Multifunctional hybrid materials composed of [60]fullerene-based functionalized-single-walled carbon nanotubes

We report the synthesis and characterization of several hybrid [60]fullerene-SWCNT materials that combine [60]fullerenes with appended photoactive ferrocenyl or porphyrinyl functionalities and SWCNTs into a single multifunctional structure, where the dyads are covalently attached to the exo-surface of SWCNTs. The structural properties of all hybrids have been characterized using a large variety of spectroscopic and HR-TEM techniques. Raman spectra showed how all SWCNTs were functionalized and the presence of functional groups in the nanotube derivatives. Furthermore, these spectra reveal a new electronic activity of the compounds due to the interaction of the functional groups with the SWCNT frameworks. XPS investigations have documented the presence of [60]fullerene derivatives around the exo-surface of the oxidized SWCNT walls, exhibiting a characteristic photoelectron N 1s emission peak at 400.3 eV. Very importantly, by means of HR-TEM investigations we have also observed the presence of the [60]fullerene functions on the SWCNT outer surface by imaging spherical structures. The presence of the porphyrinyl and ferrocenyl fragments, which can act as effective chromophores and electroactive species, makes this class of materials very interesting for applications in optoelectronics and photovoltaics, and bio-applications, for example in the field of diagnosis and treatment. (C) 2008 Elsevier Ltd. All rights reserved.