Functionalization of carbon nanotubes through surface modification has attracted significant interest [1-3]. Incorporation of light absorbing antenna molecules through a linkage with the extended electrons of a carbon nanotube would constitute an ideal supramolecular nanoassembly for photon energy conversion. On this regard, porphyrins are one of molecules used in assemblies of donor-acceptor materials in molecular electronics and photovoltaic devices [4]. Supramolecular structures consisting of dendritic porphyrins to carbon nanotubes have not been synthesized so far as an efficient donor-acceptor system. We have synthesized dendrimeric porphyrins in which there are peripheral porphyrins that adsorb sunlight and transport it to a central porphyrin that is the central focal point trap. This trap is a conjugated system that transfers this energy to carbon nanotubes. For this purpose we propose an approach of plasma treatment of the surface of SWNTs by first covalently attaching fluorine and then exposing the obtained fluorinated SWNTs (F-SWNTs) to the dendritic porphyrin. We examine this result in detail by combining IR, UV-Vis spectroscopy and electron transport properties of sidewall porphyrin-functionalized SWNTs. The charge transfer power of the adsorbed porphyrin molecules is found to be sufficient to cause significant change in the electrical conductance. We show here that the conjugation of dendritic porphyrin to the F-SWNT surface makes the carbon nanotubes light-sensitive, and that illumination of porphyrin-SWNT system results in an increase of the conductivity.
SURFACE PLASMA TREATMENT OF SINGLE-WALLED CARBON NANOTUBES FOR BUILDING BLOCK SYNTHESIS OF DENDRITIC PORPHYRIN LIGHT HARVESTING SYSTEMS
VALENTINI, LUCA;ARMENTANO, ILARIA;KENNY, Jose Maria;
2005
Abstract
Functionalization of carbon nanotubes through surface modification has attracted significant interest [1-3]. Incorporation of light absorbing antenna molecules through a linkage with the extended electrons of a carbon nanotube would constitute an ideal supramolecular nanoassembly for photon energy conversion. On this regard, porphyrins are one of molecules used in assemblies of donor-acceptor materials in molecular electronics and photovoltaic devices [4]. Supramolecular structures consisting of dendritic porphyrins to carbon nanotubes have not been synthesized so far as an efficient donor-acceptor system. We have synthesized dendrimeric porphyrins in which there are peripheral porphyrins that adsorb sunlight and transport it to a central porphyrin that is the central focal point trap. This trap is a conjugated system that transfers this energy to carbon nanotubes. For this purpose we propose an approach of plasma treatment of the surface of SWNTs by first covalently attaching fluorine and then exposing the obtained fluorinated SWNTs (F-SWNTs) to the dendritic porphyrin. We examine this result in detail by combining IR, UV-Vis spectroscopy and electron transport properties of sidewall porphyrin-functionalized SWNTs. The charge transfer power of the adsorbed porphyrin molecules is found to be sufficient to cause significant change in the electrical conductance. We show here that the conjugation of dendritic porphyrin to the F-SWNT surface makes the carbon nanotubes light-sensitive, and that illumination of porphyrin-SWNT system results in an increase of the conductivity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
