Preparation And Characterization Of Rare Earth Ion Eu³⁺-doped SiO₂ Luminescent Material

The Sol-gel method was used to prepare SiO2 xerogel and the starting materials of rare earth ion Eu3+-doped luminous materials in which SiO2 acted as the principal matrix.After then, the luminous materials were calcined and prepared with Muffle furnace and high-temperature energy ball mill.The crystal configuration of sample were characterized by using X-ray diffraction(XRD), appearance of film were carried out by means of scanning electron microscope(SEM), the excitation and emission spectra were measured by spectrophotometer equipment.Various factors influencing on the luminescent properties were discussed in the experiment, and comparison between the two methods were also made.The luminous materials of SiO2 xerogel was prepared by tetraethylorthosilicate (TEOS)which was a silicon source.Through studying on the influence of the catalyst,water content,reaction time and aging temperature on the gelation time of the SiO2, the experimental scheme was determined as follows:hydrochloric acid was chosen as the catalyst,the ratio of H2O and TEOS was 4 with 4 h reaction time and aging tmeperature at 80℃.In addition,the photoluminescence property of SiO2 xerogel was studied, the luminescence intensity of SiO2 decreased as the temperature raising.Eu3+ ion doped SiO2 luminescent materials were prepared by Muffle furnace, and the emisson spectra of Eu3+-doped SiO2 xerogel featured in the visible band with peaks at 579 nm,590 nm,616 nm,654 nm and 703 nm.The influence of the Eu3+ ions concentration,the annealing temperature and fluxing agent on the PL intensity of Eu3+ were studied. The results showed that the intensity of the emission of sample had the maximum value when the xerogel annealed at 900℃; when the doping concentration was 2.0%,the Eu3+ ions had the strongest luminescence.Furthermore,the luminous intensity of the Eu3+ ions can be effectively improved by adding the fluxing agent boric acid.Eu3+ ion doped SiO2 luminescent materials were prepared by the high-temperature energy ball mill.Through studying on the influence of the milling time and balls/material weight ratio on the luminescent properties, the experimental scheme was determined as follows:the balls/material weight ratio was 10 to 1 and the milling time was 2 hours. The effects of calcination temperature and the doping concentrations on the PL intensity of Eu3+ showed that: powders were annealed at 600℃had the strongest luminescence;When the Eu3+ ion concentration changed within the range 0.2%～4.0%,the concentration quench was not observed.When the two calcination methods were compared,a condusion could be made that the luminous intensity of the powders which were prepared by the high-temperature energy ball mill are obviously superior to the sample which are prepared through calcinating by the muffle furnace.