(21b) Environmentally Benign Synthesis of Ultra-Thin Metal Telluride Thermoelectric Nanowires

Metal telluride nanowires are attractive materials for many applications, yet most synthesis recipes require hazardous reducing agents such as hydrazine or sodium borohydride. We describe a two-step large-scale production of various metal tellurides with nanowire morphology using a non-hazardous reducing agent. In the first step, Te grows one-dimensionally to form ultra-thin nanowires; in the second step, these nanowires are converted to metal telluride nanowires by adding metal precursors. Analysis of the reaction products versus time provides insights into the growth and conversion mechanisms as well as the reaction rates.  The yield of each metal telluride nanowire synthesis have been calculated based on the mass of starting precursors and the mass of the washed and dried reaction products. For PbTe, CdTe, and Bi₂Te₃ the yields were approximately 83.3%, 87.5%, and 77.3%, respectively, which points to the feasibility of large-scale synthesis of these materials. For Ag₂Te and Cu_1.75Te, the yields were about 24.5% and 58.9%, respectively. These nanowires exhibit extremely narrow size distribution and a significantly enhanced thermoelectric properties.