| Autor: |
M.P. de Haas, John M. Warman, B. Wegewijs, Jan W. Verhoeven, R.M. Hermant |
| Rok vydání: |
1990 |
| Předmět: |
|
| Zdroj: |
Chemical Physics Letters. 168:185-190 |
| ISSN: |
0009-2614 |
| DOI: |
10.1016/0009-2614(90)85127-x |
| Popis: |
The fluorescent behaviour of a donor-bridge-acceptor compound was studied in apolar solvents as a function of temperature. In the ground-state conformation donor and acceptor are held far apart by the interconnecting saturated hydrocarbon bridge. Photoexcitation at room temperature in an apolar solvent nevertheless leads to exciplex-like emission at 454 nm from a “folded” conformation. Emission spectra at low temperatures reveal a totally different fluorescence band at 380 nm that is ascribed to a CT state with a stretched conformation. With time-resolved fluorescence measurements it was shown that this state is the precursor to the folded exciplex-state, indicating that charge separation takes place in an extended conformation. At room temperature charge separation is followed by rapid Coulomb-induced interconversion to a folded conformation, thereby efficiently quenching the 380 nm fluorescence. Further confirmation of our interpretation was obtained by time-resolved microwave conductivity experiments. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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