Eu^(3+)在CaYBO_4中的取代和发光

Displacement and Luminescence of Eu^(3+) Ion in CaYBO_4

用固相法制备化合物CaY1 -xBO4∶xEu ,研究Eu3+在CaYBO4中的取代格位和发光特性。当Eu3+掺杂浓度不大时 ,存在两个发光中心 ,认为是取代基质中有两个Y格位的结果 ;通过对Eu O的电荷迁移激发带位置的分析 ,表明Eu3+所处八面体中心格位的对称性越低 ,Eu O的电荷迁移带越偏向于短波 ;当Eu3+的掺杂浓度较大 (x >0 1 0 )时 ,Eu3+离子也可占据Ca2 +格位 ,同时Eu3+还原成Eu2 +。

The host CaY 1-x BO 4∶xEu was synthesized by solid state reaction method and the displacement and luminescence of Eu 3+ ion in CaYBO 4 host were studied. Two luminescent centers could be observed at certain Eu 3+ concentration, indicating that Eu 3+ ions occupy two different crystallographic sites. This result shows that Eu 3+ ions occupy two different Y 3+ sites in CaYBO 4. The investigation on Eu O charge transfer bands indicates that the lower symmetry of Eu 3+ site is, the shorter wavelength of the Eu O charge transfer band is. When the Eu 3+ concentration is high(x>0 10), Eu 3+ ions would occupy the sites of Ca 2+ ions and surprisely Eu 3+ ion is reduced to Eu 2+ ions.