MIL-53(Al)/Eu3+ luminescent nanocrystals: Solvent-adjusted shape-controllable synthesis and highly selective detections for Fe3+ ions, Cr2O72- anions and acetone

Luminescent aluminum-based coordination polymers, MIL-53(A1)/Eu3+ nanocrystals, were successfully fabricated by a simple mixed solvothermal method without the addition of any surfactants or capping agents. The product was characterized by XRD, SEM, TEM, IR, and EDS technologies. Experiments uncovered that the morphology of luminescent MIL-53(A1)/Eu3+ nanocrystals could be tuned by changing the volume ratio of mixed solvents; and the as-obtained nanocrytals presented shape-dependent fluorescent properties. Sheet-like nanocrystals prepared from the system containing the DMF/H2O/ethanol volume ratio of 20:5:5 (V-total = 30 mL) presented the strongest PL emission and the biggest BET surface area. It was found that the as-obtained luminescent MIL-53(A1 )/Eu3+ nanocrystals could be prepared into fluorescent probes for the selective detections of Fe3+ and Cr2O72- ions in aqueous systems and acetone in CHC1(3) since its emission peak could be quenched by these matters. Simultaneously, the mechanism to cause the fluorescent quenching was discussed.