Skutterudites: promising power conversion thermoelectrics

The past dozen years or so have witnessed a major resurgence of interest in thermoelectrics and specifically in identifying novel, potentially promising materials that might deliver better performance than the existing thermoelectric structures. Among the materials that have generated considerable interest are skutterudites. The open crystal environment of skutterudite compounds typified by the presence of structural voids offers a terrific opportunity to modify the material by inserting foreign species into the voids and thus dramatically alter both electronic and phonon transport. With a judicious choice of the filler species one can prepare both n- and p-type filled skutterudites that display exceptionally high thermoelectric figure of merit ZT in excess of unity in the range of temperatures between 700K-1000K. Filled skutterudites are therefore excellent candidates for thermoelectric power generation applications in the intermediate to high temperature regime of operation. In this paper I will briefly review the progress made in improving the thermoelectric properties of filled skutterudites and point out areas where I believe further improvement is likely to be achieved.