Study On Preparation And Properties Of Nanoscale Rare Earth Eu～(3+) Luminescent Materials

Rare-earth ions luminescence materials have attracted of interest because of its low wastage in communication wavelength and its application in the field of fiber communication and photoelectron integration technology. In the dissertation, nano-meter Y_2-xSiO₅:Eu_x material was synthesized by sol-gel method, preparation of ordered mesoporous silicon basic luminescence materials doped by Eu was explored. The contents of this thesis consist of the following main points.(1) Nano-meter Y_2-xSiO₅:Eu_x material was synthesized by sol-gel method, and its structure and morphology were characterized by XRD, FTIR and TEM. The influence of phase structure, calcination temperature and Eu³⁺ doping concentration on luminescence properties was investigated. The results show that the materials obtained at calcination temperature below 900℃mainly present non-crystal state, while the materials mainly exhibit crystal state structure when calcined over 900℃. The particle size increased with the calcination temperature. The particle size was 15-45 nm and 60-80 nm for amorphous and crystal forms, respectively. The excitation and emission spectra of materials are both affected by phase structure, calcining temperature and Eu³⁺ doping concentration and Y_2-xSiO₅:Eu_x in crystalline state shows finer excitation and emission spectrum band than that in amorphous state and Y_1.6SiO₅:Eu_0.4 shows the largest luminescence intensity.(2) The ordered Eu³⁺ doped silicon mesoporous materials were synthesized by using a triblock copolymer as a molecular template under strongly acidic condition. Its structure were characterized by XRD, FTIR, TEM and BET. The results show that the pore size distribution is affected by Eu³⁺ doping concentration and change wider in high doping concentration. It is found in the material preparation process that the hydrothermal treatment will make crystallization degree of materials increase and result in finer luminescence spectrum bands. Simultaneously, it is found that the fluorescence lifetimes of ⁵D₀ energy level of Eu₃₊ obviously become short(only 0.36～0.37 ms) in contrast to bulk materials(1.7 ms).