Oxychalcogenides as new efficient p-type thermoelectric materials

During the past two years, we have underlined the great potential of p-type oxychalcogenides, with parent compound BiCuSeO, for thermoelectric applications in the medium temperature range (400-650°C). These materials, which do not contain lead and are less expensive than Te containing materials, exhibit large thermoelectric figure of merit, exceeding 1 in a wide temperature range, mainly due to an intrinsically very low thermal conductivity. This paper summarizes the main chemical and crystallographic features of this system, as well as the thermoelectric properties. It also gives new directions to improve these properties, and discuss the potential of these materials for wide scale applications in thermoelectric conversion system in the medium temperature range.