| 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 directlyto the SWNT surface using a divergent methodology. This approach allows the number of functional groupson the nanotubes to be increased without provoking significant damage to the conjugated π-system of theSWNTs. Several tetraphenylporphyrin moieties can be linked to the periphery of the dendrimers, and thephotophysical 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 isthat some porphyrin units do not interact with the nanotubes, thus exhibiting a fluorescence lifetime similarto that of the free porphyrin. Complementary transient absorption measurements not only corroborate thefast decay of the photoexcited tetraphenylporphyrin but also confirm that intraconjugate charge separationevolves from the excited porphyrin to the SWNTs.
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