The role of hetero-interface structures in enhancing the power factor of Cu2Se/x% Y2O3 composite thermoelectric materials.

• Cu 2 Se/x%Y 2 O 3 composites were fabricated using solid state recation. • The oxidation states are confirmed by XPS studies. • Composite samples exhibit enhanced micro- hardness. • The lowest resistivity was observed for the sample with x = 0.25 wt%. • The highest power factor was exhibited for the sample with x = 0.75 wt%. In this study, we have investigated the structural, thermal, electrical, and mechanical properties of the composite system Cu 2 Se/ x % Y 2 O 3 (0 ≤ x ≤ 1.00) as a function of varying Y 2 O 3 concentration, x. The successful incorporation of Y 2 O 3 in the Cu 2 Se matrix is carried out using the solid-state reaction method, and the same is confirmed by X-ray diffraction analysis. Due to the low concentration of Y 2 O 3 , all the prepared composites exhibit monoclinic crystal structure with P2/m space group within the X-ray detection limit at room temperature. The oxidation state of the studied composites is investigated using X-ray photoelectron spectroscopy (XPS). The composites exhibit an increase in mechanical hardness as a function of Y 2 O 3 concentration, whereas the electrical resistivity shows no systematic variation with Y 2 O 3 concentration. The highest resistivity is observed for the sample with x = 1%. The measured Seebeck coefficient (S) value increases with increasing temperature. The positive values of S indicate that the positive charge carriers (holes) dominate the thermoelectric transport. The thermal conductivity of the composites increases as compared to the Cu 2 Se pristine sample. The overall power factor and ZT of studied composites were found to decrease with the addition of Y 2 O 3 to the Cu 2 Se system. [Display omitted] Temperature dependent thermoelectric quality factor of Cu 2 Se/x% Y 2 O 3 compounds [ABSTRACT FROM AUTHOR]