SYNTHESIS AND CHARACTERIZATION OF PBSE AND PBTE NANOSTRUCTURES FOR THERMOELECTRIC APPLICATIONS

Abstract

Lead telluride (PbTe) and Lead selenide (PbSe) and its alloys are currently best known thermoelectric (TE) materials for the application of thermoelectric generators. Lead telluride is an intermediate thermoelectric power generator. Lead selenide is widely used in LED’s, photovoltaic cells, sensing applications, biology (as biological markers) [1] and as again media in very special types of micro-lasers. Lead selenide and Lead telluride nanostructures such as nanoparticles, nanorods have been successfully synthesized by Organic precursor method, Co-precipitation approach in organic solvent and hydrothermal method and so on. Hydrothermal method is the one of the simplest method by which we can synthesize the nanoparticles of the size ranging 18nm to 23nm. Hydrothermal reaction of selenium and tellurium with lead acetate in sodium hydroxide solution in presence hydrazine hydrate as a reductive was investigated to prepare lead chalcogenides, PbE (E=Se,Te). Nanocrystals with different morphology could be obtained under mild conditions. The formation of Lead chalcogenides in our process is based on the direct elemental combination pathway. The product was characterized by XRD, SEM and TEM. Further characterization was done using FTIR, UV- visible spectroscopy. The cubic structure of PbTe and PbSe was confirmed by XRD spectra. The optical properties of the samples were studied by UV-visible spectroscopy. The primary goal of this thesis is to dig up the thermoelectric properties of Lead selenide and Lead telluride and to learn the synthesis techniques and characterization of nanostructure TE materials for better energy conversion.