Study on Luminescence Properties of a Novel Rare Earth Complex Eu（ TTA）2 （N-HPA） Phen

A novel rare earth complex Eu（TTA）2（N-HPA）Phen （TTA = thenoyltrifluoroacetone, N-HPA = N-phenylanthranilic acid, and phen = 1,10-phenathroline ）, which contains three different ligands, was synthesized. The Eu complex was blended with poly N-vinylcarbazole （PVK） in different weight ratios and spin coated into films. The luminescence properties of films were investigated and energy transfer between PVK and the complex was discussed. Multilayer structural devices consisting of ITO/PVK： Eu （TTA）2 （N-HPA） phen/BCP/Alq3/Al were fabricated with PVK ： Eu （TTA）2（N-HPA） as light-emitting layer. Increasing the concentration of Eu in the PVK thin film would inhibit the emission of PVK to different degrees. Finally, the pure red luminescence of europium（ Ⅲ ） was observed when the doping weight ratio was approximately 1 ： 5, which indicated an effective energy transfer from PVK to rare earth complex.     

Tb^3＋ concentration dependent optical properties and energy transfer in GdF3 nanocrystals

By controlling the concentration of Tb3＋, a series of GdF3 samples were synthesized by a hydrothermal method without any surfactant. The samples were characterized by X-ray diffraction （XRD） patterns, field emission scanning electron microscopy （FE-SEM） images, photoluminescence （PL） excitation and emission spectra as well as luminescent dynamic decay curves. The opti-cal properties of Tb3＋, the concentration quenching phenomenon of Tb3＋, and the energy transfer from host Gd3＋to Tb3＋were inves-tigated and discussed based on the concentration of Tb3＋in the GdF3 samples. The experimental results suggested that the optical properties of Tb3＋and the energy transfer from host Gd3＋to Tb3＋could be adjusted by the concentration of Tb3＋in the samples.     

Photoluminescent properties of Eu3＋ and Tb3＋ codoped Gd2O3 nanowires and bulk materials

In this paper, the Gd2O3：Eu3＋,Tb3＋phosphors with different doping concentrations of Eu3＋and Tb3＋ions were prepared by a hydrothermal method for nanocrystals and the solid-phase method for microcrystals. The interaction of the doped ions with different concentrations and the luminescent properties of the nanocrystals and microcrystals were studied systematically. Their structure and morphology of Gd2O3：Eu3＋,Tb3＋phosphors were analyzed by means of X-ray powder diffraction （XRD）, transmission electron mi-croscopy （TEM） and scanning electron microscopy （SEM）. The photoluminescence （PL） properties of Gd2O3：Eu3＋,Tb3＋phosphors were also systematically investigated. The results indicated that when the concentration of doped Eu3＋was fixed at 1 mol.%, the emis-sion intensity of Eu3＋ions was degenerating with Tb3＋content increasing, while when the Tb3＋content was fixed at 1 mol.%, the emission intensity of Tb3＋ions reached a maximum when the concentration of Eu3＋was 2 mol.%, implying that the energy transfer from Eu3＋to Tb3＋took place. In addition, Tb3＋could inspire blue-green light and the Eu3＋could inspire red light. Therefore co-doping systems by controlling the doping concentration and the hosts are the potential white emission materials.     

Electroluminescent Property of A Novel Co-Doped Rare Earth Complex

A novel co-doped rare earth complex Gd0.5Eu0.5（TTA）3Dipy was synthesized and chosen as the emitter material in the organic electroluminescent device ITO/PVK：Gd0.5 Eu0.5 （TTA）3Dipy/PBD/A1. It was proved that there was Forster energy transfer from Gd^3＋ to Eu^3＋. The electroluminescent mechanism of the device was proposed by measuring and analyzing the emission and the excitation spectra of the emissive layer. Gd^3＋ might play the role of promoting the en- ergy transfer from PVK to Eu^3＋ and inhibiting an intrinsic luminescence of PVK. The device displayed red light with good monochromaticity. The possible energy transfer process of the device was preliminarily discussed.     

Synthesis and fluorescence properties of Eu（Ⅲ）, Tb（Ⅲ） and Sm（Ⅲ） with β-diketone and 2,2＇- bipyridine

Three new rare earth ternary complexes,RE(PPP)3bpy(RE=Sm 3+ ,Eu 3+ ,Tb 3+ ),were synthesized by the reaction of 1-phenyl-3-(p-phenylethynylphenyl)-1,3-propanedione(HPPP)and 2,2′-bipyridine(bpy)with rare earth chloride RECl3,respectively,in alcohol solution. The compositions were characterized by means of infrared(IR)spectra,chemical analysis,elemental analysis,and thermodynamic analysis.Luminescent properties of the three complexes were studied.At room temperature,under UV light excitation,the Sm 3+ ,Eu 3+ and Tb 3+ complexes exhibited characteristic emission of the central ions.The fluorescence spectra showed that the fluorescence emission intensity of Eu 3+ complex was the strongest.The narrow strongest emission band of Eu 3+ complex was considered to be a valuable material with bright red fluorescence.     

Study of Electroplex Emission from Organic Electroluminescent Devices with Rare Earth Complex

A novel organic electroluminescent device was made with the structure of ITO/PVK：Tb0.5Eu0.5（TTA）3 Dipy/ BCP/Alq3/Al（a） which utilized the rare earth complex Tb0.5Eu0.5（TTA）3 Dipy as the emitting layer. When it was driven under a direct electric field, 612 nm emission from EU^3＋ and 410 nm emission from PVK were observed. In addition, in the EL spectrum a new peak at 490 nm appeared. From the analysis of different devices, the mechanism of the new emission was studied. It was concluded that the new emission was the electroplex originating from the interface between the ligand （TTA）3Dipy and BCP.     

Energy Transfer from PVK to Europium Complex in Electroluminescence

The spectra of solutions, films and light-emitting diodes of rare earth complexes were studied. It is shown that the absorption spectra of PVK-dopping rare earth complexes can be red-shifted to the visible region and overlap with the emission spectrum of PVK, which makes the energy transfer possible from PVK to the rare earth ion.     

Interaction of TbCl3 and lanthanide complexes with poly（N-vinylpyrrolidone）

The interaction of TbCl3 and lanthanide(III) β-diketonate complexes with poly(N-vinylpyrrolidone)(PVP) polymer was studied using fluorescence spectroscopy. In the presence of PVP the emission of Tb3+ in ethanolic solution of TbCl3 significantly increased owing to the excitation energy transfer from PVP to Tb3+ ions, which was more efficient as compared to a direct excitation of the Tb3+ 4f75d1 levels. In contrast, emission of NEt4Tb(hfa)4 and NEt4Eu(hfa)4 complexes was almost completely quenched in solution containing PVP. The PVP bound both Ln3+ ions and hfa ligands which caused decomposition of Ln-hfa complexes and switched off the excitation energy transfer from the ligand to the emitting Ln3+ ion. The important role of hydrogen bonds in stabilization of interaction of hfa ligands with PVP was indicated.     

Energy transfer in Tb~（3＋）,Yb~（3＋） codoped Lu_2O_3 near-infrared downconversion nanophosphors

Tb3+ and Yb3+ codoped Lu2O3 nanophosphors were synthesized by the reverse-strike co-precipitation method. The obtained Lu2O3:Tb3+,Yb3+ nanophosphors were characterized by X-ray diffraction (XRD) and photoluminescence (PL) spectra. The XRD results showed that all the prepared nanophosphors could be readily indexed to pure cubic phase of Lu2O3 and indicated good crystallinity. The Tb3+→Yb3+ energy transfer mechanisms in the UV-blue region in Lu2O3 nanophosphors were investigated. The experimental results showed that the strong visible emission around 543 nm from Tb3+ (5D4→7F5) and near-infrared (NIR) emission around 973 nm from Yb3+ (2F5/2→2F7/2) of Lu2O3:Tb3+,Yb3+ nanophosphors were observed under ultraviolet light excitation, respectively. Tb3+ could be effectively excited up to its 4f75d1 state and relaxed down to the 5D4 level, from which the energy was transferred cooperatively to two neighboring Yb3+. The Yb3+ concentration dependent luminescent properties and lifetimes of both the visible and NIR emissions were also studied. The lifetime of the visible emission decreased with the increase of Yb3+ concentration, verifying the efficient energy transfer from the Tb3+ to the Yb3+. Cooperative energy transfer (CET) from Tb3+ to Yb3+ was discussed as a possible mechanism for the near-infrared emission. When doped concentrations were 1 mol.% Tb3+ and 2 mol.% Yb3+, the intensity of NIR emission was the strongest.     

Luminescent Properties of Green Phosphor Ca8Mg（SiO4 ）4 Cl2：EU^2＋ , DY^3＋ for LED Applications

The new phosphor calcium magnesium chlorosilicate, codoped with Eu^2＋ and Dy^3＋, was synthesized with the help of the high temperature solid state reaction in reducing atmosphere. The excitation and emission spectra were very similar to that of Ca8Mg（SiO4）4Cl2 ：Eu^2＋, and the Dy^3＋ concentration influenced the emission intensity of this phosphor. The intensity of Eu^2＋ and Dy^3＋ codoped CMSC was stronger than that of Eu^2＋ singly doped CMSC. The emission spectrum of the Dy^3＋ ion overlapped the absorption band of the Eu^2＋ ion, indicating that an energy transfer from Dy^3＋ to Eu^2＋ took place in CMSC：Eu^2＋, Dy^3＋ phosphor. The mechanism of the energy transfer from Dy^3＋ tO Eu^2＋, in this phosphor, might be resonant energy transfer.     

Photoluminescence properties of（Gd1-xEux）Ba3B9O18 red emitting phosphors

Eu3+-activated GdBa3B9O18 phosphors were prepared by solid-state reaction at high temperature, and their photoluminescence (PL) properties were investigated. (Gd1-xEux)Ba3B9O18 formed solid solutions in the range x=0-1.0. The optical band gaps calculated from absorption spectra were 5.54 eV for GdBa3B9O18 and 5.17 eV for EuBa3B9O18. Unactivated GdBa3B9O18 exhibited a typical characteristic excitation and emission of Gd3+ ion. The (Gd1-xEux)Ba3B9O18 phosphors showed well-known Eu3+ excitation and emission. The energy transfer from Gd3+ to Eu3+ was verified with PL spectra. The dependence of PL intensity on Eu3+ concentration was also studied in detail. The luminescence decay measurements indicated that the lifetimes of 5D0→7F1 transition of Eu3+ were in the order of millisecond.     

Fluorescence and Judd-Ofelt analysis of rare earth complexes with maleic anhydride and acrylic acid

Two kinds of Eu-complexes, Eu(TTA)2(Phen)(AA) and Eu(TTA)2(Phen)(MA) (HTTA=2-Thenoyltrifluoroacetone, Phen=1,10- phenanthroline, AA=acrylic acid, MA=Maleic anhydride), which combined the excellent fluorescence properties of Eu(TTA)2(Phen)(H2O) and the reactivity of acrylic acid and maleic anhydride with radicals, were synthesized. The two complexes were characterized by elemental analysis, infrared (IR) spectra, and X-ray photoelectron spectroscopy (XPS). Based on the data shown from the fluorescent spectra of the Eu-MA and Eu-AA complexes, the ?λ (λ=2 and 4) experimental intensity parameters were calculated. The results demonstrated that the ?2 intensity parameters for the two complexes were smaller than those for the Eu(TTA)2(Phen)(H2O) complex, indicating that a less symmetri- cal chemical environment existed in the complexes. It implied that the radiative efficiency of the 5D0 of these two complexes could be en- hanced by ligand of MA and AA, respectively. The luminescent lifetime of the Eu-AA (τ=7.26×10–4 s) or Eu-MA complex (τ=8.12×10–4 s) was higher than that of the Eu(TTA)2(Phen)(H2O) complex, which was attributed to the substitution of the water molecule (H2O) in Eu(TTA)2(Phen)(H2O) by the MA or AA ligand.     

以香豆素为配体的三元稀土配合物的合成及发光性能的研究

以香豆素为主配体,邻菲罗啉、三苯基氧化磷、氨替吡啉、水这些中性配体作为第二配体,合成了不同稀土离子(Eu3+、Tb3+、Sm3、Dy3+)的配合物,通过元素分析、红外、紫外、荧光光谱等分析,表征了这些配合物的组成结构和发光性能.结果表明,在所合成的配合物中,香豆素与铕、邻菲罗啉形成的配合物发光强度最强,对其掺入不同比例的钆,发现可改变该配合物的发光强度.     

Synthesis, fluorescence properties of Eu(Ⅲ) complexes with novel carbazolefunctionalized β-diketone ligand

A novel carbazole functionalized β-diketone, methyl 6-(9-ethylcarbazole-3-yl)-oxoacetyl-2-pyridinecarboxylate (MEP), and its Corresponding Corresponding binary Eu(Ⅲ) complexes Eu(MEP)32H2O and ternary complex Eu(MEP)3Phen with 1,10-Phenanthroline (Phen) were pre-pared. The ligand was characterized based on elemental analysis, FT-IR, and 1H NMR, and the complexes were characterized with elemental analysis, FT-IR and thermogravimetric and differential thermal analysis (TG-DTA). The investigation of fluorescence properties of the com-plexes Eu(MEP)32H2O and Eu(MEP)3Phen showed that the Eu(Ⅲ) ion could be sensitized efficiently by the ligand to some extent, in par-titular, in the ternary system, the secondary ligand Phen acting as a light-harvesting center was involved in the highly efficient energy transfer process, and the emission was stronger than the binary complex. In addition, the introduction of the carbazole moiety enlarged the π-conjugated system of the ligand and enhanced the luminescent intensity of the complexes.     

Synthesis, fluorescence properties of Eu（III） complexes with novel carbazole functionalized β-diketone ligand

A novel carbazole functionalized β-diketone, methyl 6-(9-ethylcarbazole-3-yl)-oxoacetyl-2-pyridinecarboxylate (MEP), and its corresponding binary Eu(III) complexes Eu(MEP)₃·2H₂O and ternary complex Eu(MEP)₃Phen with 1,10-Phenanthroline (Phen) were prepared. The ligand was characterized based on elemental analysis, FT-IR, and ¹H NMR, and the complexes were characterized with elemental analysis, FT-IR and thermogravimetric and differential thermal analysis (TG-DTA). The investigation of fluorescence properties of the complexes Eu(MEP)₃·2H₂O and Eu(MEP)₃Phen showed that the Eu(III) ion could be sensitized efficiently by the ligand to some extent, in particular, in the ternary system, the secondary ligand Phen acting as a light-harvesting center was involved in the highly efficient energy transfer process, and the emission was stronger than the binary complex. In addition, the introduction of the carbazole moiety enlarged the π-conjugated system of the ligand and enhanced the luminescent intensity of the complexes.     

稀土铕,铽β-二酮配合物的合成与发光性能

采用Claisen缩合反应合成了一种新型的β-二酮化合物1-(4-溴苯)-3-苯基丙烷-1,3-二酮(L),并以其为第一配体,邻菲罗啉(phen)为第二配体,合成出新型稀土铕,铽二元及三元配合物。通过元素分析、红外光谱、紫外光谱、荧光光谱对合成的配体及配合物进行了表征。元素分析确定了配合物的组成。红外光谱的分析表明第一配体L中的氧原子以及第二配体phen中的氮原子与稀土离子进行了配位。紫外光谱表明第一配体L为能量的给体,第二配体phen起协同作用。通过荧光光谱研究了配合物的发光性质,结果显示三元配合物的发光强度大于二元配合物,三元配合物Eu(L)3phen表现出Eu3+的特征发射,在593,615,653,701 nm处的发射峰分别归属于Eu3+的5D0→7Fj(j=1,2,3,4)能级间的跃迁,并且以位于615 nm处的5D0→7F2电子跃迁所发出的荧光强度最大;而铽配合物中并没有出现Tb3+的特征发射。进一步的研究表明,这是由于配体L的最低三重态能级较适合Eu3+的发射能级,配体L吸收的能量可以有效的通过Antenna效应传递给稀土中心离子,使得三元配合物Eu(L)3phen的发光强度较大。     

Synthesis, Characterization and Fluorescence Properties of Europium, Terbium Complexes with Biphenyl-4-Carboxylic Acid and o-Phenanthroline

Two series of solid complexes of europium and terbium with biphenyl 4-carboxylic acid and phen were synthesized and characterized in this report. Their elemental analysis, molar conductivities and TG-DTA studies indicate that the complexes have the composition of Eu(phen)L3·1/2H2O, Eu0.5RE0.5(phen)L3·1/2H2O; Tb(phen)L3·H2O and Tb0.5RE0.5(Phen)L3·1/2H2O. (RE=Y3 , La3 and Gd3 ; L=biphenyl 4-carboxylic acid; phen=o-Phenanthroline). The studies of their IR, UV 1H NMR and molar conductivities demonstrate that biphenyl 4-carboylic acid is bounded with RE(Ⅲ) ion. Rare earth ions coordinate with two nitrogen atoms of phen molecules directly in these rare earth complexes. The fluorescence spectra and fluorescence lifetimes of the rare earth complexes show that the fluorescent intensity and lifetime of a series of europium complexes are longer than those of the series of terbium complexes as having the some ligands. There are better fluorescent intensity and lifetime of hetero-nuclear rare earth complexes than homo-nuclear rare earth complexes for europium complexes. The fluorescence emission intensity of Eu3 is raised by inert fluorescent rare earth ions (Y3 , Gd3 and La3 ), but in Tb3 hetero-nuclear rare earth complexes the intensity of Tb3 ions are quenched by the inert fluorescent rare earth ions.     

Synthesis, Characterization and Fluorescence of Rare earth Nitrate Complexes with Triaza-crown Ether Derivative

Sinceaza crownethershowsspecialcoordinationpropertiestotransitionmetalandheavymetalions[1,2 ] ,therearemanyreportsofthecomplexesinhost guestchemistry ,molecularrecognition[3 ,4] andionophoreinmembranetransportation[5] ,butthereislittlereportontheirrareearthscomplexesandthefluorescenceaboutthecomplexes[6] ,andthefluorescenceintensityoftheircomplexesarenotverystrong .Weinsetbenzoylgroupintothemacrocycle ,expectingthatitsrareearthscomplexeshavebetterfluorescenceproperties .Inthispaperthesynthesis…