| 초록 |
Upon confronting present energetic and environmental challenges, the global need for utilizing exhausted waste heat has been accelerated. In effect, thermoelectric materials are gathering a great interest as a potential alternative energy source because of their capability of direct energy conversion between heat and electricity. The increase of thermoelectric efficiencies is one of the main challenges of our scientific community. The performance of a thermoelectric material is assessed with the figure of merit ZT defined as (S2σ/κ)T; where S is the Seebeck coefficient (or thermopower), σ electrical conductivity, κ thermal conductivity, and T is the temperature. Recent theoretical and experimental studies show that the use of thermoelectric materials comprising nanostructured components increases ZT relative to that of the bulk counterparts of these materials. Minimizing thermal conductivity while maintaining the electrical conductivity is the key point in formation of nanoscaled or nanocomposite thermoelectric. Controlling the size and content of the nanoscale constituents within the bulk materials is especially important to achieve high ZT. Thus, new routes for the preparation of these components as nanoscale powders are essential for incorporating them as nanoscale constituents of the bulk materials. In this presentation, an overview of recent advances in the development of high performance nanoscaled thermoelectric materials, especially nano-engineering in Bi2Te3 based materials, is presented. Recent results on Bi2Te3 based nanocomposites prepared through several novel approaches to fabricate nanoscaled bulk thermoelectric materials and their theoretical investigation of thermoelectric properties are presented. |
