Eu2+在多铝酸钠体系中的发光

应用高温固相法合成了Na的多铝酸盐,并研究了Eu^2＋在体系中的发光性能．结果表明,Na_1＋xMgAl_11－xO₁₇体系在整个组成范围内保持Na的β－Al₂O₃结构不变,而对于Na_1．67－2xBa_xAl1_0．33O₁₇体系,在x＝0．30附近体系结构发生转变,x＜0．30,体系形成Na的外β－Al2O3结构的固溶体,x＞0．30,体系形成Ba的β－Al₂O₃结构的有序体;与体系组成和结构的变化相对应,Eu^2＋的发射能量和发光强度产生相应的变化,在Na的β－Al₂O₃中Eu^2＋存在高、低能两种发射中心;通过系列化研究,获得了新的组成的、具有β－Al₂O₃结构的荧光体Na_0．67Ba_0．50Mg_0．67Al_10．33O₁₇：Eu^2＋,在较低的掺杂浓度（0．05mol）下可以产生较强的发光．     

Crystal,electronic and luminescence properties of Eu2+-doped Sr2Al2–xSi1+xO7–xNx

The crystal and electronic structures, as well as the luminescence properties of Sr₂Al_2–xSi_1+xO_7–xN_x:Eu²⁺ are reported. First-principles calculations energetically confirm that the Al and Si atoms are in partial ordering in the 2a and 4e sites in Sr₂Al₂SiO₇. In addition, the band structure calculation shows that Sr₂Al₂SiO₇ has an indirect band gap with an energy gap of about 4.07 eV, which is in good agreement with the experimental data (～5.3 eV) obtained from the diffuse reflection spectrum. The crystal structure of Sr₂Al₂SiO₇ can be modified by Si–N substitution for Al–O in the lattice with a maximum solubility of about x ¼ 0.6. The average bond length of Eu_Sr^–(O,N) slightly increases although the lattice parameters decrease with the incorporation of Si–N in Sr₂Al₂SiO₇:Eu²⁺. Under excitation in the visible spectral region, Sr₂Al_2–xSi_1+xO_7–xN_x:Eu²⁺ emits blue to yellow light with a broad emission band in the range of 480–570 nm, varying with both the Eu concentration and the x value. The red shift of the emission band of Eu²⁺ is associated with an increase in the crystal-field splitting and the covalency, which arise from the incorporation of nitrogen as well as the energy transfer between the Eu ions at high Eu concentrations. Moreover, the Eu ions have a strong effect on both the concentration quenching and the thermal quenching in Sr₂Al_2–xSi_1+xO_7–xN_x. The temperature dependence of photoluminescence indicates that Sr₂Al_2–xSi_1+xO_7–xN_x:Eu²⁺ shows strong thermal quenching due to the dominant nonradiative process at room temperature.     

Determination of Some Photoluminescence Parameters of Ca(AlxGa1 –x)2S4:Eu2+

Technical Physics Letters - We synthesized a solid solution of Ca(AlxGa1 – x)2S4 activated with europium ions Eu2+. The photoluminescence spectra and photoluminescence excitation spectra of...     

Eu2+激活的碱土金属铝酸盐磷光体的研究进展

主要概述了Eu^2 激活的碱土金属铝酸盐磷光体的光谱特性，总结了近年来在铝酸盐基质研究以及长余辉机理研究等方面所取得的进展，同时对今后的研究提出了展望。     

Optical absorption and photoluminescence properties of Eu3+-doped ZnF2–PbO–TeO2 glasses

Several physical, optical absorption and photoluminescence properties of Eu3+-doped ZnF2–PbO–TeO2 glasses have been studied. From the measured intensities of various absorption bands of these glasses the Judd–Ofelt parameters 2, 4 and 6 have been computed. The Judd–Ofelt theory has been applied to characterize the photoluminescence spectra of these glasses. From this theory, various radiative properties, such as transition probability, A, branching ratio, r, and emission cross-section, EP, for various emission levels of these glasses, have been determined and reported. © 1998 Chapman & Hall.     

Luminescence properties and tunable emission of Ca3MgSi2O8:Eu3+, Bi3+ phosphor with Bi3+ → Eu3+ energy transfer

Journal of Materials Science: Materials in Electronics - In this work, Ca3MgSi2O8:Bi3+, Ca3MgSi2O8:xEu3+ (x?=?0, 2, 4, 6, 8, and 10 mol%), and Ca3MgSi2O8:6%Eu3+, yBi3+...     

Characterization and photocatalysis of Eu3+–TiO2 sol in the hydrosol reaction system

In this paper, 3.0 mol% lanthanide europium ion modified TiO₂ sol (Eu³⁺–TiO₂) was fabricated by chemical coprecipitation–peptization method with TiCl₄ as precursor. Eu³⁺–TiO₂ sol particles were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), transmission electron microscope (TEM) and particle size distribution (PSD). Eu³⁺–TiO₂ sol particles prepared at low temperature (70 °C) had anatase semicrystalline structure. Eu³⁺–TiO₂ sol sample homogeneously dispersed in the aqueous medium and presented narrow distribution characterization with 7 nm in mean size. Interfacial adsorption experiment shows that small particle size and positive charge of sol particles contributed to the good adsorption of X-3B dye on the TiO₂ surface. The photoelectrochemical property was investigated about electrons transfer efficiency between dye molecule and TiO₂ particles. A novel hydrosol reaction system was designed to conduct X-3B photodegradation reaction. The excellent photocatalytic activity for X-3B degradation under visible light irradiation was ascribed to effective scavenging electrons by Eu³⁺ ion. Moreover, X-3B photocatalytic degradation mechanism under visible light excitation was proposed as photosensitization–photocatalysis.     

Eu3+和Sm3+共掺杂TiO2光催化剂的协同效应

采用溶胶-凝胶法制备了纯TiO2和Eu3+/Sm3+共掺杂TiO2复合粉体,采用XRD,DRS和SEM等技术进行表征,以亚甲基蓝(methylene blue,MB)的光催化降解为目标反应,评价了其光催化活性,探讨了Eu3+/Sm3+共掺杂对TiO2粉体光催化的影响机制.结果表明,Eu3+/Sm3+共掺杂可以显著提高TiO2粉体光催化活性,Eu3+/Sm3+共掺杂在TiO2粉体中产生协同作用,可以抑制TiO2由锐钛矿相向金红石相转变,使TiO2的粒径减小.Eu3+/Sm3+共掺杂增大了TiO2粉体的晶格畸变,使TiO2粉体吸收带边蓝移.当Eu3+/Sm3+的掺杂量分别为0.05%和0.1%,TiO2光催化活性最高,光催化降解率达到84.8%.     

SrAl2O4:Eu2+材料的发光性能研究

制备了发光性能良好的SrAl2O4:Eu^2 材料，对其激光光谱、发射光谱和长余辉曲线进行了测试与分析讨论，结果表明长余辉衰减符合函数L＝ct^a（a＝0.754）形式。讨论SrAl2O4:Eu^2 材料的长余辉机理，指出长余辉应来自陷阱对空穴的俘获与缓慢释放。发现了SrAl2O4:Eu^2 材料的力至发光性能并分析了其可能原因。     

SrAl2O4:Eu2+发光材料的合成工艺研究

以碳粉作还原剂,SrCO3、Al2O3、Eu2O3为原料,在还原气氛下采用固相烧结法合成了SrAl2O4:Eu2+发光材料;对合成物进行了X射线粉晶衍射、荧光光谱测定;并初步探讨了Eu2+的含量、制备工艺过程中的焙烧温度、保温时间、冷却方式等因素对合成样品发光性能的影响.     

一种Eu2+激活的铝酸锶长余辉结构

采用高温烧结工艺制备了一系列铝酸锶铕体系的长余辉发光粉。其荧光光谱表明,铝锶比例对长余辉颜色有明显的影响。通过ＸＲＤ分析,讨论了铝锶比例对发光粉基质结构的影响,并对发光颜色变化的原因作了进一步的解释。当铝锶比例达到５：１时,荧光光谱只在４１０ｎｍ左右显示一个单峰,ＸＲＤ分析表明,该发射峰是Ｅｕ＾２＋在一基质结构－－ＳｒＡＩ１２Ｏ１９中产生的,ＳｒＡＩ１２Ｏ１０：Ｅｕ＾２＋发光结构的长余辉特性亦得到验证。     

SiO2气凝胶薄膜中Eu3+离子的跃迁

利用溶胶－凝胶法制得了Ｅｕ＾２＋掺杂ＳｉＯ２气凝胶薄膜,并对其发光及跃迁性质进行了研究。使用原子力显微镜对样品的型貌结构做了观测、采用ＸＲＤ和ＩＯＲ对所得样品的结构进行了研究,测量了样品的激发一发光谱、吸收光谱和时间分辨光谱。通过Ｊｕｄｄ－Ｏｆｅｌｔ理论计算了Ｅｕ＾３＋的＾Ｄ０的辐射跃迁几率,并根据时间分辨光谱研究了＾５Ｄ１的无辐射跃迁几率及弛豫性质。虽然结果与掺Ｅｕ＾３＋的体硅玻璃没有很大差别,     

Pr3+掺杂对SrAl2O4:Eu2+、Dy3+磷光体发光性能的影响

用燃烧法制备Pr~(3+)掺杂的SrAl_2O_4:Eu~(2+)、Dy~(3+)长余辉发光粉体,研究了Pr~(3+)掺杂对其发光性能的影响。结果表明,合成的单相SrAl_2O_4样品具有单斜晶系结构,荧光发射光谱是连续宽带谱,峰位于515 nm,激发光谱是峰值在320 nm和360 nm的连续宽带谱。掺杂Pr~(3+)对形成晶粒尺寸均匀的固溶体有一定的促进作用,使其余辉初始亮度为不掺杂时的3倍。     

Preparation and luminescence properties investigation of Eu3+, Tb3+-doped LaNbO4:RE3+ (RE = Eu,Eu/Tb,Tb)

Journal of Materials Science: Materials in Electronics - In this work, doped and co-doped LaNbO4:RE3+ (RE?=?Eu, Eu/Tb, Tb) single crystals were prepared by a unique hydrothermal method...     

Ba2+离子对Sr2Al2SiO7:Eu2+荧光体微结构及发光性能的影响

采用复合胶体喷雾工艺制备了Ba2 离子掺杂的Sr2-xBaxAl2SiO7:Eu2 (x=0、0.1、0.2、0.4)荧光体.研究了Ba2 离子在基质Sr2Al2SiO7中的取代位置和机理,分析了Ba2 离子取代Sr2 离子对基质微结构及Sr2Al2SiO7:Eu2 荧光体发光性能的影响.XRD结果表明Ba2 离子取代Sr2 格位进入Sr2Al2SiO7晶格,导致晶胞体积增大.进入Sr2Al2SiO7晶格的Ba2 离子由于电负性较大,处在其周围的Eu2 离子外层电子受Ba2 离子影响,电子云膨胀,使发光波长发生红移.同时,掺入Ba2 离子后Sr2-xBaxAl2SiO7晶场强度增强,晶体场对Eu2 离子5d能级的劈裂程度增大,劈裂重心下降.Ba2 离子掺杂的Sr2-xBaxAl2SiO7:Eu2 (x=0、0.1、0.2、0.4)荧光体发射主峰位于520nm,与未掺杂Sr2Al2SiO7:Eu0.022 荧光体的发射峰相比出现红移.     

微波场作用下球形亚超细 CaS:Mn2+，Eu2+的快速合成

在微波场作用下,首次快速合成了球形亚超细尺寸的CaS: Mn2+,Eu2+ 深红色荧光体,SEM 照片显示其粒径为250 400nm,并可观察到纳米粒子的团聚现象,呈现零维纳米材料的特性. 实验结果证实,Mn2+与Eu2+离子间存在着能量传递过程,因而Mn2+对Eu2+的发光具有明显的敏化和增强作用.     

Mg2+离子对Sr2Al2SiO7∶Eu2+荧光体微结构及发光性能的影响

采用复合胶体喷雾工艺制备了Sr2Al2SiO7∶Eu2 荧光体及掺入Mg离子后Sr2-xMgxAl2SiO7∶Eu2 (x=0.1, 0.2, 0.4, 0.6, 0.8, 1.0)荧光体.XRD分析及晶格常数计算结果表明,Eu2 离子部分取代Sr2 格位进入Sr2Al2SiO7晶格.Sr2Al2SiO7∶Eu2 荧光体激发谱由峰值位于326nm附近的宽带构成,属于Eu2 的4f→5d 跃迁吸收带;发射光谱主峰位于约500nm,属于Eu2 离子4f65d→4f7跃迁导致的宽带发射.XRD结果表明Mg2 添加浓度从x=0.1～1.0增加,Mg2 离子以取代离子形式进入Sr2Al2SiO7晶格.Mg2 离子添加浓度x=0.1时对Sr2Al2SiO7∶Eu2 发射光谱影响不大,Sr1.9Mg0.1Al2SiO7∶Eu2 0.02发射主峰仍位于500nm;x＞0.2后,Mg2 离子取代Sr2 离子使晶体场强度减弱,Eu2 离子5d能级晶场劈裂减小,导致Sr2-xMgxAl2SiO7∶Eu2 发射峰蓝移至460nm.     

纳米Y2O2S∶Eu的燃烧法合成和Eu3+离子荧光探针物相分析

将硝酸钇铕和较便宜的水溶性含硫燃烧剂溶于乙醇-水溶液,通过新的乙醇辅助燃烧法合成了一次粒径约20nm的硫氧化钇(Y2O2S∶Eu)发光材料.研究结果表明:采用硫代乙酰胺作为燃烧剂时,燃烧反应产物为Y2O2S∶Eu及微量的Y2O3∶Eu.而采用硫脲作为燃烧剂,燃烧反应产物为Y2O3∶Eu,Y2O2S∶Eu和/或Y2O2SO4 ∶Eu的混合物.利用Eu3 离子的5D0→7Fj跃迁导致的红色发光作为荧光探针,根据其在Y2O3(λem=610nm),Y2O2S(λem1=625nm,λem2=615nm),Y2O2SO4(λem1=613,λem2=615nm)基质中的光致发光光谱和X射线发光光谱位置和强度不同,来确定生成物中Y2O3∶Eu,Y2O2S∶Eu,Y2O2SO4 ∶Eu物相的组成.