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

Abstract 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 Al x PbTe 1- y Se y samples are remarkably enhanced compared with the unalloyed ones. The highest average ZT of 0.82 is achieved in Al 0.02 PbTe 0.75 Se 0.25 , which is 60% higher than that of Al 0.02 PbTe. Combining strategies of dynamic doping and/or hierarchical phonon scattering, the thermal performance of n-type PbTe-based materials may be further enhanced.