Dual-emissive RhB-embedded UiO-67-NH₂ fluorescent sensor for multi-analyte detection in water system via fluorescence...

By encapsulating Rhodamine B (RhB) within UiO-67-NH₂, three dual-emissive fluorescent materials, RhB@UiO-67-NH₂ (R@U-N) were developed using a one-pot solvothermal process. Their luminescence could be readily adjusted from green (∼482 nm, ligand-based emission) to red (∼580 nm, RhB emission) owing to resonance energy transfer between the MOF host and guest dye. The resulting dual-emissive R@U-N3 exhibits high water stability and multimodal responses, enabling selective detection of Arg/Lys (fluorescence enhancement), TC/OTC/Fe³⁺/Cr₂O₇^2- (quenching), and chromaticity shifts with visible color transitions. Sensing mechanisms involved ligand release (amino acids) and photoinduced electron/energy transfer (antibiotics/ions). Nanomolar-to-micromolar detection limits were attained, and interference studies confirmed their high selectivity in the presence of competing species. Real-world applicability was demonstrated by testing on tap and river water. The sensor achieved high recovery rates for spiked analytes, validating its performance in complex matrices. This work establishes a novel dual-emissive MOF-based platform for multiplexed pollutant monitoring in complex aqueous environments.