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

Abstract

It is known that the addition of plazmon metal nanoparticles to the lasant 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 applied point of view, has not been well investigated and requires additional studies. In this paper, the fluorescence of the solutions of the Rhodamine 6G and Rhodamine C dyes at different excitation wavelengths when there are silver nanoparticles is investigated. The effect of the mixture components concentration on the fluorescence amplification coefficient of the dye molecules is studied. It is shown that 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, as a generalized parameter that has influence on the fluorescent characteristics of nanocomposites. The relative optical density is maximized with increase in the concentration of nanoparticles as well as with decrease of 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, the increase in the fluorescence amplification coefficient is observed. If the pumping spectrum is far from the wavelength of maximum of the plasmon resonance, the concentration of the nanoparticles is low, and the dye concentration is high, then the relative optical density is small, the fluorescence gain becomes insignificant, and even its quenching may occur. 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.