Y2O3:Eu3+ core-in-multi-hollow microspheres: facile synthesis and luminescence properties

Y2O3:Eu3+ core-in-multi-hollow microspheres were synthesized via a facile hydrothermal method in the presence of glucose followed by a subsequent heat-treatment process. X-ray diffraction (XRD) pattern shows that the as-obtained hollow spheres are cubic phase of Y2O3. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images indicate that the samples are three layer hollow spheres with a diameter of 2-4 microm and the outermost wall thickness of 100 nm, the size of the inner core is about 300-400 nm, and the sub-outer wall thickness is about 100 nm. X-ray energy dispersive spectrum (EDS) shows that the samples are composed of Y, Eu and O. Photoluminescence spectra show that the hollow spheres have a strong characteristic red emission corresponding to the 5D0 - 7F2 transition of Eu3+ ions under ultraviolet excitation. This method can be used to synthesize other rare earth oxide hollow luminescent materials.     

Fabrication of novel luminor Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+) with core/shell heteronanostructure

A novel polychromic phosphor with core-shell heteronanostructure has been prepared to improve the chromatic index of phosphors. As for the first example, Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+), its synthetic route, structure and optical properties are presented in this paper. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), energy-dispersive x-ray spectra (EDS) and photoluminescence (PL) were all employed to characterize the composite core-shell phosphors. The XRD, FE-SEM and HR-TEM results indicate that the SiO(2) and YVO(4):Eu(3+) layers have been successfully coated on Y(2)O(3):Eu(3+) nanoparticles and SiO(2) layer, respectively: these layers were further verified by the EDS. The PL showed that the red-emitting phosphor Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+) possessed the independent luminescent properties of both the core Y(2)O(3):Eu(3+) and the shell YVO(4):Eu(3+). The emissions were dominated by [Formula: see text] or [Formula: see text] transitions of Eu(3+) when excited with different wavelengths. Since this broad-band response to excitation in the range of 225-340?nm gave more red/dark red emissions found at 612, 616 and 620?nm, the novel phosphor Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+) could have potential biological labeling applications with wide flexibility.     

Fabrication of nano-sized emitting phosphors for photoluminescence films via hydro-thermal synthesis

Nano-sized red and blue emitting phosphors for a photoluminescence film were fabricated via hydrothermal synthesis through the sol-gel process. The nano-sized phosphors had a spherical shape such as the 60-110 nm Y2O2S:Eu3+ phosphor and the 45-90 nm of Y2SiO5:Ce phosphor. Firing at 1000 degrees C for 2 hours resulted in an increase in their size to 90-190 nm for the Y2O2S:Eu3+ phosphor and 70-160 nm for the Y2SiO5:Ce phosphor. Heat treatment of the gel powders of the emitting phosphors above 730 degrees C was recommended because of their crystallization. The maximum excitation and emission intensities of the red and blue phosphors with Y2O2S:Eu3+ and Y2SiO5:Ce were at the wavelengths of 308 nm and 617 nm, and 254 nm and 464 nm, respectively. The photoluminescence of the films increased as increasing the content of the red and blue phosphor powder mixture in the plastic films. The 100 microm-thick PVB film with the nano-sized phosphors showed the maximum photoluminescence of 537 x 1000 counts/sec.     

Fabrication of SiO2@ZrO2@Y2O3:Eu3+ core-multi-shell structured phosphor

ZrO2 interface was designed to block the reaction between SiO2 and Y2O3 in SiO2@Y2O3:Eu coreshell structure phosphor. SiO2@ZrO2@Y2O3:Eu core-multi-shell phosphors were successfully synthesized by combing an LBL method with a Sol-gel process. Based on electron microscopy, X-ray diffraction, and spectroscopy experiments, compelling evidence for the formation of the Y2O3:Eu outer shell on ZrO2 were presented. The presence of ZrO2 layer on SiO2 core can block the reaction of SiO2 core and Y2O3 shell effectively. By this kind of structure, the reaction temperature of the SiO2 core and Y2O3 shell in the SiO2@Y2O3:Eu core-shell structure phosphor can be increased about 200-300 degrees C and the luminescent intensity of this structure phosphor can be improved obviously. Under the excitation of ultraviolet (254 nm), the Eu3+ ion mainly shows its characteristic red (611 nm, 5D0-7F2) emissions in the core-multi-shell particles from Y2O3:Eu3+ shells. The emission intensity of Eu3+ ions can be tuned by the annealing temperatures, the number of coating times, and the thickness of ZrO2 interface, respectively.     

Y2O2S:0.03Eu,0.03Ti的长余辉特性及Ti向Eu3+的余辉传能机制

采用高温还原法合成了Eu，Ti共激活橙红色Y2O2S长余辉发光材料，并测量了Y2O2S：0．03Eu,0．03Ti磷光体的荧光光谱，余辉分辨和余辉衰减曲线谱．实验结果表明，Y2O2S：0．03Eu,0．03Ti磷光体的发射谱由一系列Eu^3＋离子内部能级跃迁的尖峰组成；余辉分辨谱则不同，由一个主峰位于565nm的宽发射带和一系列波长范围位于500nm以上的窄发射带两种峰形组成，可分别归为Ti离子的宽带余辉发射和三价Eu^3＋的线状余辉发射,分析认为，样品中存在Ti余辉发射向Eu^3＋内部能级间产生选择性的余辉传能机制，从而导致Y2O2S：0．03Ti，0．03Eu磷光体中同时出现两种发光中心离子的余辉分辨谱现象．     

两步法制备单分散的Li掺杂Y2O3:Eu3+微球及其发光性能

Y2O3:Eu3+是最重要的红色荧光材料,通过两步法制备了具有单分散性的Li掺杂Y2O3:Eu3+微球并研究了其发光行为.首先采用共沉淀法制备出单分散Y2O3:Eu3+微球,而后在含有LiOH的乙醇悬浊液中利用超声-水热法获得Li掺杂Y2O3:Eu3+微球.通过SEM、XRD、PL光谱等分析,发现Li掺杂可明显降低Y2...     

Ce3+共掺杂对Y2O3:Eu3+荧光粉的发光性能和颗粒形貌的影响

采用化学反应与高温固相反应相结合的方法制备了Ce3和Eu3+共掺杂Y2O3荧光粉,利用X射线衍射和扫描电镜分析,发现Ce3+离子共掺杂对Y2O3:Eu3+荧光粉的颗粒形貌有显著的影响,随着Ce3+离子浓度的改变,形貌可从球型转变为管状.荧光光谱分析表明,所制备的共掺杂荧光粉主要发射位于614纳米的红光峰和位于587纳米...     

Synthesis and photoluminescence properties of (Y,Gd)BO3 : Eu phosphor prepared by ultrasonic spray

The mixed solution of acetate of Y, Gd, Eu and boric acid diluted in water was used as the precursor for the ultrasonic spray for the synthesis of (Y,Gd)BO₃ : Eu phosphor. It was found that (Y,Gd)BO₃ : Eu phosphor made by ultrasonic spray pyrolysis had a spherical shape and a narrow size distribution having a mean size of 1.3 m, while it had irregular, coarse and non-uniform size distribution for the phosphor formed by solid-state reaction. The as-sprayed particles was amorphous but they converted into the same polycrystalline phase of solid state reaction after post heat treatment at 1100 °C for 2 hr. The emitting intensity under 147 nm VUV excitations for the spray-formed (Y,Gd)BO₃ : Eu phosphor, however, was inferior to the later one. It was found that the optimum concentrations of Gd and Eu were 30% and 5%, respectively in (Y_1–x Gd _x )_1–y BO₃ : Eu _y phosphors prepared both by spray and solid state reaction.     

Selective and controlled synthesis of multiform morphologies Y2O3:Eu3+ and luminescence properties

Uniform Y2O3 nanorods, nanosheets, nanotubes and nanoshperes were controllably synthesized via an urea-based homogeneous precipitation and hydrothermal synthesis through choosing appropriate yttrium sources, the water/ethanol ratio of mixed solvents and precipitators. The nanopheres and nanotubes were obtained through homogeneous precipitation method using soluble yttrium nitrate as the yttrium source. The nanosheets and nanorods were obtained via a facile hydrothermal synthetic method using yttrium chloride and yttrium acetate as the yttrium source. During these experiments Urea and NaOH were used as precipitators and added in correct order. We also studied the spectroscopic properties of Y2O3:Eu3+ phosphor. The Eu3+ ion mainly shows its characteristic red (611 nm, 5D0 --> 7F2) emissions in all kinds of morphologies Y2O3:Eu3+ phosphor, but emission intensity are different. It can be explain from the viewpoint of their different absorption properties closely related to their micro-morphologies.     

Spherical SiO2 @ GdPO4: Eu3+ core-shell phosphors: sol-gel synthesis and characterization

Nanocrystalline GdPO4 : Eu3+ phosphor layers were coated on non-aggregated, monodisperse and spherical SiO2 particles by Pechini sol-gel method, resulting in the formation of core-shell structured SiO2 @ GdPO4 : Eu3+ particles. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL), low-voltage cathodoluminescence (CL), time-resolved PL spectra and lifetimes were used to characterize the core-shell structured materials. Both XRD and FT-IR results indicate that GdPO4 layers have been successfully coated on the SiO2 particles, which can be further verified by the images of FESEM and TEM. Under UV light excitation, the SiO2 @ GdPO4 : Eu3+ phosphors show orange-red luminescence with Eu3+ 5D0-7F1 (593 nm) as the most prominent group. The PL excitation and emission spectra suggest that an energy transfer occurs from Gd3+ to Eu3+ in SiO2 @ GdPO4 : Eu3+ phosphors. The obtained core-shell phosphors have potential applications in FED and PDP devices.     

Synthesis and photoluminescence of Y2O3:RE3+ (RE=Eu, Tb, Dy) porous nanotubes templated by carbon nanotubes

Y2O3:RE3+(RE=Eu, Tb, Dy) porous nanotubes were first synthesized using carbon nanotubes as template. The morphology of the coated precursors and porous Y2O3:Eu3+ nanotubes was determined by scanning electron Microscopy (SEM) and transmission electron microscopy (TEM). It was found that the coating of precursors on carbon nanotubes (CNTs) is continuous and the thickness is about 15 nm, after calcinated, the Y2O3:Eu3+ nanotubes are porous with the diameter size in the range of 50-80 nm and the length in micrometer scale. X-ray diffraction (XRD) patterns confirmed that the samples are cubic phase Y2O3 and the photoluminescence studies showed that the porous rare earth ions doped nanotubes possess characteristic emission of Eu3+, Tb3+, and Dy3+. This method may also provide a novel approach to produce other inorganic porous nanotubes used in catalyst and sensors.     

Y2O3：Eu超微粉末的合成及发光性质研究

本文用络合－沉淀法制备了Ｙ２Ｏ３：Ｅｕ超微粉末，平均粒径０．０４μｍ－０．１μｍ，ＸＲＤ分析为立方晶系，试验结果表明，Ｙ２Ｏ３：Ｅｕ的平均粒径和相对亮率随焙烧温度的增加而明显增加；超微状态下的Ｙ２Ｏ３：Ｅｕ相对亮度低；Ｙ２Ｏ３：Ｅｕ的平均粒径对相对亮度有很大的影响。     

纳米Y_2O_3:Eu~(3+)(Y_2O_3)粉体的红外光谱研究

采用均相沉淀法和燃烧合成法制备了不同粒径的粉体材料Y2O3:Eu3+,着重研究了样品的红外光谱,探讨了纳米晶Y2O3:Eu3+与同质微米材料相比的微观结构的变化.研究发现,波数位于563 cm-1的Y(Eu)—O键的吸收峰校正高度和面积对于纳米级粒径的粉体材料随着颗粒的减小而减小,而对于同质微米材料却相反.经分析认为:Y(Eu)—O键的吸收峰校正高度和面积由Y(Eu)—O键的平均键长和Y(Eu)—O键振动态数目这两个因素决定.对于微米粉体Y(Eu)—O键长的变化起主要作用,而对于纳米粉体由于不饱和键和悬空键的形成,Y(Eu)—O键振动态数目的变化起主要作用.     

柠檬酸溶胶-凝胶法制备纳米Y_2O_3:Eu~(3+)粉体

以Eu2O3,Y2O3为原料通过柠檬酸溶胶-凝胶法合成了Y2O3:Eu3+纳米粉,研究了pH值、柠檬酸用量(n[H3Cit]:n[Y3++Eu3+])及煅烧温度对粉体制备过程的影响。利用TG-DTA、XRD、SEM等测试手段对粉体的形成过程进行了分析。结果表明:Y2O3:Eu3+纳米粉体的一次粒径为25nm左右,二次粒径为250nm左右。纳米Y2O3:Eu3+粉体制备最佳实验条件为pH=5,n[H3Cit]:n[Y3++Eu3+]为2:1,煅烧温度为600℃。     

Controllable morphology and high photoluminescence of (Y, Gd)(V, P) O4:Eu3+ nanophosphors synthesized by two-step reactions

Multi-ion doped YVO(4):Eu(3+) nanophosphors with high photoluminescence intensity were successfully prepared by a two-step reaction process for the first time, including YVO(4):Eu(3+) seeds synthesized by hydrothermal reaction and co-doping P(5+) and Gd(3+) in a sol-gel process. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and photoluminescence spectroscopy were adopted to detect the structure, grain size, morphology and optical properties of the nanophosphors, respectively. Owning to the template-induced effect of the seeds, the morphology and size of the nanophosphors could be controlled by adjusting the molar ratios between the seeds and doping ions. The size of these nanophosphors increased as P(5+) and Gd(3+) co-doped. However, most of the samples kept approximately spherical morphology and narrow size distribution. The composition-optimized (Y, Gd)(V, P)O(4):Eu(3+) nanophosphors with spherical morphology in the 80-100 nm range exhibit better red emission and superior color saturation under vacuum ultraviolet excitation compared with that of the commercial phosphor (Y, Gd)BO(3):Eu(3+).     

Eu3+掺杂的硼酸锶系列荧光体的合成及其发光性能

采用溶胶-凝胶法和高温固相反应法合成了Eu^3 掺杂的SrB4O7、SrB2O4、Sr2B2O5、Sr3B2O6荧光体．荧光光谱测试结果表明在不同基质中Eu^3 的荧光发射是有区别的，Sr2B2O5：Eu^3 、Sr3B2O7：Eu^3 发射峰在610nm左右的红光区，SrB2O4：Eu^3 的发射峰在593nm的橙色区，而SrB4O7：Eu^3 则表现出了Eu^2 离子的特征峰，产生这种区别主要是由Eu^3 所处的配位环境不同造成的．荧光体SrB4O7：Eu^3 、SrB2O4：Eu^3 、Sr2B2O5：Eu^3 、Sr3B2O6：Eu^3 的最佳掺杂浓度为2％左右．     

Eu-doped CsBr phosphor as a new optically-stimulable phosphor material for medical X-ray imaging sensor

CsBr phosphor ceramics doped with different luminescence centres such as In2O3, Eu2O3, EuCl3, SmCl3, TbCl3, GdCl3 or NdCl3 as the candidate for a new optically-stimulable phosphor for medical X-ray imaging sensor were prepared using a conventional ceramic fabrication process. It was found that X-ray-irradiated Eu-doped CsBr (CsBr:Eu) exhibited intense optically stimulated luminescence (OSL). The peak wavelength of the OSL emission and stimulation spectra of CsBr:Eu phosphor ceramic sample were 450 and 690 nm, respectively. The dependence of OSL properties on the conditions of preparation of phosphor ceramic samples, such as Eu concentration, sintering temperature and sintering time, were studied. The optimum preparation conditions were also studied. It was found that the OSL intensity of CsBr:Eu phosphor ceramics fabricated under optimum preparation conditions is higher than that of commercially available imaging plates using BaFBr:Eu.     

BaAl_2O_4:Eu~(2+),Dy~(3+)长余辉发光材料的燃烧合成及其发光特性

以金属硝酸盐和尿素为原料,采用燃烧法合成了发青绿光的BaAl2O4:Eu2+,Dy3+长余辉发光材料。采用XRD、SEM、荧光分光光度计等手段对其进行分析表征。研究结果表明:随着燃烧温度升高,燃烧反应加剧,副产物BaCO3的含量减少,BaAl2O4的结晶程度增加,晶粒尺寸增大。Ba-Al2O4:Eu2+,Dy3+的激发光谱和发射光谱峰值分别为310nm和500nm,均呈宽谱带特征,其发光是由Eu2+的4f65d1→4f7跃迁引起,长余辉特性主要基于Dy3+的电子陷阱作用。     

纳米Y2O3:Eu3+粉体的表面包膜处理

本文采用高分子网络凝胶法制备了粒径约为２０ｍｍ的纳米Ｙ２Ｏ３：Ｅｕ＾３＋粉体,并采用ＫＡｌ（ＳＯ４）２及Ｎａ２ＳｉＯ３溶液进行表面包膜处理。     

The two-photon excitation of SiO(2)-coated Y(2)O(3):Eu(3+) nanoparticles by a near-infrared femtosecond laser

In order to improve the photoluminescence property of Eu(3+)-doped nanoparticles, Y(2)O(3):Eu(3+) nanoparticles were synthesized using the Pechini-type sol-gel method, then coated with SiO(2) shells by using the St?ber method for different coating times. The SiO(2)-coated nanoparticles were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy, and their photoluminescence spectra were recorded under 800?nm femtosecond laser excitation. The results indicate that a two-photon simultaneous absorption upconversion luminescence is obtained, and their upconversion luminescence intensities are further enhanced after the surfaces of the nanoparticles are coated with different thickness SiO(2) shells. Compared to the upconversion luminescence intensity of non-coated nanoparticles at 611?nm, the upconversion luminescence intensities of SiO(2)-coated Y(2)O(3):Eu(3+) nanoparticles with coating times of 60, 90 and 120?min were enhanced by 3.30, 3.96 and 4.13 times, respectively. This can be attributed to the contributions of the increased amounts of Eu(3+) ions populated at the (5)D(0) level on the surfaces of the nanoparticles because the cooperative ligand fields between the Y(2)O(3) core and non-crystalline SiO(2) shell interfaces activate the 'dormant' Eu(3+) ions near or on the surfaces of the nanoparticles. From a Judd-Ofelt (J-O) theory analysis, the coated shell structures can improve the radiative quantum efficiencies of Eu(3+)-doped nanoparticles. It is therefore concluded that more intense red upconversion luminescence with high radiative quantum efficiencies can enable the SiO(2)-coated Y(2)O(3):Eu(3+) nanoparticles to have the great potential to be used as a fine resolution phosphor.