MIGRATION OF THE ELECTRONIC EXCITATION ENERGY IN LANGMUIR – BLODGETT FILMS OF XANTHENE DYES

Abstract

The concentration and temperature dependencies of the photophysical properties of three new amphiphilic xanthene dyes in the Langmuir-Blodgett (LB) films have been studied. The mechanisms of excitation-energy relaxation were discussed in terms of the excitons migration among energetically disordered monomers and the energy trapping by molecular aggregates. The experimental results were analyzed in view of carried out molecular mechanics and MO calcuations. Triplet states of eosin in the LB films were investigated. The observed nonexponential decay kinetics of delayed fluorescence (DF) and phosphorescence were analyzed in the framework of an annihilation model for both exchange and multipolar interactions.