痕量Yb掺杂诱导的阳离子空位簇增强p型PbTe热电性能

Alloying has been widely used to enhance thermoelectric (TE) performance, but achieving high TE performance remains challenging due to strong coupling between electrical and thermal transport in lead telluride-based materials. In this Letter, trace doping of the rare earth element Yb in a Pb0.95Na0.04Te matrix effectively regulates charge carriers by competing with cation vacancies. This mechanism optimizes carrier concentration and phonon scattering, resulting in a high power factor of ∼27 _μ_ W cm−1 K−2 and a low lattice thermal conductivity of ∼0.42 W m−1 K−1 at 823 K in Pb0.94Na0.04Yb0.01Te. First-principles calculations reveal that Yb doping induces local lattice distortions in PbTe, potentially forming pseudo-nanostructures in localized regions. This strategy leads to a peak _zT_ of ∼2.4 at 823 K and an average _zT_ of ∼1.4 from 303 to 823 K in Pb0.94Na0.04Yb0.01Te. Our findings suggest that the competition between dopant cations and cation vacancies reduces thermal conductivity