Enhanced thermoelectric performance of n-type polycrystalline SnSe via NdCl3 doping

Abstract

A series of n-type polycrystalline SnSe0.95 - xmol% NdCl3 samples were synthesized using the melting method combined with spark plasma sintering (SPS). Doping NdCl3 significantly improves the electrical conductivity and suppresses the deterioration of the Seebeck coefficient after thermal excitation, which leads to significantly higher power factors than SnSe0.95. In addition, excessive doping of NdCl3 not only introduces a large number of point defects but also produces NdCl3 precipitates, which largely enhances the phonon scattering and significantly reduces the thermal conductivity. As a result, a maximum ZT value of 1.3 at 773 K has been obtained in SnSe0.95 - 1.5 mol% NdCl3 sample, indicating that the doping of rare earth halides can effectively enhance the thermoelectric performance of n-type SnSe0.95 by simultaneously improving the power factor and reducing the lattice thermal conductivity.