Synergistically optimized electronic and phonon transport properties in cubic SnSe thermoelectric materials via Pb doping

The rock-salt cubic SnSe compound with multiple valleys and inherent low thermal conductivity is considered to be a promising thermoelectric compound. In this study, heterogeneous Pb atoms were strategically introduced into the lattice of cubic SnSe matrix, synergistically adjusting the thermoelectric transport properties of samples by optimizing hole carrier concentration (n) and suppressing thermal conductivity (κ_tot). When the doping content reached 0.08 mol, the peak power factor (PF) at 300 K increased to 20.00 μW·cm^–1·K^–2. The growing internal microstrain induced by the differences in atomic size strengthened the phonon scattering and effectively reduced the lattice thermal conductivity (κ_L). With further decoupling of the electrical and thermal transport properties, a peak thermoelectric figure of merit (ZT) of 0.82 and an average ZT of 0.42 (300–750 K) were achieved in the samples doped with 0.10 mol Pb. These findings highlight the effectiveness of the selected dopants and demonstrate their synergy in improving the performance of thermoelectric materials.

Graphical Abstract