n-type Bi-doped PbTe Nanocubes with Enhanced Thermoelectric Performance

In this study, Bi was selected to dope PbTe nanocubes to develop high performance n-type PbTe-based thermoelectric materials via nanostructure engineering using a facile solvothermal method. Bi dopants effectively improve the electrical transport properties of the as-sintered PbTe nanomaterials by tuning the carrier concentrations, achieving promising electrical conductivity and Seebeck coefficient which are comparable to bulk materials. Moreover, a low lattice thermal conductivity has been secured in the sintered Bi-doped PbTe nanomaterials, which is remarkably lower than its bulk counterparts. Extensive experimental and theoretical evidences reveal that such low lattice thermal conductivity is attributed to the enhanced phonon scattering by the high density of grain boundaries and dislocations, in turn, leading to an enhanced peak ZT similar to 1.35 at 675 K for n-type Pb0.99Bi0.01Te.