Enhancement of thermoelectric performance of Al doped PbTe-PbSe due to carrier concentration optimization and alloying

摘要

Al doped PbTe-PbSe alloys were successfully prepared with high pressure synthesis followed by spark plasma sintering. The incorporation of Se shows a dual effect on the system. Firstly, the carrier concentration can be further modified with varying Se content, on the basis of Al doping. Secondly, the lattice thermal conductivity can be greatly suppressed due to the alloying effect. Beneficial from this, the average ZT of AlxPbTe1-ySey samples are remarkably enhanced compared with the unalloyed ones. The highest average ZT of 0.82 is achieved in Al0.02PbTe0.75Se0.25, which is 60% higher than that of Al0.02PbTe. Combining strategies of dynamic doping and/or hierarchical phonon scattering, the thermal performance of n-type PbTe-based materials may be further enhanced. (C) 2019 Elsevier B.V. All rights reserved.