Lattice defect engineering advances n-type PbSe thermoelectrics

Area of Science:

• Materials Science
• Solid-State Physics
• Nanotechnology

Background:

• Te-free thermoelectrics offer low cost and high potential but suffer from low performance.
• Key challenges include conflicting electron/thermal transport and poor material interface compatibility.

Purpose of the Study:

• To enhance the thermoelectric performance of Te-free materials.
• To overcome limitations in electron/thermal transport and interface stability in lead selenide (PbSe).

Main Methods:

• Lattice defect engineering via copper (Cu) doping in polycrystalline PbSe.
• Micro/nanostructural characterizations and first-principles calculations.
• Designing a robust Cobalt (Co)/PbSe interface to improve stability and reduce contact resistivity.

Main Results:

• Achieved a record-high figure of merit (~1.9) in n-type PbSe through Cu doping.
• Cu-induced defects and nanoprecipitates optimized both electron and phonon transport.
• Co/PbSe interface demonstrated low contact resistivity (~10.9 μΩ cm²), durability, and stability.
• Record-high thermoelectric conversion efficiency of 13.1% achieved in segmented modules at ΔT = 460 K.

Conclusions:

• Cu doping is an effective strategy for lattice defect engineering in PbSe.
• Optimized interfaces and transport properties lead to high thermoelectric performance.
• This work advances Te-free selenide-based thermoelectric materials for practical applications.