Zusammenfassung
The fluorescence and phosphorescence behavior of the fluorone dyes disodium fluorescein (uranine), 4,5-dibromofluorescein, eosin Y, erythrosine B, and rose bengal in biofilms of chitosan, gelatin, and starch was studied in the temperature range from 293 K to 12 K. Luminescence quantum yields, fluorescence quantum yields, and triplet quantum yields were determined. The fluorescence quantum yield ...
Zusammenfassung
The fluorescence and phosphorescence behavior of the fluorone dyes disodium fluorescein (uranine), 4,5-dibromofluorescein, eosin Y, erythrosine B, and rose bengal in biofilms of chitosan, gelatin, and starch was studied in the temperature range from 293 K to 12 K. Luminescence quantum yields, fluorescence quantum yields, and triplet quantum yields were determined. The fluorescence quantum yield generally increased with lowering the temperature at a high level of absolute quantum yield, while the phosphorescence quantum yield increased with decreasing temperature at a low level of absolute quantum yield. The strongest phosphorescence was found for erythrosine B in starch where the phosphorescence quantum yield increased from 6% at 293 K to 25% at 12K. The temperature dependent luminescence behavior is discussed considering radiative and non-radiative transitions in a spectroscopic-state potential energy surface scheme. (C) 2011 Elsevier B.V. All rights reserved.