Enhanced Thermoelectric Performance and Mechanical Property in Layered Chalcostibite CuSb<inf>1-x</inf>Pb<inf>x</inf>Se<inf>2</inf>

In this work, the thermoelectric properties of p-type layered chalcostibite CuSb1-xPbxSe2 (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 Pb2+ doping at Sb3+ site in CuSbSe2 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, κtotal has been noticed, from ∼1.7 W/mK (pristine CuSbSe2) to ∼0.72 W/mK at 323 K for CuSb0.90Pb0.10Se2 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, zT, has been enhanced to ∼0.27 at 623 K for the composition of CuSb0.90Pb0.10Se2, which is 3-fold higher than that of the undoped CuSbSe2. 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.