Microstructurally Tailored Thin β-Ag₂ Se Films toward Commercial Flexible Thermoelectrics.

Area of Science:

• Materials Science
• Nanotechnology
• Energy Conversion

Background:

• Flexible thermoelectric power generators face limitations in structural integrity and commercial viability.
• Developing efficient and scalable fabrication methods for thermoelectric materials is crucial for practical applications.

Purpose of the Study:

• To design an efficient room-temperature aqueous selenization reaction for fabricating thin β-Ag2Se films.
• To overcome structural and commercial limitations of current flexible thermoelectric devices.

Main Methods:

• A rapid (<1 min), air-compatible aqueous selenization reaction was developed.
• Thin β-Ag2Se films with specific crystalline structure (large columnar grains, in-plane randomness, [201] preferred orientation) were fabricated.
• Thermoelectric properties, including power factor and figure-of-merit, were measured.

Main Results:

• Achieved a high power factor (PF) of 2590 ± 414 µW m⁻¹ K⁻² and a figure-of-merit (zT) of 1.2 ± 0.42 for ≈1 µm thick β-Ag2Se films.
• Demonstrated excellent crystalline quality with large columnar grains and controlled orientation.
• The best 4-leg thermoelectric generator sample reached a maximum output power density of 124 ± 8.78 W m⁻² at 60 K temperature difference.

Conclusions:

• The developed aqueous selenization method enables direct fabrication of high-performance β-Ag2Se films.
• The resulting thermoelectric properties are promising for flexible thermoelectric power generation.
• This approach holds potential for advancing future flexible electronic devices.