Study On The Synthesis, Organic Intercalation And Photoluminescence Of Eu-doped LDH

Layered double hydroxides (LDHs) have been attracted because of its special interlayer tunnel structure. At present, the study on LDHs is mainly focused on ion-exchanges, organic intercalation and exfoliation/self-assembly etc., while the study on the luminescence of LDHs is quite insufficient. Although some attempts at intercalation of rare earth ions complex into the interlayer of LDHs and preparation of rare earth layered compounds with emission property, it is worthwhile to investigate the incorporation of luminescent centers into the layer in views of cheap raw and simple processing.Therefore, a serials of ternary LDHs (Mg-Al-Eu and Zn-Al-Eu LDHs) with different M2+/(M3+) molar ratios have been synthesized by co-precipitate method (M3+:Al3++Eu3+; M2+:Mg2+, Zn2+) in the paper, and their chemical composition, structure, and photoluminescent property have been investigated. In addition, the study on the effects of annealing temperature on the structure and photoluminescent property has been carried out. Furthermore, the fluorescence of Mg-Al-Eu and Zn-Al-Eu LDHs sensitivity to Phenylalanine has also been researched. From these work, some original results were found as following:1. Eu+-doped layered double hydroxides with photoluminescence were synthesized at the first time. It was found that the structure and crystallinity of LDHs obviously depended on the M+/M+molar ratios.2. The study on the effects of annealing temperature on the Mg-Al-Eu LDH and Zn-Al-Eu LDH showed that the structure and fluorescence of LDHs changed with the increase of annealing temperature. The layered structure of the Mg-Al-Eu LDH collapsed as annealing temperature increased to 400℃, but the structure of the Zn-Al-Eu LDH was broken up at 200℃. This indicated that thermal stability of the Mg-Al-Eu LDH was higher than that of the Zn-Al-Eu LDH. It was also confirmed that the LDHs and their annealed products were favorable for the Eu3+ emissions.3. The research on the fluorescence of Mg-Al-Eu and Zn-Al-Eu LDHs sensitive to phenylalanine indicated that the fluorescence attributed to those LDHs are almost quenched by the phenylalanine, which is an important property to be used in biological technique probe the changes of DNA or Proteins. This special interlayer tunnel structural material may be a promising candidate for fluorescent material applied in biological probe, which would be possessed of larger surface area than other structural bulk materials, higher thermal stability and less toxicity compared with those of organic materials, and healthier to human beings.