Structure Analysis and Fluorescence of Mg-Al-Tb Ternary Layered Double Hydroxides and Their Calcined Products

Layered double hydroxides (LDHs) doped with Tb3+ ions in the brucite-like layers were prepared successfully by the co-precipitation method. The structure and fluorescence properties of Mg-Al-Tb ternary LDHs and their products calcined at different temperatures were studied for the first time. X-ray diffraction patterns indicated that as-synthesized LDH samples maintained a hexagonal crystal structure, and Tb(OH)3 was detected as Tb3+ dopant content increasing to 5 at.%. In the fluorescent spectra, the green emission intensity arising from 5D4 → 7F5 transition became stronger with the increasing ratio of Tb3+ dopant. When the annealing temperature rose above 500°C, the layer structure collapsed and phases of MgO and MgAl2O4 formed. Meanwhile, compared with MgAlTb-LDHs, the Tb-doped calcined LDHs (CLDHs) showed stronger luminescent intensity of 5D4 → 7F5 transition. These results revealed that the calcined Mg-Al-Tb ternary LDHs may become a series of novel materials with potential applications in fluorescent devices.