Realization of promising power generation and thermoelectric cooling in polycrystal SnSe with cubic structure

Cubic SnSe has garnered significant interest due to its distinctive electrical and thermal transport characteristics differing from those of Pnma phase. In this work, we achieve a synergistic optimization of electrical and thermal properties in p-type cubic (SnSe)0.6(AgSbTe2)0.4 polycrystal by isoelectronic doping with Pb and Ge atoms. This reduces the carrier concentration and promotes the band divergence to decrease the effective mass m⁎ and thus significantly improves the carrier mobility μ. Furthermore, the isoelectronic doping caused a significant deviation from the stoichiometric ratio of Ag/Sn, which in turn induced numerous lattice defects and reduced thermal conductivity. Finally, the room-temperature ZT value reached ~ 0.5, with an impressive ZTave value of ~ 0.9 across the 300-673 K. More importantly, the fabricated SnSe-based full-scale devices achieve an outstanding power generation performance of ~ 4.6% and a promising cooling temperature difference of ~ 47.3 K, showing important application prospects for SnSe polycrystals in both power generation and electronic cooling.