Condensed-Matter Physics & Materials Science Seminar

The talk will give an introduction to thermoelectric phenomena and current applications. A short review of some of the important work over the last several years will be given with an emphasis on non-traditional materials such as skutterudites which employ cage structures, oxides and thin film superlattices grown by MOCVD and MBE methods. Recently, there has been an ever-increasing research effort on thermoelectric nanocomposite materials. Composites using a mixture of bulk thermoelectric materials with nanoparticles incorporated within the bulk are of specific interest. One of the main goals is to have additional design or tuning parameters for materials (such as dimensionality) in order to manipulate and control the phonon scattering mechanisms, without significantly deteriorating the electrical transport properties. The ability to decouple the electron and phonon scattering mechanisms is very important in the development of higher efficiency thermoelectric (TE) materials, wherein the figure of merit, ZT, can be greater than unity. New opportunities are being explored in order to improve existing TE materials and significantly increase ZT. The role of phonons may be one of the most important parameters to understand in these novel materials. A review of recent results in low dimensional and nanocomposite TE materials from several research groups, including my own, will be presented. In addition, a perspective of the potential contribution that thermoelectric energy conversion technologies might have on the overall energy picture will be discussed.