Advances in thermoelectric (GeTe) x (AgSbTe2)100-x

The (GeTe)( x )(AgSbTe2)(100 - x ) alloys, also called TAGS-x in short, have long been demonstrated as a promising candidate for thermoelectric applications with successful services as the p-type leg in radioisotope thermoelectric generators for space missions. This largely stems from the complex band structure for a superior electronic performance and strong anharmonicity for a low lattice thermal conductivity. Utilization of the proven strategies including carrier concentration optimization, band and defects engineering, an extraordinary thermoelectric figure of merit, zT, has been achieved in TAGS-based alloys. Here, crystal structure, band structure, microstructure, synthesis techniques and thermoelectric transport properties of TAGS-based alloys, as well as successful strategies for manipulating the thermoelectric performance, are surveyed with opportunities for further advancements. These strategies involved are believed to be in principle applicable for advancing many other thermoelectrics.