Fluorescence Quantum Yields and Their Relation to Lifetimes of Rhodamine 6G and Fluorescein in Nine Solvents: Improved Absolute Standards for Quantum Yields¶

Abstract Absolute fluorescence quantum yields are reported for the rhodamine 6G cation and the fluorescein dianion dyes in nine solvents. This information is combined with previously reported fluorescence lifetimes to deduce radiative and nonradiative decay rates. Along the alcohol series from methanol to octanol, rhodamine 6G displays an increasing radiative rate, in parallel with the square of the refractive index increase, and a slightly decreasing nonradiative rate. Fluorescein is different: the apparent radiative rate actually decreases, suggesting that the emissive species is perturbed in some fashion. For both dyes, fluorescence yields are enhanced in D2O, rising to 0.98, in parallel with a corresponding increase in lifetimes. Protonated solvents invariably give shorter lifetimes and lower quantum yields, contrary to some previous speculation. From this work and an analysis of existing literature values, more precise values have been obtained for two previously proposed absolute quantum yield standards. The yield of fluorescein in 0.1 N NaOH(aq) is 0.925 ± 0.015, and for rhodamine 6G in ethanol, it is 0.950 ± 0.015. In both cases, the solutions are assumed to be in the limit of low concentration, excited close to their long-wave absorption band and at room temperature but may be either air-saturated or free of oxygen.

[1]  V. P. N. Nampoori,et al.  Solvent Effect on Absolute Fluorescence Quantum Yield of Rhodamine 6G Determined Using Transient Thermal Lens Technique , 1999 .

[2]  J. Callis,et al.  CALORIMETRIC, PHOTOMETRIC AND LIFETIME DETERMINATIONS OF FLUORESCENCE YIELDS OF FLUORESCEIN DYES * , 1969, Photochemistry and photobiology.

[3]  W. M. Haynes.  CRC Handbook of Chemistry and Physics , 1990 .

[4]  K. Drexhage,et al.  Fluorescence and lasing properties of rhodamine dyes , 1991 .

[5]  A. Fletcher,et al.  Fluorescence quantum yields of some rhodamine dyes , 1982 .

[6]  Joseph Georges,et al.  FLUORESCENCE QUANTUM YIELD OF RHODAMINE 6G IN ETHANOL AS A FUNCTION OF CONCENTRATION USING THERMAL LENS SPECTROMETRY , 1996 .

[7]  C A Carter,et al.  Comparison of models describing the thermal lens effect. , 1984, Applied optics.

[8]  K. Drexhage.  Structure and Properties of Laser Dyes , 1973 .

[9]  M. D. Galanin,et al.  Measurement of photoluminescence quantum yield of dye solutions by the Vavilov and integrating-sphere methods , 1982 .

[10]  J. Callis,et al.  Absolute Quantum Efficiencies. , 1972, Journal of research of the National Bureau of Standards. Section A, Physics and chemistry.

[11]  V. Nampoori,et al.  Fluorescence quantum yield of rhodamine 6G using pulsed photoacoustic technique , 1990 .

[12]  D. Magde,et al.  Absolute quantum yield determination by thermal blooming. Fluorescein , 1978 .

[13]  P. Seybold,et al.  Solvent Dependence of the Fluorescence Lifetimes of Xanthene Dyes , 1999 .

[14]  Monique M. Martin.  Hydrogen bond effects on radiationless electronic transitions in xanthene dyes , 1975 .

[15]  S. J. Strickler,et al.  Relationship between Absorption Intensity and Fluorescence Lifetime of Molecules , 1962 .

[16]  Jun Shen,et al.  Thermal lens measurement of absolute quantum yields using quenched fluorescent samples as references , 1989 .

[17]  W. Lahmann,et al.  Opto—acoustic determination of absolute quantum yields in flourescent solutions , 1977 .

[18]  J. Georges,et al.  Limitations arising in the study of the fluorescence quenching of rhodamine 6G by iodides using cw-laser thermal lens spectrometry , 1998 .

[19]  J. Demas,et al.  Measurement of photoluminescence quantum yields. Review , 1971 .

[20]  J. Whinnery,et al.  New thermooptical measurement method and a comparison with other methods. , 1973, Applied optics.

[21]  J. Olmsted.  Calorimetric determinations of absolute fluorescence quantum yields , 1979 .

[22]  C. Davis,et al.  Direct measurement of dilute dye solution quantum yield by photothermal laser heterodyne interferometry , 1985 .

[23]  R. C. Weast.  CRC Handbook of Chemistry and Physics , 1973 .

[24]  G. Weber,et al.  Fluorescence excitation spectrum of organic compounds in solution. Part 1.—Systems with quantum yield independent of the exciting wavelength , 1958 .

[25]  Jun Shen,et al.  Two-beam thermal lens spectrometer for ultra-trace analysis , 1989 .