Carbon nanotube functionalization with carboxylic derivatives: a DFT study

Area of Science:

• Materials Science
• Computational Chemistry
• Nanotechnology

Background:

• Single-walled carbon nanotubes (CNTs) possess unique electronic properties.
• Functionalization is a key strategy to tailor CNT properties for specific applications.

Purpose of the Study:

• To theoretically investigate the geometric, energetic, and electronic properties of CNTs functionalized with various carboxylic derivatives.
• To understand how different functional groups impact CNT characteristics.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Geometric, energetic, and electronic properties were analyzed.
• Reaction energies and HOMO/LUMO energy gaps were computed.

Main Results:

• Reaction energies ranged from -0.23 to -7.07 eV, increasing with the electron-withdrawing nature of functional groups.
• Functionalization generally increased the CNTs HOMO/LUMO energy gap by 0.32-0.35 eV.
• Lowering of LUMO, HOMO, and Fermi levels was observed, particularly with -CH2NO2 and -CH2CN groups, increasing the work function.

Conclusions:

• The electron-withdrawing strength of carboxylic derivatives significantly influences CNT functionalization energetics and electronic structure.
• Functionalization can increase the work function of CNTs, which may impede field electron emission applications.