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 °C, which is 600 °C lower than that of traditional solid state reaction. In the excitation spectrum of Gd0.95Eu0.05AlO3 (image), the broad bands with maximum at 157 and 170 nm are observed and assigned to AlO3 group absorption and the CT transition of Gd3+–O2−, respectively. Under 147 nm excitation, Gd0.95Eu0.05AlO3 shows a typical Eu3+ emission. The strongest emission peak is located at 614 nm, 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.