Luminescence modification of Eu3+-activated molybdate phosphor prepared via co-precipitation

Eu-activated CaMoO4 phosphors were co-precipitated in an aqueous solution, and NH3·H2O, NH4HCO3 and (NH2)2CO as pre-cipitating aid agents were compared based on the morphology and particle size distribution of the phosphor samples. Sm3+ as sensitizer ion was investigated on the luminescence of CaMoO4:Eu, and it could strengthen the 406 nm absorption of this phosphor. At last, the scheelite CaMoO4:Eu and wolframite ZnMoO4:Eu were selected to compare their host absorption. The result showed that the scheelite molybdate host exhibited stronger UV absorption than wolframite one.     

Fluorescence of complexes of EuⅢwith aromatic carboxylic acid-1,10-phenanthroline

Fluorescence of complexes of EuⅢwith aromatic carboxylic acid-1,10-phenanthroline@舒万艮 @周忠诚 @牛聪伟~~     

固溶体Ce1-xEuxO2-δ的导电性能

利用溶胶-凝胶法,经800℃焙烧10h合成了Ce1-xEuxO2-δ(x=0.05～0.50)固溶体.用X射线衍射仪检测了样品的结构,测量了样品的阻抗谱和电子顺磁共振谱.结果表明:当掺杂量x≤0.40时,固溶体的结构为单相立方萤石结构,晶胞参数随x的增加而增大.样品中存在Ce3 ,掺杂Eu3 可以抑制Ce4 离子的还原.通过掺杂使固溶体Ce1-xEuxO2-δ(x=0.10～0.40)的电导率提高,随着掺杂量x增加,电导率增大,并在x=0.20时达到最大值(500℃的电导率σ500℃=1.07×103S/cm);电导活化能减小,x=0.20时,电导活化能Ea达到最小值,为0.72eV.     

金属铕制备工艺的研究

本文采用正交实验的方法,研究了金属铕的制备工艺条件。实验结果表明,还原－蒸馏温度１１００℃,还原剂过量系数０．３,保温时间１．５小时,金属铕的纯度大于９９．９％,直收率大于９０％     

Eu(1-X)LnX(TTA)3Phen荧光配合物的原位合成和光固化荧光防伪油墨的性能研究

在EA基质中,合成了Eu(1-X)LnX(TTA)3Phen配合物(Ln=G d、Y和L a,TTA=噻吩甲酰三氟丙酮,Phen=1,10邻-菲咯啉,X=掺杂元素的摩尔分数)。红外光谱的分析表明,配合物的吸收峰被EA(EA=双酚A-环氧丙烯酸酯)基质掩盖,表现为EA的特征吸收;荧光激发光谱、荧光发射光谱的研究表明,在EA基质中Eu(1-X)LnX(TTA)3Phen配合物已经形成,并且表现出强的铕离子特征荧光。荧光体系经固化后的荧光强度明显低于固化前的荧光强度,并讨论了荧光猝灭机理。     

用BPhen作基质的铕配合物OLED发光机制研究

用具有良好电子传输/空穴阻挡性能的BPhen(4,7-diphenyl-1,10-phenanthroline)作基质,Eu(DBM)3pyzphen(pyzphen=pyrazino-[2,3-f][1,10]-phenanthroline,DBM=Dibenzoylmethane)作发射材料,成功制得了高效率、高亮度的有机电致发光器件OLED.器件的最大外量子效率为2.5%,最大电流效率为5.3 cd/A,最大亮度为1 320 cd/m2.在亮度为200和1 000 cd/m2时,器件的色坐标分别为(0.66,0.33)和(0.65,0.34).深入研究了该器件的发光机制,发现在电致发光(EL)过程中,载流子直接被Eu(DBM)3pyzphen陷获是主要的发光机制,同时在BPhen与Eu(DBM)3pyzphen间还存在着有效的能量传递.     

稀土离子掺杂对钛酸钡铁电记忆的影响

少量稀土离子并入钛酸钡晶格时降低晶粒尺寸和提高电绝缘性能的优势适于电子器件微小型化的开发,尤其是对于基于钛酸钡的铁电记忆功能的评价具有研究价值．由冷压陶瓷技术制备了镧系稀土中两个特殊元素铈和铕掺杂的钛酸钡陶瓷,电滞回线被测量,评价了稀土铈和铕在钛酸钡晶格并入对钛酸钡铁电记忆功能的影响．     

Luminescence and Preparation of LED Phosphor Ca_8Mg(SiO_4)_4Cl_2∶Eu~(2 )

Eu2 isthemostwell knownandextensivelyused activatorinmanysilicates,boratesandotherinorganic compounds[1～4].Itsemissioncomesfrom5d→4ftran sition,andtheemissionwavelengthcanvaryinvery broadranges.Sincethe5delectronsarelocatedat outershelloftheeuropiumion,…     

高纯金属铕的研制

采用二次蒸馏后铸锭的方法获得了氧含量低于300×10-6的高纯金属铕,用双层包装,内外包装都充氩气,外层内加稀土吸气剂,在储存和运输过程中,包装的金属铕不会氧化。采用此方法,可实现批量生产。     

Emission from Mo‐O charge‐transfer state and Yb3+ emission in Eu3+‐doped and nondoped molybdates under UV excitation

Molybdates of Li⁺ and Yb³⁺ are studied to investigate the luminescence under UV excitation. LiYb(MoO₄)₂ and Eu³⁺‐doped LiYb₁‐_xEux(MoO₄)₂ (x=001–1.0) phosphors were synthesized by solid state reaction under mixing of Eu₂O₃, Yb₂O₃, Li₂CO₃ and MoO₂ in air atmosphere. Two broad absorption bands centered at 333 and 236 nm are observed in LiYb(MoO₄)₂ compound. They are attributed to the ¹A₁→¹T₁ and ¹T₂ transitions due to the O^2?→Mo⁶⁺ electron transfers in MoO₄ tetrahedron. An emission band with a peak at about 440 nm is found, which is attributed to the ³T₁→¹A₁ transition of MoO₄. Appearance of near‐infrared (NIR) Yb³⁺ emission observed under UV excitation is understood by the MoO₄→Yb³⁺ Foerster‐Type energy transfer due to spectral overlap between the low‐energy tail of the broad 440 nm emission band and the high‐energy tail of the broad Yb³⁺ absorption band and due to short Yb³⁺‐MoO₄ distance. Yb³⁺ emission observed in LiYb_1?xEu_x(MoO₄)₂ by Eu³⁺ excitation is understood by the Eu³⁺→Yb³⁺ energy transfer by cross‐relaxation (CR) process between the ⁵D₀→⁷F₆ Eu³⁺ transition and the ²F_7/2→²F_5/2 Yb³⁺ transition. The CR efficiency shows maximum efficiency of 0.24 at x=0.15 of higher acceptor Yb³⁺ concentration than donor Eu³⁺ concentration. Three Yb³⁺ emission bands with peaks at 994, 1002, and 1023 nm are observed, depending on the excitation wavelength. This is explained by less‐shielded 4f electrons of Yb³⁺ by the 5s²5p⁶ outermost electron shells, which are also responsible for unusual broadband Yb³⁺ absorption and emission. From appearance of NIR Yb³⁺ emission under excitation by not only UV light but also red light, these compounds are expected to be suitable for efficient photovoltaic application to Si‐based solar cells.