Vibrational properties of thin films and solid state of perylenediimide-fullerene dyads

Analysis of the vibrational properties of Langmuir-Blodgett multilayers of the perylenediimide-fullerene (PDI-C60), perylenediimide-tetrathiafulvalene (PDI-TTF) dyads, and reference molecules adsorbed on various surfaces was performed. The comparison of their absorption and reflection-absorption spectra suggests small redistribution of the charges in both moieties of the dyads after formation of the Langmuir-Blodgett layers. This effect is observed as shifts of selected vibrational bands of the dyad layers in comparison with respective bands of the dyads in the bulk. Orientations of organic chain molecules grafted to a metal surface were suggested on the ground of IR reflection-absorption investigations.