Enhanced Thermoelectric Performance of N-Type Polycrystalline Snse Via Ndcl3 Doping

Abstract

A series of n-type polycrystalline SnSe 0.95 - x mol% NdCl 3 samples were synthesized using the melting method combined with spark plasma sintering (SPS). Doping of NdCl 3 significantly enhances the electrical conductivity after thermal excitation and inhabits the deterioration of Seebeck coefficient by intrinsic excitation, which leads to significantly higher power factors than SnSe 0.95 . In addition, excessive doping of NdCl 3 not only introduces a large number of point defects but also produces NdCl 3 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 SnSe 0.95 - 1.5mol% NdCl 3 sample, indicating that the doping of rare earth halides can effectively enhance the thermoelectric performance of SnSe 0.95 by simultaneously improving the power factor and reducing the lattice thermal conductivity.

Keywords: thermoelectric, polycrystalline SnSe, n-type, NdCl3, lattice thermal conductivity