Defect Engineering for High-Performance n-Type PbSe Thermoelectrics

Introducing structural defects such as vacancies, nanoprecipitates, and dislocations is a proven means of reducing lattice thermal conductivity. However, these defects tend to be detrimental to carrier mobility. Consequently, the overall effects for enhancing ZT are often compromised. Indeed, developing strategies allowing for strong phonon scattering and high carrier mobility at the same time is a prime task in thermoelectrics. Here we present a high-performance thermoelectric system of Pb0.95(Sb0.033□0.017)Se1–yTey (□ = vacancy; y = 0–0.4) embedded with unique defect architecture. Given the mean free paths of phonons and electrons, we rationally integrate multiple defects that involve point defects, vacancy-driven dense dislocations, and Te-induced nanoprecipitates with different sizes and mass fluctuations. They collectively scatter thermal phonons in a wide range of frequencies to give lattice thermal conductivity of ∼0.4 W m–1 K–1, which approaches to the amorphous limit. Remarkably, Te alloying incr...