CaSiO3:Eu的发光性质

采用高温固相反应法合成出CaSiO3：Eu^3 荧光体。研究了其荧光性质。样品的晶体结构为α-CaSiO3和β-CaSiO3的混合相，其激发光谱的峰位位于240，320，362，383，394，415nm，分别对应于O→Eu的电荷迁移带和^7F0．1-^5H3，^5D4，^5GJ，^5L6，^5D3的吸收跃迁。在240nm和394nm激发下，Eu^3 离子的^5D0→^7F2电偶极跃迁最强，表明Eu^3 离子占据更多的非反演中心格位。研究了不同电荷补偿剂对发光性能的影响，以Li^ 离子的电荷补偿效果最好。     

配合物Eu(Sal)_2(phen)_2(NO_3)的合成及荧光性能的研究

用硝酸铕、水杨酸与邻菲罗啉为原料合成了配合物Eu(Sal)2(phen)2(NO3),考察了配体用量和溶剂用量等因素对反应的影响。通过元素分析、红外光谱和紫外光谱确定了配合物的组成及结构,并通过荧光光谱对其荧光性质进行了研究。     

溶胶-凝胶法制备的BaMgAl_(10)O_(17)∶Eu前驱体的晶化过程(英文)

采用柠檬酸作为螯合物的溶胶-凝胶法制备了BaMgAl10O17∶Eu(bariummagnesiumaluminate,BAM)蓝色荧光粉,并研究了其晶 化过程。通过X 射线衍射、扫描电镜和荧光光谱等表征手段,研究了前驱体晶化过程的焙烧条件、结晶动力学、颗粒大小和发光性能等。BAM 晶相在1100℃开始产生。温度达1200℃时,前驱体由无定型态完全转变成BAM晶相。在1120～1300℃时晶化反应的表观活化能为 233kJ/mol。在室温下测得荧光粉的最大吸收峰和发射峰分别处在334nm和454nm。合成荧光粉的粒径为5μm左右,其形态和粒径取决于 前驱体。     

KINETIC SPECTROPHOTOMETRIC DETERMINATION OF TRACE AMOUNT OF EUROPIUM BASED ON ITS INHIBITORY EFFECT OF THE OXIDATION OF SWITZERLAND PIGMENT BY POTASSIUM BROMATE

In 4.0 × 10^?3 mol/L of hydrogen chloride medium, a trace of europium(III) plays a good inhibitory role in the fading reaction of Switzerland pigment oxidized by potassium bromate. Based on this principle, an inhibitory kinetic spectrophotometric method for the determination of trace europium was developed. A maximum absorption wavelength locates at 600 nm and a good linear range is presented over 0 – 0.18 µg/mL of europium(III) under the optimum conditions. The regression equation for the determination of europium(III) is ΔA = 4.495C(C:μg/mL) + 0.0278 with a correlation coefficient of 0.9965. The detection limit of the method was 19 ng/mL. The apparent activation energy of the inhibitory reaction and the reaction half-life period were 5.76 KJ/mol and 15.61 min, respectively. This method has been successfully used in the determination of europium in molecular sieve samples.     

Effect of the Concentration of Metal Ions on their Adsorption on Various Hydrous Iron and Aluminum Oxides

The adsorption of Eu(III) and Co(II) on laboratory-prepared amorphous hydrous iron and aluminum oxides, goethite and gibbsite, was studied as a function of pH over a wide range of metal ion concentrations, in order to see the effect of the change in the degree of site occupation by metal ions. When the metal ion concentrations were low, a simple Langmuir equation with a single adsorption constant was able to describe adsorption on these hydrous oxides. At high metal ion concentrations, adsorption on goethite and gibbsite exhibited clear saturation maxima expected from a simple one-to-one interaction between the metal ion and the adsorption site, while adsorption on laboratory-prepared hydrous oxides continued to increase gradually even at high metal ion concentrations.     

Displacement and Luminescence of Eu~(3 ) in CaYBO_4

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Rapid Determination of Bitterness in Beer Using Fluorescence Spectroscopy and Chemometrics

Two fluorescence spectroscopic methods with the aim to develop a fast quantitative determination of bitterness in beer were tested. The first method was based on autofluorescence of the diluted and degassed beer samples without any further processing. A total of 21 dark and light beer samples were analyzed and multivariate Partial Least Squares (PLS) regression models to bitterness in form of international bitter units (IBU) were performed. A prediction error in the form of Root Mean Square Error of Cross‐Validation (RMSECV) of 2.77 IBU was obtained using six PLS components. Focusing only on the light beer samples the RMSECV was reduced to 1.81 IBU. The second method developed was based on addition of europium to induce delayed fluorescence signals in the beer samples. PLS models yielded an RMSECV of 2.65 IBU for all beers, while a model on the light beer samples gave an RMSECV of 1.75 IBU. The obtained prediction errors were compared to the errors given in the literature for the traditional extraction method of determining IBU.     

Syntheses and cofluorescence of complexes of Eu（Ⅲ）/Y（Ⅲ） with terephthalic acid, 2-thenoyltrifluoroacetone and trioctylphosphine oxide

A series of Eu（ Ⅲ）/Y（Ⅲ） complexes of terephthalic acid（TPA） with 2-thenoyltrifluoroacetone（HTTA） and trioctylphosphine oxide（TPPO） were synthesized. Compositions of these complexes are revealed to be Eu2（1-x）Y2x（TPA）（TTA）4- （TPPO）4 or EU1-xYx（TPA）（TTA）（TPPO）2. Their 1R spectra, fluorescent spectra and the thermal and optical stability were studied. The fluorescent excitation spectra of these complexes show more broad excitation bands than those of Eu2（TPA）3（TPPO）4 and Eu（TTA）3（TPPO）2 corresponding to their formations. In addition, both the binuclear complex EuY（TPA）（TTA）4（TPPO）4 and the chain complex EU0.4Y0.6（TPA）（TTA）（TPPO）2 present higher thermal stability and better optical stability than the mononuclear complex Eu（TTA）3（TPPO）2 does. And their thermal and optical stabilities are preferably interpreted from the binuclear structure together with the chain polynuclear structure of the complexes. The fluorescence enhancement of cofluorescence Y^3＋ ions to the Eu（Ⅲ） complexes is clear. The optimum content of Y^3＋ is 0.6 （molar fraction） for the chain complexes Eu1-xYx（TPA）（TTA）- （TPPO）2 and 0.5 for the binuclear complexes Eu^2（1-x）Y2x（TPA）（TTA）4（TPPO）4. The formation of polynuclear structure of the complex Eu1-xYx（TPA）（TTA）（TPPO）2 appears to be responsible for the good cofluorescence effect of Y^3＋ ions.     

Electroluminescence Based on Eu0.5 La0.5 （TTA） a phen Doped Poly N-Vinylcarbazole

A novel rare earth complex Eu_0.5La_0.5(TTA)₃phen, displaying electroluminescent property, was synthesized, and monolayer and double-layer devices were fabricated by doping it into poly N-vinylcarbazole. The characteristics of these optimized devices were investigated, and the emitting mechanism was explained through the energy band diagram. Optimized double-layer devices with a turn-on voltage of 6.5 V were achieved. At the current density of 68.48 mA·cm⁻², the maximum brightness and the current efficiency of the device reached 238.4 cd·m⁻² and 0.35 cd·A⁻¹, respectively.     

Ho~(3 )对二苯亚砜高氯酸铕配合物发光的影响

合成了高氯酸铕二苯亚砜和不同物质量比的高氯酸 ( )、钬 ( )二苯亚砜异核配合物 (Eux Ho1 - x)(DPSO) 7(Cl O4) 3 。测定了配合物的组成、IR、粉晶荧光激发和发射光谱。荧光光谱表明 :虽然 Ho3 的发射几率较高的 5S2 激发态能级高于 Eu3 ,但并未对 Eu3 的发光产生敏化作用 ,相反当掺入 0 .0 0 2 mol的 Ho3 时即对 Eu3 的发光产生猝灭作用。另外从 Eu3 的荧光光谱知 :5D0 → 7F2 的电偶极跃迁强度大大高于 5D0 → 7F1 的磁偶极跃迁 ,这表明铕 ( )在配合物晶体中处于非对称中心的位置。