Properties and evolution of emission in molecular aggregates of a perylene ammonium derivative in polymer matrices

Abstract

5Size-dependent fluorescent properties of aggregates of a perylene ammonium derivative (PeryAm) were studied by steady-state and time-resolved spectroscopic methods. Quantitative analyses of aggregated states in aqueous solution indicated that the aggregation proceeded through dimer units of PeryAm. Fluorescence of the aggregate in the PVA film prepared from the aqueous solution continuously redshifted with an increase in the concentration of PeryAm in the mother liquor, while keeping the 10 absorption spectra almost the same band shapes. Fluorescence anisotropy values of aggregates in the PVA film were dependent on the monitoring wavelength and time profiles of the fluorescence in longer wavelength showed fast rise just after the pulsed excitation. These results indicated the efficient energy transfer to the stable sites in aggregates. Fluorescence microscope images showed aggregates were segregated in the PVA film and the color of the emission was dependent on the size of the aggregate. 15Under the steady-state irradiation, the emission color of the aggregates was changed from green to yellow, which was attributable to the association of a small cluster of PeryAm with the green emission resulting in the formation of yellow-colored aggregates. On the basis of these results, we discussed the mechanisms and the dynamics of the aggregation and size-dependent emission in aggregates.

Targeted design leads to tunable photoluminescence from perylene dicarboxdiimide–poly(oxyalkylene)/siloxane hybrids for luminescent solar concentrators

“…The concentration-dependent formation of stacked dimers has recently been shown to result in a series of chromic shifts in the UV/Vis absorption spectrum of a perylene ammonium derivative. 47 We similarly attribute the gradual change in the solution colour of PDI-Sil (pH 2) to the formation of molecular dimers, followed by their subsequent stacking. The stacking process is believed to be concentration-dependent (Z10 À4 mol dm À3 ), as no change is observed in the UV/Vis absorption spectrum at lower concentrations ( Fig.…”

“…This may indicate that covalent-grafting of PDI-Sil to the ureasil prevents the formation of dimers or stacked aggregates, which has been demonstrated to result in multiexponential emission decay. 47 However, if reabsorption effects were significant in these materials, a change in the emission lifetime would be expected, which is also not the case. 62 We suggest that covalent grafting of PDI-Sil to the ureasil may potentially reduce the efficiency of energy transfer, either through better isolation of individual fluorophores within the matrix (thereby increasing the D-A distance) or by reducing the overlap of the absorption and emission transition dipole moments.…”

Concentration-Dependent Fluorescence Color Tuning of the Difluoroboron Avobenzone Complex in Polymer Films

“…We have investigated the fluorescence properties of a pyrene ammonium derivative 16 and a perylene ammonium derivative 17,18 in a PVA matrix and perylene in a PMMA matrix. At low dye concentrations in the polymer films, the films only showed monomer emission.…”

Fluorescence Enhancement of a Dicyanostilbene Derivative Film Casted from an Alcoholic Solution Triggered by UV-light Irradiation

“…The initial liquid-like state can reorganize and planarize so that the excited non-emissive species will mainly deactivate by a non-radiative path, leading to activating the rotational motion around olefin moieties and to an elevation of the local temperature (photo-thermal annealing). 15 The phenyl rings in DBDCS of the G-phase form on the same plane due to the structural change by UV irradiation. This finding supports the results of the X-ray structure analysis of the G-phase.…”