Chiang Mai Journal of Science

     Thermoelectric materials have attracted significant attention recently due to their potential to convert waste heat into usable electrical energy. This study focused on investigating a defect perovskite layerstructured PrBa₂Cu₃O_7-y (PrBCO) compound as a viable material for thermoelectric applications. To improve the thermoelectric properties of PrBCO, Ni was substitutionally doped at the Cu site. The samples of PrBa₂(Cu_1-xNi_x)₃O_7-y (x = 0.00, 0.05, 0.10, 0.15, and 0.20) were prepared by sintering at 920˚C for 12 hours in a normal air atmosphere. X-ray diffraction patterns indicated that a second phase appeared when Ni concentration was equal to or higher than 0.10 mol fraction. Scanning electron microscope (SEM) images indicated that the grain size slightly decreased with increasing Ni concentrati on. X-ray absorption spectroscopy (XAS) analysis showed that the local structures of Ni, Cu, and Pr were unchanged, with oxidation states of Pr, Cu, and Ni being higher than +3, between +2 and +3, and +4 , respectively. The study determined that Ni doping in PrBCO at a concentration of x = 0.10 significantly improved the thermoelectric properties, achieving the highest figure of merit with a ZT value of 0.015 at 773 K.