Optical and vibrational studies on single walled carbon nanotubes/short oligo-para-methoxy-toluene composite

In a solution state, an oligophenylene prepared by electrochemical oxidation of para-methoxy-toluene exhibited luminescence in the violet-to-blue region. However, in a solid state, a clear red shift was observed as a signature of a supramolecular π-stacking interaction between oligomer chains. In a de-doped state, by chemical reduction, a fine structure in the form of two peaks was observed and luminescence intensity was strongly improved. When mixed with single walled carbon nanotubes (SWNTs), a quenching in the luminescence intensity accompanied by a slight blue shift of the PL peak of the nanocomposite was observed. This implies the shortening of the oligomer's effective π-conjugation length caused by the added amount of SWNTs. A charge transfer in the photo-excited state was also noted. The interaction taking place between the two materials was supported by optical infrared absorption and Raman scattering measurements and then a functionalizing mechanism was proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011