CHED 277 |
| Asymmetric perylene diimide (PDI) cations have been synthesized. Fluorescence spectra of these molecules bound to four different polyelectrolytes in solution have been obtained. The decrease in PDI fluorescence observed in the presence of polyelectrolyte provides evidence of binding and a means to gauge the strength and cooperativity of binding. At high polyelectrolyte concentrations, red shifted fluorescence appears, resulting from formation of excimers. This peak disappears upon introduction of an organic semiconducting polymer, demonstrating electron transfer in solution. The binding has been modeled using a modified version of the Hill equation. It reveals that strongly cooperative interactions between the PDIs play a role in polyelectrolyte binding. Such interactions have been utilized to make films with semiconducting properties. Atomic force microscopy studies on these films reveal the formation of long fibrous structures. Far-field light microscopy and multiphoton-excited fluorescence microscopy (MPEFM) images indicate the perylene chromophores likely align perpendicular to the long axis of the fibers. These films are being investigated for use in organic solar cells. |
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Undergraduate Research Poster Session: Analytical Chemistry
11:00 AM-1:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |