Cofluorescence of dyes in nanoparticles formed from metal complexes and possibilities of its application

Abstract

A brief review on the regularities of nanoparticle (NP) formation in aqueous solution from Ln, Y, Al, Sc, and In diketonates, which capture fluorescent dye molecules upon formation, is presented. The intensive sensitized fluorescence of the dyes (cofluorescence) is observed upon the excitation of NPs in the band of absorption of organic ligand complexes. The concentration range of ions and ligands in water that initiate the self-organization of these NPs is discussed, as is the dependence of this process on the method of preparation and the choice of ligand and ion. It was proven that the energy migration from S1L levels of the ligand to the S1D level of the incorporated dye is accomplished in all NPs. Energy transfer from Eu(III) and delayed cofluorescence is observed in NPs of Eu(III) with a dye that has a 1D level below the emitting 5D0 level of Eu(III). It was shown that the sensitization of dye fluorescence in NPs allows for the increased sensitivity of their luminescent detection in aqueous solutions by one to two orders of magnitude. The confident detection of up to 50 pM of Rhodamine 6G is possible on a standard spectrofluorometer using NPs from low-luminescent Lu(III) complexes.