Low Temperature Synthesis and Electrical Characterization of Solid Chalcogenides using Molten Salts

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Molten polychalcogenide salt and hydrothermal techniques will be used to explore the synthesis of new chalcogenide materials at low and intermediate temperatures. Both synthetic techniques will use various A2Qx salts in reactions with late transition metals and main-group elements. Reactions at temperatures between 200-500 oC will be studied because this range has been little explored previously. It has been demonstrated that in this temperature range new materials with new structure types can form and crystallize. The remarkable ability of sulfur, selenium, and tellurium to bridge different sub-structures in two and three dimensions, and the relatively low temperatures provide a lucrative opportunity for synthesis of a very large number of new compounds. Physical properties of these new compounds to be explored include magnetic, sorption as a function of temperature, and redox properties. In order to probe unusual electronic phenomena, the charge transport properties of the new compounds will be studied in detail via variable temperature four-probe resistivity as well as thermoelectric power (Seebeck) measurements. The measurements will be primarily done on single crystal samples. This grant is jointly supported by the Division of Materials Research, and the Chemistry Division.