Switchable conductance in functionalized carbon nanotubes via reversible sidewall bond cleavage

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Carbon nanotubes (CNTs) are promising nanomaterials with unique electrical properties.
• Controlling the conductance of metallic CNTs is crucial for developing advanced electronic devices.
• Current methods for functionalizing CNTs often lead to irreversible changes in their electrical properties.

Purpose of the Study:

• To propose novel covalent functionalization strategies for metallic carbon nanotubes.
• To achieve switchable on/off conductance in metallic CNTs through reversible chemistry.
• To enable direct, real-time control over the electrical properties of CNTs.

Main Methods:

• Utilizing [1 + 2] cycloadditions for reversible covalent functionalization.
• Inducing sp(3) ⇌ sp(2) rehybridization to modulate CNT conductance.
• Designing specific addends that balance orbital interactions and strain energy for reversible bond cleavage.
• Proposing control strategies based on redox reactions, hydrolysis, cis-trans isomerization, and excited-state proton transfer.

Main Results:

• Demonstrated that specific covalent functionalizations can lead to switchable on/off conductance in metallic CNTs.
• Showcased remarkable conductance changes even at low functionalization degrees.
• Identified addends that facilitate reversible bond-cleavage chemistry crucial for switching.
• Proposed multiple pathways for real-time control of the functionalization and conductance.

Conclusions:

• Developed designer functional groups for precise control over metallic CNT electrical properties.
• Enabled the first direct control of electrical conductance in metallic carbon nanotubes.
• Opened avenues for extensive applications in nanoscale electronic devices and sensors.