Preferential functionalisation of carbon nanotubes probed by Raman spectroscopy

We have chemically grafted methoxypheny functions on HiPco single-walled carbon nanotubes through a radical procedure. To characterise the efficiency of this functionalisation, the materials have been examined via Raman spectroscopy at five laser excitation energies (1.96, 2.33, 2.41, 2.54 and 2.71 eV). This work concentrates mostly on the radial breathing mode band between 150 and 300 cm−1. Clear evidence is put forward showing that those tubes which are preferentially functionalised are the smaller-diameter semiconducting tubes and the metallic tubes.