Boosting Thermoelectric Performance of Bi₂ Te₃ Material by Microstructure Engineering.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Thermoelectric materials face a trade-off between electrical conductivity and Seebeck coefficient, limiting power factor (PF) enhancement.
• Improving PF is crucial for efficient thermoelectric energy conversion and power output.

Purpose of the Study:

• To enhance thermoelectric properties of Bi2Te3 by fabricating multilayer films with Sb and W.
• To investigate strategies for overcoming the intrinsic contradiction in thermoelectric materials for higher PF.

Main Methods:

• Fabrication of Bi2Te3/Sb and Bi2Te3/W multilayer films.
• Characterization of structural and thermoelectric properties at various temperatures.
• Analysis of microstructural changes under thermal stress.

Main Results:

• Achieved ultrahigh power factors: 1785 µWm⁻²K⁻² for Bi2Te3/W and 1566 µWm⁻²K⁻² for Bi2Te3/Sb at 600 K.
• Demonstrated simultaneous increase in electrical conductivity and Seebeck coefficient with temperature.
• Observed distinct microstructural responses: Bi2Te3/W maintained structure with confined grains, while Bi2Te3/Sb showed phase changes and precipitates.

Conclusions:

• Multilayer engineering of Bi2Te3 with Sb and W effectively enhances thermoelectric performance.
• Compositional effects, confinement, and structural defects in multilayer films contribute to ultrahigh power factors.
• Microstructure engineering provides a viable strategy for optimizing commercial Bi2Te3 thermoelectric materials.