Photochemical Behavior of High Quantum Yield SWNTs Functionalized with Anthracene Salts

Two different fluorescent single walled carbon nanotubes (SWNT) were prepd. First by a reaction of oxidized SWNT-K salt with 1,3-bis(9-anthracenylmethyl)imidazolium chloride (bamim)Cl to provide a fluorescent system SWNT-(bamim), via ion exchange and formation of KCl. Second, by phys. mixing of non-functionalized SWNTs with (bamim)Cl salt to provide SWNT/[bamim]Cl in which anthracene units adhere to the walls of the nanotube via π-π stacking interactions. The SWNT-[bamim] material exhibits a partially reversible photodimerization process that was investigated using UV/Vis spectroscopy, fluorescence emission spectroscopy, and HR-TEM. This study establishes the concept of photoinduced/photoswitchable org.-SWNT conjugated systems based on anthracene dimerization as a prototypical reaction. Hierarchical nanoscale hybrid structures based on the above materials and an understanding of their optical properties may facilitate the construction of SWNT based materials.