Fluorescence spectroscopy of Rhodamine 6G: Concentration and solvent effects

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 121; pp. 147 - 151
• Main Authors: Zehentbauer, Florian M., Moretto, Claudia, Stephen, Ryan, Thevar, Thangavel, Gilchrist, John R., Pokrajac, Dubravka, Richard, Katherine L., Kiefer, Johannes
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 2014
• Subjects: Alcohol; Coloring Agents - chemistry; Dye laser; Flow visualization; Laser-induced fluorescence; Molecular Conformation; Rhodamine 590; Rhodamine 6G; Rhodamines - chemistry; Signal Processing, Computer-Assisted; Solvents - chemistry; Spectrometry, Fluorescence; Water - chemistry; Dye laser; Rhodamine 590; Flow visualization; Laser-induced fluorescence; Alcohol; Rhodamine 6G
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2013.10.062

[Display omitted] •Both concentration and solvent effects can be utilized for tuning the optical emission of Rhodamine 6G.•Rhodamine 6G fluorescence in aqueous solutions has been studied from highly dilute to high concentration systems.•At low concentration isolated dye molecules are present while aggregates are formed at high concentration. Rhodamine 6G (R6G), also known as Rhodamine 590, is one of the most frequently used dyes for application in dye lasers and as a fluorescence tracer, e.g., in the area of environmental hydraulics. Knowing the spectroscopic characteristics of the optical emission is key to obtaining high conversion efficiency and measurement accuracy, respectively. In this work, solvent and concentration effects are studied. A series of eight different organic solvents (methanol, ethanol, n-propanol, iso-propanol, n-butanol, n-pentanol, acetone, and dimethyl sulfoxide (DMSO)) are investigated at constant dye concentration. Relatively small changes of the fluorescence spectrum are observed for the different solvents; the highest fluorescence intensity is observed for methanol and lowest for DMSO. The shortest peak wavelength is found in methanol (568nm) and the longest in DMSO (579nm). Concentration effects in aqueous R6G solutions are studied over the full concentration range from the solubility limit to highly dilute states. Changing the dye concentration provides tunability between ∼550nm in the dilute case and ∼620nm at high concentration, at which point the fluorescence spectrum indicates the formation of R6G aggregates.