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- Physical study individualized Double-wall Carbon Nanotubes by Optical techniques

Auteur(s): Tran H.-N., Sauvajol J.-L., Paillet M., Zahab A. A.

(Affiches/Poster) GDR-I GNT 2013 (Lorient, FR), 2013-04-09


Résumé:

Double-wall carbon nanotubes (DWNTs) appear as prototypal nanomaterial for studying coupling interactions [1-4] and screening effects at the nanoscale [5]. In this context, we prepared suspensions of individualized DWNTs in sodium deoxycholate (DOC) from pristine DWNTs (p-DWNTs) and covalently functionalized DWNTs (f-DWNTs). F-DWNTs are prepared by the diazonium route which has been shown to selectively functionalize outer-walls [6, 7]. The samples were studied by UV-Vis-NIR absorption, Raman spectroscopy, and photoluminescence (PL). The optical absorption of DWNTs suspensions in surfactant have been measured up to 2500 nm in order to confirm that the DWNTs are individualized and the covalent functionalization of outer-walls. Raman spectra were measured with several excitation wavelengths between 532 nm and 800 nm. According to [8, 9], we identified the (n,m) of small diameter inner-walls by using radial-breathing-like modes (RBLM) frequencies. Compared with the RBM of individualized HiPCO single-wall nanotubes (SWNTs) samples prepared using the same protocol, we observed a slight upshift of RBLM of inner-walls [1-3]. We measured PL maps with excitation wavelengths in the range 700-950 nm and compared them with results from the literature [11, 12] as well as data obtained on HiPCO SWNTs suspension. The results obtained suggest that inner-walls are luminescent. In order to confirm this conclusion, preliminary results of combined PL/Raman experiments performed at the individual DWNT level will be presented.