稀土长余辉发光材料的研究进展

长余辉发光材料是属于光致发光材料的一种,是指经日光和长波紫外线等光源的短时间照射,关闭光源后,仍能在很长一段时间内持续发光的材料。由于稀土长余辉发光材料的储光-发光的特性,它们可作为发光涂料、发光薄膜、发光油墨、发光纤维、发光纸等,在建筑装潢、军事设施、交通运输、消防应急等领域得到了广泛应用。     

稀土长余辉发光材料

20世纪90年代以来，为了发展更优良的长余辉发光材料，人们尝试使用稀土，成功开发了二价铕和其他稀土离子掺杂的绿色、蓝绿色及蓝色长余辉发光材料。目前商用的蓝色长余辉发光材料是铕、     

稀土长余辉发光材料的开发应用与改性处理

介绍了以铝酸盐为基质以铝酸盐为基质稀土为激活剂或主激活剂的新型光致长余辉的特点、开发现状、应用领域及蓄光机理。重点综述了将蓄光体制成性能优良的发光树脂、发光陶瓷、着色蓄光性复合体及用作灯粉时的改性处理工艺、产品特点和用途。     

稀土长余辉发光材料的研究现状和发展趋势

回顾了不同稀土长余辉发光材料的研究进展;讨论了稀土长余辉发光材料的发光机理;对稀土长余辉发光材料存在的问题和进一步的发展进行了探讨。     

稀土离子掺杂对长余辉发光玻璃发光性能的影响

选择制备了系列Eu^2＋，Dy^3＋共掺杂的硼铝酸锶长余辉发光玻璃。利用发光光谱、余辉衰减曲线、热释光谱系统研究了稀土离子掺杂对长余辉玻璃发光性能的影响。研究结果表明，不同掺量组合的Eu^2＋及Dy^3＋对长余辉玻璃发光性能有不同影响，在Eu^2＋及Dy^3＋掺量比为l：l（摩尔比）的情形下，随Eu^2＋离子掺量的增多，发光性能下降；在Eu^2＋及Dy^3＋掺量比为1：2的情形下，随Eu^2＋离子掺量的增多，发光性能增强。在此实验基础上，围绕缺陷形态及其与稀土离子间的能量传递，提出了可能的长余辉机制。     

铝硅酸盐掺杂稀土蓝色长余辉发光材料的研究

研究了掺Si的Sr4Al14O25:Eu,Dy体系晶体结构,光谱特性以及热释发光曲线.结果表明,Sr3.92Al13.95Si0.05O25∶Eu0.042+,Dy0.043+能级陷阱为-0.667eV,掺硅后有利于提高该长余辉材料的初始发光亮度.其次,通过调整Eu2+浓度,实现荧光粉的y色坐标从0.211到0.295变化可调.     

红色长余辉发光材料Sr_5Al_2O_7S∶Eu~(2+)的制备及发光性能

以工业铝酸钠溶液制备的氢氧化铝为原料,采用高温固相反应法合成了Sr5Al2O7S∶Eu2+红色长余辉材料。用X射线衍射仪及荧光分光光度计对材料的物相及光谱性能进行了分析,考察稀土掺杂量对样品发光性能的影响。结果表明,在稀土激活剂的掺杂量x(Eu)=6%、硼酸加入量9%、1 200℃烧结8h的条件下合成的样品为Sr5Al2O7S∶Eu2+的纯相,激发光谱位于400～500nm,主发射波长在600nm左右,余辉为桔红色。     

稀土长余辉发光材料在消防标志中的应用进展

从蓄光型光致发光型标志牌的特点、组成、制作方法、目前的应用状况等角度综述了稀土长余辉发光材料在消防标志中的应用进展,分析了该领域目前发展的不足之处,为该领域今后工作的发展重点提出了建议.     

燃烧法合成稀土纳米长余辉发光材料SrO·xAl2O3:Eu2+,Dy3+

应用燃烧法在空气中较低的温度(<900℃)下成功地合成了SrO·xAl2O3∶Eu2+,Dy3+稀土纳米长余辉发光材料,并研究了炉温、反应物中铝锶比、助溶剂和可燃物等对发光材料性能的影响。研究结果表明,反应物置于温度为600℃的高温炉中时燃烧得到的产物性能最好,发光粉的粒径在70nm左右,发射光谱的最大波长在520nm左右。与其它合成方法相比,该方法具有合成温度低、反应时间短,获得的产物疏松、硬度小、粒度小等优点。     

Properties of red-emitting phosphors Sr2MgSi2O7:Eu3+ prepared by gel-combustion method assisted by microwave

Novel red-emitting phosphors Sr2MgSi2O7:Eu3+ were prepared by gel-combustion method assisted by microwave. The phase struc-ture and luminescent properties of as-synthesized phosphors were investigated by XRD and fluorescence spectrophotometer, respectively. The results showed that the as-synthesized sample was Sr2MgSi2O7 with tetragonal crystal structure. The excitation spectrum of Sr2MgSi2O7:Eu3+ was composed of two major parts: one was the broad band between 200 and 350 nm, which belonged to the charge transfer of Eu3+-O2-; the other consisted of a series of sharp lines between 350 and 450 nm, ascribed to the f-f transition of Eu3+. The emission spec-trum consisted of two emission peaks at 593 and 616 nm, which was attributed to 5D0→7F1 and 5D0→7F2 of Eu3+, respectively. The concen-tration of Eu3+ (x) had great effect on the emission intensity of Sr2-xMgSi2O7:Eu3+x. When x varied in the range of 0.04-0.18, the intensity of emission peaks at 593 and 616 nm increased gradually with the concentration of Eu3+ increasing. It was interesting that no concentration quenching occurred. Moreover, the luminescent intensity could be greatly enhanced with incorporation of charge compensator Li+ ions.     

Structure and luminescent properties of luminous polypropylene fiber based on Sr2MgSi2OT：EU^2＋,Dy^3＋

The luminous polypropylene fiber based on long afterglow luminescent material Sr2MgSi2O7：Eu^2＋,Dy^3＋was prepared by melt-spinning process. Micro-morphology, phase composition, crystal structure, spectral features and afterglow properties of the lu-minescent fiber were tested and analyzed. The results indicated that the fiber had independent superposition phase features of both Sr2MgSi2O7：Eu2＋,Dy3＋and polypropylene. The range of its excitation wavelength was located between 250-450 nm;therefore, the luminescent fiber could be excited by ultraviolet or visible light. It could emit blue light of 460 nm wavelength after excitation, which was caused by the 5d-4f transition of Eu^2＋ions within the host lattice. The initial luminescent intensity was more than 0.8 cd/m^2, and afterglow life lasted 7 h. The afterglow decay was composed of rapid-decaying and slow-decaying processes, and the decay charac-teristics depended on the depth and concentration of trap level in the Sr2MgSi2O7：Eu^2＋,Dy^3＋.     

Luminescence Properties of Sm^3＋ doped Bi2ZnB2O7

The phosphors of （Bi1- x Smx ） 2ZnB2O7 （ x = 0. 01, 0. 03, 0. 05, 0. 07, and 0. 09） were synthesized by conventional solid state reaction. The purity of all samples was checked by X-ray powder diffraction （XRD）. XRD analysis shows that all these compounds are of a single phase of Bi2ZnB2O7, indicating that the Bi^3＋ in Bi2ZnB2O7 can be partly replaced by the Sm^3＋ without the change of crystal structure. The excitation and emission spectra at room temperature show the typical 4f-4f transitions of Sm^3＋ . The dominant excitation line is around 404 nm due to ^6H5/2→^4K11/2 and the emission spectrum consists of a series of lines at 563, 599, 646, and 704 nm due to ^4G5/2→^6H5/2, ^6H7/2, ^6H9/2, and ^6H11/2, respectively. The optimal concentration of Sm^3＋ in Bi2ZnB2O7 is about 3mol% （relative to lmol Bi^3＋ ） and the critical distance Rc was calculated as 2.1 nm. The temperature dependence of the emission intensity of Bi1.94Sm0.06ZnB2O7 was examined in the temperature range between 100 and 450 K. The quenching temperature where the intensity has dropped to half of the initial intensity is 280 K. The lifetime for Sm^3＋ in Bi1.94Sm0.06ZnB2O7 is fitted as a value of 0.29 and 1.03 ms.     

Synchrotron radiation investigations of the Sr2MgSi2OT：Eu^2＋,R^3＋ persistent luminescence materials

The electronic and defect energy level structure of polycrystalline Sr₂MgSi₂O₇:Eu²⁺,R³⁺ persistent luminescence materials were studied with thermoluminescence and different synchrotron radiation spectroscopies (UV-VUV emission and excitation, X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS)). Special attention was paid on the effect of the R³⁺ co-dopants on the persistent luminescence properties of the materials. Theoretical calculations using the density functional theory (DFT) were carried out simultaneously with the experimental work. The experimental band gap energy (E_g) value of ca. 7.1 eV agreed very well with the DFT value of 6.7 eV. The variation of the E_g value was attempted to relate with the trap structure as well as with the different properties of the R³⁺ co-dopants. The trap level energy distribution depended strongly on the R³⁺ co-dopant except for the shallowest trap energy above the room temperature remaining practically the same, however. The different processes in the mechanism of persistent luminescence from Sr₂MgSi₂O₇:Eu²⁺,R³⁺ were assembled and their contributions discussed.     

稀土氧化物复合ZrO2陶瓷的制备及应用研究进展

稀土氧化物可作为稳定剂、烧结助剂、掺杂改性剂加入到ZrO₂陶瓷材料中,能极大地提高和改善陶瓷材料的强度、韧性,降低其烧结温度,减少生产成本.文中简要综述了稀土氧化物ZrO₂陶瓷材料的制备及应用研究状况,包括Y₂O₃复合ZrO₂陶瓷粉体、富铈稀土氧化物复合ZrO₂陶瓷粉末、Nd₂O₃复合ZrO₂陶瓷材料、Pr₂O₃\Pr₆O₁₁复合ZrO₂陶瓷、La₂O₃复合ZrO₂陶瓷、Yb₂O₃复合ZrO₂陶瓷、Sm₂O₃复合ZrO₂陶瓷材料及氧化锆中掺杂多种稀土氧化物陶瓷粉体的制备和应用,分析讨论了一些需要解决的问题,并展望了稀土复合ZrO₂陶瓷制备技术及未来研究发展趋势.      

Growth and interface of amorphous La2Hf2O7/Si thin film

Amorphous La2Hf2O7 thin films were deposited on Si(100) substrate by pulsed laser deposition (PLD) method under different con-ditions. The interfacial states of the La2Hf2O7/Si films were studied by synchrotron X-ray reflectivity (XRR) and X-ray photoelectron spec-troscopy (XPS). When grown under vacuum condition, silicate, silicide and few SiOx were formed in the interface layer. However, the Hf-silicide formation could be effectively eliminated by the ambient oxygen pressure during film growth. The result revealed that the La2Hf2O7/Si interlayer was intimately related with growth condition. Insufficient supply of oxygen would cause Hf-silicide formation at the interface and it could be most effectively controlled by the ambient oxygen pressure during film growth.     

X射线荧光光谱分析稀土的研究进展（综述）

本文对近二十年来X射线荧光光谱仪在稀土分析方面的应用进行了综述。总结了环境、矿物、稀土富集物、单一稀土化合物、稀土金属、合金、稀土功能材料以及过程分析中稀土元素的X射线荧光光谱分析方法,检测方法涉及钢铁、有色金属、石油化工、地质、生物、电子材料等领域。展望了X射线荧光分析方法在稀土行业的应用前景。     

Effect of mixing process on the luminescent properties of SrAl_2O_4:Eu~(2+),Dy~(3+) long afterglow phosphors

A new mixing method was developed for solid-state reaction synthesis of SrAl2O4:Eu2+,Dy3+ long afterglow phosphors.The morphology and crystal structure of the phosphors were analyzed with scanning electron microscope(SEM) and X-ray diffractometer(XRD).The excitation and emission spectra of the long afterglow phosphors were measured,and the main emission band was around 514 nm.The decay time of the product was measured and compared with the phosphors prepared using dry-mixing method and wet-mixing method.It ...     

Sol-gel processed Ce^3＋, Tb^3＋ codoped white emitting phosphors in Sr2Al2SiO7

Sr2Al2SiO7：Ce^3＋, Tb^3＋ white emitting phosphors were fabricated using the sol-gel method. X-Ray Powder Diffraction （XRD） analysis confirmed the formation of Sr2Al2SiO7：Ce^3＋, Tb^3＋. Scanning Electron Microscopy （SEM） observation indicated that the microstructure of the phosphor consisted of regular fine grains with an average size of about 0.5-1 μm. Luminescence properties were analyzed by measuring the photoluminescence spectra. The Ce^3＋, Tb^3＋-codoped Sr2Al2SiO7 phosphors showed four main emission peaks： one at 414 nm for Ce^3＋ and three at 482, 543, and 588 nm for Tb^3＋. The emission spectra of the samples with different doping concentrations showed that the Tb^3＋ emission was dominant because of the persistent energy transfer from Ce^3＋. The decay characteristic was better than that prepared by the solid-state process in the comparable condition. The codoped phosphor displayed long persistent white phosphorescence.     

Structure and luminescent properties of luminous polypropylene fiber based on Sr_2MgSi_2O_7:Eu~(2+),Dy~(3+)

The luminous polypropylene fiber based on long afterglow luminescent material Sr2MgSi2O7:Eu2+,Dy3+ was prepared by melt-spinning process. Micro-morphology, phase composition, crystal structure, spectral features and afterglow properties of the luminescent fiber were tested and analyzed. The results indicated that the fiber had independent superposition phase features of both Sr2MgSi2O7:Eu2+,Dy3+ and polypropylene. The range of its excitation wavelength was located between 250–450 nm; therefore, the luminescent fiber could be excited by ultraviolet or visible light. It could emit blue light of 460 nm wavelength after excitation, which was caused by the 5d-4f transition of Eu2+ ions within the host lattice. The initial luminescent intensity was more than 0.8 cd/m2, and afterglow life lasted 7 h. The afterglow decay was composed of rapid-decaying and slow-decaying processes, and the decay characteristics depended on the depth and concentration of trap level in the Sr2MgSi2O7:Eu2+,Dy3+.