Abstract：
Eu3+ is not only a major red-emitting activator, but also an excellent spectral probe ion. This work reports the Eu3+-sites and luminescence in the cation-deficient perovskite tungstates, A-site deficient SrLa2(Mg2W2)O12 [Sr1/2□1/2La(MgW)O6] and B-site deficient Sr2La2(MgW2)O12 [SrLa(Mg1/2□1/2W)O6]. The 7F0→5D0 excitation spectra of Eu3+ activators in two lattices were measured via pulsed dye laser. In SrLa2(Mg2W2)O12:Eu3+, there is only one 7F0→5D0 transition, which could be related to the Eu3+ center on La3+ sites; while, two 7F0→5D0 transitions in Sr2La2(MgW2)O12 indicate Eu3+ ions occupy Sr2+ in addition to La3+, resulting in the luminescent centers related to heterovalent substitution defects. The different Eu3+ sites make two phosphors exhibit different red luminescence properties. SrLa2(Mg2W2)O12:Eu3+ shows higher luminescent efficiency and thermal quenching due to its regular distribution of the activators resulting in lower dispersion losses of the energy transfer. The experimental results show that rare earth ions occupy different crystallographic positions in A-site and B-site deficient perovskite oxides, and this microstructure can be important for the corresponding luminescent properties.
摘要：
Eu3+不仅是一种主要的红色发射活化剂，也是一个优秀的光谱探针离子。这项工作报告了阳离子不足的钙钛矿钨酸盐中的Eu3位点和发光，A位缺陷型SrLa2(Mg2W2)O12[Sr1/2□1/2La(MgW)O6]和B位缺陷型Sr2La2(MgW2)O12[SrLa(Mg1/2□1/2W)O6]。通过脉冲染料激光测量了两种晶格中Eu3活化剂的7F0→5D0激发光谱。在SrLa2(Mg2W2)O12:Eu3+中,只有一个7F0→5D0过渡，这可能与La3+站点上的Eu3+中心有关；而，Sr2La2（MgW2）O12中的两个7F0→5D0跃迁表明Eu3离子除La3外还占据Sr2，导致与杂价取代缺陷相关的发光中心。不同的Eu3+位点使两种荧光粉表现出不同的红色发光特性。SrLa2（Mg2W2）O12：Eu3显示出更高的发光效率和热猝灭，这是由于活化剂的规则分布导致能量转移的分散损失较低。实验结果表明,稀土离子在缺A位和缺B位的钙钛矿氧化物中占据不同的结晶位置,并且这种微观结构对于相应的发光性能可能是重要的。
