Modification On Luminescent Properties Of SrAl₂O₄: Eu²⁺, Dy³⁺ Phosphors By Lanthanon Ions Doping

SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor is a new type of long lasting phosphorescent material, which is discovered in 1990'. Compared with traditional sulfide phosphors, this phosphor possesses safer, chemically stable, and very bright and long-lasting phosphorescence, which leads to a large filed of applications。However, the luminescent intensity of the phosphorescent material is very low and the color is not rich, therefore, it is very necessary to further improve the luminescent properties to realize more advanced and practical applications. As is known that lanthanon doping is a good method to improve the luminescent properties of the material and it is our original intention as well.The modification on long afterglow properties of SrAl₂O₄ Eu²⁺, Dy³⁺ phosphor by Holmium,Ytterbium or Neodymium doping were studied for the first time. The phosphors were synthesized by the combustion method at the temperature of 600℃. X-ray diffraction patterns and emission spectra indicate that the Holmium,Ytterbium or Neodymium doping almost does not make any change of the crystal structure and the Eu²⁺ transition environment between 4f⁶5d and 4f⁷.The decay curves demonstrate that luminescent intensity can be enhanced by Holmium and Ytterbium doping, but the decay time of the phosphors do not have any improvement. Further research of thermally stimulated luminescence discovers that different trap levels exist in different phosphors and the depth of the trap levels are well corresponded with decay time of the phosphors.Finally, it can be drawn a concludsion that the phosphors doped with appropriate amount of Holmium and Ytterbium result in very intense and bright phosphorescent emission, which can be used in more extensive application field.