High-Power-Density and Excellent-Flexibility Thermoelectric Generator Based on All-SWCNTs/PVP Composites.

Area of Science:

• Materials Science
• Nanotechnology
• Thermoelectrics

Background:

• Development of n-type flexible polymer/single-wall carbon nanotube (SWCNT) composites lags behind p-type counterparts.
• Limited understanding exists regarding SWCNT-polymer interactions, particularly with unconjugated polymers, and their influence on conduction mechanisms.

Purpose of the Study:

• To fabricate n-type flexible SWCNT/Polyvinyl Pyrrolidone (PVP) films.
• To investigate the interaction mechanism between SWCNTs and PVP and its effect on thermoelectric properties.
• To optimize the performance of SWCNT/PVP composites for wearable thermoelectric applications.

Main Methods:

• Fabrication of n-type flexible SWCNTs/PVP films.
• Analysis of SWCNT-PVP interactions via hydrogen bonding.
• Tuning synthesis temperature to modify hydrogen bond strength and thermal activation energy.
• Assembly of a thermoelectric module using optimized SWCNTs/PVP films.

Main Results:

• PVP's oxygen atoms interact with SWCNTs via hydrogen bonds, facilitating electron tunneling and transfer.
• Increased synthesis temperature strengthens hydrogen bonds and improves thermal activation energy, enhancing PVP's electron-donating ability.
• Achieved a high power factor of 260 µW m⁻¹ K⁻².
• Thermoelectric module demonstrated a power density of 400 µW cm⁻² at ΔT = 56 K.
• Exhibited excellent flexibility with <1% resistance change after 5000 bending cycles.

Conclusions:

• The interaction mechanism involving hydrogen bonds between SWCNTs and unconjugated polymers like PVP is crucial for enhancing n-type thermoelectric performance.
• Optimized SWCNTs/PVP films offer superior output performance and flexibility compared to existing SWCNT-based thermoelectric modules.
• This research provides valuable insights for designing high-performance hybrid thermoelectric composites for flexible and wearable electronics.