ZnO-B2O3∶Tb3+长余辉玻璃的发光性质

通过还原方法制备了Tb3+离子掺杂的硼酸锌玻璃,并观察到在254 nm紫外光激发后有明亮的绿色长余辉发光现象,余辉时间达6 h.通过激发与发射光谱、余辉光谱、余辉衰减曲线、热释光谱、热释光释出速率衰减曲线等得到的信息,研究了Tb3+离子掺杂的硼酸锌玻璃的发光性质.     

ZnO-B2O3∶Tb3+长余辉玻璃的发光性质

通过还原方法制备了Tb³⁺离子掺杂的硼酸锌玻璃，并观察到在254 nm紫外光激发后有明亮的绿色长余辉发光现象，余辉时间达6 h。通过激发与发射光谱、余辉光谱、余辉衰减曲线、热释光谱、热释光释出速率衰减曲线等得到的信息，研究了Tb³⁺离子掺杂的硼酸锌玻璃的发光性质。     

(CaO)20.68(MgO)1.32(SiO2)4S2∶Eu2+,Dy3+红光材料的制备与发光特性

研究了峰值波长651nm的红色发光材料(CaO)20.68(MgO)1.32(SiO2)4S2∶Eu2 ,Dy3 的制备及发光特性。通过XRD分析表明硫气氛中合成的材料为具有硫成分的硅酸盐相。红光发射带为硫元素进入晶格后在发光中心周围形成了类似长余辉材料CaS∶Eu2 ,Cl-的局域结构。这也使材料具有了硫化物长余辉材料的发射光谱特征和硅酸盐材料高化学稳定性和高亮度的优点。热释光测量揭示它可能是一种潜在的红色长余辉材料。     

（CaO）20．68（MgO）1．32（SiO2）4S2：Eu^2＋，Dy^3＋红光材料的制备与发光特性

研究了峰值波长651nm的红色发光材料（CaO）20.68（MgO）1.32（SiO2）4S2：Eu^2＋，Dy^3＋的制备及发光特性。通过XRD分析表明硫气氛中合成的材料为具有硫成分的硅酸盐相。红光发射带为硫元素进入晶格后在发光中心周围形成了类似长余辉材料CaS：Eu^2＋，Cl^-的局域结构。这也使材料具有了硫化物长余辉材料的发射光谱特征和硅酸盐材料高化学稳定性和高亮度的优点。热释光测量揭示它可能是一种潜在的红色长余辉材料。     

Ho3+对CaGa2S4:Eu2+发光性能的影响

研究了二价铕离子与三价钬离子共同掺杂的荧光体CaGa2S4:Eu2 (0.5%), Ho3 (1.0%)的荧光、三维热释发光及其长余辉发光特性. 作为对比, 同时研究了CaGa2S4:Eu2 (0.5%)及CaGa2S4:Ho3 (1.0%)的荧光和三维热释发光性质, 发现CaGa2S4:Eu2 (0.5%), Ho3 (1.0%)的发射波长为552 nm的黄绿色余辉长达40 min, CaGa2S4:Eu2 (0.5%)不具有长余辉, 而CaGa2S4:Ho3 (1.0%)具有很弱的余辉. 热释光及其三维图谱的研究表明, 由于Ho3 的引入而产生了一个新的陷阱能级, 从而使CaGa2S4:Eu2 (0.5%), Ho3 (1.0%)具有长余辉的发光特性.     

Sr3SiO5：Eu^2＋，RE^3＋（RE=Sm，Dy，Ho，Er）的表征及其在LED上的应用

采用高温固相法合成出系列黄光Sr3SiO5:Eu2+,RE3+(RE=Sm,Oy,Ho,Er)化合物,从XRD,荧光光谱以及热释光曲线方面系统研究其荧光、长余辉发光性质及其在固态照明(LEO)上的应用.研究结果表明:利用某些三价稀土离子的共掺杂,获得荧光增强的高亮度橙黄色荧光材料Sr3SiO5:Eu2+,RE3+,并且观察到橙黄色长余辉现象(RE=Oy,Ho,Er);热释光谱的主峰位于100℃左右.将其和近紫外LEo(～395 nm)或蓝光LED封装成高亮度橙黄光和白光LED,光效高达约40 lm·w-1以上.此化合物将在固态照明与显示、信息存储等方面获得应用.     

稀土红色长余辉发光材料研究进展

综述了稀土元素掺杂红色长余辉发光材料的研究进展，总结了硫化物、钛酸盐、硫氧化物、硅酸盐、氧化物和磷酸盐等基质体系的红色长余辉发光，并指出硫氧化物和磷酸盐等基质是最具有发展前景的红色长余辉发光体系，讨论了Eu^2 在硫化物、Pr^3 在钛酸盐以及Eu^3 和Sm^3 等稀土离子在硫氧化物和硅酸盐等体系中的红色长余辉发光机制。介绍了传统的高温固相法以及溶胶．凝胶法、微波合成法等稀土红色长余辉材料的制备技术。提出了从基质材料、制备技术和稀土离子发光机制入手是稀土红色长余辉发光材料今后研究与开发的发展方向。     

Er~(3 ),Ho~(3 )和Tm~(3 )在硫氧化钆中的余辉发光

非放射性长余辉磷光粉作为美化和清洁光源在发光陶瓷、交通安全标志、紧急突发事件的照明设施、工艺美术涂料等众多领域得到越来越广泛的应用,引起人们的重视.到目前为止,文献报道的稀土长余辉磷光体的激活离子主要有铕离子(Eu3+和Eu2+[1-4]、三价铈离子(Ce3+)[5]、三价铽离子(Tb3+)[6]、三价镨离子(Pr3+)[7]、三价钐离子(Sm3+)[8].Ho3+,Er3+,Tm3+等稀土离子作为红外上转换发光材料的激活离子[9～12],而关于它们的长余辉发光的报道极少.最近,雷炳富等在Tm3+离子[13]激活的硫氧化钇体系中发现了长余辉发光.在此,我们通过高温固相法合成了Er3+,Ho3+和Tm3+掺杂的硫氧化钆长余辉磷光粉,观察到该体系中迄今未见文献报道的Er3+,Ho3+和Tm3+离子的长余辉发光.     

共掺La3+对Sr2SnO4∶Sm3+的余辉增强

研究了以La3+离子为辅助激活剂,对Sm3+掺杂的发光材料Sr2SnO4:Sm3+余辉性能的影响。采用传统的高温固相法合成Sr2SnO4∶Sm3+,La3+红色长余辉发光材料。利用X射线粉末衍射仪、荧光光谱仪、热释光剂量仪等手段对粉末样品进行了表征。分析结果表明,在1400℃得到了单相Sr2SnO4,Sr2SnO4∶Sm3+,La3+发光粉末有563、599和646 nm 3个发射峰,与Sm3+单掺杂的Sr2SnO4∶Sm3+相比,其光谱发射峰位没有明显变化。余辉亮度衰减曲线表明适量的La3+掺杂可以延长Sr2SnO4∶Sm3+的余辉时间。通过对热释光谱的分析,解释了双掺杂发光粉余辉性能增强的原因,La3+掺杂增加了更多适宜深度的陷阱(VSr″),可以有效存储光能,增强余辉的时间和强度。     

共掺Tm~(3+)离子对CaAlSiN_3∶Eu~(2+)红色荧光粉发光性能的影响

通过高温固相法,合成了Eu~(2+)单掺和Eu~(2+)、Tm~(3+)共掺CaAlSiN_3荧光粉。结合荧光光谱、余辉发射光谱和余辉衰减曲线及热释发光等测试手段对其进行了表征分析。结果表明,CaAlSiN_3∶Eu~(2+)具有主峰位于630 nm的明显的红色长余辉发光;共掺杂Tm~(3+)离子的引入,产生了654和800 nm的荧光和余辉,同时,Tm~(3+)的共掺,使CaAlSiN_3∶0.1%Eu~(2+),Tm~(3+)样品位于89.0℃热释光峰位消失,表明Tm~(3+)共掺杂改变了CaAlSiN_3∶Eu~(2+)荧光粉中的陷阱能级及其分布,从而减弱了CaAlSiN_3∶Eu~(2+)的630 nm红色可见光部分余辉发光性能。     

Li+,Eu3+共掺杂La2MoO6红色荧光粉的Pechini法合成及近紫外/蓝光激发下的发光特征

采用Pechini法合成了白光LED用红色荧光粉La_1.9-xMoO₆:0.10Eu³⁺,xLi⁺(x=0,0.10,0.20,0.25),并对样品分别进行了X射线衍射(XRD)、扫描电子显微镜(SEM)、电子能谱(EDX)以及荧光光谱(PL)等技术手段分析。 PL光谱显示该荧光粉可被近紫外光(395 nm)和蓝光(466 nm)有效激发,产生616和623 nm强的红光发射,归属于Eu³⁺的⁵D₀→⁷F₂电偶极跃迁。该荧光粉与近紫外LED芯片(370~410 nm)和蓝光LED芯片(450~470 nm)均匹配良好,具有潜在的商业应用价值。 共掺Li⁺离子作为敏化剂能显著提高荧光粉的发光强度,且最优掺杂量为x=0.20。     

Ba_3Y(PO_4)_3∶Dy~(3+),Eu~(3+)单基质白光荧光粉的制备与发光性能

为了探究在Dy~(3+)掺杂Ba_3Y(PO_4)_3荧光粉中共掺Eu~(3+)离子对其发光性能的影响,我们采用传统高温固相法制备了一系列Dy~(3+)、Eu~(3+)单掺杂和共掺杂Ba_3Y(PO_4)_3荧光粉。通过X射线衍射(XRD)、荧光发射光谱和荧光衰减曲线对样品进行了表征。结果表明,所制备的荧光粉呈闪铋矿立方相。在近紫外光激发下,Ba_3Y(PO_4)_3∶Dy~(3+)发射光谱在487和578 nm处有两个窄带发射峰,呈冷白光发射;Ba_3Y(PO_4)_3∶Eu~(3+)发射光谱的窄带发射位于594和616 nm处,呈发橙红光。在Ba_3Y(PO_4)_3∶Dy~(3+),Eu~(3+)中,由于Eu~(3+)离子补偿Dy~(3+)冷白光发射所缺的红色组分,从而实现了色纯度高、色温适中的暖白光发射。进一步探索了Ba_3Y(PO_4)_3∶Dy~(3+),Eu~(3+)荧光粉发光机理。所制备的Ba_3Y(PO_4)_3∶Dy~(3+),Eu~(3+)单基质白光荧光粉在白光近紫外激发白光二极管(UVWLED)领域具有潜在应用价值。     

Long Lasting Phosphorescence Properties and Multi-peak Fitting on Thermoluminescence of Red LaAlO3: Eu3+ Phosphor

Red long lasting phosphorescence(LLP) was firstly observed in LaAlO₃:Eu³⁺ phosphor synthesized by solid state method at 1773 K. It reveals that the Eu³⁺ ions occupy the asymmetric La³⁺ sites, resulting in the orange-red emission of Eu³⁺. The LLP of the optimum LaAlO₃:0.6%Eu³⁺ sample can come to about 2000 s according to a definition of 0.32 mcd/m². The LLP decay curve can not be fitted even by a function of three exponential terms, due to the complicated retrapping process of carriers. The result of a classical multi-peak fitting method on thermoluminescence reveals that the excellent LLP performance of LaAlO₃:Eu³⁺ material originates from the rich distribution of shallow traps(E=0.7875 eV).     

Eu2+掺杂KCaCl3晶体的生长及发光性能

通过坩埚下降法生长出不同物质的量分数Eu²⁺掺杂的KCa_1-xEu_xCl₃(x=0.005、0.01、0.02、0.03、0.05)单晶,并对晶体进行了X射线粉末衍射、热重、透过率、光致发光光谱、衰减时间、X射线激发发射光谱等测定。通过相图及结构分析,判断出该晶体为一致熔融化合物,并得出其为正交结构,晶胞参数为a=0.75604 nm,b=1.04823 nm,c=0.72657 nm,空间群为Pnma(62)。在紫外光的激发下,晶体在434 nm左右有一个宽的发射峰,对应于Eu²⁺的4f⁶5d¹→4f⁷跃迁;光致衰减时间1.473μs,晶体在X射线激发下的发光强度随Eu²⁺离子浓度增加而增强。     

Studies on long lasting optical properties of Eu2+ and Dy3+ doped di-barium magnesium silicate phosphors

Di-bariummagnesium silicate phosphors doped with europiumand dysprosium were prepared under a weak reducing atmosphere. X-ray diffraction pattern of the sample was also done that confirmed the proper preparation of the phosphor. Scanning electron microscope (SEM) images confirmed that the sample has regular surface and uniform grain size distribution. Comparative studies of phosphorescence decay of Ba₂MgSi₂O₇:Eu²⁺, Dy³⁺ phosphors with different concentration of Dy³⁺ were done. The phosphor with 0.5/1.5 mol% of Eu/Dy, exhibited optimum green color afterglow properties. This emission is expected to arise due to transition of Eu²⁺ ions from any of the sublevels of 4f⁶5d¹ configuration to ⁸S_7/2 level of the 4f⁷ configuration. For a suitable trap depth, the trap concentration is expected to be proportional to the concentration of Dy³⁺. These traps are responsible for holding the charge career for a reasonable time, subsequently for increasing the time of afterglow. Hence, optimum Dy³⁺ concentration produces the longer afterglow duration with higher intensity of luminescence signals. Trap depth were also calculated using thermoluminescence glow curve which was indicative of formation of traps suitable for long afterglow.     

荧光粉Ba5-3x/2B4O11∶xEu3+的制备及发光性能

采用高温固相烧结法成功制备了Ba_5-3x/2B₄O₁₁∶xEu³⁺(x=0.02~0.22)荧光粉,利用XRD和SEM等对荧光粉进行了结构和形貌表征。 在激发波长为393 nm的条件下,发射峰(596、621、657和706 nm)与Eu³⁺的⁵D₀-⁷F_J(J=1,2,3,4)电子跃迁相对应,其中621 nm最强发射峰由Eu³⁺离子⁵D₀→⁷F₂电偶极跃迁造成。 文章还研究了Eu³⁺掺杂浓度对Ba_5-3x/2B₄O₁₁∶xEu³⁺发光性能的影响,结果表明,荧光粉的发光强度随着Eu³⁺掺杂量的增加呈现先增大后减小的趋势,Eu³⁺最佳掺杂量为0.16。     

Preparation and Luminescence Behavior of CaSiO3：Eu^3＋（Bi^3＋）

CaSiO3：Eu0.08^3＋Bi0.002^3＋ with a monoclinic perovskite structure was synthesized by using sol-gel method, and its luminescence characteristics were investigated. From the excitation spectrum, it can be seen that the main peaks located at 238,396,415,437 and 359 nm correspond to the charge-transfer band of Eu^3＋-O^2- , the absorption transitions of ^7F0.1→^3L6, ^7F0→^5D3, ^7F1→^5D3 of Eu^3＋ ions, and ^3P1→^1S0 of Bi^3＋ ions, respectively. When the samples were excited with a light of wavelength 359 or 395 nm, it can be seen from the emission spectrum that the electronic dipole transition located at 609 nm corresponding to ^5D0→^7F2 of Eu^3＋ ions was stronger than the magnetic dipole transition located at 587 nm corresponding to ^5D0→^7F1 of Eu^3＋ ions, which shows that more Eu^3＋ ions were located in nonreversion center lattices. The energy transfer from Bi^3＋ ions to Eu^3＋ ions in the phosphor was also discussed. The results show that Eu^3＋ ions could be well sensitized by ^3＋ions, and the energy-transfer pattern between Bi^3＋ ions and Eu^3＋ ions was resonance energy transfer.     

The luminescent properties of divalent europium complexes of crown ethers and cryptands

The luminescent properties of divalent europium complexes with crown ether, azacrown ether, N-pivot-azacrown ether, and cryptand in methanol or water have been systematically investigated under UV irradiation. These divalent europium complexes show greatly enhanced emission from 417 nm to 488 nm in the visible blue region in comparison with that of the methanol solution of EuCl₂. The aqueous solution of EuCl₂ is non-luminescent. This obvious distinction in luminescent properties between the macrocyclic ligand-coordinated divalent europium and uncoordinated divalent europium is attributed to the “insulation effect” of Eu²⁺ ion from the solvent molecules of CH₃OH and H₂O by the macrocyclic crown ether or cryptand encapsulation to divalent europium. Moreover, these macrocyclic ligands provide an additional restriction to the electronic charge expansion of the excited Eu²⁺. This also contributes to the enhancement of the Eu²⁺ luminescence. Among all the investigated macrocyclic ligands, 15-crown-5 (15C5) affords the largest enhancement to the Eu²⁺ emission. The intensity of the Eu²⁺–15C5 complex is 690 times that of the EuCl₂ methanol solution with the same Eu²⁺ concentration. This special emission enhancement effect is related to the particular complex composition of 1:3 (Eu²⁺:15C5) and corresponding configuration of Eu²⁺–15C5 complex in methanol. Concerning the mechanism, the luminescence enhancement of divalent europium by complexation with these macrocyclic crown ether or cryptand ligands is found to be initiated from the decrease in non-radiative rate constant rather than from the increase in radiative one.

The divalent europium complexes of methacrylate polymeric polyether derivatives such as 15C5-, 18-crown-6- (18C6), and cryptand [2.2.1]- or [2.2.2]-containing polymer and copolymer have also been prepared. Their luminescent properties in solid state have been studied to aim for practical application. As a similar situation to the simple polyether complexes, the divalent europium complex with 15C5-containing polymer or copolymer shows the largest luminescent enhancement effect. Its emission intensity reaches about 20% that of the commercial inorganic luminescence product CaWO₄:Pb (NBS 1026). In addition, the doping effect of several divalent ions, namely Mg, Sr, Ba and Zn in polymeric complexes, has also been investigated according to the luminescence concentration quenching mechanism in solid state luminescence materials. The emission intensity of 15C5-containing polymer europium(II) complex is raised to twice stronger by doping of Zn²⁺ ion.     

在发光二极管背光源上极具应用前景的Beta-sialon (Si6-zAlzOzN8-z):Eu2+窄带绿色荧光粉

基于氮化镓的白光发光二极管(LED)是目前一项崭新的背光源技术,广泛应用于宽色域、高光效的液晶显示屏。 在此项技术中,作为关键材料的荧光粉决定着背光单元的色域范围、发光效率和可靠性,因而要求它应具合适的发射波长和窄带发射。 β-sialon:Eu²⁺(sialon:silicon aluminum oxynitride(赛龙))就是一款非常适合背光应用的绿色荧光粉,这得益于其位于525~545 nm发射峰和只有55 nm狭窄的峰宽。 此文回顾和综述了β-sialon:Eu²⁺的合成方法、光谱特性、电子结构、晶体结构、可靠性和它的具体应用。 计算模拟和实验测试结果表明,Eu²⁺位于沿c轴方向的大孔道之中,并与6个最紧邻的(O,N)原子等距离配位。 因而,Eu²⁺的狭窄发射峰源自于Eu²⁺局域结构的高度对称性。 β-sialon:Eu²⁺的发射波长和带宽都能通过组成裁剪,即z值,进行调控;低z值组成能够实现更短波长发射和更窄带宽。 与传统的基于钇铝石榴石(YAG)荧光粉的背光源相比,β-sialon:Eu²⁺再搭配红色荧光粉制备的背光源具有更宽的色域,色域范围可提高15%以上。 其优异的发光性能和高可靠性使得β-sialon:Eu²⁺成为应用于先进显示屏的极其重要的绿色发光材料。