Radical-Mediated Dispersion Breaks Aggregation Limits in Carbon Thermoelectrics

Area of Science:

• Materials Science
• Nanotechnology
• Energy Harvesting

Background:

• Single-walled carbon nanotubes (SWCNTs) offer excellent electrical and mechanical properties for flexible thermoelectrics.
• SWCNT self-aggregation severely limits their thermoelectric performance.
• Existing dispersion methods are largely ineffective against SWCNT aggregation.

Purpose of the Study:

• To develop an effective strategy for dispersing SWCNTs to enhance thermoelectric performance.
• To overcome the challenge of SWCNT aggregation in flexible thermoelectric materials.

Main Methods:

• A novel radical-mediated dispersion (RMD) strategy using a designed small molecule (OTN) was developed.
• OTN features a donor-acceptor backbone for π-interactions and radical terminals for radical-radical interactions.
• OTN-SWCNT hybrid films were fabricated and characterized for thermoelectric properties.

Main Results:

• The RMD strategy significantly suppressed SWCNT aggregation.
• OTN-SWCNT hybrid films achieved a high power factor of 30.1 µW cm^-1 K^-2.
• A nine-leg thermoelectric device demonstrated a normalized power density of 0.653 µW cm^-2 K^-2, a leading performance for CNT-based thermoelectrics.

Conclusions:

• The pioneered RMD strategy effectively addresses SWCNT aggregation.
• This approach enhances thermoelectric performance and mechanical flexibility.
• The findings pave the way for practical, flexible carbon-based thermoelectric energy harvesting.