Gd_3Al_5O_(12)∶Eu~(3+)柠檬酸盐硝酸盐燃烧法合成及其发光性能研究

采用柠檬酸盐硝酸盐燃烧法,在较低的温度(900℃)下成功地合成单一晶相Gd3Al5O12∶Eu3+发光粉体,紫外激发荧光光谱分析表明,粉体615 nm和593 nm荧光发射源于Eu3+的5D0-7F2和5D0-7F1跃迁.该方法中各工艺条件(如pH值、柠檬酸/金属离子比、煅烧温度)对Gd3Al5O12∶Eu3+发光性能均有影响,通过试验得出了获得最佳发光性能荧光粉体的工艺参数.     

EXAFS, SAXS and Eu3+ Luminescence Spectroscopy of Sol-Gel Derived Siloxane-Polyethyleneoxide Hybrids

Hybrid Eu³⁺-doped silica-poliethyleneoxide (PEO) nanocomposites with covalent bonds between the inorganic (siloxane) and organic (PEO) phases have been obtained by sol-gel process. These materials are transparent, flexible and present high Eu³⁺ luminescence output. Their luminescence properties, local environment around europium ions and structure have been investigated as a function of europium content. EXAFS measurements indicate that the increase in Eu-doping induces a decrease in Eu³⁺ coordination number. An increase in symmetry degree around the metal ion is also observed for increasing Eu³⁺ concentration, while non radiative decay paths from the ⁵D₀ excited state become more important. SAXS results suggest the preferential interaction of europium ions with ether-type oxygens of the polymer chains. However, the existence of interactions between the cations and the carbonyl groups from urea bridges located at the siloxane-PEO interface can not be excluded.     

Preparation of CaS:Eu2+ Phosphor by Microwave Heating Method and its Luminescence

Alkaline-earth sulfides have been found to be excellent host materials for the cathodo-,photo-, thermo-, and electfo-luminescent phosphorsl-3. Red-emitting CaS:Eu2+ havealready been described in the literatUre4,5. In the past, calcium sulphide was mainlyprepared by conventional high temperatUre solid state method through the stream of H,Sand HZ or CS, as sulphurizing and protection atmosphere, which expended quite longreaction time of 2-72 h6 and consumed a great deal of the sources of ene…     

掺杂Eu2+的新型锶铝复合硫氧化物红色发光材料

合成了掺杂Eu2+的新型锶铝复合硫氧化物红色发光材料Sr5Al2O7S∶Eu。用粉末X射线衍射法表征了其晶体结构,计算的晶胞参数为:单斜晶系,a=0.90748(41)nm,b=0.71029(25)nm,c=0.63021(26)nm,β=103.588(41)°,V=0.39485(23)nm。研究了其激发光谱、发射光谱和余辉光谱。发射光谱峰值位于586nm处,半宽度为50nm;激发带主要在可见区,峰值位于500nm处。讨论了Eu的添加量、基质组成、S的含量等与荧光强度的关系。     

R_3GeVO_9(R=Y,La)∶Eu~(3+)(或Dy~(3+))的合成及其发光性质

采用高温固相法合成了稀土复合钒锗酸盐R3GeVO9(R =Y ,La)体系 ,并以此为基质研究了Eu3+和Dy3+在其中的发光性质 ,以Eu3+为结构探针探讨了Eu3+在R3GeVO9(R =Y ,La)中的格位情况。同时 ,还研究了被取代离子R3+的Z/r对Eu3+的红橙比和Dy3+的黄蓝比的影响以及浓度、温度和Bi3+对它们发光强度的影响。     

Synthesis and characterization of red-luminescent graphene oxide functionalized with silica-coated Eu3+ complex nanoparticles

Traditional dye-doped fluorescent graphene oxide (GO) reveals a low quantum yield and a short life expectancy. Herein, red-luminescent silica-coated Eu(3+) complex nanoparticles were synthesized and covalently coupled to GO nanosheets by means of a carbodiimide-mediated amidation process. SEM and TEM studies demonstrated successful attachment of the silica-coated Eu(3+) complex nanoparticles onto the GO surface. Spectroscopic studies showed that the GO-nanoparticle conjugates exhibit strong luminescence, long lifetimes, as well as good photostability, which suggests that this new type of luminescent nanomaterial has the potential for highly sensitive time-resolved fluorescence cyto- and histochemistry imaging.     

Crystal Structure and Luminescence of Eu(DBM)_3TPPO Complex

The crystal structure of tris(dibenzoylmethanato)(triphenylphosphine oxide)europium (Ⅲ), C63H51O7PEu, has been determined by single crystal X-ray diffraction. The complex crystallizes in the tri-clinic space group P 1 with two molecules in a unit cell. The cell dimensions are a=12. 336 (3), b=18. 729 (5), c=11. 502 (3) A, α=95. 86 (2), β=103.14 (2), γ=87.89 (2)0. The total number of 6969 independent reflections was used for the structure determination. The final calculated R value is 0. 055. The central europium ion is hepta-coordinated by seven oxygen atoms. The polyhedron is a distorted capped trigonal prism with the Eu-O separation of 2. 305-2. 367 A. The high resolution excitation and emission spectra measured at 77 K indicate two Eu (Ⅲ) sites in the complex. The symmetries of the Eu (Ⅲ) sites are C2v and Cs respectively. The lower symmetrical Cs site predominates. A comparison of the emission spectra for Gd(DBM)3TPPO doped by 1% Eu(Ⅲ) with those for Eu(DBM)3TPPO complex shows no significant     

Reduction of Eu3 + to Eu2 + in Al-Codoped Silica Glasses Fabricated by the Sol-Gel Technique and CO2-Laser Processing

The spectroscopic properties of europium in aluminium codoped silica glasses produced by the sol-gel technique have been studied with respect to the dopant concentrations and the thermal processing applied to the samples. After thermal annealing at temperatures up to 950_°C the bright red fluorescence around 613 nm characteristic for the trivalent europium ions (Eu^{3 +}) has been observed. The lifetime was measured to be 0.1–2.4 ms depending on dopant concentrations and thermal treatment. Subsequent CO₂-laser processing in air (short time remelting) gave rise to a bright blue fluorescence consisting of two broad bands, lying around 450 and 490 nm, with their peak position depending on the ratio between the aluminium and europium concentrations. The fluorescence lifetimes were found to be shorter than 1 s. This blue fluorescence is attributed to the divalent europium ion (Eu^{2 +}), leading to the conclusion that the CO₂-laser processing of europium doped alumina-silica glasses resulted in the reduction of the trivalent to the divalent europium ion. Laser processing could therefore be a valid alternative to conventional thermal annealing for the generation of Eu^{2 +} in alumina-silica glasses.     

溶胶-凝胶工艺制备发光薄膜研究进展

本文综述了通过深胶－凝胶工艺制备发光薄膜的基本过程、薄膜的表征方法、发光薄膜的当前发展及应用情况。依据组成特点,对溶胶－凝胶法制备的发光薄膜乾地了分类阐述,并预言了今后该法制备发光薄膜的发展趋势。     

Luminescence Properties of Mn2+-Doped Sol-Gel Glasses

Mn²⁺-doped 1Al₂O₃-99SiO₂ glasses have been prepared by a sol-gel method and their photoluminescence (PL) properties have been studied for the first time. The effect of ZrO₂ and TiO₂ on the luminescence properties has also been studied. In addition, the PL of Mn: 1Al₂O₃-99SiO₂ is compared with Mn:SiO₂. The emission spectra of all the samples containing Al₂O₃ show a band around 620 nm, and the sample without Al₂O₃ shows two bands around 620 and 650 nm. These emission bands are all assigned to the ⁴T₁ ⁶A₁ transition of octahedrally coordinated Mn²⁺ · ZrO₂ and TiO₂ have fluorescence quenching effect. The relative fluorescence intensity of Mn²⁺-doped sol-gel 1Al₂O₃-99SiO₂ is much stronger than that of Mn²⁺-doped sol-gel SiO₂. The difference of the emission wavelength between host materials is explained in terms of the ligand field effect.     

铕(钆)-水杨酸-邻菲啰啉配合物的合成及光致发光性能

在无水乙醇中，以水杨酸（Hsal）和邻菲啰啉（phen）为配体，不同摩尔比铕钆离子为中心体，合成了一系列组成为NaEuxGd1-x（sal）4（phen）2（x=0．1～1．0）的固体配合物。IR光谱表明，水杨酸的酚羟基没有参与配位，羧基以桥联方式与钠和铕或钆原子配位；UV光谱显示，配合物中phen与稀土离子之间的能量传递是主要过程，配合物的最大吸收与phen相比略有红移；FS光谱表明，在该系列配合物中，不仅配体可以将吸收的能量传递给铕离子，使其发光，而且不发光的钆配合物也可将其吸收的能量传递给铕离子，增强铕的发光强度。     

Eu3+掺杂ZMCB和ZMLB基光致发光玻璃纤维性能的研究

在发光粉废料处理中发现用高温固相反应和玻璃流股牵引方法,人工拉制了Eu3 掺杂ZnO-MgO-CdO-B2O3基质的光致发光玻璃纤维,直径为0.01～0.30 mm,长10余米.Eu3 离子613 nm的强发射归属于5D0-7F2电偶极跃迁,相对613 nm发射强度40%的591 nm发射归属于5D0-7F1磁偶极跃迁.说明Eu3 在局域环境中主要占据非对称中心格位.对不同浓度Eu3 的光衰曲线进行拟合,发现随着掺杂Eu3 浓度的增加,发光由单指数衰减变为双指数衰减.用SEM观察到玻璃纤维的表面光滑、低析晶、断口质密度高、断口贝纹呈明显沟状.并测试了发光玻璃纤维的一系列力学参数,也研究了Eu3 掺杂ZnO-MgO-La2O3-B2O3基玻璃纤维的光谱性能.     

不同方法制备CaMoO4∶0.05Eu3+红色荧光粉的对比研究

分别以高温固相法、溶胶-凝胶法、水热法和共沉淀法合成Eu3+掺杂的CaMoO4红色荧光粉,通过X-射线衍射(XRD)、场发射扫描电镜(FESEM)、傅立叶变换红外光谱(FTIR)、光致荧光光谱(PL)进行表征,考察荧光粉晶相、形貌及发光性能对制备方法的依赖性。实验表明,由于Ca2+的半径(0.099 nm)与Eu3+半径(0.094 7 nm)大小相差不大,Eu3+容易取代Ca2+的位置进入晶格,Eu3+掺杂的CaMoO4在晶体结构上保持白钨矿结构。FESEM结果表明:未经后处理的水热法所得样品为片状、多孔结构;高温固相法所得样品尺寸大、团聚严重;溶胶-凝胶法所得样品分散度好、呈条形结构;共沉淀法所得样品形貌、尺寸比较均一。荧光光谱显示,四种样品发光强度差异很大,共沉淀法制得样品的发光强度为未经后处理的水热法制得样品的6-7倍,该现象主要是由样品形貌及表面缺陷的差异引起的。     

Eu^2＋在BaF2—xYF3体系中的光谱性质及其对Tb3＋的能量传递

研究了钡钇复合氟化物体系中Ｅｕ＾２＋的光谱性质和变化规律，讨论了影响Ｅｕ＾２＋光谱的因素，特别是氧的存在对Ｅｕ＾２＋激发和发射能量的影响，发现在ＢａＹＦ５基质中Ｅｕ＾２＋对Ｔｂ＾３＋的有效参量传递。     

GdF3∶Eu3+/NaGdF4∶Eu3+纳米晶的水热合成及发光性质

采用水热法,以聚乙二醇(400)为分散剂,以NaOH和HNO3溶液调节初始溶液pH值,合成GdF3∶Eu3+和NaGdF4∶Eu3+纳米晶。XRD和SEM结果表明:在酸性溶液(pH=3,5)、中性溶液(pH=7)和碱性溶液(pH=9)中,分别获得具有正交结构的GdF3∶Eu3+纳米晶,GdF3∶Eu3+和NaGdF4∶Eu3+混合晶,六方结构NaGdF4∶Eu3+棒状微米晶。根据Scherrer公式估算pH=3和pH=5时制备纳米晶的一次性粒径分别为49和28 nm。样品的发射光谱结果表明:特征发射峰来自于5D2、5D1、5D0到7FJ跃迁。在主晶相为GdF3样品中,主发射峰来自于Eu3+的5D0→7F1的磁偶极跃迁;晶相为NaGdF4样品的主发射峰来自于Eu3+的5D0→7F2电偶极跃迁。5D0→7F1和5D0→7F2跃迁发射相对强度比值显示:Eu3+在NaGdF4晶体中的格位对称性下降。激发光谱显示出Gd3+和Eu3+具有较好的能量传递。     

LaF3:Eu3+纳米粒子的水热法制备及发光性质研究

用水热法制备了LaF3及Eu^3＋掺杂的LaF3纳米粒子, 通过X射线粉末衍射（XRD）、透射电子显微镜（TEM）和荧光光谱（FS）对样品进行了表征. 结果表明： 所得的纳米粒子粒度均匀、结晶完好, 呈规则的六边形形状;研究了反应温度和时间对LaF3纳米粒子形成的影响, 初步探讨了纳米粒子的生长机制. 研究了掺杂Eu^3＋后的发光性质, 发现纳米粒子经高温煅烧后, 荧光强度有明显下降, 适宜的煅烧条件为600 ℃/6 h, Eu^3＋的掺杂量在5%（摩尔分数）时, 纳米粒子的荧光强度最强, 更高的掺杂浓度将导致荧光猝灭.     

Luminescence behavior of Eu3+ in polytitanasiloxane solution

Polytitanasiloxane solutions containing Eu³⁺ ions have been prepared by the hydrolytic cocondensation of tetraethoxysilane and tetrabutyl titanate. The UV‐vis absorption and the luminescence intensity were both found to increase with the increase of tetrabutyl titanate/tetraethoxysilane (TBT/TEOS) molar ratio. This revealed that the incorporation of TiO₂ can result in the increase of absorption energy of the Ti? O group by near‐UV excitation and in the increase of energy transfer to the metal ion. At the same time, the intensity ratio of ⁵D₀→⁷F₂ to ⁵D₀→⁷F₁ increases as the TBT/TEOS molar ratio increases, indicating the formation of Eu³⁺? O^2?? Ti⁴⁺ bonding. A longer decay time means that the Eu³⁺ ions are better dispersed and less clustered with the increase of TBT/TEOS molar ratio. The results on the luminescence properties of the Eu³⁺ in different media containing ethanol or water suggest that the incorporation of TiO₂ can shield Eu³⁺ ions from the effect of water and ethanol molecules, which leads to an improvement of the Eu³⁺ surroundings. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1357–1363, 2006     

Anion-Dependent Outstanding Luminescence Enhancement of Eu(D-facam)3 Upon Coexistence With the Tetramethylammonium Cation

The effect of a series of tetramethylammonium salts with different counter anions on the photophysical properties of a chiral Eu(III) complex (Eu(D-facam)₃) was investigated. Anion-dependent luminescence of the Eu(III) complex was observed, and particularly in the presence of acetate ions, an outstanding luminescence enhancement (>300 times) and induced circularly polarized luminescence (g_lum=−0.63) were obtained. The energy transfer process was then evaluated using key photophysical parameters, and it was found that the sensitisation efficiency of the Eu(III) complex significantly increased in the presence of tetramethylammonium acetate (TMAOAc). The interactions between Eu(D-facam)₃ and TMAOAc were confirmed by luminescence analysis, circular dichroism spectroscopy, Fourier transform infrared spectroscopy and mass spectral measurements.     

溶胶—凝胶法制备掺Eu^3＋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Eu^3 和不同退火温度下的SiO2凝胶和玻璃,通过在不同退火温度下样品的激光发谱,发射光谱,红外光谱和差热－热重曲线,研究了掺Eu3 的SiO2玻璃材料的结构和发光性能,结果显示,当Eu3 的掺杂量大于1．86％（质量分数）,Eu^3 的发光强度趋于稳定,当样品的退火温度大于300度时,SiO2凝胶玻璃中吸附的水已基本除净,此时显示出Eu^3 的特征发射光谱,谱带位置分别是614,596,577nm,分别归属于^5Do-7F2,5D0-7F1,^5D0-^7F0跃迁,对应的激光发光谱显示6个峰,位置分别是318,362,380,393,412,462nm,说明300－500度是凝胶向玻璃转变的关键温度,而水对Eu^3 的发光有强烈的淬灭作用。