title: Dendrimer-functionalized single-wall carbon nanotubes: synthesis, characterization, and photoinduced electron transfer.
abstract: We describe the synthesis and characterization of a series of single-wall carbon nanotubes (SWNTs) functionalized with polyamidoamine dendrimers. Importantly, the dendrimers are linked directly to the SWNT surface using a divergent methodology. This approach allows the number of functional groups on the nanotubes to be increased without provoking significant damage to the conjugated pi-system of the SWNTs. Several tetraphenylporphyrin moieties can be linked to the periphery of the dendrimers, and the photophysical properties of the resulting nanoconjugates have been investigated with a series of steady-state and time-resolved spectroscopy. The fluorescence kinetics provide evidence for two transient decays, one very short-lived (i.e., 0.04 +/- 0.01 ns) and one long-lived (i.e., 8.6 +/- 1.2 ns). A possible explanation is that some porphyrin units do not interact with the nanotubes, thus exhibiting a fluorescence lifetime similar to that of the free porphyrin. Complementary transient absorption measurements not only corroborate the fast decay of the photoexcited tetraphenylporphyrin but also confirm that intraconjugate charge separation evolves from the excited porphyrin to the SWNTs.
authors.affiliation: INSTM and Dipartimento di Scienze Farmaceutiche, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy. scampidelli@units.it
authors.forename: Stéphane
authors.initials: S
authors.lastname: Campidelli
authors.forename: Chloé
authors.initials: C
authors.lastname: Sooambar
authors.forename: Enrique
authors.initials: E
authors.lastname: Lozano Diz
authors.forename: Christian
authors.initials: C
authors.lastname: Ehli
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Guldi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Prato
mesh_terms: D050091:Dendrimers; D004583:Electrons; D018625:Microscopy, Atomic Force; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010777:Photochemistry; D011073:Polyamines / Q000138:chemical synthesis / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D019265:Spectroscopy, Near-Infrared
chemical_list: D050091:Dendrimers; D037742:Nanotubes, Carbon; C104700:PAMAM Starburst; D011073:Polyamines