Composition-dependent tunability of thermoelectric properties at low temperature for Pr-doped LPFCO double perovskite

The current research focuses on the synthesis, characterization, and low temperature thermoelectric characteristics along with optical bandgap analysis of La 2− x Pr x FeCoO 6 ( x = 0, 0.25, 0.50, 0.75, and 1) double perovskite. The sintered sample’s crystal structure, microstructural features, electrical properties, and thermal transport parameters were examined. The nanocrystalline single-phase material was confirmed after 6 h of sintering, and the crystallite size increases with increasing Pr concentration along with the occurrences of various oxidation states of La, Pr, Fe, Co, and O. The conductivity analysis confirms the presence of a closest neighbor hopping charge carrier conduction mechanism due to decreased bandgap in entire samples. For all the compositions ( x ), conductivity, power factor, and figure of merit were increased with increasing temperature and Pr-content, confirming the presence of larger charge carrier concentration along with decreased bandgap. Positive S values indicate the presence of p-type charge carriers in LPFCO double perovskite and intrinsic behavior was conserved with increasing Pr-doping concentration ( x ). The highest Figure of Merit (ZT = ~ 0.007) was observed for the LaPrFeCoO 6 compound at 300 K. The observed results of ZT and their narrow optical bandgap suggested that, at ambient temperature, the LaPrFeCoO 6 compound can be also a good choice for solar cells, sensors, bolometers, and other optoelectronic devices as well.