CNTs in optoelectronic devices: New structural and photophysical insights on porphyrin-DWCNTs hybrid materials

The preparation and physical characterization of diverse porphyrin-derived double-walled carbon nanotubes (DWCNTs) conjugates are described. A porphyrin molecule is covalently linked and physically adsorbed to COOH-derived DWCNTs. The photophysical properties of all porphyrin-CNTs derivatives are studied in solution and in polymeric matrices. Definitive experimental evidence for photoinduced electron and/or energy transfer processes involving the porphyrin chromophores and the CNT wall is not obtained, but solid-state UV-vis absorption profiles display electronic transitions fingerprinting J- and H- type aggregates, where porphyrin molecules intermolecularly interact "head-to-tail" and "face-to-face", respectively. In parallel, molecular modeling based on force-field simulations is performed to understand the structure of the porphyrin-CNTs interface and the nature of the interactions between the porphyrins and the DWCNTs. Finally, multilayered-type devices are fabricated with the aim of investigating the interaction of the porphyrin-derived DWCNTs with poly(3-hexylthiophene)-pyrene matrices containing small amounts of 1-[3-(methoxycarbonyl)propyl]-1-phenyl-[6.6]C .