A label-free fluorescence sensing platform based on NaY0.47F4:Ce0.1,Gd0.4,Eu0.03@PEIF down-conversion for selective detection of Cu2+ in aqueous environments

Abstract

The issue of Cu2+ contamination is severe due to its potential to induce diseases upon exposure. This study has developed a novel down-conversion fluorescent material, α-phase NaY0.47F4:Ce0.1,Gd0.4,Eu0.03@PEIF nanoparticles (Eu@PEIF NPs). It was synthesized using thermal decomposition combined with epitaxial growth methods, to synthesize the Eu NPs that show high crystallinity and regular morphology; after functionalization with fluorinated PEI (PEIF) to obtain Eu@PEIF NPs with good water solubility and optical properties. The Cu2+ can bind to Eu@PEIF NPs through surface amino groups resulting in fluorescence quenching attributed to inner filter effect (IFE) and Förster resonance energy transfer (FRET). Thus, a new label-free fluorescence sensing platform based on Eu@PEIF NPs was constructed and quantitatively analysize Cu2+ over the concentration range of 0.03-2.5 μM, with a low detection limit and high selectivity to Cu2+. And this fluorescence sensor exhibits excellent recovery rates (94.93 % ~ 104.61 %) when applied to the detection of Cu2+ in real water samples. This proposed method provides a new approach for Cu2+ detection and offers guidance for the design of Cu2+-sensitive fluorescent probes.