Effects of crystallinity of raw material Y₂O₃ on luminescent character of Y₂O₂S:Eu³⁺

In order to improve the luminescent character of Y₂O₂S:Eu³⁺, the method of improving crystallinity of primary raw material Y₂O₃ is used. The emission intensity of red phosphors Y₂O₂S:Eu³⁺ is effectively enhanced 5% and 10% respectively at the voltages of 20 kV and 25 kV while the other primary properties of application in chromaticity, granularity and decentralization are not changed. The voltage resistance character (relation between emission intensity and excitation voltage) is elevated. The origins of the emission intensity enhancement and excitation voltage elevation are discussed and analyzed preliminarily. It is likely that the abnormal change and defect of crystal lattice led by the substitution of larger radius Eu³⁺ ion for smaller radius Y³⁺ ion are reduced by the better crystal quality of Y₂O₂S:Eu³⁺ from the better crystallinity of raw material Y₂O₃. Because the crystal field condition of Eu³⁺ ion is improved, radiationless process and energy loss led by crystal defect are cut down, the emission efficiency of Y₂O₂S:Eu³⁺ phosphors is enhanced and its voltage character is improved. The experiment shows that the decomposing temperature to get the high crystallinity Y₂O₃ is about 1400°C.