Efeito de nanopartículas metálicas na formação de agregados e nas propriedades ópticas de rodamina 6G

Abstract

The aggregation effect on Rhodamine dyes is an issue extensively explored in the literature. In recent years, the research on the interactions between metal nanoparticles and organic dyes have grown considerably due to its applications in areas such as medicine, chemistry and engineering. We study the effects of concentrations of the xanthene dye Rhodamine 6G (Rh-6G) and nanoparticles (NPs) of Au (gold) and Ag (silver) on the thermal and optical properties of Rh-6G. The studies were performed on three sets of samples: set Rn, consisting of aqueous solutions with varying concentration of Rh-6G; AuRn set, that consists of aqueous solutions with fixed concentration of gold nanoparticles (NPsAu) and varying concentration of Rh-6G, and the hybrid combination of silver NPs and aqueous Rh-6G, with a concentration NPsAg fixed and varying the concentration of Rh-6G. For these studies we used conventional absorption and luminescence spectroscopic measurements. To characterize the formation of dimers, the Förster theory for energy transfer by dipole-dipole was used. We conclude that energy transfer between monomer-monomer and monomer-dimer, are very efficient and should be considered in these systems. Preliminary results of the effects of NPsAu NPsAg and on the optical properties of Rh-6G was also discussed, particularly on the formation of aggregates. The behavior obtained for aqueous solutions of Rh-6G with NPsAu NPsAg and indicate that we should consider the presence of these NPs in determining dimers in solutions.