白光LED用氧化物体系的制备和光学性质(含任务书,开题报告,外文翻译,毕业论文12900字,答辩PPT)
摘要
目前，广泛使用的白光LED主要采用蓝光+黄色荧光粉的方式，这种方式产生的白光中缺乏红光成分，显色指数偏低，发光效率也不高。为了提高所发白光的稳定性和光学性质等，本文研究采用紫外光激发，且是单一基质的白光荧光粉。实验中采用高温固相法和水热合成法在Y2O3中掺杂不同比例的Eu3+和Tb3+制备出氧化物荧光粉（Y2O3:Eu3+,Tb3+），并通过XRD、TEM发射光谱和激发光谱对样品进行物相分析和光学性质分析。
研究发现，在激发谱中，由于Eu–O的电荷迁移带（CTB)和Tb3+的4f5d跃迁吸收会在紫外光区域形成强度很高的吸收带，在发射谱中有则有蓝色(490 nm)，绿色(545 nm)，红色(615 nm)三种颜色的峰，并可以通过不同的掺杂比例和激发光波长来调节三种颜色的光强比。因此，所发出的白光稳定性好，显色指数高。共掺杂Eu3+和Tb3+时，Tb3+不仅可以吸收紫外光和作为敏化剂将能量传给Eu3+，而且可以作为活化剂和能量受体，并且Tb3+作为Eu3+敏化剂的效率与其掺杂浓度密切相关。同时，还发现采用水热合成法制备的样品对紫外光的吸收和发射光强度比固相法的要强很多。
关键词：氧化铕 氧化铽 白光 荧光粉 能量转移 光谱性质
Preparation and optical properties of the
white LED oxide system
Abstract
Now yttrium aluminum garnet yellow phosphor coating (Y3Al5O12:Ce,YAG:Ce) was widely applied in lighting lamp and commercial pc-WLEDs. However, due to the shortage of red emission, the WLEDs made by means of blue chip + YAG:Ce have poor color rendering index and the light emitting efficiency is very low. In order to improve the stability and optical properties of the WLEDs, this study try to research a single matrix phosphor, which can be excited by UV light. In this study, the Y2O3:Eu3+ ,Tb3+ white phosphors were obtained by high-temperature solid-phase and hydrothermal synthesis method. Their structure and morphology have been analyzed by X-ray powder diffraction (XRD), the transmission electron microscopy (TEM), and the optical properties were analyzed by the spectra of samples.
The experiment results show that: due to the charge transfer band (CTB) of Eu3+-O2- bond and 5D4-7F5 transition of the Tb3+, the absorption bands formed in the UV region. In the excitation spectra, three excitation peaks are observed. by changing doping ratio and the wavelength of the excitation light, we can adjust the ratio of the intensities of the three colors. When co-doped with Eu3+ and Tb3+, the Tb3+ not only absorbs UV radiation and efficiently transfer its energy to Eu3+, but also act as activators and energy acceptors. The energy transfer efficiency from Tb3+ to Eu3+ depends strongly on their doping concentrations. In addition,the intensity of UV absorption and emission by High-temperature solid-phase is much stronger than that by hydrothermal synthesis method.
Keyword：europium oxide；Terbium oxide；White；phosphor；Energy transfer；Luminescence property
目录
摘要 1
Abstract 2
一、引言 3
1.1 白光LED发展背景 3
1.2 白光LED基本原理 3
1.2.1 发光二极管的原理 3
1.2.2白光LED的实现方式 4
1.3 白光LED用荧光粉的研究现状 6
1.3.1 基于蓝光 LED 芯片激发的荧光粉 6
1.4 本课题的研究意义及内容 8
1.4.1 本课题的研究意义 8
1.4.2 本课题的研究内容 9
二、实验方法 10
2.1 实验试剂及设备 10
2.1.1 实验试剂 10
2.1.2 实验设备 10
2.2 高温固相法制备Y2O3:Eu3+,Tb3+ 10
2.3 水热合成法制备Y2O3:Eu3+,Tb3+ 11
2.4 样品检测 12
2.4.1 XRD检测 12
2.4.2 TEM检测 12
2.4.3 荧光光谱检测 12
三、结果与讨论 13
3.1 物相分析 13
3.2 荧光光谱分析 14
3.2.1 样品Y2O3:Eu3+(1 mol%Eu3+)的光谱分析 14
3.2.2样品Y2O3:Tb3+(1 mol%Tb3+)光谱分析 15
3.2.3 1 mol%Eu3+,2 mol%Tb3+的光谱分析 17
3.2.4 1 mol%、2 mol%、4 mol%Tb3++1%Eu3+的光谱分析 18
3.2.5 1 mol%、2 mol%、4 mol%Eu3+1%Tb3+的光谱分析 19
3.2.6 不同掺杂组合的发射光谱分析 21
3.3高温固相法与水热法对荧光粉的发光性能影响 21
四、结论 23
参考文献 24
致谢 28
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