Ba_5CaAl_4O__(12):Tb^(3+)荧光粉的制备与发光特性

Preparation and Luminescent Properties of Ba_5CaAl_4O__(12):Tb^(3+) Phosphor

采用高温固相法合成Ba5CaAl4O12:Tb3+绿色荧光粉,并对其发光性质进行研究。Ba5CaAl4O12:Tb3+在239nm激发下,跃迁发射峰值位于489,543,550,587和623nm,分别对应于Tb3+的5D4→7F6,5D4→7F5,5D4→7F4和5D4→7F3的能级跃迁。样品的紫外激发光谱表明,Ba5CaAl4O12:Tb3+基质吸收是位于240nm附近的宽带吸收。研究Tb3+浓度对样品发光强度的影响,当Tb3+掺杂摩尔分数为4%时,发光强度达到最大。加入H3BO3和NH4Cl两种助熔剂均不同程度地提高了该荧光粉的发光强度,且随着助熔剂浓度的增加发光强度先逐渐增强后下降。相比两种助熔剂发现,NH4Cl比H3BO3的效果更好,更有利于荧光粉的发光。

The Ba5CaAl4O12：Tb^3＋ phosphor was synthesized by high temperature solid state reaction, and its luminescent properties were investigated. The emission spectrum of Ba5CaAl4O12：Tb^3＋ excited by 239 nm light shows four major emission peaks locating at 489, 543, 550, 587 and 623 nm corresponding to the D4→7F6,5D4→7F5, D4→7F4 and 5 5 5D4→7F3 typical transitions of Tb^3＋, respectively. The UV excitation spectra indicates that the host absorption is located at about 240 nm. The effect of the molar concentration Tb3＋ on the emission intensity is studied. The result shows that the emission spectrum intensity reaches the maximum value when the mole fraction of Tb^3＋ is 4%. Fluxing H3BO3 and NH4Cl on the sample increases the luminescent intensity in various degree. The emission spectrum intensity increases with increasing the H3BO3 and NH4Cl concentration, and then decreases. Compared with the fluxing H3BO3, the NH4Cl can enhanced the luminescent intensity better.