Furoic Acid-Capped LaF₃:Tb Nanoparticles for Al³⁺ Detection Based on Aggregation-Induced Luminescence Enhancement

High Resolution Image Download MS PowerPoint Slide The importance of aluminum usage in our everyday life and its adverse impact on health and the environment stimulate the development of excellent probes for the detection of Al 3+ ions. In this study, we developed a luminescence enhancement-based detection probe for the selective detection of Al 3+ ions. For this purpose, we developed water-dispersible 2-furoic acid-capped LaF 3:5%Tb 3+ nanocrystals (NCs) via the microwave irradiation method. Here, 2-furoic acid acts as a surfactant and an antenna for the Tb 3+ ions. Oxygen in the furan ring has a hard base nature and prefers to bind with hard acid-natured metal ions. Upon excitation at 258 nm, the NCs show characteristic Tb 3+ emissions via 2-furoic acid sensitization. The excitation and emission spectra of the NCs increased continuously with the gradual addition of Al 3+ ions from 1 to 700 μm in the aqueous medium. More than 2-fold enhancement was found for 700 μM Al 3+ ions. The luminescence enhancement results from aggregation caused by hard acid and hard base interactions between Al 3+ ions and oxygen atoms in the furan ring. In this way, the quenching of nonradiative energy transfer by solvent molecules was reduced, and the efficiency of energy transfer from ligand to Tb 3+ ions was increased. The luminescence increment is highly selective toward Al 3+ ions with very minimal interference. The developed method shows a remarkably high sensitivity for Al 3+ ion detection, and the calculated LOD was 1.67 μM, which is much lower than the maximum aluminum content allowable by the WHO in drinking water. Furthermore, we applied this method for the determination of Al 3+ ions in actual water samples.