白光LED用LiBaBO_3:Eu^(2+)材料发光特性研究

Luminescence characteristics of LiBaBO_3:Eu^(2+) phosphor for white LED

采用高温固相法制备了LiBaBO3:Eu2+绿色发光材料.测量了Eu2+浓度为1mol%时样品的激发与发射光谱,其发射光谱为双峰宽谱,主峰分别为482和507nm,与理论计算值符合很好;监测482nm发射峰时,对应激发光谱的峰值为287和365nm,监测507nm发射峰时,对应的激发峰为365和405nm.研究了Eu2+浓度对材料发射光谱的影响,结果显示,随Eu2+浓度的增大,蓝、绿发射峰均发生了红移,当Eu2+浓度大于3mol%时,蓝色发射峰消失,只有绿色发射峰存在.测量了LiBaBO3:Eu2+材料发光强度随Eu2+浓度的变化情况,结果显示随Eu2+浓度的增大发光强度呈现先增大后减小的趋势,在Eu2+浓度为3mol%时到达峰值,根据Dexter理论,其浓度猝灭机理为电偶极-偶极相互作用.

The LiBaBO3：Eu^ 2＋ green phosphor was synthesized by high temperature solid-state method. With the Eu^ 2＋ doping of 1 mol% , the emission and excitation spectra of LiBaBO3：Eu^ 2＋ phosphor were measured. The emission spectrum shows two peaks at 482 and 507 nm, which are in good agreement with the theoretical values. The excitation spectrum for 482 nm emission has two excitation peaks at 287 and 365 nm, and for 507 nm excitation emission at 365 and 405 nm. The effect of Eu^ 2＋ concentration on the emission spectrum of LiBaBO3：Eu^ 2＋ phosphor was investigated. The results show that red shift takes place in the blue and green emission spectra with increasing Eu^ 2＋ concentration, and the blue emission disappears at 3 mol% Eu^ 2＋ . However, the green emission always exists. The dependence of luminescent intensity of LiBaBO3：Eu^ 2＋ phosphor on the Eu^ 2＋ concentration was studied, and the results show that the luminescent intensity firstly increases with the increasing Eu^ 2＋ concentration, then decreases, and reaches the maximal value at 3 mol% Eu^ 2＋ . According to the Dexter theory, the concentration quenching mechanism is the d-d interaction.