Ce^(3+)在LiBaBO_3中的发光特性及晶体学格位

Luminescence characteristics and crystallographic sites of Ce^(3+) in LiBaBO_3

采用固相法制备了LiBaBO3:Ce3+发光材料.测得LiBaBO3:Ce3+材料的发射光谱为一不对称的单峰宽谱,主峰位于440nm;监测440nm发射峰,可得其激发光谱为一主峰位于370nm的宽谱.利用vanUitert公式计算了Ce3+取代LiBaBO3中Ba2+时所占晶体学格位,得出438nm发射带归属于九配位的Ce3+发射,而469nm发射带起源于八配位的Ce3+发射.研究了Ce3+浓度对LiBaBO3:Ce3+材料发光强度的影响,结果显示,随Ce3+浓度的增大,发光强度呈现先增大后减小的趋势,Ce3+浓度为3mol%时强度最大,造成其浓度猝灭的原因为电偶极-偶极相互作用.引入Li+,Na+或K+可增强LiBaBO3:Ce3+材料的发射强度.利用InGaN管芯(370nm)激发LiBaBO3:Ce3+材料,获得了很好的蓝白光发射,色坐标为(x=0.291,y=0.297).

LiBaBO3：Ce^3＋ phosphor was prepared by solid-state method, and its luminescence characteristics were investigated. LiBaBO3 ： Ce3 ＋ phosphor shows one asymmetrical band at 440 nm. Monitored at 440 nm, the excitation spectrum has a broad band at 370 nm. The crystallographic sites of Ce3 ＋ in LiBaBO3 were calculated by van Uitert formula, the results show that the emission band centered at 438 nm originates from the Ce3＋ center of the nine compounds, and at 469 nm originates from the Ce3＋ center of the eight compounds. The effect of Ce3＋ concentration on luminescent intensity of LiBaBO3： Ce3＋ phosphor was investigated, the result shows that the luminescent intensity firstly increases with increasing Ce3 ＋ concentration, and reaches the maximal value at 3mol% Ce3＋ , then decreases. The concentration quenching mechanism is the dipole-dipole interaction by Dexter theory. Under the condition of doping charge compensator Li ＋ , Na＋ or K＋ , the emission intensity of LiBaBO3 ： Ce3＋ was all heightened. The relative emission spectrum of the InGaN-based LiBaBO3 ：Ce3＋ light emitting diode（LED） was investigated, and the CIE chromaticity of InGaN-based LiBaBO3 ：Ce3＋ LED is （x = 0.291, y = 0.297）,and shows the blue white emission.