DEPENDENCE OF FLUORESCENT CHARACTERISTICS OF NANOCOMPOSITES ON THE BASIS OF DYE MOLECULES AND SILVER NANOPARTICLES ON THE OPTICAL DENSITY OF COMPONENTS

Abstract

Subject and purpose. It is known that the addition of plazmon metal nanoparticles to active media can be used to improve the radiative characteristics of the medium. However, the problem of the influence of the component ratio on the intensity of the nanocomposites fluorescence, which is relevant from an applied point of view, has not been sufficiently investigated and requires additional studies. Methods and methodology. In this paper fluorescence of solutions of Rhodamine 6G and Rhodamine C dyes in the presence of silver nanoparticles at different excitation wavelengths was studied. The effect of the mixture components concentration on the fluorescence amplification coefficient of the dye molecules was studied. Results. It is shown that as a generalized parameter determining the fluorescent characteristics of nanocomposites, one can consider the relative optical density of the mixture components, which is the ratio of the optical density of the nanoadditive to the optical density of the dye at the excitation wavelength. The relative optical density increases with an increase in the concentration of nanoparticles, a decrease in the concentration of the dye, or in the case of excitation by radiation with the spectrum closest to the maximum of plasmon resonance of nanoparticles. In this case, an increase in the fluorescence amplification coefficient was observed. If the pump spectrum is far from the maximum wavelength of the plazmon resonance, the concentration of the nanoparticles is low, and the dye concentration is high, then the relative optical density is small, the fluorescence intensification becomes insignificant, and even its quenching may occur. Conclusions. The results of these studies allow us to formulate a general approach to assessing the effect of the components ratio of mixtures composed of dye molecules and metallic nanoparticles on the fluorescence intensity of fluorophore molecules.

Keywords

• fluorescence
• laser dye
• nanoparticles
• plazmon resonance