method simple general, opening possibilities similar systems yield exhibiting low without it being necessary embed nanoscale (5–20 nm) features.