Study on a Novel Binary Zn n Eu Layered Double Hydroxide with Excellent Fluorescence.

A group of binary ZnnEu-LDHs with Zn2+/Eu3+ molar ratios of 5.0, 6.0, 7.0, and 8.0 have been obtained in ammonia water media by hydrothermal treatment. The structure, composition, and fluorescent property of samples have been investigated using various techniques. Compositional analyses revealed that the composition of samples was in agreement with that of the initial reactants. X-ray diffraction (XRD) suggested that the ZnnEu-LDHs exhibited typical layered structure with orthorhombic symmetry. All the ZnnEu-LDHs appeared strong red emissions attributed to 5D0 → 7F J (J = 1, 2) transitions of Eu3+. Moreover, the intensity of emissions due to 5D0 → 7FJ (J = 1, 2) transitions of Eu3+ tended to increase with the Zn2+/Eu3+ molar ratio varied from 8.0, 7.0 to 6.0, then decreased as the Zn2+/Eu3+ molar ratio reduced to 5.0. The strongest fluorescence was found to be at Zn2+/Eu3+ molar ratio of 6.0. Further the fluorescence decay spectra show that the Zn n Eu-LDH have similar behavior of fluorescent decay and decayed more slowly than that of the Eu(OH)3. These results indicate that the novel binary ZnnEu-LDHs have better fluorescent property and may be potential application as fluorescent materials.