Facile synthesis and photoluminescence of europium ion doped LaF3 nanodisks

LaF3 : Eu3+ (5.0 mol-% EU3+) nanodisks with perfect crystallinity were successfully synthesized by a simple method. The synthesis was carried out in an aqueous solution at room temperature without the use of templates or organic additives, The mechanism of formation of the nanodisks was explored, and the fluoride source (KBF4) is believed to play a key role in controlling the morphology of the final product. Furthermore, the size of the disk can be simply moderated by varying the concentration of the initial reactants. The room-temperature photoluminescence of LaF3 : Eu3+ with different morphologies and sizes were also investigated, and the results indicate that the emission intensity of the product is strongly affected by their size, shape, and other factors.

Europium ion labeling anti-HBs

A microsecond time-resolved laser fluorescence spectroscopic analysis set was developed, A chelate-cyclic anhydride of diethylenetrimin pentaacetic acid anhydride (DTPAA) was synthesized. An anti-HBs antibody was purified, A EU3+ -DTPAA-anti-HBs label was prepared by two step procedure. We described the optimal condtion with EU3+ as marker and DTPAA as chelate bounding to antibody molecule. Labeling parameters such as solvent pH, protein and chelate molar ratio, reaction time, separation method were discussed in detail.

DYNAMIC PROCESS OF VALENCE CHANGE OF EUROPIUM ION IN EUROPIUM DIFLUORIDE AT HIGH-TEMPERATURE

The dynamic process of the ionic valence changing from Eu~(2+) to Eu~(3+) in EuF_2 at high temperature has been investigated by ESCA, high,temperature X-ray diffraction, high temperature spectrum, high temperature magnetic Isusceptibility and Mssbauer spectrum. It has been shown that the formed Eu~(3+) exists in different compounds when EuF_2 is heated to high temperature in different atmospheres. In air, Eu~(3+) exists in the form of hexagonal EuOF, in nitrogen, in the form of orthogonal EuF_3 and non-hexa...

Structural and spectroscopic study of oxyfluoride glasses and glass-ceramics using europium ion as a structural probe

Transparent oxyfluoride glasses and beta-PbF(2) nanocrystals containing glass-ceramics were prepared with varying Eu(3+) content (0.3, 0.4, 0.5 and 0.6%). The effect of Eu(3+) content on the preparation of glass-ceramics was investigated. From differential scanning calorimetry, the T(x)-T(g)(T(x)-temperature of the onset of crystallization; T(g)-glass transition temperature) parameter for glasses has shown slight variation, and an exothermic peak near T(g) called the ceramization temperature (T(c)) has been observed. Heat treatments were performed at this temperature to obtain transparent glass-ceramics containing beta-PbF(2) nanocrystals, identified by x-ray diffraction. Heat treatments for different periods of time were performed and were observed to be very important in the control of the crystal size and of the crystallization rate. Based upon the absorption spectra, the scattering level due to the presence of beta-PbF(2) nanocrystals in the glass-ceramics was observed to be similar to that for the mother glasses. Detailed analysis of emission spectra and decay time measurements led to the identification of Eu(3+) ions as the beta-PbF(2) crystalline phase. Excitation spectra at 70 K show the interaction of Eu(3+) ions with the fluorogermanate network.

Improved efficiency of organic light-emitting diodes based on a europium complex by fluorescent dye

Improved efficiency of organic light-emitting diodes (OLEDs) based on europium complexes have been realized by using a fluorescent dye 4-(dicyanomethylene)-2-t-butyl-6 (1,1,7,7-tetramethyljulolidyl-9-enyl))-4H-pyran (DCJTB) doping. The luminous efficiency of the devices with a fluorescent dye in the emissive layer was found to improve two times of that in devices without fluorescent dye. The devices showed pure red light, which is the characteristic emission of trivalent europium ion with a full-width at half-maximum of 3 nm. The maximum brightness and luminous efficiency reached 1200 cd/m(2) at 23 V and 7.3 cd/A (2.0 Im/w), respectively, at a current density of 0.35 mA/cm(2).

Luminescent sol-gel thin films based on europium-substituted heteropolytungstates

Polyester thin films containing europium-substituted heteropolytungstate were obtained on quartz plate by the sol-gel method. The films exhibited the characteristic emission bands of the europium ion. The red to orange intensity ratio (R:O) of Eu3+ in the films increased as compared to the corresponding heteropolytungstate solids. The fluorescence lifetime of europium is shorter in the thin film than in the heteropolytungstate solid. The results indicated that the formation of europium-substituted heteropolytungstate/polyester thin film has great effect on the luminescence of europium- substituted heteropolytungstate.

Efficient red organic light-emitting devices based on a europium complex

An efficient organic light-emitting device using a trivalent europium (Eu) complex Eu(Tmphen)(TTA)(3) (TTA=thenoyltrifluoroacetone, Tmphen=3,4,7,8-tetramethyl-1,10-phenanthroline) as the dopant emitter was fabricated. The devices were a multilayer structure of indium tin oxide/N,N-diphenyl-N,N-bis(3-methylphenyl)-1,1-biphenyl-4,4-diamine (40 nm)/ Eu complex:4,4-N,N-dicarbazole-biphenyl (1%, 30 nm)/2,9-dimethyl,4,7-diphenyl-1,10phenanthroline (20 nm)/AlQ (30 nm)/LiF (1 nm)/Al (100 nm). A pure red light with a peak of 612 nm and a half bandwidth of 3 nm, which is the characteristic emission of trivalent europium ion, was observed. The devices show the maximum luminance up to 800 cd/m(2), an external quantum efficiency of 4.3%, current efficiency of 4.7 cd/A, and power efficiency of 1.6 lm/W. At the brightness of 100 cd/m(2), the quantum efficiency reaches 2.2% (2.3 cd/A).

Preparation and luminescence properties of hybrid materials containing europium(III) complexes covalently bonded to a silica matrix

A new kind of luminescent organic-inorganic hybrid material (denoted Hybrid I) consisting of europium 1,10-phenanthroline complexes covalently attached to a silica-based network was prepared by a sol-gel process. 1,10-Phenanthroline grafted to 3-(triethoxysilyl)propyl isocyanate was used as one of the precursors for the preparation of an organic-inorganic hybrid materials. For comparison purposes, the hybrid material (denoted Hybrid II) in which phenanthroline was not grafted onto the silica backbone of the frameworks was also prepared. Elemental analysis; NMR, FT-IR, UV/vis absorption, and luminescence spectroscopies, and luminescence decay analysis were used to characterize the obtained hybrid materials. It is shown that the homogeneity of Hybrid I is superior to that of Hybrid II, and a higher concentration europium can be incorporated into Hybrid I than Hybrid II. Excitation at the ligand absorption wavelength (283 nm) resulted in the strong emission of the Eu3+ D-5(0)-F-7(J) (J = 0-4) transition lines as a result of the efficient energy transfer from the ligands to the EU3+ in Hybrid I. The number of water molecules coordinated to the europium ion was estimated, and the structure of the as-synthesized Hybrid I was predicted on the basis of the experimental results.

Preparation of europium induced conformation-specific anti-calmodulin monoclonal antibody

Monoclonal antibody technique was employed to detect the conformational difference of CaM induced by metal ions. A trivalent europium ion induced conformation-specific anti-calmodulin monoclonal antibody was successfully prepared with europium-saturated calmodulin as antigen.

Preparation and luminescence properties of the ternary europium complex incorporated into an inorganic polymer matrix by a sol-gel method

Ternary europium complexes with thenoyltrifluoroacetone (TTA) and phenanthroline (phen) were incorporated into SiO2/polymer matrix by a sol-gel method. The gels exhibit the characteristic emission bands of europium ion. In addition, Eu3+ presents a longer fluorescence lifetime in gel than in the corresponding pure complex powder. Concentration effects on the luminescence intensity were investigated. The reasons that are responsible for above results are also discussed in the context.

The phase transitions of hetero atoms substituted molecular sieves Me-VPI-5(Me=Mg, Ti, Sn, Si) and their influence on spectra structures of Eu(III) ion

The hetero atom substituted aluminophosphate molecular sieves Me-VPI-5(Me = Mgt Ti, Sn, Si) were synthesized hydrothermally. Rare earth ions are originally doped into these microporous materials by aqueous solution ion exchange procedures. The phase transitions of the microporous materials are investigated by high-temperature and high-pressure experimental techniques. The influence of the phase transitions on the rare earth ions' spectral structures is discussed, With the increase of temperature, Eu(II)Mg-VPI-5 is converted into Eu(II)Mg-AIPO(4)-8, then into tridymite phase. The pressure has a notable influence on Eu(II) ion's spectral structures. The spectral structures have changed regularly with the increase of pressure.

MOSSBAUER-EFFECT STUDIES ON SOME BIOINORGANIC COMPLEXES OF EUROPIUM

The bioinorganic complexes of europium with N-acetyl-DL-alanine, N-acetyl-DL-valine, and DL-alanyl-DL-alanine have been synthesized and the Mossbauer spectra at room temperature have been measured for these solid state complexes. The Mossbauer parameters indicate that the water molecules in these complexes are not directly linked to the central europium ion and are outside the coordination sphere of europium and biological ligands, and that the chemical bond between the europium ion and the ligands may be predominantly ionic in character, with the possibility of partial covalent contribution.

THERMAL DECOMPOSITIONS OF SOME BIOINORGANIC COMPLEXES OF EUROPIUM

Thermogravimetric and derivative thermogravimetric investigations for three kinds of bioinorganic complexes of europium with N-acetyl-DL-alanine, N-acetyl-DL-valine and DL-alanyl-DL-alanine have been performed. It was found that the water molecules in these solid state complexes are not directly coordinated to the europium ion and that there may be three or four steps in the thermal decomposition process of these complexes after dehydration. The possible thermal decomposition reactions of these bioinorganic complexes have been suggested and discussed.

Visible light sensitisation of europium(III) luminescence in a 9-hydroxyphenal-1-one complex

The 9-hydroxyphenal-1-one ligand forms stable 3 : 1 complexes with trivalent lanthanides, in which it acts as an antenna suitable for the visible light excitation ( up to 475 nm) of the trivalent europium ion.

Correlation between structural data and spectroscopic studies of a new beta-diketonate complex with trivalent europium and gadolinium

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