Eu~(2+)在碱土金属氯磷酸盐中的发光

考察了Eu~(2+)在Ca~(2+)、Sr~(2+)、Ba~(2+)三种碱土金属氯磷酸盐中的发光性质。用晶胞参数法测得了Sr_(5-x)Ca_x(PO_4)_3Cl和Sr_(3-3x)/5Ca_2-2x/5Ba_x(PO_4)_3Cl两个体系固相线下的关系。通过实验证实了Eu~(2+)在氯磷酸盐基质中存在两个发光中心。同时研究了固溶体Sr_(4.5)Ca_(0.5)(PO_4)_3Cl:Eu~(2+)中Eu~(2+)的d→f能级跃迁强度随Eu~(2+)浓度的变化关系,以及Eu~(2+)的浓度猝灭机理。     

卤磷酸锶基质中Ce^3＋的发光性质

通过对发射光谱、激发光谱和漫反射光谱的研究,发现Ce~(3+)在Sr_5(PO_4)_3Cl基质中,形成两个发光中心。研究了Sr_5(PO_4)_3X(X=F,Cl、Br)基质中,Ce~(3+)的发光性质,测定了Sr_5(PO_4)_3Br的晶体结构,确定了二元卤磷酸锶体系固相线下的相关系,并研究了卤离子组成改变对Ce~(3+)发光性质的影响。     

通过能量传递实现Ba5-2x-yTbxNax(PO4)3Cl∶yEu2+荧光粉的光谱调控

通过[Na~+,Tb~(3+)]离子对取代[Ba~(2+),Ba~(2+)]离子对,制备了一系列的Ba_(5-2x-y)Tb_(x )Na_x(PO_4)_3Cl∶y Eu~(2+)荧光粉。通过X射线粉末衍射、扫描电子显微镜、光致激发和发射光谱对其结构、形貌、组成及发光性能进行研究。结果表明:在354 nm激发下,Ba_(3.97)Tb_(0.50)Na_(0.50)(PO_4)_3Cl∶0.03Eu~(2+)样品的发射光谱既包含了Eu~(2+)位于450 nm左右的宽带特征发射,又包含了Tb~(3+)位于490、545、583和622 nm的窄峰特征发射。由于存在Eu~(2+)→Tb~(3+)的能量传递,使得Ba_(3.97)Tb_(0.50)Na_(0.50)(PO_4)_3Cl∶0.03Eu~(2+)中Tb~(3+)的发光强度相对于Ba_(4.00)Tb_(0.50)Na_(0.50)(PO_4)_3Cl中Tb~(3+)的发光强度显著提高。通过改变[Na~+,Tb~(3+)]离子对的浓度,实现了对Ba_(5-2x-y)Tb_(x )Na_x(PO_4)_3Cl∶y Eu~(2+)荧光粉的光谱调控。当x=0.50时,Ba_(4.97-2x)Tb_(x )Na_x(PO_4)_3Cl∶0.03Eu~(2+)中Tb~(3+)的发光强度达到最大。     

Sr_3Ca_2(PO_4)_3X:Eu~(2+)(X=F,Cl,Br)的光激励发光与F色心

研究了Eu~(2+)激活的Sr_3Ca_2(PO_4)_3X晶体中的F色心及光激励发光。讨论了不同卤离子对F色心及其能级结构的影响。探讨了在X光辐照下和光激励发光过程中Eu~(2+)的价态变化及光激励发光过程的机理。     

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。     

Ca_2Y_8(SiO_4)_6O_2:Eu~(3+)荧光粉的制备、结构与荧光性质研究

采用高温固相法合成了具有高热稳定性的Ca_2Y_8(SiO_4)_6O_2:Eu~(3+)红色荧光粉。通过X射线衍射和扫描电子显微镜对样品的结构和形貌进行了系统地表征,结果表明成功地合成了Ca_2Y_8(SiO_4)_6O_2:Eu~(3+)荧光粉。在394 nm激发下,样品发出很强的红光,该发射来自于Eu~(3+)的5D~0→~7F_J(J=1, 2, 3, 4)。通过变温光谱分析了样品在303～563 K温度范围的热稳定性。随着温度的升高, Ca_2Y_8(SiO_4)_6O_2:0.3Eu~(3+)样品的发光先增强后减弱,在483 K时的发光最强为室温时的1.5倍。将Ca_2Y_8(SiO_4)_6O_2:0.3Eu~(3+)样品与蓝色荧光粉BaMgAl_(10)O_(17):Eu~(2+)和绿色荧光粉BaSiO_4:Eu~(2+)以及近紫外LED芯片(395 nm)进行封装,在不同电流激发下(20～140 mA),均获得了显色指数高于92,色温低于4000 K的暖白光。以上结果表明Ca_2Y_8(SiO_4)_6O_2:Eu~(3+)在白光LED领域具有非常好的潜在应用。     

Ca3La3(BO3)5中Eu3+的光致发光

本文详细地研究了紫外光激发下,Ca_3La_3(BO_3)_5中Eu~(3+)的发光光谱和激发光谱与组成、结构的关系.发现Eu~(3+)在此基质中可能不止一个发光中心;Eu~(3+)自身浓度猝灭的机理为电四极-四极相互作用.     

(Li,Ca,A)_2SiO_4:Eu,Bi发光体的合成和发光性能的研究(A=Al,Y,La,Gd)

为了寻找新的发光基质材料,用高温固相反应合成了(Li,Ca,A)_2SiO_4:Eu,Bi系列发光体(A=Al,Y,La,Gd).通过激发光谱和发射光谱的测试.首次在碱土金属硅酸盐体系中研究了Al,Y,La,Gd等三价金属离子对Bi~(3+)、Eu~(3+)发光特性和Bi~(3+)敏化Eu~(3+)发光性能的影响,得到了良好的基质组成.实验结果表明.基质中适当含量的Gd~(3+)可大幅度提高Eu~(3+)的发光强度,使~5D_0-~7F_2发射强度增加6倍.Bi~(3+)对Eu~(3+)有很好的敏化作用,以A=Gd或Al时较好,对~5D_0-~7F_1辐射跃迁的敏化效果尤为突出.     

La_7O_6(BO_3)(PO_4)_2∶Eu~(3+)/Tb~(3+)荧光材料的制备及其光致发光性能

采用优化的高温固相方法制备了稀土离子Eu~(3+)和Tb~(3+)掺杂的La_7O_6(BO_3)(PO_4)_2系荧光材料,并对其物相行为、晶体结构、光致发光性能和热稳定性进行了详细研究。结果表明,La_7O_6(BO_3)(PO_4)_2∶Eu~(3+)材料在紫外光激发下能够发射出红光,发射光谱中最强发射峰位于616 nm处,为5D0→7F2特征能级跃迁,Eu~(3+)的最优掺杂浓度为0.08,对应的CIE坐标为(0.610 2,0.382 3);La_7O_6(BO_3)(PO_4)_2∶Tb~(3+)材料在紫外光激发下能够发射出绿光,发射光谱中最强发射峰位于544 nm处,对应Tb~(3+)的5D4→7F5能级跃迁,Tb~(3+)离子的最优掺杂浓度为0.15,对应的CIE坐标为(0.317 7,0.535 2)。此外,对2种材料的变温光谱分析发现Eu~(3+)和Tb~(3+)掺杂的La_7O_6(BO_3)(PO_4)_2荧光材料均具有良好的热稳定性。     

碱土金属锡酸盐掺铕体系荧光粉合成和荧光性质研究

本文报道了MSnO_3∶Eu~(3+)和M_2SnO_4∶Eu~(3+)(M=Ca,Sr,Ba)体系荧光粉的合成和荧光性质。产品经X射线确证CaSnO_3∶Eu~(3+)和Ca_2SnO_4∶Eu~(3+)为正交晶系,SrSnO_3∶Eu~(3+)和BaSnO_2∶Eu~(3+)为立方晶系,而Sr_2SnO_4∶Eu~(3+)和Ba_2SnO_4∶Eu~(3+)为四方晶系。激发光谱表明,随Ba—Sr—Ca离子半径减小,Eu~(3+)的电荷迁移能量紫移,而Eu~(3+)的f-f跃迁红移。发射光谱表明,CaSnO_3∶Eu~(3+)和Ca_2SnO_4∶Eu~(3+)以电偶极跃迁为主,而其它4种化合物不存在电偶极跃迁。     

Luminescence and microstructures of Eu(3+)-doped Ca9LiGd(2/3)(PO4)7

A red-emitting phosphor, Eu(3+)-doped Ca(9)LiGd(2/3)(PO(4))(7), was synthesized by the conventional high-temperature solid-state reaction. X-ray powder diffraction (XRD) analyses confirmed the pure crystalline phase of Whitlockite-type structure. The excitation spectra of Eu(3+) doped Ca(9)LiGd(2/3)(PO(4))(7) were measured in the VUV and UV region indicating an efficient energy transfer process from the host and Gd(3+) to Eu(3+) ions. Upon excitation with VUV and UV radiation, the phosphor showed strong red emission around 611 nm corresponding to the forced electric dipole (5)D(0)→(7)F(2) transition of Eu(3+) ions. The VUV- and UV-excited luminescence spectra of Ca(9)LiGd(2/3)(PO(4))(7):Eu(3+) together with the dependence of the integrated emission intensities on the doping levels were investigated. The Eu(3+) ions were investigated by a tunable laser as an excitation source. The excitation spectra of (7)F(0)→(5)D(0) transitions suggest that there are two families of inequivalent sites for Eu(3+) in this host. The concentration quenching and crystallographic site-occupancy of Eu(3+) ions in Ca(9)LiGd(2/3)(PO(4))(7) host were discussed on the basis of the site selective excitation and emission spectra, the luminescence decay and its crystal structure.     

Ce3+,Tb3+,Eu3+共掺杂Sr2MgSi2O7体系的白色发光和能量传递机理

通过正交试验,采用高温固相法制备了Sr2-x-y-zMgSi2O7∶xCe3+,yTb3+,zEu3+系列样品.使用X射线衍射仪和荧光光谱仪表征了样品的物相和发光性质,并讨论了Ce3+-Tb3+-Eu3+共掺杂Sr2MgSi2O7体系中的能量传递过程.实验结果表明,在327 nm波长激发下,所合成荧光粉的发射峰主要位于387 nm(蓝紫)、542nm(绿)和611 nm(红)处;分别以387,542和611 nm为监控波长,所得激发光谱显示荧光粉在327 nm处有最好的激发.在327 nm光激发下,系列样品发光进入白光区.最优化的荧光粉为Sr1.91MgSi2O7∶0.01Ce3+,0.05Tb3+,0.03Eu3+,其色坐标为(0.337,0.313),是一种潜在的发光二极管(LED)用白色荧光粉.     

掺杂铕和铽的卤硼酸盐荧光体的制备及光谱特征

采用高温固相法在空气中合成了一系列掺杂稀土离子的卤硼酸盐荧光体, 研究了其发光性质和基质组成对稀土离子共掺杂的荧光体发光性质的影响. 研究结果表明, 在Eu3+和Tb3+共掺杂的体系中存在电子转移, 因此出现了Eu3+, Eu2+和 Tb3+共存于同一基质共同发射的现象. Ce3+对Eu2+和Tb3+具有敏化作用, 可增强其发射强度. 基质的组成对稀土离子的发射峰位和发射强度有明显影响.     

Photoluminescence characterization of Ca10Na(PO4)7:Eu3+ red-emitting phosphor

Eu3+-doped Ca10Na(PO4)7 phosphors were successfully synthesized by solid-state reaction techniques. Their structures and photoluminescence characteristics were carefully studied. An efficient red emission under near-ultraviolet excitation is observed. The maximum intensity of luminescence was observed at the Eu3+ concentration around 9 mol%. The quadrupole-quadrupole interaction between Eu3+ ions is the dominant mechanism for concentration quenching of fluorescence emission from Eu3+ ions in Ca10-xNa(PO4)7:xEu3+. Due to the excitation spectrum is well coupled with near UV light, Ca10-xNa(PO4)7:xEu3+ phosphors have potential application as red phosphors in near UV chip-based white light emitting diodes.     

M5(PO4)3F (M=Ca, Sr, Ba)中Sm3+的电荷迁移态及Sm3+和Eu3+的电荷迁移能量关系

采用高温固相反应合成了M_5-2xSm_xNa_x(PO₄)₃F(M=Ca,Sr,Ba)荧光体,研究了其在真空紫外-可见光范围的发光特性。发现在Ca₅(PO₄)₃F中Sm³⁺的电荷迁移带约在191 nm,在Sr₅(PO₄)₃F中约在199 nm,而在Ba₅(PO₄)₃F中约在204 nm,随着被取代碱土离子半径的增大电荷迁移能量逐渐减小。比较了M₅(PO₄)₃F (M=Ca,Sr,Ba)中Sm³⁺和Eu³⁺电荷迁移能量的关系。     

Spectroscopic properties and intense red-light emission of (Ca, Eu, M)WO4 (M=Mg, Zn, Li)

The red-emitting phosphors of (Ca, Eu, M)WO4 (M=Mg, Zn, Li) were prepared through solid-state reactions, and their spectroscopic properties were studied. After the addition of a small amount of Mg2+, Zn2+ or Li+ in (Ca, Eu)WO4, the red-light emission intensity of Eu3+ increases obviously. In the luminescence spectra of the phosphors, the predominant transition emission is 5D0-->7F2 (616nm), whereas the other emissions are very weak. The excitation spectra are composed of interweaved ligand-to-metal charge-transfer bands (CTB) of W6+-O(2-) and Eu3+-O(2-), and a few 4f excitation transitions of Eu3+. Among the 4f excitation transitions of Eu3+, there are three strong excitation lines corresponding to 7F0-->5L6, 7F0-->5D2 and 7F0-->5D1 transitions, whose relative excitation intensity ratio is seriously affected when Li+ doped in the host. The new phosphors may be applied as red-emitting phosphors for white light emitting diodes.     

在空气中合成MBPO5:Eu2+和MBPO5:Yb2+(M=Ca,Sr,Ba)荧光体

以含RE₂O₃(RE=Eu, Yb)为起始物, 在空气中成功地合成了MBPO5:RE(²⁺)(M=Ca, Sr, Ba;RE(²⁺)=Eu(²⁺), Yb(²⁺))荧光体, 测定了它们的激发和发射光谱峰位以及发射半高宽.     

Eu2+在碱土金属氟卤化物MFX(M=Ca、Sr或Ba,X=Cl、Br或I)中的发光

我们合成了六种Eu²⁺激活的碱土金属氟卤化物MFX:Eu²⁺(M=Ca、Sr或Ba;X=Cl、Br或I)。研究了它们的荧光发射光谱和激发光谱,讨论了Eu²⁺离子的跃迁发射随基质晶体组成和结构变化的规律。根据晶体场理论,按照C_4v点对称性,计算得到在MFCl:Eu²⁺(M=Ca、Sr或Ba)晶体中Eu²⁺离子的4?⁶5d¹激发态能级分裂的数值。     

YTao4：Nb，Eu的发光性能研究

用高温固相反应法合成了铌酸根NbO^3-4和Eu^3 共掺杂的正钽酸盐化合物Y1－xEuxTa1-yNbyO4,研究该体系中紫外光和X射线激发下的发光性能,研究表明,在紫外光激发下,YTaO4:Nb,Eu是一种比较有效的红色发光材料,激发能可以通过NbO^3 4离子传递给Eu^3 ,随钽酸盐中NbO^3-4基团浓度的增中,化合物的结构从M'型YTaO4变成褐钇铌型YNbO4结构,它的发光性质也随之改变。