Abstract
The phosphorescence and delayed fluorescence behaviour of the fluorone dyes disodium fluorescein (FL, uranine), 4,5-dibromofluorescein (DBF), eosin Y (EO), erythrosine B (ER), and rose bengal (RB) in bio-films of gelatine, starch, and chitosan at room temperature is studied. Phosphorescence and delayed fluorescence quantum yields and lifetimes were measured. The singlet-triplet dynamics is ...
Abstract
The phosphorescence and delayed fluorescence behaviour of the fluorone dyes disodium fluorescein (FL, uranine), 4,5-dibromofluorescein (DBF), eosin Y (EO), erythrosine B (ER), and rose bengal (RB) in bio-films of gelatine, starch, and chitosan at room temperature is studied. Phosphorescence and delayed fluorescence quantum yields and lifetimes were measured. The singlet-triplet dynamics is described and applied to the fluorone dyes for parameter extraction. For uranine films at room temperature no phosphorescence could be resolved. The efficiency of singlet-triplet intersystem crossing increased in the order phi(ISC)(DBF) < phi(ISC)(EO) < phi(ISC)(ER) < phi(ISC)(RB) due to the heavy atom effect on spin-orbit coupling. The phosphorescence quantum yields increased in the order phi(P)(DBF) < phi(P)(EO) < phi(P)(RB) < phi(P)(ER). The phosphorescence lifetimes followed the order tau(P)(DBF) > tau(P)(EO) > tau(P)(ER) > tau(P)(RB). (C) 2010 Elsevier B.V. All rights reserved.
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