Ce3+激活的LiSrBO3材料发光特性及晶体学格位研究

采用固相法制备了蓝白色LiSrBO3∶Ce3+材料. 测得LiSrBO3∶Ce3+材料的发射光谱为一个主峰位于436 nm的非对称单峰宽谱; 监测436 nm发射峰时所得材料的激发光谱为一个主峰位于369 nm的宽谱. 利用Van Uitert公式计算了Ce3+取代LiSrBO3中Sr时所占晶体学格位, 得出433 nm发射带归属于九配位的Ce3+发射, 469 nm发射带起源于八配位的Ce3+发射. 研究了Ce3+浓度对LiSrBO3∶Ce3+材料发光强度的影响, 研究结果显示, 随着Ce3+浓度的增大, 发光强度呈现先增大后减小的趋势, 在Ce3+摩尔分数为3%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. 引入Li+, Na+和K+作为电荷补偿剂时发现, LiSrBO3∶Ce3+材料的发射光谱强度均得到了明显的增强. 利用InGaN管芯(370 nm)激发LiSrBO3∶Ce3+材料时, 获得了很好的蓝白光发射, 色坐标为(x=0.289, y=0.293).

Luminescent Characteristics and Crystallographic Sites of Ce~(3+) Activated LiSrBO_3 Phosphor

The blue white LiSrBO3∶Ce3+ phosphor was synthesized with solid-state method. The emission spectrum of LiSrBO3∶Ce3+ phosphor shows one dissymmetrical band at 436 nm. The excitation spectrum for 436 nm emission has broad band at 369 nm. The crystallographic sites of Ce3+ in LiSrBO3 were calculated by Van Uitert formula. The results show that the emission band centered at 433 nm originates from the Ce3+ center of the nine compounds, the other emission band centered at 469 nm originates from the Ce3+ center of the eight compounds. The effect of Ce3+ molar fraction on luminescent intensity of LiSrBO3∶Ce3+ phosphor was investigated, the result shows that the luminescent intensity firstly increases with increasing Ce3+ molar fraction, then decreases, and reaches the maximal value at 3% Ce3+. The concentration quenching mechanisms are the D-D interaction by Dexter theory. Under the condition of doping charge compensation Li+, Na+ and K+, the emission spectrum intensity of LiSrBO3∶Ce3+ was heightened. The relative emission spectrum of the blue white-emitting InGaN-based LiSrBO3∶Ce3+ LED was investigated, and the CIE chromaticity of InGaN-based LiSrBO3∶Ce3+ LED is (x=0.289, y=0.293).