Thermoelectric properties of cobalt-doped nanostructured CdO synthesized via chemical precipitation method

In this article, the effect of Cobalt dopant on the thermoelectric properties of nanostructured Cadmium Oxide has been reported at high temperatures. The pristine and 2, 4, 6, and 8% Cobalt-doped nanostructured Cadmium Oxide were synthesized simply by the Precipitation method. The Rietveld refinement of XRD data revealed that all the synthesized samples are highly crystalline and have Face Centered Cubic phase of space group Fm\(\stackrel{-}{3}\)m. The decrease in lattice parameters in Co-doped CdO verified the successful substitution of Cd²⁺ ions by the Co²⁺ ions in the CdO matrix. FESEM micrographs revealed that the as-prepared samples have a circular disk-shaped morphology. The elemental analysis was done by EDX spectroscopy which confirmed the existence of Cd, O, and Co in the respective samples. Fourier Transform Infra-Red spectroscopy was used to study the various chemical bonds in the synthesized samples. The charge carrier concentration and Hall mobility were rising simultaneously with the increase in Cobalt concentration at room temperature. The Seebeck coefficient and electrical resistivity were recorded in a temperature range of 300–950 K. The electrical resistivity was found to be decreasing with an increase in Cobalt concentration. The negative values of the Seebeck coefficient of all the samples confirmed their n-type behavior. The thermoelectric power factor calculated from electrical resistivity and Seebeck coefficient data was found to be the highest of about \({2.64\times 10}^{-3}W{m}^{-1}{K}^{-2}\) for 6% Co-doped CdO at 950 K which is more than that for pristine CdO. Hence, Cobalt doped nanostructured Cadmium Oxide is a potential high-temperature thermoelectric material.