The thermoelectric performance of anisotropic SnSe doped with Na

摘要

Lead-free polycrystalline SnSe is a promising thermoelectric compound consisting of earth-abundant elements. However, the poor electrical transport property for low intrinsic defect concentration (3 × 10 ~(17) cm ~(?3) ) limits the usage of the stoichiometric SnSe compound. In this work, Na _(2) Se as an acceptor was doped into SnSe in order to optimize the electrical transport properties, especially to increase the carrier concentration. As a result, the carrier concentrations increased and saturated at about 1.0 × 10 ~(19) cm ~(?3) for Na _(0.01) Sn _(0.99) Se at 300 K, and a maximum power factor of 0.48 mW m ~(?1) K ~(?2) was obtained. A maximum zT value of 0.75 was obtained at 823 K for Na _(0.01) Sn _(0.99) Se along the direction perpendicular to the sintering pressure, which is 25% higher than that (0.6) of the undoped SnSe compound.