title: Accurate Diffusion Coefficients of Organosoluble Reference Dyes in Organic Media Measured by Dual-Focus Fluorescence Correlation Spectroscopy.
abstract: Dual-focus fluorescence correlation spectroscopy (2fFCS) is a versatile method to determine accurate diffusion coefficients of fluorescent species in an absolute, reference-free manner. Whereas (either classical or dual-focus) FCS has been employed primarily in the life sciences and thus in aqueous environments, it is increasingly being used in materials chemistry, as well. These measurements are often performed in nonaqueous media such as organic solvents. However, the diffusion coefficients of reference dyes in organic solvents are not readily available. For this reason we determined the translational diffusion coefficients of several commercially available organosoluble fluorescent dyes by means of 2fFCS. The selected dyes and organic solvents span the visible spectrum and a broad range of refractive indices, respectively. The diffusion coefficients can be used as absolute reference values for the calibration of experimental FCS setups, allowing quantitative measurements to be performed. We show that reliable information about the hydrodynamic dimensions of the fluorescent species (including noncommercial compounds) within organic media can be extracted from the 2fFCS data.
authors.affiliation: †KU Leuven, Department of Chemistry, Celestijnenlaan 200F (PO Box 2404), 3001 Heverlee, Belgium.|‡Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), 101-dong, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan 689-798, Republic of Korea.
authors.forename: Karel
authors.initials: K
authors.lastname: Goossens
authors.affiliation: §Georg August University, Third Institute of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
authors.forename: Mira
authors.initials: M
authors.lastname: Prior
authors.affiliation: ⊥Research Centre Jülich, Institute of Complex Systems: Structural Biochemistry (ICS-6), Wilhelm-Johnen-Straße, 52425 Jülich, Germany.|∥Albert Ludwigs University, Institute for Macromolecular Chemistry, Hermann-Staudinger-Haus, Stefan-Meier-Straße 31, 79104 Freiburg, Germany.
authors.forename: Victor
authors.initials: V
authors.lastname: Pacheco
authors.affiliation: ⊥Research Centre Jülich, Institute of Complex Systems: Structural Biochemistry (ICS-6), Wilhelm-Johnen-Straße, 52425 Jülich, Germany.|#Heinrich Heine University, Institute for Physical Biology, Universitätsstraße 1, 40225 Düsseldorf, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Willbold
authors.affiliation: ∇Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.affiliation: §Georg August University, Third Institute of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Enderlein
authors.affiliation: †KU Leuven, Department of Chemistry, Celestijnenlaan 200F (PO Box 2404), 3001 Heverlee, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Hofkens
authors.affiliation: §Georg August University, Third Institute of Physics, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Gregor
keywords: calibration; diffusion; dual-focus fluorescence correlation spectroscopy; fluorescence; organic media