兰州大学机构库 >物理科学与技术学院
稀土掺杂氮化物M-Si-Al-N发光材料的制备及其性能研究
Alternative TitlePreparation and luminescence properties of rare-earth doped M-Si-Al- N materials
吴泉生
Thesis Advisor王育华
2017-03-01
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword白光LED 荧光材料 Ca-α-SiAlON Ca1.4Al2.8Si9.2N16 LiSi2N3 Ca3Li4-xSi2N6-yOy LiCaAlN2
Abstract

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:Eu2+(Ca1.4-xAl2.8Si9.2N16:xEu2+-CASN:xEu2+,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:Eu2+和商用黄粉YAG:Ce3+(P46-Y3),CASN:xEu2+具有更长波长的发射和更好地热稳定性。结果表明,CASN:xEu2+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Ce3+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: xCe3+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: xCe3+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(Al3+→Si4+)的方式调控CASN:Eu2+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Al3+对Si4+的取代,样品结晶度也逐渐提高,从而导致CASN:xAl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Eu2+掺杂和Eu2+,Ce3+共掺的锂氮化物LiSi2N3荧光材料。LiSi2N3:Eu2+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LiSi2N3:Eu2+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Ce3+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LiSi2N3:Eu2+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Ca3Li4-xSi2N6-yOy:Eu2+/Ce3+(CLSN: Eu2+/Ce3+)(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。Eu2+和Ce3+激活的CLSN同样表现出深红光发射。同时,研究了CLSN: Eu2+/Ce3+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LiCaAlN2:Eu3+/Tb3+(LCAN:Eu3+/Tb3+)荧光材料。系统研究了LiCaAlN2:Eu3+/Tb3+的光致发光性能和LCAN:Tb3+的阴极射线发光性能。Eu3+/Tb3+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LiCaAlN2:Eu3+/Tb3+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:Tb3+表现出良好的耐电流饱和性。将红色LiCaAlN2:Eu3+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。

Other Abstract

In recent years, white light-emitting diodes (WLED) is known as the fourth generation light source, with energy saving, environmental protection, long life, low power consumption, high brightness and so on. Phosphors is an important part of the phosphor converted white LED, which are used in combination with blue or near ultraviolet LED chip to produce white light. The quality of the phosphors directly determines the performance of white LED, such as color rendering index, color temperature and luminous efficiency etc. Nitride phosphors have attracted much attention of researchers because of its excellent luminescent properties. At present, the performance of most of the nitride phosphors needs to be further improved, and the types of nitride red fluorescent materials are too small and the related mechanism research is incomplete. Therefore, in this paper, the research work is carried out from the following four aspects:
1. (1) Pure nitride Ca-α-sialon orange phosphors with the composition Ca1.4-xAl2.8Si9.2N16:xEu2+ (CASN:xEu2+, x = 0–0.3) were successfully prepared by gas-pressed sintering using metal nitride as raw materials. Compared with the oxygen containing Ca-α-sialon:Eu2+ and commercial YAG:Ce3+ phosphors (P46-Y3), CASN:xEu2+ exhibit a longer wavelength emission and better thermal stability. The results indicate that CASN:xEu2+ is a promising yellow phosphor for white LED. (2) The Photoluminescence and cathodoluminescence properties of Ce3+ doped CASN were investigated. The luminescent properties of the phosphors were controlled by changing the Ce3+ concentration and the composition of the matrix. Under the excitation of 395nm, the emission peak of CASN: xCe3+ is located at 525nm, and the FWHM is 135 nm. At 150℃, the emission intensity of the sample was reduced by only 13%. Under the excitation of electron beam, the sample CASN: xCe3+ has good resistance to current saturation and excellent resistance to degradation and good color stability. (3) The structure and luminescent properties of the CASN:Eu2+ phosphors were modify by cation substitution (Al3+→Si4+). And the mechanisms of the red-shift of emission and the improvement of the emission intensity and thermal quenching have been explored. Owing to the increase of the crystallinity with Al3+ introducing, the emission intensity of the phosphors increases. The modified structure results in a strong covalence of Eu-N and an improvement of the thermal quenching.
IV2.(1) Eu2+ doped and Eu2+, Ce3+ co-doped LiSi2N3 phosphors were successfully prepared by gas-pressed sintering. The dominant excitation band of LiSi2N3:Eu2+ was found at about 355 nm and exhibited a broad-band yellow emission centered at 592 nm instead of the early reports of 310 nm and 580 nm, respectively. The shifting behavior dominantly contributed to different oxygen content in the host. The detailed energy transfer mechanism from Ce3+ to Eu2+ in the LiSi2N3host was also explored. (2) The effects of a solid solution of AlN on the crystal structure, morphology, thermal quenching and photoluminescence properties of LiSi2N3:Eu2+ phosphor were studied. The luminescence intensity of LiSi2N3:Eu phosphor is significantly improved by the solution of AlN, but the emission position is unchanged. The results show that these solid solutions could be the most useful way to improve the luminescence intensity of phosphors. 3. Eu2+/Ce3+ doped Ca3Li4-ySi2N6-yOy (0≤y≤1.5) (CLSN) were successfully prepared by conventional solid-state reaction and their luminescence properties and electronic structure were studied. The undoped CLSN shows red defect-related luminescence, Eu2+ and Ce3+ doped CLSN also show red emission centered at 702 nm and 673nm, respectively. The thermal stability of CLSN is also investigated.The results indicate that CLSN:Eu2+/Ce3+ could be conducive to the development of phosphor-converted light-emitting diodes. 4. A series of LiCaAlN2:Eu3+/Tb3+ phosphors were successfully prepared by solid-state reaction. The photoluminescence (PL) properties of LiCaAlN2:Eu3+/Tb3+ and the cathodoluminescence (CL) properties of LiCaAlN2:Tb3+ were investigated in detail The Eu3+ (Tb3+) doped LiCaAlN2 shows red (green) emission peaking at 615 nm (550 nm). Monitored at 615 nm (550 nm), it is interesting to found that LiCaAlN2:Eu3+ (LiCaAlN2:Tb3+) has a broad charge transfer band ranging from 350-450 nm (275-375 nm). LiCaAlN2:Tb3+ exhibits a good resistance to the current saturation. The white LED has also been fabricated with blue, green, and LiCaAlN2:Eu3+ red phosphor. The results indicate that LiCaAlN2:Eu3+/Tb3+ could be conducive to the development of phosphor-converted LEDs and FEDs.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229190
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
吴泉生. 稀土掺杂氮化物M-Si-Al-N发光材料的制备及其性能研究[D]. 兰州. 兰州大学,2017.
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