Thermoelectric properties of medium-entropy PbSbTeSe alloy prepared by reactive spark plasma sintering

Abstract

Reactive spark plasma sintering combining the synthesis and densification stages has been at the first time applied to prepare medium-entropy grained PbSbTeSe alloy. This alloy is prospect medium-temperature p-type thermoelectric. Self-propagating high-temperature synthesis in initial mixture of elemental Pb, Sb, Te and Se powders, resulting in synthesis of single-phased PbSbTeSe, was stage of synthesis. Lattice thermal conductivity of the alloy is very low (∼0.7 at ∼ 755 K). Owing to this low lattice thermal conductivity, thermoelectric performance of PbSbTeSe alloy is promising . Highest thermoelectric figure-of-merit equal to ∼ 0.43 is observed at ∼ 720 K. Anomalies of thermoelectric properties were found at ∼ 490 K. These anomalies can be related to specific features of energy bands, consisting of two valence bands, which are close in energy.