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1.
Two ternary solid complexes, Tb3+ (Eu3+)-ciprofloxacina-acetylacetone, have been synthesied and chara-cterized by elemental analysis, IR. Ciprofloxacina is one kind of bacteriophage containing α-carbonyl carboxylic acid configurayion and acetylacetone contains β-diketonate configurayion. They are the ideal ligands for Tb3+ and Eu3+. The fluorescence spectra of Tb3+ and Eu3+ complexes showed that the ligands were suitable for efficient energy transfer from ligands to the Tb3+ or Eu3+ ion with a high fluorescence quantum yield, large stoke shift, narrow emission bonds and large fluorescence lifetime. So the complexes were the new kind of solid fluorescence materials. Moreover, the mechanisms of the fluorescence of Tb3+ (Eu3+)-ciprofloxacina-acetylacetone ternary solid complex were investigated. 相似文献
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A pair of novel chiral fluorescent and colorimetric sensors L1 and D1 had been designed and synthesized, which were based on phenanthroline as the fluorophore and mandelohydrazide as the binding site. They showed selective recognition toward Eu3+ ion as ‘turn-off’ mode in DMSO-H2O solution (v/v = 1:5, 10 mM HEPES, pH = 7.4). The fluorescence discrimination towards chiral carboxylate anions had been studied for L1-Eu3+ and D1-Eu3+ complex and they showed good enantioselective recognition ability towards malate as ‘turn-on’ mode. The interaction of sensor L1, D1 with Eu3+ and L1-Eu3+, D1-Eu3+ towards malate caused different color changes in the naked eye. 相似文献
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M. Ferrari A. Piazza M. Montagna G. Carturan R. Campostrini 《Journal of Sol-Gel Science and Technology》1994,2(1-3):783-786
Silica gels doped with Eu3+ ions were studied at temperatures between 10 K and 300 K by site selection spectroscopy in samples heated up to 200°C. The 5D0 7F0 transition shows internal structures due to the different environments of the europium ions. Lifetimes, energy levels and homogeneous linewidths are site dependent. In the wet gel the Eu3+ ions prefer a liquid-like environment and only when the liquid is removed by heat treatment, the ion is linked more strongly to the silica network. 相似文献
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Y2O3:Eu3+红色荧光粉由于色纯度高、化学性质稳定和量子效率接近100%而广泛用于荧光灯和投影电视等方面.近年来,Y2O3:Eu3+的大量研究工作主要集中于纳米粉末的制备方法及其与体相材料不同的发光特性[1~3].最近,有关Y2O3:Eu3+及其稀土化合物的纳米管、纳米线和纳米带一维材料的制备成为研究热点.Wu Changfeng等[4,5]利用表面活性剂合成了Y2O3 : Eu3+纳米管.激光格位选择激发测试结果表明,Eu3+在纳米管中占据3个不同的格位,其611 nm处的红色发光峰出现了宽化.He Yu等[6]采用水热法及退火处理制备出了Y2O3:Eu3+纳米带,发现Eu3+的发射峰不仅宽化,而且出现了625 nm的新峰.Li Yadong等[7~9]采用水热法制备了稀土氧化物、硫氧化物和氢氧化物等的纳米线和纳米管,并探索了其形成机理,同时发现Y2O3S : yb3+,Er3+具有上转换的性质. 相似文献
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SiO2 crystals have been used in electroluminescence devices and thermoluminescence (TL) dosimeters. However, their emission mechanisms have not yet been clearly explained. Recently, it has become possible to obtain amorphous, highly pure, SiO2 prepared by the sol-gel method. The emission mechanism of TL was investigated using Al3+ and/or Eu3+-doped SiO2 crystalline samples prepared by heat-treating under much lower temperature than the melting point of SiO2. The TL spectrum of Eu3+-doped sample had main peaks due to the electron transitions from 5D2 to 7F5 (ca. 570 nm, yellow peak) and from 5D0 to 7F2 (ca. 610 nm, red peak). The yellow peak intensity has a maximum value in the SiO2 doped with near 1 mmol% of Eu2O3, while the red peak intensity was almost constant. These facts suggest that bright yellow emission of SiO2TL phosphor is synthesized by the diffusion of Eu3+ ion in SiO2 matrix prepared by sol-gel method. 相似文献
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采用芳香族π共轭及含氮原子有机连接剂,合成同构铽、铕发光配位聚合物(CPs){[Eu(PLIA)1.5(H2O)2]·H2O}n (1)和{[Tb(PLIA)1.5(H2O)2]·H2O}n (2),其中H2PLIA=5-((吡啶-4-基甲基)氧基)苯-1,3-二甲酸。对合成的配合物进行了结构测定、表征和荧光痕量识别实验研究。2个同构配合物具有理想的三维框架结构,π…π堆积及氢键等弱相互作用增强了其化学稳定性;表征显示配位聚合物1和2具有良好的荧光性质、结晶性、热力学稳定性及结构完整性,可作为荧光传感的材料。1和2对水溶液中的Zr4+、Cr2O72-和Fe3+、HPO42-具有选择性好、灵敏度高的荧光识别能力,其检出限分别为0.139 μmol·L-1(1,Zr4+)、0.626 μmol·L-1(1,Cr2O72-)、0.430 μmol·L-1(2,Fe3+)、1.36 μmol·L-1(2,HPO42-)。探究了1和2作为探针的荧光猝灭机理。更有趣的是,1和2具有指纹识别性能,其荧光指纹纹路清晰连贯,细节明显,可被清晰观察。 相似文献
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Calcium and barium zirconate powders based upon CaZrO3:Eu3+,A and BaZrO3:Eu3+,A (A=Li+, Na+, K+) were prepared by combustion synthesis method and heating to ~1000℃ to improve crystallinity.The structure and morphology of materials were examined by X-ray diffraction (XRD) and scanningelectron microscopy (SEM). XRD results showed that CaZrO3:Eu3+,A and BaZrO3:Eu3+,A (A=Li+, Na+, K+) perovskites possessed orthorhombic and cubic structures, respectively. The morphologies of all powderswere very similar consisting of small, coagulated, cubical particles with narrow size distributions andsmooth and regular surfaces. The characteristic luminescences of Eu3+ ions in CaZrO3:Eu3+,A (A=Li+, Na+, K+) lattices were present with strong emissions at 614 and 625 nm for 5D0→7F2 transitions with other weakeremissions observed at 575, 592, 655, and 701 nm corresponding to 5D0→7Fn transitions (where n=0, 1, 3, 4 respectively). In BaZrO3:Eu3+ both the 5D0→7F1 and 5D0→7F2 transitions at 595 and 613 nm were strong.Photoluminescence intensities of CaZrO3:Eu3+ samples were higher than those of BaZrO3:Eu3+ lattices. Thisremarkable increase of photoluminescence intensity (corresponding to 5D0→7Fn transitions) was observedin CaZrO3:Eu3+ and BaZrO3:Eu3+ if co-doped with Li+ ions. An additional broad band composed of manypeaks between 440 to 575 nm was observed in BaZrO3:Eu3+,,A samples. The intensity of this band wasgreatest in Li+ co-doped samples and lowest for K+ doped samples. 相似文献
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N. Lakshminarasimhan 《Journal of solid state chemistry》2004,177(10):3536-3544
Eu3+ luminescence is studied in apatite-related phosphate BiCa4(PO4)3O. Compositions of the formula Bi1−xEuxCa4(PO4)3O [x=0.05, 0.1, 0.3, 0.5, 0.8 and 1.0] are synthesized and they are isostructural with parent BiCa4(PO4)3O. Room temperature photoluminescence shows the various transitions 5D0→7FJ(=0,1,2) of Eu3+. The emission results of compositions with different Eu3+ content show the difference in site occupancy of Eu3+ in Bi1−xEuxCa4(PO4)3O. The intense 5D0-7F0 line at 574 nm for higher Eu3+ content is attributed to the presence of strongly covalent Eu-O bond that is possible by substituting Bi3+ in the Ca(2) site. This shows the preferential occupancy of Bi3+ in Ca(2) site and this has been attributed to the 6s2 lone pair electrons of Bi3+. This is further confirmed by comparing the emission results with La0.95Eu0.05Ca4(PO4)3O. 相似文献
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Wang Z Zhang W You B Yin M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(4):835-839
Nanocrystalline Lu(2)O(3):Eu(3+) was prepared by co-precipitation method using ammonium hydrogen carbonate and ammonium oxalic acid as precipitants, respectively. The crystal structure and morphology were analyzed by means of XRD and TEM. The resultant powders were sintered into transparent ceramics in vacuum and then in nitrogen without any additive. The surface morphology of the unpolished sintered specimens was characterized using SEM. The effect of different precipitants on microstructure of the nanopowders and transparency of the ceramics are compared. The excitation and emission spectra of Lu(2)O(3):Eu(3+) powders and ceramics were measured at room temperature by using synchrotron radiation as the light source. The fluorescence decay times of all specimens were analyzed. Luminescence of the ceramics decays faster than the corresponding nanopowders. 相似文献
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Ye Jin Weiping Qin Jisen Zhang Yan Wang Chunyan Cao 《Journal of solid state chemistry》2008,181(4):724-729
Eu3+-doped Gd3PO7 nanospheres with an average diameter of ∼300 nm and a narrow size distribution have been prepared by a facile combustion method and structurally characterized by X-ray diffraction and field emission scanning electron microscopy. The luminescent properties were systemically studied by the measurement of excitation/emission spectra, and emission spectra under different temperatures, as well as by photostability. The strong red-emission intensity peaking at 614 nm originates the 5D0→7F2 transition and is observed under 254-nm irradiation, indicating that Eu3+ ions in Gd3PO7 mainly occupied non-centrosymmetry sites. The CIE1931 XY chromaticity coordinates of Gd3PO7:Eu3+ nanospheres are (x=0.654, y=0.345) in the red area, which is near the National Television Standard Committee standard chromaticity coordinates for red. Thus, Gd3PO7:Eu3+ nanospheres may be potential red-emitting phosphors for PDP and Xe-based mercury-free lamps. 相似文献
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Ce3+,Tb3+,Eu3+共掺杂Sr2MgSi2O7体系的白色发光和能量传递机理 总被引:1,自引:0,他引:1
通过正交试验,采用高温固相法制备了Sr2-x-y-zMgSi2O7∶xCe3+,yTb3+,zEu3+系列样品.使用X射线衍射仪和荧光光谱仪表征了样品的物相和发光性质,并讨论了Ce3+-Tb3+-Eu3+共掺杂Sr2MgSi2O7体系中的能量传递过程.实验结果表明,在327 nm波长激发下,所合成荧光粉的发射峰主要位于387 nm(蓝紫)、542nm(绿)和611 nm(红)处;分别以387,542和611 nm为监控波长,所得激发光谱显示荧光粉在327 nm处有最好的激发.在327 nm光激发下,系列样品发光进入白光区.最优化的荧光粉为Sr1.91MgSi2O7∶0.01Ce3+,0.05Tb3+,0.03Eu3+,其色坐标为(0.337,0.313),是一种潜在的发光二极管(LED)用白色荧光粉. 相似文献
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Lingyun Liu Zhiqing Zhang Shi‐Zhao Kang 《Journal of Dispersion Science and Technology》2013,34(5):769-772
Silica xerogels containing Eu3+ ions and SnO2 nanocrystals were prepared in the sol‐gel process, and characterized by x‐ray diffraction (XRD) and photoluminescence spectra. Under the excitation at 393 nm, characteristic emission of Eu3+ ions at 614 nm was enhanced with increasing amount of SnO2 nanocrystals. Moreover, when the Eu3+/SnO2 co‐doped samples were excited at 345 nm, corresponding to the sideband of SnO2 nanocrystals, the emission of Eu3+ ions at 614 nm was clearly observed, while no emission of Eu3+ ions for the Eu3+‐doped sample. It may be ascribed to the energy transfer from SnO2 conduction band to Eu3+ conduction band. Further experimental results suggest that the energy transfer may be achieved through surface transition state. 相似文献
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YBO3:Eu荧光粉的水热法制备及形貌控制 总被引:5,自引:0,他引:5
用水热法在低于300℃成功地制备出具有不同形貌的YBO3:Eu3+荧光粉,其反应温度比固相反应了约800℃.研究了初始原料、pH值、反应温度、反应溶剂和催化剂等条件对目的产物形貌及粒度的,得到了具有Vaterite结构、粒度分布均匀的球形荧光粉的最佳合成工艺.在254nm激发下,水热法的球形Y0.95Eu0.05BO3荧光粉最强发射峰位于598nm处,属于Eu3+的5D0→7F1的跃迁,是固相反应所品的1.5倍.这些结果表明,在PDP和荧光灯等显示和照明用荧光粉的制备中水热法具有潜在的应用. 相似文献
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Spectral-luminescent characteristics of Sr2Y8(SiO4)6O2: Eu powder crystal phosphor with the apatite structure and high-intensity luminescence of Eu3+ ions have been studied. The charge state of europium in the samples has been characterized by means of X-ray L3-adsorption spectroscopy. It was established that Eu3+ forms two types of optical centers. Besides, luminescence of Eu2+ions was found. Reduction Eu3+→Eu2+ was considered, which may be due to vacancy formation in the 4f crystal lattice position and to negative charge transfer by this vacancy to two ions. Thus, in the silicate lattice there exist inhomogeneously distributed oxygen-deficient centers, which are responsible for nonradiative transfer of excitation energy to Eu3+ and Eu2+ ions. To study electron-vibrational interactions in the crystal phosphor samples, their IR and Raman spectra were examined. In the luminescence spectrum of Eu2+, a series of low-intensity bands caused by interaction of the 4f65d state of Eu2+ with silicate lattice vibrations was observed. 相似文献
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白色荧光粉NaGd(MoO4)2:Dy3+,Eu3+的水热合成及发光性能 总被引:1,自引:0,他引:1
采用谷氨酸辅助水热法合成了八面体形NaGd(MoO4)2:Dy3+,Eu3+白色荧光粉.X射线衍射结果表明,合成的样品为四方晶系的NaGd(MoO4)2纯相.扫描电子显微镜照片显示所制备的粒子为八面体形,各边长约为2μm.荧光光谱结果表明,在NaGd(MoO4)2:4%Dy3+,yEu3+(y=0,0.5%,0.6%,0.7%,0.8%,0.9%,1.0%)样品中,随着Eu3+掺入量的增加,Dy3+的发射峰逐渐减弱,而Eu3+的发射峰逐渐增强,说明Dy3+-Eu3+之间存在能量传递.通过色坐标图可知,当Eu3+掺杂量y=0.9%时,荧光粉的色坐标(0.338,0.281)与标准的白光色坐标(0.33,0.33)接近,表明NaGd(MoO4)2:4%Dy3+,0.9%Eu3+是很好的近紫外光激发下的白色荧光粉. 相似文献
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采用共沉淀法及1 200 ℃后续煅烧4 h,成功制备了CaSb2O6:Bi3+,Eu3+荧光粉,并对其结构及发光性能进行了研究。所制备荧光粉颗粒为六边形类圆饼状,平均尺寸在100~600 nm之间。对CaSb2O6:Bi3+,Eu3+发光的机理分析表明,Bi3+对Eu3+的发光存在高效的敏化与能量传递。当Bi3+和Eu3+的掺杂浓度分别为0.5%和8%,Eu3+位于580 nm(5D0→7F0 )处的荧光发射显著增强,Bi3+,Eu3+共掺样品的荧光强度是CaSb2O6:Eu3+的10倍左右。调节Bi3+/Eu3+离子掺杂比,色坐标呈现了从蓝、白光到红光的变化,表明该荧光粉可分别作为蓝或红色荧光粉使用,甚至可实现从蓝、白光到红光的自由调控,这为白光LED荧光粉的发展提供了参考。 相似文献