白光LED用LiCaBO_3:Ce^(3+)材料发光特性研究  

Luminescent characteristics of LiCaBO_3:Ce^(3+) phosphor for white LED

作　　者：李盼来[1] 王志军[1] 杨志平[1] 郭庆林[1] 

机构地区：[1]河北大学物理科学与技术学院,保定071002

出　　处：《科学通报》2009年第7期866-870,共5页Chinese Science Bulletin

基　　金：河北省自然科学基金(编号:2009000209);河北省科学技术发展基金(编号:51215103b);河北大学青年基金(批准号:2006Q06)资助项目

摘　　要：采用固相法制备了LiCaBO3:Ce3+发光材料.测得LiCaBO3:Ce3+材料的发射光谱为不对称的单峰宽谱,主峰位于428nm处;监测428nm发射峰时所得材料的激发光谱为主峰位于364nm的宽谱.通过VanUitert公式证明Ca在LiCaBO3中只存在一种晶体学格位,造成LiCaBO3:Ce3+材料非对称发射的原因是Ce3+离子能级劈裂.研究了Ce3+浓度对LiCaBO3: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,在Ce3+浓度为3%(摩尔分数)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,发现LiCaBO3:Ce3+材料的发射强度均得到了明显增强.利用InGaN管芯(370nm)激发LiCaBO3:Ce3+材料,呈现很好的蓝白光发射,测得的色坐标为(x=0.287,y=0.290).The LiCaBO3：Ce^3＋ phosphor was synthesized by solid-state reaction method and its luminescent characteristics were investigated. LiCaBO3：Ce^3＋ shows one dissymmetrical band at 428 nm, and the excitation spectrum for 428 nm emission has one broad band at 364 rim. The crystallographic sites of Ca^2＋ in LiCaBO3 were researched, and only one Ca site exists in LiCaBO3 crystal which can be calculated by Van Uitert formula. Therefore the reason that leads to the dissymmetrical emission band of LiCaBO3：Ce^3＋ phosphor is the energy lip. Effect of Ce^3＋ concentration on luminescent intensity of LiCaBO3：Ce^3＋ phosphor was investigated. The results show that the concentration quenching effect exists, viz. the luminescent intensity firstly increases with increasing Ce^3＋ concentration, and then decreases. The Ce^3＋ concentration corresponding to the maximal luminescent intensity is 3 mol%, and the concentration quenching mechanisms are the d-d interaction by Dexter theory. Under the condition of doping charge compensation of Li^＋, Na^＋ and K^＋, the emission intensity of LiCaBO3：Ce^3＋ was heightened. The relative emission spectrum of the InGaN-based LiCaBO3：Ce^3＋ LED was investigated, and the CIE chromaticity of InGaN-based LiCaBO3：Ce^3＋ LED is （x = 0.287, y = 0.290）.

关 键 词：白光LED LiCaBO3:Ce^3+ 晶体学格位 发光特性 

分 类 号：O482.31[理学—固体物理]