Synthesis and Characterization of Ca_2.5Ag_0.3Pr_0.2Co₄O₉ Semiconducting Materials via Sol-Gel Process for Thermoelectric Applications

This article pr es ents a study o n t he synthesis and characterization of Ca2.5Ag0.3Pr0.2Co4O9, ap-type semiconducting material, to evaluate its potential for thermoelectric generator applications. The material is designed by partially substituting calcium in the Ca3Co4O9 matrix with Ag and Pr, aiming to enhance its thermoelectric performance using improved electrical conductivity and Seebeck coefficient. The material is synthesized through a sol-gel method, followed by extensive structural and morphological characterization through differential thermal analysis- thermogravimetry (DTA-TG), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and TM devices. Thermoelectric properties, including electrical resistivity, Seebeck coefficient and thermal conductivity, are systematically measured to calculate the material's figure of merit. The doping of Ag and Pr leads to an optimized balance between electrical and thermal transport properties, making Ca2.5Ag0.3Pr0.2Co4O9 a strong candidate for high-temperature thermoelectric applications, particularly for waste heat recovery and power generation. The findings from this study demonstrate the material's potential for enhancing the efficiency of thermoelectric generators used in challenging operational environments.