Influence of the chemical structure of polymethine dye on spectral – fluorescent and generation properties

Abstract

The present study examines the spectral-luminescent properties of a cationic polymethine dye in ethanol solutions at two concentrations (10⁻⁵ 33 mol/L and 2∙10⁻⁴ mol/L). The absorption and fluorescence spectra were ana lyzed under conditions of low molecular aggregation and at the threshold concentration for stimulated emission. The results demonstrate that increas ing the dye concentration leads to spectral broadening, a hypsochromic shift of the absorption maximum, and a bathochromic shift of the fluorescence maximum. Additionally, at 2∙10⁻⁴ mol/L, stimulated emission is observed. These findings provide insights into the optical behavior of polymethine dyes under different aggregation conditions and their potential applications in laser technologies.