ICT2014 Abstracts

Lead selenide (PbSe), a cubic semiconductor with low thermal conductivity consisting of earth-abundant elements, has been widely investigated as a promising thermoelectric (TE) material in recent years. In this study, homogeneous n-type Pb_1-xSn_xSe (x=1%,5%,10%,20%) bulks with high density were fabricated by a facile method combining mechanical alloying and spark plasma sintering with PbCl₂ added to stabilize the carrier concentration. The substitution of Sn for Pb was found to modify the PbSe band structure by tuning the host band gap, which brought about a large increase in electrical conductivity with no obvious decrease in Seebeck coefficient, leading to an enhancement in power factor. In addition, alloy scattering against phonons induced by Sn substitution effectively reduced lattice thermal conductivity. The unusual increase in the power factor and reduction in thermal conductivity led to the large enhancement in thermoelectric performance of PbSe-SnSe solid solutions, and a maximum ZT ~ 1.0 was obtained at 773K in 10% Sn sample.

Key words: lead selenide; thermoelectric materials; band modification; solid solutions.