Luminescence Quantum Yield Determination for Molecules Adsorbed onto Solid Powdered Particles

Abstract

A new methodology for the determination of the fluorescence quantum yield of dyes adsorbed onto microcrystalline cellulose is presented and applied to rhodamine 101, cresyl violet and auramine O. It is based on a previously reported method by Ruetten and Thomas (J. Phys. Chem., 1998, 102, 598-606), which is not applicable to the dyes used in the present study. It uses ground-state diffuse reflectance spectra obtained with and without filters, which prevents the luminescence of the dye from reaching the integrating sphere and the photodetector. New equations are presented here, correcting for the fluorescence emission of the dye, which depends on the detector sensitivity. Cut-on filters, which have a transmittance close to unity in the absorption region, and close to zero in the emission region, of the dye are used to obtain corrected reflectance spectra. The influence of the substrate was also taken into account. This methodology may be applied to other probes and surfaces or emissions of a different nature (i.e., phosphorescence or delayed fluorescence), and constitutes a very simple and general procedure to solve the important problem of luminescence quantum yield determination of probes adsorbed onto solid powdered surfaces.

Effect of Concentration on the Photophysics of Dyes in Light‐Scattering Materials.

“… and Vieira Ferreira et al . , and consists in comparing diffuse reflectance values obtained with and without an optical filter interposed between the sphere and the photomultiplier detector. The filter has to block a substantial fraction of the sample luminescence.…”

Eosin Y Triplet State as a Probe of Spatial Heterogeneity in Microcrystalline Cellulose

“…wavelength (28,29). Absolute fluorescence quantum yields were calculated from total reflectance measurements with and without a suitable filter (Schott BG38, 2 mm thickness), which cuts a substantial amount of the emission of the solid sample.…”

“…For strongly fluorescent solid samples, reflectance is overestimated by luminescence reaching the photodetector. Observed fluorescence quantum yields can be calculated from reflectance spectra with and without filter in front of the detector and considering thick layer emission spectra corrected for changes in the detector responsivity with wavelength (28,29). Absolute fluorescence quantum yields were calculated from total reflectance measurements with and without a suitable filter (Schott BG38, 2 mm thickness), which cuts a substantial amount of the emission of the solid sample.…”

Photophysical Studies of a New Water Soluble Indocarbocyanine Dye Adsorbed onto Microcrystalline Cellulose and beta-Cyclodextrin

“…With this set-up, both fluorescence and phosphorescence spectra were easily available (by the use of the variable time gate width and start delay facilities of the ICCD). The determination of fluorescence quantum yield in solution and on solid supports was done in accordance with references [35,37]. …”

“…One of our group’s interests is the photophysical processes of several probes [30,31,32,33,34,35,36,37,38,39,40,41,42], including cyanine dyes [30,31,32,40,43] adsorbed on various heterogeneous powdered supports, particularly onto microcrystalline cellulose. Probes included within cyclodextrin [40,41] and calixarene [42] cavities were also investigated.…”