β-SiAlON:Eu2+蓝色荧光粉的合成及光谱性能

以Si,SiO2,AlN和Eu2O3为原料,采用金属热还原法合成了β-SiAlON:Eu2+蓝色荧光粉。利用X射线衍射研究了不同煅烧温度对β-SiAlON:Eu2+组成的影响; 通过荧光分光光度计分析荧光光谱特性。实验结果表明,β-SiAlON:Eu2+发光材料的激发光谱为中心位于290 nm和325 nm的两条宽带,发射光谱位于~485 nm,半峰宽为75 nm,来自Eu2+的5d-4f跃迁,激活剂临界浓度为8%。机理分析表明,Eu2+- Eu2+之间出现能量传递,能量传递的临界距离为1.44 nm;Eu2+占据β-SiAlON晶体中[001]方向管状通道中的空位。     

退火温度对PLD法制备ZnO:Eu3+,Li+薄膜结构和发光性质的影响

采用脉冲激光沉积(PLD)法在Si(111)衬底上制备了Eu3+,Li+共掺杂的ZnO薄膜,分别在450,500,550和600℃条件下进行退火,退火气氛为真空。利用X射线衍射(XRD)仪和荧光分光光度计研究了退火温度对薄膜结构和光致发光(PL)的影响。研究结果表明,Eu3+,Li+共掺杂的ZnO薄膜具有c轴择优取向,Eu3+,Li+没有单独形成结晶的氧化物,均以离子形式掺入ZnO晶格中。PL谱中有较宽的ZnO基质缺陷发光,ZnO基质与稀土Eu3+之间存在能量传递,但没有有效的能量传递。随着退火温度的增加,薄膜发光先增强后减弱,退火温度为550℃时发光最强。当用395 nm的激发光激发样品时,仅观察到稀土Eu3+在594 nm附近的特征发光峰,但发光强度随退火温度变化不明显。     

Role of dopant concentration and surface coating on photophysical properties of CdS: Eu3+ nanocrystals

Here, we report the role of dopant concentration and surface coating of CdS: Eu3+ nanocrystals on the modification of crystal structure and their photoluminescence properties by steady-state and time resolved fluorescence studies. It is found that photoluminescence properties are sensitive to the crystal structure which is controlled by surface coating and dopant concentration. The emission intensity of the peak at 614 nm (5D0 --> 7F2) of the Eu3+-ions is found to be sensitive to the doping and surface coating of CdS nanocrystals. It is found that the average decay times tau are 248, 353 and 499 micros for 0.25, 0.5 and 1.0 mol% Eu ions doped into CdS nanocrystals, respectively. From the decay time measurements, it is evident that the energy transfer occurs from CdS nanoparticles to Eu3+ ions and the calculated energy transfer efficiency from CdS nanoparticles to Eu3+ ions is 9.2 and 35% for Eu3+ ions coated and doped CdS nanoparticles, respectively. Our analysis suggests that site symmetry of ions plays a very important role in the modifications of radiative and nonradiative relaxation mechanisms.     

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。     

Luminescence behavior of Eu3+ doped LaF3 nanoparticles

Europium-doped LaF3 nanoparticles have been prepared by the ionic reaction in the ethanol at 60 degrees C. From the XRD pattern of nanoparticles and the emission spectra of Eu3+ ions, it has been concluded that the Eu3+ ions could easily substitute the La3+ sites and the solid solution La(1-x)Eu(x)F3 can be synthesized. Due to very low phonon energies of LaF3 matrix, the 5D1 emission of Eu3+ ions in La(1-x)Eu(x)F3 nanoparticles can be observed at room temperature when doping concentration of Eu3+ ions is lower than 30 mol%. The quenching process of 5D1 emission can be attributed to cross-relaxation. Since clusters of Eu3+ ions and resonance energy transfer only occurs within one particle due to the hindrance by the particle boundary, the concentration quenching resulted from resonance energy transfer between neighboring Eu3+ ions occurs at higher Eu3+ concentrations in the Eu3+ doped LaF3 nanoparticles.     

Sr2SiO4:Eu3+发光材料的制备及其光谱特性

采用溶胶-凝胶法制备了Sr2SiO4:Eu3+发光材料. 测量了Sr2SiO4:Eu3+材料的激发与发射光谱, 发射光谱主峰位于618 nm处;监测618 nm发射峰时, 所得激发光谱主峰分别为320、397、464 和518 nm. 研究了Sr2SiO4:Eu3+材料在618 nm的主发射峰强度随Eu3+浓度的变化情况. 结果显示, 随Eu3+浓度的增大, 发射峰强度先增大; 当Eu3+浓度为7%时(x), 峰值强度最大; 而后随Eu3+浓度的增大, 峰值强度减小. 在Eu3+浓度为7%的情况下, 研究了电荷补偿剂Li+的掺杂浓度(x(Li+))对Sr2SiO4:Eu3+材料发射光谱强度的影响. 结果显示, 随x(Li+)的增大, 材料发射光谱强度先增大后减小, 当x(Li+)为8%时, 峰值强度最大.     

Preparation and photoluminescence properties of Y2SiO5:Eu3+ nanocrystals

The sol-emulsion-gel method is used for the preparation of about 5-7 nm size Eu2O3 doped and coated Y2SiO5 nanoparticles at 1300 degrees C. Here, we report the role of surface coating, dopant concentration and temperature of heating on the modification of crystal structure and the photoluminescence properties of Y2SiO5:Eu3+ nanocrystals. It is found that photoluminescence properties are sensitive to the crystal structure which is again controlled by surface coating, concentration and heating temperature. The decay times are 0.76, 1.14, 1.23 and 1.40 ms for 0.25, 0.5, 1.0 and 2.5 mol% Eu2O3 doped Y2SiO5 nanocrystals prepared at 1100 degrees C (X1-Y2SiO5). However, in X2-Y2SiO5 crystal phase (at 1300 degrees C) the average decay times are 1.05, 1.35, 1.55 and 1.60 ms for 0.25, 0.5, 1.0 and 2.5 mol% Eu2O3 doped Y2SiO5 nanocrystals, indicating the photoluminescence properties depend on both the crystal structure and the concentration of ions. The emission intensity of the peak at 612 nm (5D0-->7F2) of the Eu3+-ions is found to be sensitive to the doping and surface coating of Y2SiO5 nanocrystals. The decay times are 1.55 and 1.70 ms for 1300 degrees C heated 1.0 mol% Eu2O3 doped and coated Y2SiO5 nanocrystals, respectively. Our analysis suggests that the site symmetry of ions plays a most important role in the modification of radiative relaxation mechanisms and as a result on the overall photoluminescence properties.     

特殊形貌GdF3:Eu3+纳米发光材料的制备及性能

以PEG-2000、柠檬酸和甘氨酸为表面活性剂,采用水热法制备出扁平纳米棒、纳米花和纳米片状的GdF3:Eu3+发光材料,并对其结构和性能进行了表征.XRD结果表明,所得样品均为正交晶系.FESEM照片表明,使用不同表面活性剂所制备的产物形貌不同.研究了以PEG-2000为表面活性剂时反应物浓度对产物形貌的影响,并对其...     

溶胶-凝胶法制备掺Sm3+的SiO2玻璃的结构及发光性能

利用溶胶-凝胶技术制备了掺不同量Sm3+和不同退火温度下的SiO2凝胶和玻璃,通过三维荧光光谱、激发光谱、发射光谱的测试,确定了Sm3+在SiO2凝胶玻璃中的最佳激发波长为360 nm,最强发射波长为610 nm,激发光谱的峰位置在360、393、464 nm处,发射光谱的峰位置在578、591、595、610、732nm处,分别归属于4G5/2-6H5/2、4G5/2-6H7/2、4G5/2-6H11/2跃迁,并证明当掺杂量达到1.15%时,Sm3+的发光最强,当Sm3+的掺杂量超过1.15%时,发生浓度猝灭效应.     

Synthesis and photoluminescence properties of Ce3+ and Eu2+-activated Ca7Mg(SiO4)4 phosphors for solid state lighting

Ce(3+) and Eu(2+) singly doped and Ce(3+)/Eu(2+)-codoped Ca(7)Mg(SiO(4))(4) phosphors are synthesized by the conventional solid state reaction. The Ce(3+) activated sample exhibits intense blue emission under 350 nm excitation, the composition-optimized Ca(7)Mg(SiO(4))(4)?:?4%Ce(3+) shows better color purity than the commercial blue phosphor, BaMgAl(10)O(17)?:?Eu(2+) (BAM?:?Eu(2+)) and exhibits superior external quantum efficiency (65%). The Ca(7)Mg(SiO(4))(4)?:?Eu(2+) powder shows a broad emission band in the wavelength range of 400-600 nm with a maximum at about 500 nm. The strong excitation bands of the Ca(7)Mg(SiO(4))(4)?:?Eu(2+) in the wavelength range of 250-450 nm are favorable properties for applications as light-emitting-diode conversion phosphors. Furthermore, the energy transfer from the Ce(3+) to Eu(2+) ions is observed in the codoped samples, the resonance-type energy transfer is determined to be due to the dipole-dipole interaction mechanism and the critical distance is obtained through the spectral overlap approach and concentration quenching method.     

Eu^2＋和Mn^2＋在SrMgP2O7中的光致发光及其能量传递

研究了Ｅｕ＾２＋、Ｍｎ＾２＋共激活的ＳｒＭｇＰ２Ｏ７的发光性质、浓度与荧光性质的关系，Ｅｕ＾２＋和Ｍｎ＾２＋的发射光谱分别在４００ｎｍ及６７０ｎｍ附近，它们是Ｅｕ＾２＋的５ｄ－４ｆ跃迁和Ｍｎ＾２＋的＾４Ｔ１（＾４Ｇ）－＾６Ａ１ｇ（＾６Ｓ）跃迁发射，实验结果表明，Ｅｕ＾２＋对Ｍｎ＾２＋的荧光发射有较强的敏化作用，Ｍｎ＾２＋对Ｅｕ＾２＋的荧光寿命和强度也有显著影响。     

稀土掺杂氟化镁钾纳米晶的合成及其光谱特性

采用微乳液法合成了Eu²⁺,Ce³⁺单掺和双掺KMgF₃纳米晶,分析了样品的结构与形态. 结果表明,所合成的样品均为单相,颗粒粒度分布均匀. 讨论了光谱特性并与高温固相法合成的产物作了对比. 研究发现,在KMgF₃纳米晶双掺体系中,由于Eu²⁺和Ce³⁺竞争吸收激发能,只能观察到Ce³⁺的发射带; 而在KMgF3多晶共掺体系中,因为存在Ce³⁺→Eu²⁺能量传递过程,只能观察到Eu²⁺的发射峰.     

CaAl12O19基质中Eu2+-Cr3+的能量传递与发光性质

在还原气氛下高温固相法合成了CaAl12O19:Eu2+,Cr3+荧光粉.样品光谱显示:Eu2+发射带与Cr3+吸收带有重叠,具备Eu2+-Cr3+之间发生能量传递必要条件.在290 nm近紫外光激发下,单掺杂Eu2+和Cr3+时样品均无691 nm发射,仅在Eu2+,Cr3+共掺时才出现691 nm发射,这证明Eu2+和Cr3+之间发生了能量传递,且监测691 nm时样品的激发光谱也证实了这一点.CaAl12O19:1%Eu2+,x%Cr3+样品组的发射光谱研究表明:增大x能提高Cr3+红光与Eu2+蓝紫光发射强度之比及Eu2+-Cr3+之间能量传递效率.CaAl12O19:2%Cr3+,x%Eu2+样品组的激发光谱分析表明:x>2时,Cr3+在415 nm处的吸收效率相对于565 nm有显著提高.还对样品CaAl12O19:1%Eu2+,1%Cr3+荧光寿命和能量传递速率进行了简单分析.     

Eu^2＋和Mn^2＋在Sr3MgSi2O8中的光致发光研究

研究了Ｅｕ＾２＋和Ｍｎ＾２＋共激活的Ｓｒ３ＭｇＳｉ２Ｏ８的荧光性质。Ｅｕ＾２＋和Ｍｎ＾２＋在４６０ｎｍ和６９０ｎｍ的发射峰分别由Ｅｕ＾２＋的５ｄ→４ｆ跃迁和Ｍｎ＾２＋的＾４Ｔ１（＾４Ｇ）→＾６Ａ１ｇ（＾６Ｓ）跃迁产生。未观察到单掺杂Ｍｎ＾２＋的Ｓｒ３ＭｇＳｉ２Ｏ８的荧光发射，而掺入Ｅｕ＾２＋后则出现了Ｍｎ＾２＋的６９０ｎｍ光致发光峰，表明Ｅｕ＾２＋对Ｍｎ＾２＋有敏化作用。Ｅｕ＾２＋的荧光寿命也受Ｍ     

YAl3（BO3）4∶Eu3+荧光粉的化学沉淀法制备研究

以化学沉淀法制备单相的铕离子掺杂硼铝酸盐红色荧光粉YAl3(BO3)4∶Eu3+,考察了焙烧温度、掺铕量等因素对材料性能的影响,用X射线衍射、扫描电镜、激发光谱和发射光谱对荧光粉的结构、形貌和发光性能进行了表征.以尿素为沉淀剂,900℃焙烧沉淀前驱体可得到单相荧光粉YAl3(BO3)4∶Eu3+,反应温度比传统高温固相法降低了300℃;沉淀法制备的荧光粉粒径分布范围小,无团聚现象,粒径约300nm.掺铕量为10%(物质的量比)时发光强度最大.在260nm的紫外光激发下,Eu3+的5 D0→7 F2的电偶极跃迁最强,发射光为618nm的红光.     

Monodisperse and core-shell-structured SiO2@YBO3:Eu3+ spherical particles: synthesis and characterization

Y0.9Eu0.1BO3 phosphor layers were deposited on monodisperse SiO2 particles of different sizes (300, 570, 900, and 1200 nm) via a sol-gel process, resulting in the formation of core-shell-structured SiO2@Y0.9Eu0.1BO3 particles. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL), and cathodoluminescence (CL) spectra as well as lifetimes were employed to characterize the resulting composite particles. The results of XRD, FE-SEM, and TEM indicate that the 800 degrees C annealed sample consists of crystalline YBO3 shells and amorphous SiO2 cores, in spherical shape with a narrow size distribution. Under UV (240 nm) and VUV (172 nm) light or electron beam (1-6 kV) excitation, these particles show the characteristic 5D0-7F1-4 orange-red emission lines of Eu3+ with a quantum yield ranging from 36% (one-layer Y0.9Eu0.1BO3 on SiO2) to 54% (four-layer Y0.9Eu0.1BO3 on SiO2). The luminescence properties (emission intensity and color coordinates) of Eu3+ ions in the core-shell particles can be tuned by the coating number of Y0.9Eu0.1BO3 layers and SiO2 core particle size to some extent, pointing out the great potential for these particles applied in displaying and lightening fields.     

Vacuum Ultraviolet Excited Photoluminescence Properties of Y202S:Eu3+,Bi3+ Phosphor

As an Hg-free lamp using phosphor,the Bi3+ and Eu3+ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum uitraviolet(VUV) excitation were investigated.The VUV photolumineseent intensity of Y2O2S:Eu3+ was weak,however,considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S:Eu3+,Bi3+ systems.Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S:Eu3+,Bi3+ at 147 nm is mainly because the Bi3+ acts as a medium and effectively performs the energy transfer process: Y3+-O2→Bi3+→Eu3+,while the intense emission band at 172 nm is attributed to the absorption of the characteristic 1So-1P1 transition of Bi3+ and the direct energy transfer from Bi3+ to Eu3+.The Y2O2S:Eu3+,Bi3+ shows excellent VUV optical properties compared with the commercial (Y,Gd)BO3:Eu3+.Thus,the Y2O2S:Eu3+,Bi3+ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.     

Bright white light through up-conversion of a single NIR source from sol-gel-derived thin film made with Ln3+-doped LaF3 nanoparticles

White light was generated from a single silica thin film made with Yb0.75La0.2Eu0.05F3, La0.45Yb0.5Er0.05F3, and La0.75Yb0.2Tm0.05F3 nanoparticles by exciting with a single source near-infrared light (980 nm CW diode laser). Eu3+ and Tm3+ ions are responsible for red and blue emission, respectively. Er3+ ion is responsible for green as well as red emission. The Commission Internationale de l'Eclairage (CIE) coordinates of the resulting light were easily adjusted by controlling the concentration of Ln3+ (Eu3+, Er3+, Tm3+) ions in the nanoparticles as well as the concentration of Ln3+-doped nanoparticles in the sol-gel thin layer.     

TiO2对ZnO/ZnS:Eu3+荧光粉发光性能的影响

采用溶胶-凝胶-沉淀法制备ZnO/ZnS/2TiO2:Eu3+荧光粉,并采用X射线衍射(XRD)、红外光谱(IR)、透射电镜(TEM)以及荧光光谱技术对其结构、组成、形貌和发光性能进行表征,探讨其发光机理。结果显示,ZnO/ZnS/2TiO2:Eu3+荧光粉的结构在温度高于600℃时趋于稳定状态,呈不规则结构,由ZnO、TiO2和ZnS构成。IR谱图表明,Ti-O-Ti桥氧键网络结构有利于Eu3+之间的能量传递。荧光光谱分析表明,引入TiO2使Eu3+光谱选律禁阻解除,提高了ZnO/ZnS/2TiO2:Eu3+荧光粉的发光性能,且当nZn(NO3)2:nTiO2=1:2时荧光粉的发光性能最好,612 nm处的5D0→7F2电偶极跃迁为最强发射峰,最佳退火温度为600℃。     

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.