Preparation of (Gd,Y)AlO3:Eu3+ by citric-gel method and their photoluminescence under VUV excitation

By using inorganic salts as raw materials and citric acid as chelating agent (Gd,Y)AlO3:Eu3+ phosphors were prepared by citric-gel method. The single phase of samples was obtained at 1000 deg. C, which is 600 deg. C lower than that of traditional solid state reaction. In the excitation spectrum of Gd0.95Eu0.05AlO3 (λem=614nm), the broad bands with maximum at 157 and 170nm are observed and assigned to AlO3 group absorption and the CT transition of Gd3+-O2-, respectively. Under 147nm excitation, Gd0.95Eu0.05AlO3 shows a typical Eu3+ emission. The strongest emission peak is located at 614nm, which is due to 5D0-7F2 transition of Eu3+. The partial substitution of Y3+ for Gd3+ is very convenient to improve the emission intensity of Eu3+, which is because higher energy is absorbed and transfer to activators efficiently