Excitation transfer in functionalized carbon nanotubes

Tailoring properties of carbon nanotubes properties by functionalizing their side-wall is one of the key challenges towards the realization of carbon nanotube-based optoelectronic devices [1, 2]. This technique aims at combining the great transport properties of the nanotube [3, 4] with the versatility of the optical properties of organic molecules. The extraordinary properties of carbon nanotubes reside in their one dimensional feature. Therefore, using these properties inside devices require preserving this unique feature. Photoluminescence experiment is one of the most sensitive tools to the changes in the electronic structure of semi-conductors. Preserving photoluminescence of semi-conducting nanotubes means preserving their one dimensional feature and therefore their remarkable properties. We present our results about "p-stacking" functionalization of single wall carbon nanotubes with different porphyrins molecules [5]. These complexes show a total quenching of the porphyrin fluorescence, while the photoluminescence of the nanotubes is preserved and even enhanced when the excitation is tuned in resonance with the Soret band of the porphyrins. This is the evidence for an efficient excitation transfer within the nanotube/porphyrin complex, which corresponds to the implementation of a key functionnality: an organic graft acting as an antenna and the nanotube acting as a collector [5, 6]. [1] M.S. Strano, C.A. Dyke, M.L. Usrey, P.W. Barone, M.J. Allen, H. Shan, C. Kittrell, R.H. Hauge, J.M. Tour, R.E. Smalley, Science 2003, 301, 1519-1522. [2] D.M. Guldi, J. Phys. Chem. B 2005, 109, 11432-11441. [3] P. Avouris, Z. Chen, V. Pereibeinos, Nature nanotechnology 2007, 2, 605-615. [4] A.D. Mohite, P. Gopinath, H.M. Shah, B.W. Alphenaar, Nano Lett. 2008, 8, 142-146. [5] G. Magadur, J.S. Lauret, V. Alain-Rizzo, C. Voisin, Ph. Roussignol, E. Deleporte, J. A. Delaire ChemPhysChem 2008 (in press) [6] J.P. Casey, S.M. Bachilo, R.B. Weisman, J. Mat. Chem. 2008, DOI: 10.1039/b716649d