Tailoring Electronic and Phononic Properties at Nanoscale for Higher Thermoelectric Power Generation Efficiency

<strong>Seminar of the School of Physical Sciences --------------------------------------------------</strong> Title: <strong>Tailoring Electronic and Phononic Properties at Nanoscale for Higher Thermoelectric Power Generation Efficiency</strong> Speaker:<strong> Biplab Paul</strong> (Linkoeping University, Linkoeping) Date: <strong>August 3, 2016 </strong> <strong>Abstract: </strong>Thermoelectric converter (TEC) is a solid state device that converts temperature gradient ?T into electrical power. For high conversion efficiency of a TEC its constituent materials must have high Seebeck coefficient S so that output voltage become high for a fixed ?T, high electrical conductivity (s) to promote high output power density, low thermal conductivity ? so that temperature gradient across TEC be high. Such materials are referred to as 'phonon-glass-electron-crystals'. Design of such materials is quite challenging as simultaneous increase in Seebeck coefficient and electrical conductivity is not possible. S and s are inversely coupled, as follows from solid state transport theory. On the other hand, an increase in electrical conductivity results in an increase in electronic contribution to thermal conductivity deteriorating thermoelectric efficiency. The focus of the present talk is to discuss various approaches for decoupling electronic properties from that of phononic properties so that independent or at least quasi-independent tuning of S, s and ? become possible in bulk and thin film materials leading to the enhancement of thermoelectric efficiency.