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1.
采用微乳液法合成了MAl2O4:Eu^2+,Dy^3+(M=Ca,Sr,Ba)长余辉发光材料,并对其晶体结构和发光性能进行了比较与讨论。XRD分析表明,所合成的Ca2O4:Eu^2+,Dy^3+,SrAl2O4:Eu^2+,Dy^3+粉体为单斜晶系结构,BaAl2O4:Eu^2+,Dy^3+粉体为六方晶体结构。MAl2O4:Eu^2+,Dy^3+(M=Ca,Sr,Ba)发光材料的激发光谱都为一宽带连续谱,表明从紫外至可见光均可有效的激发该材料。发射光谱的发射波长峰值分别为440nm(M=Ca),520nm(M=Sr)和496nm(M=Ba)。对应的发光颜色分别为蓝色、黄绿色和蓝紫色。余辉衰减曲线分为快衰减、中间过渡衰减和随后极长的慢衰减过程,符合双曲线方程I=At^-n,余辉亮度与时间顺序为Sr〉Ca〉Ba。  相似文献   

2.
用高温固相反应法制备了稀土离子Eu^3+掺杂的三元稀土硼酸盐Ba3Gd(BO3)3发光材料,通过X射线衍射(XRD)、荧光光谱和扫描电镜(SEM)等测试手段对Ba3Gd(BO3)3∶Eu^3+荧光粉的制备条件、发光性能以及形貌进行了研究。XRD结果表明,在1000℃时可得到Ba3Gd(BO3)3纯相。扫描电镜照片显示颗粒基本为球形,粒径约为200-400 nm。发光光谱测试表明,Ba3Gd(BO3)3∶Eu^3+荧光粉在近紫外区(UV)(396 nm)和蓝光区(466 nm)可以被有效地激发,分别用255和396 nm的紫外光激发样品时,以Eu3+的5D0-7F2(611和616 nm)超灵敏跃迁为主要发射峰。当Eu3+的掺杂浓度为10%(摩尔分数)时,Ba3Gd(BO3)3∶Eu3+在611和616 nm处的发光强度最大。因此,这种荧光粉是一种可能应用在白光LED上的红色荧光材料。  相似文献   

3.
采用碳酸盐前躯体高温分解法合成了Sr1-xZnxY2S4∶Er^3+,Sr1-xZnxY2S4∶Eu^2+和Sr1-xZnxY2S4∶Er^3+,Eu^2+红色荧光粉。XRD图谱表明,Zn^2+掺杂量x〈0.2 mol时,粉末样品为CaFe2O4型正交晶体。Zn^2+离子在Sr1-xZnxY2S4∶Er^3+,Eu^2+中的固溶量(xmol)对荧光粉的发射强度影响很大。随着Zn^2+离子掺杂浓度的增加,Sr1-xZnxY2S4∶Er^3+,Eu^2+(SZYSEE)紫外区激发峰(200-413 nm)发生红移,并与可见光激发带(413-600 nm)形成一个连续的宽带谱,与紫外和GaN基LED芯片辐射都有良好的匹配性。当Zn^2+掺杂量为0.1 mol时,SZYSEE的发光强度达到最大,其发光强度比未掺Zn2+的增强10.7倍。Sr0.9Zn0.1Y1.76S4∶0.24Er^3+,0.006Eu^2+是一种潜在的白光LED用红色荧光粉。  相似文献   

4.
采用高温固相反应法分别合成了变价稀土镨和镱离子掺杂的绿色荧光粉[Ba(2-n-1.5x)REx]SiO4∶nEu^2+(n=0.03,RE=Pr,Yb;x=0,0.02,0.05,0.10)。结果表明:所有合成荧光粉的激发峰均为250-400 nm的宽峰,与近紫外LED的发射光波长相匹配。发射峰位于450-550 nm之间,是Eu2+的5d-4f跃迁的典型发射。Pr^3+和Yb3+的掺入并未改变Ba2SiO4∶Eu^2+的相组成,但对荧光强度的影响大,且与掺杂元素、掺杂量和煅烧温度相关。当掺杂Pr^3+和Yb3+的量为x=0.02时,经1150℃煅烧所得荧光粉的发光强度分别是未掺杂时的595%和168%。证明三价稀土离子掺杂可以导致基质中的电荷缺陷而敏化Eu^2+离子的发光,而变价稀土离子的掺杂可以大大提高电荷缺陷,导致荧光强度的进一步提高。  相似文献   

5.
于敏  林君 《中国稀土学报》2001,19(6):579-582
采用溶胶-凝胶法制备了稀土离子掺杂(Eu^3 ,Tb^3 )的氧磷灰石三元稀土硅酸盐Ca2Y8(SiO4)6O2发光薄膜。通过X射线衍射(XRD),红外光谱(IR),扫描电镜(SEM)等方法对薄膜的组成、结构、颗粒尺寸、形貌及厚度进行了研究,通过发光光谱对薄膜的发光性质进行了分析。XRD结果表明700℃时薄膜尚处于非晶态,800℃时已开始有Ca2Y8(SiO4)6O2的物相形成,1000℃时结晶已完全。这一点和红外光谱的结果相符。发光光谱测试表明Ca2Y8(SiO4)6O2:Eu^3 薄膜显示了很强的红光发射,并以Eu^3+的^5D0-^7F2(616nm)超灵敏跃迁为最强一组。Ca2Y8(SiO4)6O2:Tb^3 的发射光谱由蓝光发射和绿光发射两部分组成,前者对应于^5D3-^7FJ,后者对应于^5D4-^7FJ(J=6,5,4,3),且以^5D4-^7F5(544nm)绿光发射为最强。  相似文献   

6.
Eu3+在SrZnP2O7中的发光性能和Eu3+, Bi3+间的能量传递   总被引:1,自引:0,他引:1  
采用高温固相法合成了SrZnP2O7:Eu^3+荧光粉,该荧光粉的激发主峰值位于400nm,适用于UVLED管芯的激发;在紫外激发下的发射峰由位于591和597nm(^5D0~^7F1),616,624和629nm(^5D0~^7F2),656nm(^5D0~^7F3)及688nm(^5D0~^7F4)4组线状峰构成,对应Eu^3+的特征跃迁,呈现橙红色发光。分析了Eu^3+离子浓度对样品发光效率的影响,随着浓度增加,其发射一直增强,但其发光效率已经开始减弱。Bi^3+的加入使发光强度得到很大提高,并讨论了在SrZnP2O7基质中Bi^3+对Eu^3+的能量传递和敏化作用。  相似文献   

7.
在空气中采用高温固相反应方法合成的17MO-(8-x-y)-75B2O3-xGd2O3(MLBEG,M-Mg,Ca,Sr,Ba)玻璃,在紫外光(λex=350nm)激发下发射蓝光和红光,在绿色光(λex=532nm)激发下发射红光,电子自旋共振谱研究表明玻璃体系中有Eu^2 离子存在,蓝色区的宽带发射是Eu^2 离子的5d-4f跃迁发射:红色区的窄带发射是Eu^3 离子的5Do-7FJ(J=1,2,3,4)跃迁发射,发现玻璃中的碱土金属离子对Eu^3 /Eu^2 离子的比例有很大影响,选择不同的碱土金属离子可以调节玻璃蓝色光和红色光的相对发射强度,MLBEG玻璃的发光性质可用于转换太阳能,增强植物的光合作用。  相似文献   

8.
Eu^2+激活的CaS:Eu^[1],Eu^3+和Sm^3+激活的硫氧化物^[2],Pr^3+激活的Ca0.8Zn0.2Ti03^[3]以及Eu^2+和Mn^2+掺杂的SrY2S4^[4]都是重要的红色发光材料。然而,这些红色荧光粉的发射峰波长都短于650nm,对于农用日光转换材料^[5],红色发射峰波长达到660nm才能与叶绿素的红区吸收相吻合。  相似文献   

9.
在Eu^2+掺杂的BaBrCl中,发现经X射线辐照后的光激励发光。BaClCl:Eu^2+的发光峰位于413nm,两个差吸收带分别位于-550nm和675nm。激励光能量较BaFX:Eu^2+(X=Cl,Br)低,与通常用作读出光源的HeNe激光器更为匹配。实验结果表明BaClCl:Eu^2+有望成为一类新型的X射线影像存储材料。  相似文献   

10.
LaPO4:Eu3+纳米粒子的多醇法合成及其光致发光性能研究   总被引:5,自引:0,他引:5  
以一缩二乙二醇为溶剂,采用多醇法(polyol method)合成LaPO4:Eu^3+纳米发光材料,利用XRD、FE.SEM、TG-DTA、Uv-vis光谱、光致发光光谱(PL)及寿命等手段进行了表征。结果表明:所得到的材料结晶完好,具有LaPO4的独居石型结构;粒子的形貌为球形,其粒径约为25nm;在波长为258nm的紫外光激发下,其发射光谱由Eu^3+的5D0^-7FJ(J=1,2,3,4)特征发射组成,在592nm处的磁偶极跃迁(5D0^-7F1)最强,表现为Eu^3+的橙-红特征发射;LaP04:Eu^3+纳米粒子中Eu^3+的最佳掺杂浓度为5%(摩尔比);Eu^3+的光致发光衰减曲线符合单指数行为,其寿命(τ)为3.9ms。  相似文献   

11.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

12.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

13.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

14.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

15.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.  相似文献   

16.
Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.  相似文献   

17.
用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.  相似文献   

18.
19.
A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu0 as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than CuI in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).  相似文献   

20.
(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C60, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.  相似文献   

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