Optimizing Thermoelectric Properties of Metal Chalcogenides by Engineering Composition and Crystallinity
- Author(s): Kim, Jiwon
- Advisor(s): Myung, Nosang V.
- et al.
Metal Chalcogenide nanostructures have been extensively implemented for high-performance thermoelectric applications, which can directly convert waste-heat-energy into electricity, with the support of theoretical and empirical results. In fact, finding a novel and cost effective synthesis approach that facilitates the formation of stable and reproducible nanostructured thermoelectric materials determines the commercial applicability.
The overall objective of this work is to synthesize metal chalcogenide nanostructures with outstanding thermoelectric performance by an electrodeposition technique, which is one of the most versatile methods for low dimensional nanostructures in a cost effective and scalable manner. Precise control over dimension, chemical composition, crystallinity, crystal structure, grain size, preferred orientation, and the attainment of nanoinclusions and/or intermediate phases based on thermodynamically favored solid-state phase transition yields optimal electrical transport and thermoelectric properties of the metal chalcogenide nanostructures. In this dissertation, antimony telluride (SbxTey), silver doped antimony telluride, antimony telluride (AgxSb(2-x)Te(3-x)), bismuth antimony telluride (BixSb2-xTey) thin films were electrodeposited, followed by post annealing to create various nanocrystalline thin films. Additionally, antimony telluride nanowires were synthesized by a template-directed electrodeposition. The material, electrical, and thermoelectric properties of those metal chalcogenide nanostructures are systematically investigated to depend the effect of dimension, composition, crystallinity, crystallographic properties, and temperature for thermoelectric applications.