Optical characterization of DNA-wrapped carbon nanotube hybrids

Optical characterization of DNA-wrapped CoMoCAT carbon nanotube hybrids (DNA-CNT) and semiconductor-enriched DNA-CNT was carried out using resonant Raman spectroscopy (RRS) and photoluminescence (PL) experiments. The values of radial breathing modes frequency ω_RBM were found to be relatively insensitive to the type of wrapping agents surrounding the nanotube. The values of ω_RBM and the first and second resonant interband transitions, E₁₁ and E₂₂, for a particular ( n, m) tube for all sample types in RRS and PL measurements are found to correspond to the values obtained for SDS-dispersed nanotubes measured with PL, but with a shift in E_ii ranging from 10 to 80 meV. The DNA-wrapping has shown not only to provide good isolation to the individual nanotube in a bundle, but the DNA wrapping mechanism for the CoMoCAT sample has also been shown to be diameter selective.