Preparation of bismuth telluride based thermoelectric nanomaterials via low-energy ball milling and their property characterizations

Robinson, Christopher A., M.S.M.E., Purdue University, May 2015. Preparation of Bismuth Telluride Based Thermoelectric Nanomaterials Via Low-Energy Ball Milling and their Property Characterizations. Major Professor: Xiulin Ruan, School of Mechanical Engineering. Thermoelectric materials are able to convert energy between heat and electricity with no moving parts, making them very appealing for power generation purposes. This is particularly appealing since many forms of energy generation lose energy to waste heat. The Livermore National Laboratory estimates that up to 55% of the energy created in traditional power plants is lost through heat generation [1]. As greenhouse gas emissions become a more important issue, large sources of waste like this will need to be harnessed. Adoption of these materials has been limited due to the cost and efficiency of current technology. Bismuth telluride based alloys have a dimensionless figure of merit, a measure of efficiency, near one at room temperature, which makes it the best current material. In order to compete with other forms of energy generation, this needs to be increased to three or higher [2]. Recently, improvements in performance have come in the form of random nanostructured materials [3]. Bulk bismuth telluride is subjected to particle size reduction via high-energy ball milling in order to scatter phonons between