Laser Shock Dislocation Proliferation Drives Enhanced Thermoelectric Performance in Ag₂Se

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Dense dislocations are crucial for reducing thermal conductivity and enhancing the thermoelectric figure of merit (zT).
• Conventional methods for introducing dislocations often lack universality due to doping and complex synthetic processing.

Purpose of the Study:

• To investigate the effectiveness of laser shock dislocation proliferation (LSDP) for creating high densities of dislocations in Ag2Se.
• To evaluate the impact of LSDP-induced dislocations on the thermoelectric properties of Ag2Se.

Main Methods:

• Utilized laser shock dislocation proliferation (LSDP) to introduce dislocations into Ag2Se, achieving densities of ~10^13/cm^2.
• Characterized the material properties under high pressure (peak > 4.5 GPa), specific pressure duration (198 ns), impact depth (> 0.5 mm), and strain rate (1.52 × 10^7 s^-1).

Main Results:

• LSDP introduced dislocation densities 2-3 orders of magnitude higher than spark plasma sintering (SPS).
• Reduced total thermal conductivity by 23.2% and lattice thermal conductivity by 17.1%.
• Achieved a thermoelectric figure of merit (zT) of 0.91, a 40% improvement over SPS samples.

Conclusions:

• Laser shock dislocation proliferation is a highly effective technique for generating dense dislocations in brittle thermoelectric materials like Ag2Se.
• LSDP offers a promising, universal strategy for enhancing thermoelectric performance by optimizing thermal transport properties.