Abstract The consequence of the site selective substitution of La3+ ions in modifying the local crystal structure in red emitting titanate perovskites and the resulting enhancement of the luminescence properties were investigated in two distinct series of red phosphors of Sr1-x-yLaxTiO3:yEu3+ and Sr1-x/2-yLaxTi1-x/2O3:yEu3+. Herein, the red emission line was found sharply magnified for the substitutions at the Sr2+ sites whereas broad peaks resembling the emission from the La2O3:Eu3+ red phosphor were detected for the substitution at both Sr2+ and Ti4+ sites, in the experiment of altering substitution sites of the La3+ ions in Sr1-xTiO3:xEu3+. The local asymmetry induced by the substitution of smaller aliovalent ions was found to enhance the luminescence properties in the phosphors with doping at the Sr2+ sites. The occupation of Eu3+ ions in an environment having La3+ ions as nearest neighbours relaxes the shielding of the 4f electrons of Eu3+ to produce a broad emission in the phosphors with double site doping. The substitution of rare earth ions at the Sr2+ sites in Sr1-x-yLaxTiO3:yEu3+ was verified by the enhancement in the intensity of the Raman modes at 184 cm−1 (TO2) and 476 cm−1 (LO2). In the case of the Sr1-x/2-yLaxTi1-x/2O3:yEu3+ phosphors, the presence of the substituent ions at the Ti4+ sites was confirmed by the increased intensity observed for the Raman mode at 114 cm 1 (TO1).

中文翻译：

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La3+ 离子取代位点对 SrTiO3:Eu3+ 荧光粉光致发光特性的影响

摘要 在两个不同系列的红色荧光粉 Sr1-x-yLaxTiO3:yEu3+ 和 Sr1- 中研究了位点选择性取代 La3+ 离子在改变发红光的钛酸盐钙钛矿中的局部晶体结构和由此产生的发光性能增强的结果。 x/2-yLaxTi1-x/2O3:yEu3+。在此，在改变取代位点的实验中，发现 Sr2+ 位点取代的红色发射线急剧放大，而在 Sr2+ 和 Ti4+ 位点的取代均检测到类似于 La2O3:Eu3+ 红色荧光粉发射的宽峰。 Sr1-xTiO3:xEu3+ 中的 La3+ 离子。发现由较小的异价离子取代引起的局部不对称性增强了在 Sr2+ 位点掺杂的磷光体的发光特性。在以 La3+ 离子为最近邻的环境中占据 Eu3+ 离子会放松 Eu3+ 的 4f 电子的屏蔽，从而在具有双位掺杂的磷光体中产生宽发射。通过 184 cm-1 (TO2) 和 476 cm-1 (LO2) 拉曼模式强度的增强，证实了稀土离子在 Sr1-x-yLaxTiO3:yEu3+ 中 Sr2+ 位点的取代。在 Sr1-x/2-yLaxTi1-x/2O3:yEu3+ 磷光体的情况下，Ti4+ 位点处取代离子的存在通过在 114 cm 1 (TO1) 处观察到的拉曼模式强度增加得到证实。yEu3+ 通过 184 cm-1 (TO2) 和 476 cm-1 (LO2) 拉曼模式强度的增强得到验证。在 Sr1-x/2-yLaxTi1-x/2O3:yEu3+ 磷光体的情况下，Ti4+ 位点处取代离子的存在通过在 114 cm 1 (TO1) 处观察到的拉曼模式强度增加得到证实。yEu3+ 通过 184 cm-1 (TO2) 和 476 cm-1 (LO2) 拉曼模式强度的增强得到验证。在 Sr1-x/2-yLaxTi1-x/2O3:yEu3+ 磷光体的情况下，Ti4+ 位点处取代离子的存在通过在 114 cm 1 (TO1) 处观察到的拉曼模式强度增加得到证实。