Photoluminescence and electronic interaction of anthracene derivatives adsorbed on sidewalls of single-walled carbon nanotubes

Dye molecules (anthracene derivatives) are observed to strongly adsorb to single-walled carbon nanotubes (SWNTs). The adsorption coverage of anthracene molecules on SWNTs varied with the aromatic ring substituents. The observed red shifts of emission peaks of the absorptive adduct appear to depend on the energy level of the lowest unoccupied molecular orbital (LUMO) of the adsorbate, consistent with adsorption by a charge-transfer interaction, in which the SWNT is electron donor and anthracene is acceptor. The anthracene absorptive adducts can be displaced by adsorption of pyrene.