论文总字数:11714字
摘 要
为了开发新型白光LED用荧光粉,采用固相反应法制备了一系列Ce3 -Eu2 -Sm3 掺杂的Ba2Gd2Si4O13(BGS)荧光粉,并对其发光性能进行了研究。当Ce3 和 Eu2 単掺入到BGS时,在350~550nm和420~650nm附近出现宽的发射带;将Ce3 和Eu2 同时掺入BGS中发现其能量转移很弱,这可能是由两种激活剂离子之间的竞争吸收所致;Sm3 激活的BGS在550~750nm的区域表现出红色光。为了实现白光发射,设计了BGS:0.06Ce3 ,0.04Eu2 ,ySm3 (0≤y≤0.18)荧光粉,并观察到从Ce3 /Eu2 到Sm3 的能量转移。通过控制Sm3 浓度可以调节发光颜色,并在BGS:0.06Ce3 ,0.04Eu2 ,0.06Sm3 样品中得到白色发光。对典型BGS:0.06Ce3 ,0.04Eu2 ,0.06Sm3 样品的热发光稳定性研究表明,Eu2 和Sm3 的发光强度随温度增加均呈连续下降趋势,而Ce3 的发光强度随温度的升高而增加。关键词:荧光粉,发光材料,发光二极管
Abstract: To develop new white-light-emitting phosphor, a series of Ce3 -Eu2 -Sm3 doped Ba2Gd2Si4O13 (BGS) phosphors were prepared by solid-state reaction method, and their photoluminescence properties were studied. The Ce3 and Eu2 single-doped BGS phosphors show broad emission bands around in the region of 350-550 and 420-650 nm, respectively. By co-doping Ce3 -Eu2 into BGS, the energy transfer (ET) from Ce3 to Eu2 is inefficient, which could be due to the competitive absorption between the two activator ions. The Sm3 -activated BGS exhibits an orangey-red emission in the region of 550-750 nm. To achieve white emission, the BGS:0.06Ce3 ,0.04Eu2 ,ySm3 (0 ≤ y ≤ 0.18) phosphors were designed, in which the ET from Ce3 /Eu2 to Sm3 was observed. The emission color can be tuned by controlling the Sm3 concentration, and white emission was obtained in the BGS:0.06Ce3 ,0.04Eu2 ,0.06Sm3 sample. The investigation of thermal luminescence stability for the typical BGS:0.06Ce3 ,0.04Eu2 ,0.06Sm3 sample reveals that the emission intensities of both Eu2 and Sm3 demonstrate continuous decrease but the Ce3 emission is enhanced gradually with increasing temperature.
Keywords: Phosphors, Luminescence, LEDs
目录
1 绪论 4
1.1 发光二极管实现方式 4
1.2 发光二极管的应用 4
1.3 pc-LED实现白光方式 4
1.4 应用前景 5
1.5 稀土离子发光材料 5
1.6 荧光粉基质Ba2Gd2Si4O13(BGS) 5
2 实验部分 6
2.1 主要试剂和仪器 6
2.1.1 原料 6
2.1.2 仪器 6
2.2 高温固相法介绍 6
2.3 样品制备 6
2.4 样品表征方式 6
3 结果与讨论 7
3.1 样品最佳制备条件 7
3.2 Ce3 -Eu2 共掺杂BGS荧光粉样品激发和发射光谱 7
3.3 Ce3 -Eu2 共掺杂 BGS 荧光粉发光离子的能量转移 8
3.4 Sm3 发光离子的发射光谱 9
3.5 BGS:0.06Ce3 ,Eu2 ,Sm3 的发光性质 10
3.6 热猝灭性能 13
3.7 CIE色度图 17
4 结论 18
参考文献 19
致 谢 21
1 绪论
发光二极管实现方式
发光二极管是一种多层很薄的掺杂半导体材料,一层缺乏电子所以形成带正电的“空穴”,一层有过量的电子,当接入电源或者通电时,电子和空穴结合,释放能量,激发荧光粉发出光芒[[1]1]。
发光二极管的应用
1、LED显示屏
最起初,出现文字屏或动画屏。随着时代的发展,LED显示屏的视频技术开始成熟,电视机的电视屏开始显像图像。随着技术的发展,室外的显示屏也开始逐渐被应用,比如随处可见的商场显示屏,体育馆大屏幕,街道商店的滚动屏。而且股票市场、银行、证劵场所等也都能看到浮动屏被广泛应用。
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