A study of the effects of low dimensionality, in both composites and single phase bulk materials, on thermoelectric properties was carried out. It is proposed that with the correct set of guidelines, bulk composite materials can achieve quantum confinement, inherently increasing the Seebeck coefficient, and lead to an overall increase the figure of merit. For this study, the binary system, Pb1-xNaxTe-Cd1-xNaxTe, was chosen based on those guidelines. Several synthetic approaches were employed to produce bulk quantities of nanostructures that mimic the key features of quantum well superlattices, potentially resulting in quantum confined system. This study led to an investigation of the effects of several different synthetic methods, which includes comparing aqueous based techniques such as SILAR versus inert atmosphere ampoule technique, on the thermoelectric properties of the materials. Sol-gel technique was utilized as a new facile method in synthesizing both PbTe and CdTe. The resulting materials were characterized using: thermogravimetric analysis-differential scanning calorimetry, powder X-ray diffraction, low and high temperature Seebeck and resistivity measurements, laser flash analysis, and Hall effect measurements.An additional study was carried out on the effects of low dimensionality in a lanthanum nickelate family T`-Lnn+1NinO2n+1 (n = 3 and ∞) known to demonstrate strongly correlated electron behavior. These metastable compounds are commonly formed by reducing a parent compound using low temperature techniques. The final metastable compound contains infinite layer NiO2 with Ni1+ in a square planar coordination. The T`-nickelates are of interest, due to the electronic and structural similarities to high temperature superconducting cuprates, where Cu2+ in a square planar coordination, CuO2, is a common structural element. The NiO2 similarity, both isostructural and isoelectronic, to CuO2 may display similar properties. The first parent compound, La4Ni3O10, was synthesized using traditional solid state techniques, sol-gel and ceramic methods, and was then reduced to La4Ni3O8 using hydrogen gas. The same compound was successfully synthesized with 0.20 Cu dopant, La4Ni2.8Cu0.2O8. The samples were characterized through powder X-ray diffraction, and specific heat. The second parent compound, LaNiO3, was synthesized by the same techniques, however, it was reduced to LaNiO2 using a novel solvothermal reduction technique. The same compound was successfully synthesized for the first time as a Cu doped series LaNi1-xCuxO2 where x = 0.05, 0.10, 0.15, 0.20, 0.25. The samples were characterized by powder x-ray diffraction for a structural analysis as well as for cell parameters determination.
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