Thermoelectric properties of SmS@Y2O2S and Y2O2S@SmS compounds with a core-shell nanostructure

[Display omitted] •Two new SmS@Y2O2S and Y2O2S@SmS compounds with a core-shell nanostructure was synthesized.•It was found to be a promising value of ZT parameter based on the rare earth elements.•The obtained results demonstrated the correlation between thermoelectric parameters and the real sample structure changes.•The thermoelectric compounds based on the rare earth monosulfides and oxides cause the thermal conductivity reduce. The Seebeck coefficient, the electrical resistivity, the total thermal conductivity and the thermoelectric figure of merit of Y2O2S@SmS and SmS@Y2O2S ceramic samples with core-shell nanostructure within the temperature range from 300 to 770 K was studied. It was found that the samples studied demonstrate a promising thermoelectric property in high temperature region (T ≥ 773 K). The thermoelectric parameters for SmS@Y2O2S of S = –30 µV/K, ρ = 0.53 µΩ·m and κtot = 2.60 W/m·K at T = 773 K were measured. These values result in increased ZT value of 0.48 at T = 773 K in comparison with those for lanthanide-based thermoelectric materials.