Enhanced Thermoelectric Performance and Mechanical Property in Layered Chalcostibite CuSb<sub>1–<i>x</i></sub>Pb<sub><i>x</i></sub>Se<sub>2</sub>
Manojkumar Moorthy, Bhuvanesh Srinivasan, David Berthebaud, Rajasekar Parasuraman, R Althaf, Suresh Perumal
Abstract
In this work, the thermoelectric properties of p- type layered chalcostibite CuSb 1– x Pb x Se 2 ( x = 0–0.10) compounds prepared by vacuum melting reaction and uniaxial hot press, have been studied in the temperature range of 323–623 K. Further, aliovalent Pb 2+ doping at Sb 3+ site in CuSbSe 2 notably increases the hole concentration due to its acceptor nature and thereby enhances the electrical conductivity, σ. Importantly, a huge reduction in total thermal conductivity, κ total has been noticed, from ∼1.7 W/mK (pristine CuSbSe 2 ) to ∼0.72 W/mK at 323 K for CuSb 0.90 Pb 0.10 Se 2 owing to increased phonon scattering from the introduced point defects and mass-difference between Pb and Sb. As a result, the thermoelectric figure of merit, z T, has been enhanced to ∼0.27 at 623 K for the composition of CuSb 0.90 Pb 0.10 Se 2, which is 3-fold higher than that of the undoped CuSbSe 2 . Further, the hardness value achieved was ∼125.54 Hv, which is significantly higher than the most of the state-of-the-art materials, indicating it to be an efficient thermoelectric material for intermediate temperature.