Single-phase dye-embedded triple-emitting EY&BPEA@Zr-MOFs for selective detection of inorganic ions in environmental...

The synthesis of multi-wavelength emission fluorescent metal-organic framework sensors has received widespread attention in recent years. Under solvothermal conditions, a series of triple-emission fluorescent sensors were fabricated by in situ encapsulation of red emitting Eosin Y and green emitting 9,10-bis(phenylethynyl)anthracene (BPEA) into a blue emitting naphthalene-based Zr-MOF. By combining the dye quantity regulation and the resonance energy transfer between MOFs and dyes, the single-phase EY&BPEA@Zr-MOFs exhibited tunable triple-emission fluorescence. The EY&BPEA@Zr-MOFs presented the ability to selectively detect Cr₂O₇^2- ions and Fe³⁺ ions in aqueous solution by means of fluorescence quenching and changes in color coordinates. Mechanistic studies revealed that the main mechanism for detecting Cr₂O₇^2- and Fe³⁺ ions involves a cooperative interplay between electron transfer and fluorescence resonance energy transfer between MOFs and analytes. The detection experiments conducted with real-world water samples and the portable fluorescence test papers, conclusively validated the practical applicability of EY&BPEA@Zr-MOFs.