Fluorescence of Zn–Al–Eu ternary layered hydroxide response to phenylalanine

We reported the fluorescence of a Zn–Al–Eu ternary layered double hydroxide (LDH) response to an amino acid (phenylalanine) for the first time. As shown in fluorescence, the red emissions attributed to 5D0–7FJ transitions (J = 1, 2, 3, 4) of Eu3+ ions were quenched by the phenylalanine (Phe), and a strong blue emission at around 445 nm appeared. The fluorescent changes may be due to ligand-to-metal charges transfer, which was caused by the interaction between the Zn–Al–Eu LDH and Phe. This interaction was manifested by markedly different chemical shift positions of the Zn 3p3/2, Al 2p, Eu 4d3/2, O 1s, and C 1s peaks in the XPS spectra from those of the Zn–Al–Eu LDH and Zn–Al–Eu/Phe composite. Furthermore, the interaction between the LDH and Phe was supported by the results of X-ray diffraction (XRD) measurements, Fourier transform infrared (FT-IR) spectra, and thermogravimetric and differential thermogravimetric (TG–DTG) analysis. The fluorescence of Zn–Al–Eu LDH response to Phe may be potential application in biological techniques.

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