| The electronic properties of carbon nanotubes can be altered significantly by introducing various modifications to the nanotube surface. In this study, single-walled carbon nanotubes (SWNTs) were functionalized non-covalently using designed surfactant peptides, and their effect on SWNT electronic properties was investigated. These surfactant peptides contained aromatic amino acids of different functionality, including strong electron-donating (amine) and strong electron-withdrawing (cyano) groups. Circular dichroism studies revealed that the surfactant peptides remain primarily as random coil structures, both alone and in the presence of SWNTs. The atomic force microscopy and UV-Vis-NIR spectroscopy results confirmed the ability of the surfactant peptides to disperse individual SWNTs in solution. Raman G-band peak shifts and the additional features observed near the Fermi level in the scanning tunneling spectroscopy dI/dV spectra of peptide-coated SWNTs suggested that the electronic properties of SWNTs can be successfully altered using surfactant peptides with donor or acceptor functional groups. |
