稀土掺杂的新型荧光粉的合成与光谱性质研究

发布时间：2018-04-13 17:06

本文选题：白光LED + 高温固相法　；参考：《大连海事大学》2017年硕士论文

【摘要】：白光LED具有节能、环保、高效等优点,被誉为第四代照明光源。现阶段商用的白光LED是由蓝光LED芯片与黄光荧光粉组合而成的,这种缺失红光成分的白光,相对来说显色指数并不理想。故本文主要探究的方向在于:(1)研究发光性能良好的红光荧光粉;(2)研究能被近紫外激发的单一相白光荧光粉。本文采用的制备荧光粉的方法主要是高温固相法,通过高温固相法制备了一系列不同掺杂浓度的红光荧光粉Ba_3Gd(PO_4)_3:Eu~(3+)和GdNbO_4:Sm~(3+),以及白光荧光粉GdNbO_4:Dy~(3+)样品。并探究了各样品的光学性质和色度学性质,主要内容包括:(1)通过XRD衍射图谱分析了Ba_3Gd(PO_4)_3:Eu~(3+)样品的晶体结构。利用Van Uitert模型对~5D_0能级荧光的浓度猝灭行为进行了研究,发现浓度猝灭是由于Eu~(3+)与Eu~(3+)间交换相互作用所导致。分析了~5D_0能级荧光发射对温度的依赖关系,给出了温度猝灭行为符合crossover模型的结论。利用Eu~(3+)的发射光谱和荧光衰减数据,计算了~5D_0→~7F_J辐射跃迁速率及荧光分支比,同时得到了光学跃迁强度参数。(2)GdNbO_4:Sm~(3+)样品的XRD测试结果表明该样品为纯相,Sm~(3+)的掺杂并没有改变样品的晶体结构。随着Sm~(3+)掺杂浓度的增加,样品发生了浓度猝灭。用Van Uitert模型对样品进行拟合,推断引起样品浓度猝灭的机制是电偶极-电偶极相互作用,最后对不同掺杂浓度的样品进行了色坐标计算。(3)测试了GdNbO_4:Dy~(3+)样品的XRD衍射图谱,结果表明该样品为纯相,Dy~(3+)发光中心的掺杂并没有对GdNbO_4的晶体结构造成影响。用Van Uitert模型对样品在不同掺杂浓度条件下的发射强度进行积分拟合计算,了解到引起样品浓度猝灭的机制是电偶极-电偶极相互作用。对掺杂不同浓度的样品计算了黄蓝比以及色坐标,并且计算了样品色坐标随着温度提高的变化规律,发现样品在不同温度下仍然有着良好的发光性能。
[Abstract]:White LED, with the advantages of energy saving, environmental protection and high efficiency, is praised as the fourth generation lighting source.At present, the commercial white LED is composed of blue LED chip and yellow phosphor.Therefore, the main research direction of this paper is: (1) to study the red phosphor with good luminescence performance.) to study the single phase white phosphor which can be excited by near ultraviolet.In this paper, a series of red phosphor (Ba_3Gd(PO_4)_3:Eu~(3) and white phosphor (GdNbO_4:Dy~(3) with different doping concentration were prepared by high temperature solid state method.The optical and chromaticity properties of the samples were investigated. The main contents include: 1) the crystal structure of Ba_3Gd(PO_4)_3:Eu~(3) samples was analyzed by XRD diffraction pattern.The concentration quenching behavior of 5D0 level fluorescence was studied by using Van Uitert model. It was found that the concentration quenching was caused by the exchange interaction between Eu~(3) and Eu~(3).The dependence of 5D0 energy level fluorescence emission on temperature is analyzed, and the conclusion that the temperature quenching behavior accords with the crossover model is given.Based on the emission spectrum and fluorescence attenuation data of Eu~(3, the radiation transition rate and the fluorescence branch ratio of 5D\\ +\\\At the same time, the XRD test results of the optical transition intensity parameter... GdNbOS 4: Sm3) show that the doping of the sample is pure phase, and the crystal structure of the sample has not been changed.With the increase of doping concentration of Sm~(3, the concentration quenching occurred.The Van Uitert model was used to fit the samples. It was inferred that the mechanism of concentration quenching was electric dipole-electric dipole interaction. Finally, the XRD diffraction patterns of samples with different doping concentrations were measured by color coordinate calculation.The results show that the doping of the pure phase Dy Dy + 3) has no effect on the crystal structure of GdNbO_4.The Van Uitert model was used to calculate the emission intensity of the samples with different doping concentrations. It was found that the mechanism of concentration quenching was electric dipole dipole interaction.The yellow-blue ratio and the color coordinates of the samples with different doping concentrations were calculated. The variation of the color coordinates with the increase of temperature was calculated. It was found that the samples still had good luminescence properties at different temperatures.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O482.31;TN312.8

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