Effect of Silver and Gold Nanoparticles on the Spectral and Luminescent Properties of a Merocyanine Dye

An increase in the concentration of silver nanoparticles (NP) initially causes an increase and then a decrease in the absorption and fluorescence intensities of a solution of tetramethinemerocyanine dye derived from indole and thiobarbituric acid. In the case of gold NP, the dye absorption remains unchanged, while fluorescence is reduced. The lifetime of the merocyanine fluorescent state does not change upon the addition of both types of nanoparticles. It is suggested that the observed effects are related to the action of plasmons in the metal nanoparticles on the electronic processes in the dye molecules.