Indium-Doping Advances High-Performance Flexible Ag₂Se Thin Films.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Thermoelectric materials convert heat to electricity, crucial for energy harvesting.
• Silver selenide (Ag₂Se) thin films are promising but face challenges in performance enhancement.
• Physical vapor deposition (PVD) is a common fabrication method with limitations for Ag₂Se.

Purpose of the Study:

• To enhance the thermoelectric performance of Ag₂Se thin films.
• To introduce a precursor doping strategy for improved material properties.
• To evaluate the flexibility and device performance of the fabricated films.

Main Methods:

• Fabrication of indium (In)-doped Ag₂Se thin films using a precursor doping strategy.
• Characterization of structural, electrical, and thermal properties.
• Testing of film flexibility through bending cycles.
• Construction and evaluation of a flexible thermoelectric device.

Main Results:

• Indium substitutional doping at Ag cation sites improved electrical conductivity while maintaining a high Seebeck coefficient.
• Achieved a room-temperature power factor of ≈26.3 µW cm⁻¹ K⁻² and a ZT value approaching 1.
• Demonstrated excellent flexibility, retaining over 90% conductivity after 500 bending cycles.
• A five-leg flexible device reached a power density of 630.6 µW cm⁻².

Conclusions:

• The precursor doping strategy effectively enhances thermoelectric performance of Ag₂Se thin films.
• The In-doped Ag₂Se films exhibit competitive thermoelectric properties and excellent mechanical flexibility.
• The developed flexible thermoelectric device shows significant potential for practical energy harvesting applications.