High performance of n-type (PbS)1-x-y(PbSe)x(PbTe)y thermoelectric materials

Abstract Te-free PbS has been regarded as a promising alternative candidate for PbTe thermoelectric materials due to its advances of low-cost, earth-abundant. In this work, we report an enhanced thermoelectric performance in n -type PbS system arising from synergistically optimized carrier and phonon transport properties. The electrical transport properties are optimized by tuning carrier concentrations via Sb doping, resulting in a maximum power factor of ∼16.7 μWcm −1 K −2  at 623 K, which is approximately tenfold higher than that of undoped PbS (∼1.8 μWcm −1 K −2 ). PbSe and PbTe co-alloying in PbS was carried out to reduce lattice thermal conductivity through introducing point defects scattering and second phase, resulting in a minimum lattice thermal conductivity ∼0.71 Wm −1 K −1  at 923 K. Combined the enhanced power factor with suppressed thermal conductivity, a maximum ZT value ∼1.0 was obtained in n -type (PbS) 0.53 (PbSe) 0.25 (PbTe) 0.2 Sb 0.02 at 923 K.