Noncovalent Interaction of 1-Ethyl-4-(Methoxycarbonyl)Pyridinium Iodide with Conjugated Polymer-Wrapped Single-Walled Carbon Nanotubes: Dependence of Molecular Arrangement on the Nanotube Characteristics.

Interaction between 1-ethyl-4-(methoxycarbonyl)pyridinium iodide (EMCPI) and poly[9-(1-octylonoyl)-9H-carbazole-2,7-diyl] (PCz)-wrapped pristine, I2-doped or Se chain-filled SWCNTs in dichloromethane (DCM) was investigated based on steady-state and time-resolved spectroscopic characterization. A change in the arrangement of adsorbed molecules was found in solutions that were irradiated by the light beam at a wavelength close to the charge-transfer (CT) absorption band maximum of EMCPI, indicative of excited-state radicals outcompeting ground-state ion pairs for surface sites on PCz-wrapped SWCNTs. The interaction of either ions or radicals with PCz-wrapped SWCNTs was demonstrated to be noncovalent. It was also shown that the arrangement of adsorbed molecules was affected by doping or filling the SWCNTs.