Influence of Aggregation on the Fluorescence Decay of Organic Laser Dyes

Abstract

Singlet decay times in dependence on temperature, concentration, solvent and detergent were measured in solutions of organic laser dyes. In the temperature range from 300 K to 115 K the reciprocal decay time obeys an Arrhenius relationship, the parameters of which were determined. Additional measurements were carried out on Acridinorange because a biexponential fluorescence decay due to monomers (τ = 4.2 ns) and aggregated molecules (τ = 14.7 ns) was found.

Systematic Colocalization Errors between Acridine Orange and EGFP in Astrocyte Vesicular Organelles

“…Our results suggest that the polychromatic emission of single AO-labeled astroglial organelles (Fig. 1 A) (52,53), based on a two-component regression analysis. Importantly, for equimolar AO solutions, we found no significant differences in FLIM-derived m.AO and d.AO abundances between pH 5 and pH 7 (Fig.…”

“…To prepare a pure solution of nonaggregated m.AO as a spectral reference (yellow trace on Fig. 2 A), we diluted 0.5 mM AO in 20% detergent (Triton-X100) following the protocol by Knof and co-workers (52). The measured spectra of dilute AO solutions with 0.1 mM [AO] were virtually indistinguishable from the m.AO reference spectrum.…”

Water in Biomolecular Fluorescence Spectroscopy and Imaging: Side Effects and Remedies

“…A solution containing loworder aggregates such as dimers still appears as perfectly clear to the human eye in the sense that no scattering due to unsolubilized dye particles can be observed. Nonetheless aggregation can be detected spectroscopically as it strongly affects the photophysical properties of the dyes compared to the monomeric species, [8] in particular the absorption and fluorescence band shape and position. Two geometries are often encountered and discussed in dye aggregates (Fig.…”

Competing dynamics of intramolecular deactivation and bimolecular charge transfer processes in luminescent Fe(iii) N-heterocyclic carbene complexes

“…4,6 The level of understanding is, however, much less developed compared to that of deactivation pathways in d 6 complexes. For example, while the d 5 metal complexes still retain the clear CT character of the excited state, the spin-allowed direct deactivation channel with its typical lifetimes in the 1-10 ns range is in some sense more similar to many organic chromophores 22,23 including some open-shell (doublet) organic radicals. 24 Additionally, the 2 LMCT excited state does not automatically imply long lifetime or strong photoluminescence.…”

“…Lifetimes (at 100 K and 300 K) and Arrhenius parameters for [Fe III (phtmeimb) 2 ] + (this work) in different solvent systems, [Ru II (pymbpy) 2 ] 2+ ,36,37 [Ru II (dqp) 2 ] 2+ ,29 and Coumarine 47 (ref 22). …”