Effect of Oxygen Quencher on Absorption and Fluorescence Spectra of Rhodamie-6G and Rhodamine-B Dyes in Ethanol Solvent


In this work, absorption and fluorescence spectra of R6G and RB laser dyes were studied. Different concentrations of (1-4)x10-6 mole/liter were used to solve these dyes in an organic solvent such as ethanol. Absorption spectrum of n→S* transition was determined as well as fluorescence spectrum in presence and absence of O2. It was observed that presence of O2 did not affect absorption spectra of both dyes because it has no absorption in the range studied. On the other side, intensity of fluorescence increased as O2 was removed from solvent in both cases of ethanol. Presence of O2 affects fluorescence quantum efficiency and lifetime due to collision with dye molecules. Finally, it was declared that the effect of O2 decreases as the concentration does. This may be attributed to the decrease in collision probability between O2 and dye molecules.