红色荧光粉Ca_3Y_2Si_3O_(12):Eu^(3+)的制备及发光特性

Preparation and Luminescence Properties of Red Phosphors Ca_3Y_2Si_3O_(12):Eu^(3+)

采用高温固相法合成了红色荧光粉Ca_3Y_2Si_3O_(12):Eu^(3+)。研究了Eu^(3+)离子掺杂浓度、助熔剂及Gd^(3+)共掺杂对荧光粉发光特性的影响。XRD检测结果显示,荧光粉的主晶相为Ca_3Y_2Si_3O_(12),属单斜晶系。荧光光谱分析表明:硅酸盐荧光粉Ca_3Y_2Si_3O_(12):Eu^(3+)的发射光谱包含2个主峰,峰值分别位于590和614 nm,归属于Eu^(3+)离子从~5D_0→7~F_1和~7F_2的特征跃迁。用614 nm最强峰监测,得到激发光谱为一多峰宽带(200~500 nm)。改变Eu^(3+)离子掺杂浓度发现:随着掺杂量增加,荧光粉发光强度先增加后降低,最佳掺杂量为20 mol%;讨论了几种助熔剂的影响:NaCl、CaF_2作为助熔剂,对荧光粉的发光强度影响不大,H_3BO_3作为助熔剂降低荧光粉的发光强度,而NH_4F能显著提高荧光粉的发光强度;Gd^(3+)可以作为一种很好的共激活剂,敏化Eu^(3+)离子发光。

Red phosphors Ca3Y2Si3O12：Eu^3＋ were synthesized by a high temperature solid-state method. The effects of Eu^3＋ ion doping concentration, flux and Gd^3＋ co-doping on the luminescence properties of phosphors were studied. XRD analysis shows that the principal crystalline phase is Ca3Y2Si3O12, attributed to monoclinic system. Fluorescence spectroscopy reveals that the emission spectrum of silicate phosphor Ca3Y2Si3O12：Eu^3＋ consists of two main emission peaks, located at 590 nm（-5D0 → -7F1） and 614 nm（-5D0 → -7F2）. Monitored with the strongest peak of 614 nm, excitation spectrum was obtained which ranged from 200 to 500 nm. The results indicate that the emission intensity of the phosphors firstly increases and then decreases with the increasing of the doping concentration of Eu^3＋ ion. It is found that the optimum doping concentration of Eu^3＋ ion is 20 mol%. In addition, the phosphor emission intensity decreases by adding a certain amount H3BO3, but increases significantly by adding NH4F. However, there is little effect of NaCl or CaF2 on the phosphor emission intensity. Gd^3＋ ion could act as a good co-activator, improving the emission intensity of Eu^3＋ ion.