Synergistically optimizing interdependent thermoelectric parameters of n-type PbSe through introducing a small amount of Zn

Abstract

In this work, we found that the interdependent thermoelectric parameters of n-type PbSe can be synergistically optimized through introducing a small amount of Zn. A record high power factor of 26.2 μW cm−1K−2 was achieved in PbZn0.01Se at 523 K, which is ascribed to the outstanding roles of Zn. We found that small Zn atoms first occupy Pb vacancies, which not only increases the carrier concentration but also improves the carrier mobility. When the content of Zn exceeds a certain level, the small Zn atoms will form interstitials and nanoprecipitates, which can enormously decrease the lattice thermal conductivity but slightly scatter carriers, thus maintaining a high carrier mobility. Combination of significantly enhanced power factor and remarkedly reduced lattice thermal conductivity contributes to a high thermoelectric performance. A maximum ZT ∼1.5 at 873 K and a high average ZT ∼0.84 are achieved in PbZn0.01Se, which are superior to those of the most reported n-type PbSe systems. This work provides a strategy to synergistically optimize interdependent thermoelectric parameters through introducing small metallic atoms.