硼酸镧钙中三价铕离子的辐射跃迁参数

Radiative transition parameters of trivalent europium ion in calcium borate lanthanum

采用高温固相法合成了三价铕离子掺杂的硼酸镧钙(La2CaB10O19:Eu3+)荧光粉,XRD测试表明样品属单斜晶系。La2CaB10O19:Eu3+可被近紫外和蓝光LED有效激发,发射主峰位于617nm处,对应铕离子的5 D0!7F2跃迁。Judd-Ofelt强场参数表明,在La2CaB10O19:Eu3+样品中三价铕离子周围环境具有较强的共价性和反演非对称性。计算得5 D0!7FJ(J=1,2,4)的自发辐射跃迁概率分别为80.95、155.46和41.21s-1,最大受激发射截面分别为3.05×10-22、7.41×10-22和3.00×10-22cm2。有效的红光发射表明,La2CaB10O19:Eu3+荧光粉可以作为红色荧光色彩调节剂应用于白光LED。

Trivalent europium ion doped lanthanum calcium borate（La2CaB10O19：Eu^3＋）polycrystalline phosphors were synthesized by solid-state reaction in atmosphere and XRD analysis confirms that the sample belongs to the monoclinic system.The prepared phosphors can be efficiently excited by the commercial near-UV and blue light emitting diodes and the dominant emission of Eu3＋is centered at617 nm attributed to the transition of ^5D0 →^7F2.Judd-Ofelt parameters indicate a high inversion asymmetric and strong covalent environment around Eu3＋in La2CaB10O19.The spontaneous emission probability Aradof the ^5D0 →^7FJ（J=1,2,4）are derived to be 80.95,155.46 and 41.21s-1 and the maximum values are determined to be 3.05×10^-22,7.41×10^-22 and 3.00×10^-22 cm^2,respectively.Effective red emissions demonstrate that La2CaB10O19：Eu^3＋phosphors can be potentially used as red color regulators for white light emitting diodes.