Chirality-Selective Functionalization of Semiconducting Carbon Nanotubes with a Reactivity-Switchable Molecule

Area of Science:

• Materials Science
• Organic Chemistry
• Nanotechnology

Background:

• Chirality-selective functionalization of semiconducting single-walled carbon nanotubes (SWCNTs) has been a significant synthetic challenge for over a decade.
• Precise control over SWCNT functionalization is crucial for advanced applications in electronics and materials science.

Purpose of the Study:

• To develop an on-demand covalent chemistry for the selective functionalization of specific single-walled carbon nanotube (SWCNT) chiralities.
• To enable precise chemical tailoring of SWCNTs at the single chirality level for advanced applications.

Main Methods:

• Synthesis and isolation of a chemically inert diazoether isomer.
• In situ switching of the diazoether to its reactive form using pH and visible light, tuned to the SWCNT's optical frequency.
• Monitoring reaction completion via sensitive defect photoluminescence, achieving functionalization of <0.01% of carbon atoms.

Main Results:

• Demonstrated optically driven diazoether chemistry for selective SWCNT functionalization within mixtures.
• Achieved near-complete functionalization of less reactive (7,3)-SWCNTs over highly similar (6,5)-SWCNTs by controlling the reaction with light.
• Showcased the ability to inhibit the reaction in the absence of light, ensuring high selectivity.

Conclusions:

• The developed on-demand covalent chemistry provides a breakthrough for precise, chirality-selective functionalization of SWCNTs.
• This method opens new avenues for SWCNT sorting, on-chip passivation, and nanoscale lithography by enabling tailored SWCNT properties.