Etching of surfactant from solution-processed, type-separated carbon nanotubes and impact on device behavior

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Semiconducting single-walled carbon nanotubes (SWCNTs) are crucial for advanced electronics.
• Current synthesis methods yield mixed metallic and semiconducting SWCNTs, necessitating separation.
• Surfactant-assisted purification leaves residues that can impede SWCNT properties.

Purpose of the Study:

• To investigate the removal of sodium taurodeoxycholate (STDC) surfactant from SWCNTs.
• To develop an effective method for complete surfactant removal while preserving SWCNT characteristics.
• To evaluate the impact of residual STDC on single SWCNT electronic device performance.

Main Methods:

• Vacuum annealing was used to study STDC removal, observing surfactant fragmentation.
• A novel approach combining air oxidation and mild annealing was developed for complete STDC removal.
• Single SWCNT electronic devices were fabricated and tested with and without STDC treatment.

Main Results:

• Complete removal of STDC via vacuum annealing requires very high temperatures due to strong binding.
• The air oxidation and mild annealing method successfully removed STDC without compromising SWCNT properties.
• Despite strong binding, residual STDC had a negligible effect on the performance of single SWCNT electronic devices.

Conclusions:

• Strong binding of STDC to SWCNTs necessitates high temperatures for removal via vacuum annealing.
• Air oxidation combined with mild annealing offers an effective route for surfactant removal.
• The presence of STDC, even with strong binding, does not substantially alter SWCNT device performance.