Thermoelectrics with earth abundant elements: Low thermal conductivity and high thermopower in doped SnS

The thermoelectric properties of Ag-doped SnS samples synthesized by mechanical alloying followed by spark plasma sintering were studied. We report that SnS possesses a high Seebeck coefficient of >+400 μV K^-1 and Ag doping increases the carrier concentration by more than four orders of magnitude giving significantly improving electrical conductivity. The thermal conductivity falls below 0.5 W m^-1 K^-1 at 873 K and leads to a high ZT of 0.6. The data indicate that earth-abundant and environmentally friendly SnS is a promising candidate for thermoelectric applications despite its relatively wide bandgap of 1.2 eV.