Inorganic Thermoelectric Materials: From Fundamental Concepts to Materials Design
Chapter 3: Nanostructuring Effects in Bulk Thermoelectrics and Their Composites
Published:24 Nov 2021
Special Collection: 2021 ebook collectionSeries: Inorganic Materials
Min Ho Lee, Pooja Rawat, Jong-Soo Rhyee, 2021. "Nanostructuring Effects in Bulk Thermoelectrics and Their Composites", Inorganic Thermoelectric Materials: From Fundamental Concepts to Materials Design, Anthony V Powell
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Nanostructured materials and thermoelectrics have been the subject of significant research in recent years. Bulk nanostructured thermoelectric materials are attractive as they may be produced in sufficient quantity to be of potential use in large-scale applications, whereas superlattice or quantum dot structures are currently able to be produced only as thin films, limiting their applicability. The formation of a bulk nanocomposite is an effective way of lowering thermal conductivity for the enhancement of thermoelectric performance. This chapter discusses the principles of thermoelectric energy conversion and introduces the concept of bulk nanostructured materials. A structural phase transition near 420 K in Ag2Te raises the interface potential effect, which implies its dispersion in the Bi2Te3-, Sb2Te3- and PbTe-based matrices. Composites synthesised by controlling the shape of Ag2Te particles with commercial (C), nanowire (NW) and nanopowder (NP) materials, and changing the dispersion concentration in the Bi2Te3 and Sb2Te3 matrices, show a well-ordered thermoelectric behaviour. By considering the interface potential and lattice mismatch, a charge-selective Anderson localisation while preserving the extended electronic state is introduced. From this approach, an exceptionally high thermoelectric figure of merit of ZT > 2.0 in n-type PbTe materials was successfully achieved, suggesting that this may be a versatile approach for power generation from waste heat.