Energy Barrier-Engineered Metal-Organic Framework with Full-Spectrum Tunable Multiemissions for Array Discrimination...

Given the widespread overuse and intricate toxicological features of different antibiotics, developing advanced optical sensors for synchronous analysis of multiple antibiotics is significant but still a challenge. Multiemissive material-based optical sensors possess great potential in detecting structurally similar compounds. However, an efficient and universal strategy to construct multiemissive materials is still scarce. Herein, an energy barrier strategy is utilized to achieve full-spectrum tunable multiemissions from a single lanthanide metal-organic framework (MOF). Using Eu/Tb-MOF as a model, another lanthanide ion acting as the "energy barrier" is introduced into the Eu/Tb-MOF to regulate the energy transfer process of the ligand. This approach enables the preparation of a series of isostructural Gd_xTb_yEu_z-NTB MOFs (NTB= 4,4',4″-nitrilotribenzoic acid), whose luminescent colors can be flexibly tuned across the whole color gamut under a single excitation wavelength. The universality of the strategy is validated by choosing other blue-emissive ligands and introducing other energy barrier ions. It is demonstrated that as long as the energy levels of the ligand and the barrier ion are appropriate, the tunable multiemissions can be obtained in a single Ln-MOF. Furthermore, the analytical performance of Gd_xTb_yEu_z-NTB MOFs for multiple antibiotics is investigated by assembling a sensor array. Two types of antibiotics (four nitrofurans and four tetracyclines) are selected as the model analytes. Detailed fingerprint information is outputted through differential interactions between each luminescent center and each antibiotic. The eight antibiotics are well-discriminated, with no cross interference even in real water samples. Moreover, the sensor array exhibits great potential in quantitative detection of antibiotics with high sensitivity (detection limit as low as 0.03 μM). Our work provides valuable guidance for constructing multiemissive materials and their application in antibiotic discrimination, stimulating further exploration of advanced optical materials.