稀土掺杂氮化物M-Si-Al-N发光材料的制备及其性能研究

发布时间：2018-05-01 13:31

本文选题：白光LED + 荧光材料　；参考：《兰州大学》2017年博士论文

【摘要】：白光LED被称为第四代照明光源,因其具有节能、环保、寿命长、低功耗,亮度高等优点。荧光材料是荧光转换型白光LED的重要组成部分,通过与蓝光或近紫外LED芯片组合产生白光,白光LED的显色性、色温和发光效率等发光表现由荧光材料性能的优劣直接决定。氮化物荧光材料因其优秀发光性能而受到研究者的广泛关注。本论文针对目前存在的大部分荧光材料的性能有待进一步提高、氮化物红色荧光材料种类太少和相关机理研究不够完善等问题,从以下四个方面开展研究工作:1.(1)通过气压烧结法,金属氮化物为原料,成功合成了纯氮Ca-α-sialon:Eu~(2+)(Ca_(1.4-x)Al_(2.8)Si_(9.2)N_(16):xEu~(2+)-CASN:xEu~(2+),x=0-0.3)荧光材料并研究其发光性能。相比于含氧的Ca-α-sialon:Eu~(2+)和商用黄粉YAG:Ce~(3+)(P46-Y3),CASN:x Eu~(2+)具有更长波长的发射和更好地热稳定性。结果表明,CASN:xEu~(2+)是一种有极具潜力的白光LED氮化物黄色荧光材料。(2)研究了Ce~(3+)掺杂的CASN的光致发光和阴极射线发光性能。通过改变激活剂离子浓度和基质组成的手段实现调控荧光材料的发光性能。在395nm激发下,样品的CASN:xCe~(3+)发射峰中心波长位于525nm,半高宽为135 nm。在150℃时,样品的发射强度只降低了13%。在阴极射线激发下,样品CASN:xCe~(3+)具有良好的耐电流饱和性和优异的抗退化性能及色彩稳定性。(3)通过阳离子取代(Al~(3+)→Si4+)的方式调控CASN:Eu~(2+)的结构和发光性能,探索了样品发射强度增强、发射红移和热稳定性提高的机理,结果表明,随着Al~(3+)对Si4+的取代,样品结晶度也逐渐提高,从而导致CASN:x Al的发射强度逐渐增强。发射光谱的红移和热稳定性能的提高是因Eu-N共价性增强的增强导致的。2.(1)通过气压烧结法,合成了Eu~(2+)掺杂和Eu~(2+),Ce~(3+)共掺的锂氮化物LiSi_2N_3荧光材料。LiSi_2N_3:Eu~(2+)的最强激发在~355nm,最强发射位于~592 nm。基质中含氧量的不同使本文合成的LiSi_2N_3:Eu~(2+)的激发和发射比之前文献报道的位于更长波长范围。再者,研究了Ce~(3+)与Eu2之间能量传递机制和光谱红移的机理。(2)探究AlN的固溶对LiSi_2N_3:Eu~(2+)晶体结构、形貌、热稳定性和发光性能的影响。AlN的固溶能够提高样品的发射强度。而AlN的固溶没有改变发光中心的配位环境,样品的发射光谱的形状和峰位没有发生变化。结果表明,通过固溶体的形式是一种有效的提高荧光材料发射强度的手段。3.采用传统固相反应成功合成了锂氮化物Ca_3Li_(4-x)Si_2N_(6-y)O_y:Eu~(2+)/Ce~(3+)(CLSN:Eu~(2+)/Ce~(3+))(0≤y≤1.5)荧光材料,,并研究了其发光性能和能带结构。基质CLSN具有缺陷红光发光特性。Eu~(2+)和Ce~(3+)激活的CLSN同样表现出深红光发射。同时,研究了CLSN:Eu~(2+)/Ce~(3+)的热稳定性。结果表明,锂氮化物(M-Li-Si/Al-N,M=Ca,Sr,Ba)荧光材料对荧光转换型LED用荧光材料的发展有一定的意义。4.采用传统固相反应成功合成系列锂氮化物LiCaAlN_2:Eu~(3+)/Tb~(3+)(LCAN:Eu~(3+)/Tb~(3+))荧光材料。系统研究了LiCaAlN_2:Eu~(3+)/Tb~(3+)的光致发光性能和LCAN:Tb~(3+)的阴极射线发光性能。Eu~(3+)/Tb~(3+)掺杂的LCAN表现出位于615nm/550nm的红光/绿光发射。在615nm/550nm监控下,有趣的发现LiCaAlN_2:Eu~(3+)/Tb~(3+)有一个位于350-450 nm/275-375 nm宽的电荷迁移带。在电子束激发下,样品LCAN:Tb~(3+)表现出良好的耐电流饱和性。将红色LiCaAlN_2:Eu~(3+)与蓝色、绿色荧光材料封装得到白光LED器件。结果表明,三价稀土离子激活的锂氮化物对高效窄带发射荧光材料的开发有很大意义。
[Abstract]:White light LED is known as the fourth generation lighting source. Because of its advantages of energy saving, environmental protection, long life, low power consumption and high brightness, fluorescent material is an important part of the fluorescent conversion white light LED. White light is produced by combination with blue or near ultraviolet LED chips. The color display, color temperature and luminous efficiency of white LED are characterized by fluorescent material The advantages and disadvantages of the energy are directly determined. The nitride fluorescent materials have been widely concerned because of their excellent luminescence properties. In this paper, the performance of most of the existing fluorescent materials needs to be further improved, the species of nitride red fluorescent materials are too few and the related mechanism is not perfect, and the following four aspects are carried out. 1. (1) the pure nitrogen Ca- alpha -sialon:Eu~ (2+) (Ca_ (1.4-x) Al_ (2.8) Si_ (9.2) N_ (16): xEu~ (2+) -CASN:xEu~ (2+) -CASN:xEu~ (2+)) was synthesized by the pressure sintering method, and the luminescence properties of the pure nitrogen (1.4-x) Al_ (2.8) Si_ (9.2) N_ (2+) were studied. The longer wavelength emission and better geothermal stability. The results show that CASN:xEu~ (2+) is a potential white light LED nitride yellow fluorescent material. (2) the photoluminescence and cathodoluminescence of Ce~ (3+) doped CASN are studied. The regulation of fluorescent materials by means of changing the concentration of activator ion concentration and matrix composition is realized. Under 395nm excitation, the center wavelength of the sample CASN:xCe~ (3+) emission peak is located at 525nm, and the emission strength of the sample is only reduced by the cathode ray excitation at 135 nm. at 150 centigrade. The sample CASN:xCe~ (3+) has good current saturation and excellent resistance to degradation and color stability. (3) through cation substitution The structure and luminescence properties of CASN:Eu~ (2+) are regulated by (Al~ (3+) (Si4+)). The mechanism of the enhancement of the emission intensity, the emission of red shift and the increase of thermal stability is explored. The results show that the crystallinity of the sample increases gradually with the substitution of Al~ (3+) to Si4+, which leads to the increase of the emission intensity of CASN:x Al. The enhancement of the fixed properties is due to the enhancement of Eu-N covalent enhancement..2. (1) has synthesized the strongest excitation of the Eu~ (2+) doping and Eu~ (2+), Ce~ (3+) Co doped LiSi_2N_3 fluorescent material.LiSi_2N_3:Eu~ (2+) in the ~355nm, the difference in the oxygen content in the strongest emitter matrix. The excitation and emission of 2+) is in a longer wavelength range than that previously reported in the literature. Furthermore, the mechanism of energy transfer between Ce~ (3+) and Eu2 and the mechanism of spectral redshift are studied. (2) to explore the effect of solid solution of AlN on the crystal structure, morphology, thermal stability and luminescence energy of LiSi_2N_3:Eu~ (2+), the solid solution of.AlN can improve the emission strength of the sample. The solid solution does not change the coordination environment of the luminescent center, and the shape and peak of the emission spectra of the samples have not changed. The results show that the solid solution is an effective means to improve the emission strength of the fluorescent materials,.3. (4-x) Si_2N_ (6-y) O_y:Eu~ (2+) /Ce~ (3+) (C) has been successfully synthesized by the traditional solid phase reaction. LSN:Eu~ (2+) /Ce~ (3+)) (0 < < < y < 1.5) fluorescent material, and its luminescence property and band structure are studied. Matrix CLSN with defective red light luminescence properties.Eu~ (2+) and Ce~ (3+) activation also shows deep red light emission. The optical materials have certain significance for the development of fluorescent materials for fluorescent converted LED..4. (LCAN:Eu~ (3+) /Tb~ (3+)) fluorescent material has been successfully synthesized by the traditional solid phase reaction. The photoluminescence properties of LiCaAlN_2:Eu~ (3+) LiCaAlN_2:Eu~ (LCAN:Eu~ (3+) /Tb~ (3+)) are systematically studied. /Tb~ (3+) doped LCAN shows red / green light emission at 615nm/550nm. Under the monitoring of 615nm/550nm, it is interesting to find that LiCaAlN_2:Eu~ (3+) /Tb~ (3+) has a 350-450 nm/275-375 nm wide charge transfer zone. The white light LED devices are encapsulated in blue and green fluorescent materials. The results show that lithium nitride activated by trivalent rare earth ions is of great significance for the development of efficient narrow band emission fluorescent materials.

【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O482.31

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