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采用高温固相反应法制备Sr3SiO5:Eu2+时,往往有Sr2SiO4:Eu2+共存,从而影响Sr3SiO5:Eu2+的发光性能.本文采用DSC/TG、淬冷法结合XRD,研究了Sr3SiO5:Eu2+在降温过程中的分解反应.结果表明,Sr3SiO5是在1 250℃以上稳定存在的化合物,在降温过程中Sr3SiO5在1 250℃分解为Sr2SiO4和SrO.采用快速降温的方法可以抑制Sr3SiO5的分解.当降温速率小于10℃·min-1时,Sr3SiO5全部分解为Sr2SiO4和SrO;当降温速率为15℃·min-1时,样品主要物相为Sr3SiO5,但有少部分Sr3SiO5发生分解,当降温速率增大到20℃·min-1时,Sr3SiO5分解的量更少,即随着降温速率增大,Sr3SiO5分解的量减小,从而获得几近纯相的Sr3SiO:Eu2+荧光粉. 相似文献
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Sr2SiO4:Eu3+发光材料的制备及其光谱特性 总被引:3,自引:0,他引:3
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. 相似文献
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GdPO4:Eu3+和GdBO3:Eu3+中"Gd-Eu"间的能量传递 总被引:1,自引:0,他引:1
利用同步辐射光源(德国HASYLAB实验室的SUPERLUMI实验站)对高温固相法制备的GdPO4 Eu3+和GdBO3Eu3+的发射谱与激发谱进行了研究, 并从量子剪裁的角度对"Gd3+-Eu3+"之间的能量传递作了讨论. 在两种样品监测Eu3+红光发射的激发谱上, 都显著观察到了对应Gd3+离子4f-4f跃迁的谱线, 说明从基质中Gd3+离子向掺杂的Eu3+离子之间存在非常有效的能量传递, 这有利于量子剪裁的发生. 在激发谱上还观察到了对应Eu3+-O2-电荷迁移态的宽激发带(180~270 nm), 而对应Gd3+离子8S7/2→6GJ跃迁的谱线(196 nm, 203 nm)叠加在这个宽带之上, 微弱可辨, 这不利于Gd3+-Eu3+间交叉弛豫的能量传递过程, 从而不利于量子剪裁的发生. 结合Eu3+-O2-电荷迁移态位置变化的规律, 提出了如何避开其干扰以增强量子剪裁效应的材料设计方案. 相似文献
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《Journal of solid state chemistry》1986,63(1):86-88
The critical concentration for quenching of the Eu3+ luminescence is calculated theoretically for several Gd3+ : Eu3+ systems. A comparison is made with the experimental values. The results are discussed in terms of energy migration. 相似文献
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Yuanbin Liao Yucheng Zhan Nan Chen Guoping Du 《Journal of Sol-Gel Science and Technology》2013,65(3):353-358
Well-dispersed Eu3+ and Sr2+ co-doped YVO4 luminescent particles (YVO4:Eu3+,Sr2+) on the submicron scale were prepared by a facile solvothermal method at low temperature. The effect of Sr2+ doping on the luminescence of YVO4:Eu3+,Sr2+ particles was investigated by fixing the Eu3+ doping concentration at 7 mol%. It was found that the luminescence intensity of the as-prepared YVO4:Eu3+,Sr2+ particles increased with the Sr2+ doping concentration x to reach a two-fold enhancement when x = 5 %, and then decreased for higher x. We also investigated the effect of thermal annealing on the luminescence properties of the YVO4:Eu3+ and YVO4:Eu3+,Sr2+ particles. A remarkable enhancement in their luminescence properties was observed after annealing at 900 °C in air for 30 min. It was showed that the annealed YVO4:Eu3+,Sr2+ particles exhibited a two-fold stronger emission than the annealed YVO4:Eu3+. This work indicates that Sr2+ doping is beneficial to the luminescence enhancement for both the as-prepared and annealed YVO4:Eu3+,Sr2+ particles. 相似文献
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Eu3+掺杂的Sr2CeO4荧光材料的燃烧法合成及其性能研究 总被引:8,自引:0,他引:8
以尿素作燃料,Sr,Ce和Eu的硝酸盐作反应物,采用燃烧法得到了稀土Eu3 掺杂的Sr2CeO4前驱体粉末.将前驱体在一定温度下烧结3 h,合成了红色荧光材料.经过对材料进行X射线衍射(XRD)分析,确定了烧结温度在1050~1200℃时,能够得到纯度较高的产品.用扫描电镜(SEM)观察到样品烧结后的形貌为不规则的椭圆形,粒径范围在1~3 μm之间.样品的发射光谱和激发光谱表明,Eu3 在Sr2CeO4基质中有很高的猝灭浓度(10%,摩尔分数),随着Eu3 掺杂浓度的增加,可以使蓝白光调整到红白光,进而到红光. 相似文献
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Sr2CeO4∶Eu3+柠檬酸-凝胶法的合成及发光性质研究 总被引:13,自引:0,他引:13
柠檬酸-凝胶方法促使多离子在分子水平上混合,与固相烧结方法相比,能够降低烧结温度和烧结时间。利用这种方法在1000℃下很短的时间得到单相化合物Sr2CeO4。Sr2CeO4是一种发出很强蓝光的基质发光材料。为寻找新的发光体,我们将稀土离子Eu3+掺杂在其中,从荧光光谱上可以看出存在从基质向稀土离子的能量转移。Sr2CeO4∶Eu3+的发光颜色可调谐,当Eu3+离子浓度较小(< 0.5mol%)时,体系发出很强的白光;当Eu3+离子浓度较大(>10mol%)时,体系发出很强的红光,并且猝灭浓度高。 相似文献
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Eu2+和Pb2+离子在Sr4Si3O8Cl4中发光的研究 总被引:2,自引:0,他引:2
本文研究了Sr4Si3O8Cl4基质的物理化学性质和以Eu<2+、Ph2+离子为激活剂的荧光体的发射光谱、激发光谱、反射光谱及激活剂浓度对发光性能的影响。 相似文献
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Xiangyu Xu Yuxin Liu Zhi Lv Jiaqing Song Mingyuan He Qian Wang Lijun Yan Zhaofei Li 《Journal of Thermal Analysis and Calorimetry》2014,118(3):1585-1592
Eu3+-doped boehmite nanofiber materials with different Eu3+ concentrations were synthesized without any surfactant, and followed by a series of characterizations. It was found that the boehmite nanofibers became coarser with the increase of Eu3+ concentration, which resulted in a gradual decrease of their specific surface areas. Moreover, the thermal stability of the boehmite nanofibers was studied by thermogravimetry–differential scanning calorimetry. All materials showed the phase transition from γ-Al2O3 to other forms. Yet the transition temperature was increased with the increase of Eu3+ concentration. The Eu3+-doped boehmite nanofibers with the maximum Eu3+ concentrations showed the best thermal stability. Photoluminescence spectra showed that the 2 mol% of doping concentration of Eu3+ ions in Eu3+:Al2O3 nanofiber was optimum. 相似文献
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A detailed thermodynamic examination of the selective extraction of Am(3+) from Eu(3+) by two dithiophosphinic acids was performed using DFT. By examination of two extractants with two metal ions, the most uncertain terms of these calculations were eliminated, resulting in free energies (ΔΔΔG(ext)) that are directly related to the selectivity data. The calculated relative selectivities agree well with experimental data, indicating that the extraction factor is primarily due to the binding free energy of the ligands to the metals and is not dependent on side reactions or complicated solvent effects. 相似文献
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Colín Calderón Víctor H. García Murillo Antonieta Medina Velázquez Dulce Y. Carrillo Romo Felipe de J. Garrido Hernández Aristeo Díaz Cruz Manuela 《Journal of Sol-Gel Science and Technology》2021,100(1):160-169
Journal of Sol-Gel Science and Technology - Hybrid materials based on lanthanide ions or lanthanide-doped nanostructured particles have received a lot of recent attention because organic ligands... 相似文献
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Sr4Al14O25:Eu2+长余辉发光材料浓度淬灭研究 总被引:8,自引:3,他引:8
采用固相法制备Sr4Al14O25∶Eu2 长余辉发光粉体. 研究了Eu2 离子在铝酸盐基体中的发光行为以及浓度淬灭过程与淬灭机制. 结果表明, Eu2 在基体中形成两种不同发光中心, 分别为Eu1和Eu2, 具有不同的配位数. 在紫外光激发后, 发射波长分别为400 nm和486 nm. Eu2 离子在Sr4Al14O25中的浓度淬灭包含两个不同的淬灭过程. 随着Eu2 离子浓度的增大, Eu1格位的发光通过将能量传递给Eu2而产生淬灭现象. 随着Eu2 离子浓度的继续增大, Eu2格位的发光通过将能量传递给周围晶格缺陷而淬灭. 从实验和理论计算的结果来看, Eu2 离子在Sr4Al14O25∶Eu2 中的能量传递方式有两种, 一是光能的重吸收, 二是通过电子偶极-偶极作用交互方式传递能量. 相似文献
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In this paper, we report the effects of the substitution of Sr by Eu on the properties of Bi-2201 ceramics. Samples with nominal compositions of Bi2Sr2?xEuxCuOy (x = 0–0.4) are elaborated in air by solid state reaction. They are characterized by means of X ray diffraction (XRD), scanning electron microscopy (SEM), magnetic and resistivity measurements. The undoped sample (x = 0) is monophasic and its structure belongs to phase A. No trace of superconductivity is observed down to 2 K for this sample and the variation of resistivity with temperature shows a semiconducting behaviour. As Eu is added and for x ≥ 0.2, the samples convert totally to B or Raveau phase and become superconducting. The highest Tc, obtained from both magnetic and resistivity measurements, is observed for x = 0.3. In the normal state, all the samples exhibit a semiconducting character which decreases as well as resistivity when the Eu content increases. The refinement of cell parameters is done with considering the structural modulation. The study shows that the substitution of Sr2+ by Eu3+ leads to an increase of a and b parameters, while c decreases similarly to those of the La doped phases. The a axis component of the modulation is observed to be independent of Eu content, while the c axis one increases slightly as this content increases. The XRD analysis has also revealed that the limit solubility of the used Eu2O3 oxide is situated between x = 0.3 and 0.4 of Eu content. The SEM micrographs show that the undoped sample consists of poorly connected grains with a random distribution. A quite different microstructure is obtained for the doped samples. The grains are more connected and have a flat shape which is characteristic of the Bi-based superconductors. 相似文献
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A novel method for synthesizing long afterglow silicate phosphor Sr3MgSi2O8:Eu^2+,Dy^3+using TEOS and inorganic powders as reactants was reported. Acetic acid as a catalyzer controlled the hydrolysis of TEOS by adjusting pH value of the system. The morphologies of precursor were characterized by transmission electron microscope (TEM). The structure and optical properties of the phosphor powders were systematically investigated by means of X-ray diffraction and spectrofluorometry. TEM images have reflected the core-shell structure and quasi-spherical morphology of the precursor particles. It was found that the single-phase Sr3MgSi2O8 crystalline structures were obtained at 1050 and 1250 ℃ for the samples prepared with the nano-coating method and the solid state reaction, respectively. The emission intensities of the phosphors prepared by the present method were higher than those by the conventional process. Also, the afterglow characteristic was better than that prepared by solid-state reaction in the comparable condition. 相似文献
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Jin Young Park Hong Chae Jung G. Seeta Rama Raju Byung Kee Moon Jung Hyun Jeong Jung Hwan Kim 《Solid State Sciences》2010,12(5):719-724
A series of Eu3+ ions co-doped (Gd0.9Y0.1)3Al5O12:Bi3+, Tb3+ (GYAG) phosphors have been synthesized by means of solvothermal reaction method. The XRD pattern of GYAG phosphor sintered at 1500 °C confirms their garnet phase. The luminescence properties of these phosphors have been explored by analyzing their excitation and emission spectra along with their decay curves. The excitation spectra of the GYAG:Bi3+, Tb3+, Eu3+ phosphors consists of broad bands in the shorter wavelength region due to 4f8 → 4f75d1 transition of Tb3+ ions overlapped with 6s2 → 6s16p1 (1S0 → 3P1) transition of Bi3+ ions and the charge transfer band of Eu3+–O2?. The present phosphors exhibit green and red colors due to 5D4 → 7F5 transition of Tb3+ ions and 5D0 → 7F1 transition of Eu3+ ions, respectively. The emission was shifted from green to red color by co-doping with Eu3+ ions, which indicate that the energy transfer probability from Tb3+ to Eu3+ ions are dependent strongly on the concentration of Eu3+ ions. 相似文献
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Yu J Hao Z Zhang X Luo Y Zhang J 《Chemical communications (Cambridge, England)》2011,47(45):12376-12378
Eu(2+) singly and Eu(2+), Mn(2+) co-doped Sr(2)Mg(3)P(4)O(15) exhibit not only the well known blue emission band of Eu(2+) peaking at 448 nm but also a new band at 399 nm in violet. They are attributed to Eu(2+) on different Sr(2+) sites. The Eu(2+) for the violet band can transfer energy to the red emitting Mn(2+) more efficiently than Eu(2+) for the blue band. The new Eu(2+) band could enable Sr(2)Mg(3)P(4)O(15):Mn(2+), Eu(2+) to be a promising phosphor for enriching the red component of white LEDs. 相似文献
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Preparation of Sr2CeO4:Eu3+,Dy3+ white luminescence phosphor particles and thin films by using an emulsion liquid membrane system 总被引:3,自引:0,他引:3
Sr(2)CeO(4) and Sr(2)CeO(4):Eu(3+),Dy(3+) phosphor particles and thin films were prepared by using an emulsion liquid membrane (ELM, water-in-oil-in-water (W/O/W) emulsion) system, containing VA-10 (2-methyl-2-ethylheptanoic acid) as extractant (cation carrier). A two-step extraction enabled efficient extraction for Sr(3+) and rare earth ions, and the resulting precursor metal oxalate particles produced in the internal water phase of the ELM system were about 60 nm in diameter. Calcination of the oxalate particles in air gave submicrometer-sized Sr(2)CeO(4) and Sr(2)CeO(4):Eu(3+),Dy(3+) particles, which showed blue and white luminescence, respectively, by UV excitation. Blue and white luminescence phosphor thin films were also prepared by soaking alumina substrates into the W/O emulsion containing precursor oxalate particles, followed by calcination in air. 相似文献