High thermoelectric power factor of Ag and Nb co-substituted SrTiO3 perovskite nanostructures

Abstract

Ag substituted and Ag & Nb co-substituted SrTiO3 were synthesized by hydrothermal method and their structural, morphological and thermoelectric properties were studied. The crystal structure and crystallinity of the samples were examined by X-ray Diffraction analysis. The morphology of the samples was analysed using FESEM and TEM analysis. X-ray Photoelectron Spectroscopic analysis revealed the presence of Ag and the binding state of each element present in the prepared samples. The variations of electrical resistivity with Ag content was studied in Ag substituted SrTiO3. The electrical resistivity of Ag & Nb co-substituted SrTiO3 was relatively higher than that of pure SrTiO3 and Ag alone substituted samples. The Seebeck coefficient increased as the Ag content increases in the sample. Higher Seebeck coefficient was observed for Ag & Nb co-substituted SrTiO3 when compared with other samples. The power factor of the sample significantly improved with Ag content due to high Seebeck Coefficient. The Ag & Nb co-substituted samples exhibited high power factor compared to other samples. Moreover, the Ag-substituted SrTiO3 shows relatively low thermal conductivity and thereby high figure of merit of 0.15 compared to the reported values of similar materials. The experimental results demonstrated that Ag and Nb substitution plays an important role in enhancing the thermoelectric properties of SrTiO3.