Lattice plainification advances highly effective SnSe crystalline thermoelectrics

Area of Science:

• Materials Science
• Solid-State Physics
• Nanotechnology

Background:

• Thermoelectric technology is crucial for waste-heat recovery and solid-state cooling applications.
• Tin selenide (SnSe) crystals show promise for thermoelectric power generation and Peltier cooling.
• Defects in SnSe significantly impact its transport properties, necessitating defect engineering strategies.

Purpose of the Study:

• To develop a lattice plainification strategy for defects engineering in SnSe crystals.
• To improve the thermoelectric performance of SnSe for practical applications.
• To investigate the effects of copper (Cu) doping on SnSe crystal properties.

Main Methods:

• Developed a lattice plainification strategy for defects engineering in SnSe.
• Introduced copper (Cu) to fill tin (Sn) vacancies, modifying defect scattering.
• Characterized the transport properties, power factor, and dimensionless figure of merit (ZT) of modified SnSe crystals.

Main Results:

• Copper doping boosted carrier mobility by reducing defect scattering in SnSe.
• Achieved a power factor exceeding 100 microwatts per centimeter per square kelvin.
• Obtained a dimensionless figure of merit (ZT) of approximately 1.5 at 300 kelvin and an average ZT of 2.2 between 300 and 773 kelvin.
• Demonstrated a single-leg thermoelectric conversion efficiency of 12.2% for a temperature difference (ΔT) of 300 kelvin.
• Realized a maximum Peltier cooling temperature difference (ΔTmax) of 61.2 kelvin with a seven-pair module at ambient temperature.

Conclusions:

• Lattice plainification and copper doping effectively engineer defects in SnSe, enhancing thermoelectric properties.
• The improved SnSe crystals exhibit significant potential for practical waste-heat recovery and electronic cooling applications.
• The study provides a pathway for optimizing SnSe thermoelectric materials for commercial use.