Enhancing n-Type PbTe Thermoelectrics via Valley Shape Modulation and Core-Shell Precipitates

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Achieving high thermoelectric (TE) performance requires simultaneously optimizing power factor and minimizing lattice thermal conductivity, a persistent challenge in TE materials.
• Lead telluride (PbTe)-based materials are promising for TE applications but face limitations in achieving optimal performance.
• Existing strategies often struggle to balance electronic and thermal transport properties effectively.

Purpose of the Study:

• To significantly advance the thermoelectric performance of PbTe-based materials.
• To investigate the efficacy of a combined band-sharpening and core-shell structural strategy.
• To explore the role of valley modification and defect engineering in enhancing TE properties.

Main Methods:

• Utilized a band-sharpening approach involving valley modification in n-type AgPbSnTe-Ag$_{2}$Te compounds.
• Implemented an innovative core-shell structural strategy for defect engineering.
• Synthesized and characterized Ag$_{0.03}$Pb$_{0.97}$Sn$_{0.03}$Te-0%Ag$_{2}$Te samples.

Main Results:

• Achieved substantial band sharpening, leading to enhanced carrier mobility and exceptional electronic performance.
• Demonstrated significant lattice disorder and nanostructures via core-shell defect engineering, effectively scattering phonons.
• Attained a peak thermoelectric figure of merit (zT) of approximately 1.4 at 773 K.

Conclusions:

• The combined band-sharpening and core-shell defect engineering strategy offers a robust framework for optimizing TE materials.
• Valley modification is crucial for enhancing electronic transport in single-conduction-band systems.
• This work provides a pathway for developing high-performance thermoelectric materials through advanced structural and defect engineering techniques.