Absorption spectra of associates of heterogeneous dye molecules in polymer matrices

Abstract

The formation processes for heterogeneous associates of cationic dyes in polyvinyl alcohol films are investigated. The influence of colorless anions on the heterogeneous association efficiency is established. The structures of heterogeneous dimers of various dyes in polymer matrixes are defined.Introduction. Polymeric laser elements that are both solutions of dyes [1] and polymeric matrices with incorporated molecules [2, 3] have recently become of great interest. The generating properties of such media are determined mainly by their spectral and luminescent characteristics. Complexes in the ground state (associates) that are associated states causing a change of the laser active medium spectral characteristics and also fluorescence quenching can be formed at high dye concentrations. The efficiency of association processes in polymeric systems with incorporated dye molecules depends on their structural organization and charges [4]. Association processes between various types of molecules (formation of heterogeneous associates) are interesting with respect to the use of multi-component luminescing systems for increasing the lasing energy and expanding the frequency range of its tuning. The interaction of only colored ions (cations) is usually examined in studies of formation processes of heterogeneous associates of dyes [5,6]. Therefore, an investigation of the influence of colorless anions on such processes is critical. Herein we report results from a study of association processes of dye molecules in polymeric matrices.Experimental. The following cationic dyes were studied: Rhodamine 6G (R6G) with various anions (Cl

Local Dye Concentration and Spectroscopic Properties of Monomer–Aggregate Systems in Hybrid Porous Nanolayers

“…Rhodamine 6G (Rh6G) is a strongly fluorescent and stable dye from xanthene group of well-defined concentration-dependent spectroscopic properties in solutions, polymer matrices or glasses. − Therefore, it is a perfect model molecule for aggregation and energy transport studies. It has been found that at high Rh6G concentrations its fluorescent dimers or higher order aggregates may appear, but the susceptibility to dimerization and optical properties of these aggregates are strongly different depending on the solution or matrix properties.…”

Concentration-Dependent Fluorescence Properties of Rhodamine 6G in Titanium Dioxide and Silicon Dioxide Nanolayers

“…In this paper, we use the sol–gel process to obtain and study concentration-dependent fluorescence properties of rhodamine 6G entrapped in titanium dioxide (Rh6G/TiO 2 ) and silicon dioxide (Rh6G/SiO 2 ) nanolayers. Rh6G is a strongly fluorescent dye, the photophysical properties of which have been thoroughly studied at different concentrations in solutions, polymer matrices, glasses, and nanocomposites over past years using mostly steady-state spectroscopic methods. − In particular, some recent studies of concentration-dependent behavior of Rh6G revealed that its dimers formed in viscous solutions or rigid media can be fluorescent. − In many recent studies devoted to sol–gel derived luminescent materials, optically and physically thick samples have been prepared and measured. Such results, although very interesting, can be distorted by the presence of inner filter effects (reabsorption and reemission).…”