Synergistic Optimization of n -Type PbTe via Resonant Level and Strain-Induced Phonon Scattering for High-Efficiency Thermoelectric Modules

PbTe stands as a leading n -type thermoelectric material for midtemperature applications, yet its performance is limited by a single conduction valley and high lattice thermal conductivity. To address these constraints, we propose a combined strategy integrating resonant level engineering with dislocation engineering. Precise Br codoping positions the Fermi level to maximize the resonant level effect from In, while Ge alloying introduces a substantial strain field for enhanced phonon scattering. The optimized composition, Pb 0.96 In 0.01 Ge 0.03 Te 0.988 Br 0.012, achieves a peak zT of ∼1.4 at 773 K. A fabricated module utilizing this material demonstrates a conversion efficiency of 10.5% under a 550 K temperature difference, ranking among the highest for PbTe-based modules. This work successfully bridges high-performance material design with practical device efficiency, offering a viable path for advancing thermoelectric technology.