SrAl2O4∶Eu,Dy发光粉的机械余辉与机械劣化研究

Mechanical Afterglow and Deteriorating for SrAl_2O_4∶Eu,Dy Phosphors

研究了SrAl2O4∶Eu,Dy发光粉的机械余辉与机械劣化现象。结果表明,机械余辉强度与所施加的机械压力的大小及稀土掺杂离子的浓度有关。发光粉所受机械压力越大,掺杂Dy3+浓度越高,机械余辉强度越高;掺杂Eu2+浓度的变化,对机械余辉影响较小。从机械劣化研究结果可知,机械外力会导致荧光劣化和余辉劣化,而且后者总是先于前者发生。另外还对机械余辉与机械劣化机制进行了探讨,提出机械余辉是由机械能转化而来的热能将陷阱捕获的电子和空穴激发,二者复合导致发光;机械劣化是由于机械外力破坏了晶体结构,而且率先破坏晶格畸变严重的部分(包含Dy3+或空位的部分)。

A mechanical afterglow （MAG） and deteriorating of SrAl2O4：Eu, Dy phosphors were studied in this paper. The results showed that the mechanical stress and the density of the doping rare earth irons played important roles in phosphors＇ MAG. The higher the mechanical stress and the density of the doping Dy3＋ were, the better the MAG performance was. However, the density of the doping Eu2＋ affected little on MAG of phosphors. From the results of mechanical deteriorating, it could be found that the mechanical shear force would result in fluorescence deteriorating and afterglow deteriorating, and the latter often appeared prior to the former. The mechanisms of MAG and the mechanical deteriorating were discussed respectively. The trapped electrons and holes could be thermally bleached by the thermal energy, which was transformed from mechanical energy. The recombination of the released electrons and holes would result io MAG. When the mechanical force was too high, the crystalline structure could be destroyed. The areas seriouly deformed were more easily destroyed.