Investigation the concentration effect on the absorption and fluorescence properties of Rhodamine 6G dye

Concentration dependence of the optical absorption and fluorescence spectra of Rhodamine 6G dye solution have been investigated. Shift the absorption and the fluorescence peaks with an increase the dye concentration, from 0.1 to 250 μM, is studied. By measuring the absorbed and the fluorescence spectra of Rhodamin 6G dye, enhancement of the absorbance and quenching of the fluorescence intensity are obtained. Observed fluorescence quenching of Rhodamine 6G after 60 μM is caused by the collisional mechanism. From 0.1 to 30 μM, the absorbance obeys the Beer-Lambert law. While, beyond 30 μM, due to contributions of the dimers and aggregation of dye molecules, the absorbance deviates from the Beer-Lambert law.