Production and development of ZnAlGeO semiconducting materials for thermoelectric generators in potential aerospace applications

This research aims to produce and develop semiconducting thermoelectric materials for thermoelectric generators in aerospace applications. In this context, ZnAlGeO powders were synthesized via the sol-gel method using precursor materials and a 20% toluene solution in ethanol as the solvent. Glacial acetic acid was added to accelerate gel formation. The pH and turbidity values of prepared solutions were measured using a pH meter and turbidimeter. After gelation, the obtained xerogel was dried at 200 °C for 9 h to remove moisture and undesired gases. Dried powders were calcined at 600 °C for 4 h in air, resulting in final ZnAlGeO materials. The pellets underwent thermal processing for 36 h at a temperature of 1350 °C, targeting the production of bulk samples within the n-type semiconductor category. Extensive characterization, including thermal, structural, microstructural, and thermoelectric properties, was conducted using various techniques such as DTA-TG, FTIR, XRD, XPS, SEM, and thermoelectric measurement devices. The study concludes that the produced semiconducting ceramic materials exhibit efficiency for thermoelectric generator production. Graphical Abstract Highlights Zn 1-x-y Al x Ge y O (x = 0.02, 0.04, and y = 0.02, 0.04) powders were synthesized by sol-gel method and densified under high-pressure cold pressing. Effects of dual doping on thermoelectric properties of Zn 1-x-y Al x Ge y O (x = 0.02, 0.04, and y = 0.02, 0.04) were investigated. Thermoelectric performances of Zn 1-x-y Al x Ge y O (x = 0.02, 0.04, and y = 0.02, 0.04) are enhanced by dual doping. Promising Zn 1-x-y Al x Ge y O (x = 0.02, 0.04, and y = 0.02, 0.04) oxide materials for energy harvesting and conversion technologies, particularly in aerospace applications.