Microstructure and Thermoelectric Properties of Bi2Te3 Nanoplates Prepared by Sol-gel Method

Bi-Te binary compounds are considered the best room temperature thermoelectric materials for cooling and power generation applications because of their high ZT value at room temperature. This research synthesized Bi2Te3 nanostructured thermoelectric materials by sol-gel method, using bismuth (lll) acetate and tellurium dioxide as precursors. The Bi2Te3 gel was maintained at 500 degrees C for 2 hours under nitrogen atmosphere to form powder. A defect free crystalline structure of Bi2Te3 was observed in XRD pattern. Homogeneous nanoplates and rods with vertical nanoplates were discovered by SEM and TEM techniques. HRTEM image confirmed the lattice space of Bi2Te3 phase. Although nanostructures consisting of Bi2Te3 nanoplates on Te nanotubes have been reported, this is the first time homogenous Bi2Te3 nanoplates have been reported to form on a Bi2Te3 core rod structure. Moreover, these homogenous Bi2Te3 nanostructures can be prepared by a simple sol-gel process. Finally, a maximum power factor of 4.18 mu W/cmK(2) was obtained at 473 K for the bulk Bi2Te3, calculated from Seebeck coefficient and electrical conductivity.