Synthesis and luminescent properties of novel pyrazolone rare earth complexes

A novel pyrazolone pyridine-containing ligand,2,6-bis(1-phenyl-4-ethoxycarbonyl-5-pyrazolone-3-yl)pyridine (H2L) was de-signed and synthesized from pyridine-2,6-dicarboxylic acid (1),and its Eu(III) and Tb(III) complexes were prepared.The ligand and com-plexes were characterized in detail based on FT-IR spectra,1H NMR,elemental analysis and thermal analysis,and the formula of Ln2L3·4H2O (Ln=Eu or Tb) of rare earth complexes was confirmed.The UV-vis absorption spectra and photoluminescence properties of the complexes were investigated,which showed that the Eu(III) and Tb(III) ions could be sensitized efficiently by the ligand (H2L) and emit the photolumi-nescence with high intensity,narrow half-peak width,and monochromic light.The results indicated that the complexes showed potential as excellent luminescent materials.     

Luminescent Properties of Y2O3： Eu Nanocrystalls Synthesized by EDTA Complexing Sol-Gel Process

Y2O3: Eu nanocrystals were synthesized by EDTA complexing sol-gel process at a relatively low temperature, in which ethylen-diamine-tetraacetic acid (EDTA) and polyethylene glycol (PEG) were used as the chelating agent and polymerization agent respectively. Formation process of Y2O3:Eu and structure characterization were carried out by TG-DTA, XRD, SEM/EDX. The results show that pure cubic phase Y203: Eu nanocrystalsere is produced after the precursor calcinated at 600℃ for 2 h, and the crystallinity increases with increasing calcination temperature. The nanoparticles of the Y2O3: Eu are basically spherical in shape. The mean particle size increases from about 30 to 70 nm when the calcination temperature increases from 600 to 1000℃. The luminescent properties of phosphor were analyzed by measuring the excitation and emission spectra. The main emission peak of the sample is around 612 nm, resulting in a red emission. The emission intensity increases with the calcination temperature. Compared with microsized Y2O3: Eu phosphors prepared by a conventional method, nanosized Y2O3: Eu synthesized by the present work, gives and a clear red shift in the emission spectrum. Moreover, the quenching concentration of Eu is raised.     

Photoluminescence properties and effect of Bi~（3＋） dopant of Eu~（3＋） and Dy~（3＋） co-doped Sr_3V_2O_8

Photoluminescence properties of Sr 2.5 Dy 1/3-x Eu x V 2 O 8(x=0,0.06,0.12,0.18,0.24,0.33) were investigated.The excitation spectra included a broad band in the short wavelength region and several sharp lines in the longer wavelength region,and the spectral origin were discussed.The emission spectra were measured in two different exciting ways,i.e.,exciting the VO 4 group at 270 nm and the Eu 3+ ion at 398 nm,respectively,and the energy transferring process was reasonably suggested.Furthermore,multi-color emission could be achieved in Sr 2.5 Dy 1/3-x Eu x V 2 O 8,indicating that the studied samples had potential applications in the white light emitting diodes.Further investigation showed that reducing the concentration of Eu 3+ and Dy 3+ and introducing Bi 3+ as a sensitizer ion greatly enhanced the emission intensity.     

Preparation and Luminescent Properties of BAM Blue Phosphor forPDP and CCFL

The Bax-0.05MgAl10O16 x :Eu0.05^2 (0.88≤ x≤ 1.02) phosphors with different Ba^2 content and the Ba0.85MgAl10O16.94:Eu0.05^2 phosphors with different fluxes (BaF2, MgF2, AlF3, BaCl2, MgCl2, AlCl3, H3BO3)were prepared by high temperature solid-state reaction method and their luminescence characteristics were studied under 254 nm excitation and vacuum ultraviolet (VUV) excitation. With the increase of the Ba^2 content, there is an increase in the emission intensity, and when x = 0.94, it reaches a maximum. Then, as the Ba^2 content increases, the emission intensity slowly falls. The fluorides have better flux-effects than chlorides and H3BO3. The possible mechanism in the process of particle growth was discussed when fluorides were used as fluxes. The effect of the activator concentration on this system was also investigated. The quenching concentration is 0.13 mol in per mole host.     

Luminescence study of europium(III) tris(β-diketonato)/phosphonate complexes in chloroform

The extraction of Eu(III) with β-diketone, HA, and monodentate or bidentate Lewis bases, B, into chloroform and the luminescence properties of the extracted species were studied. Pivaloyltrifluoroacetone, Hpta, and 2-thenoyltrifluoroacetone, Htta, were used as the β-diketones. The Lewis bases, B, were tetraethyl methylene diphosphonate, POPO, which was bidentate, and diethyl benzylphosphonate, PhPO which was monodentate. Based on the extraction data, the stability constants, log β of the first complexes between tris(β-diketonato)Eu(III) and the phosphonate, EuA3B, were determined to be 6.0 for the POPO complex and 3.40 for the PhPO complex. The Eu(III) luminescence intensity in the EuA3POPO was larger than EuA3 where A was either pta or tta at similar concentrations of Eu(III), while that in Eu(pta)3PhPO was stronger than EuA3; however, in Eu(tta)3PhPO, it was weaker than Eu(tta)3. The POPO functions as a sensitizer, and the PhPO functions as a quencher for the tta chelate and as a sensitizer for the pta chelate. From the lifetime and quantum yield, φ, of the Eu(III) luminescence in the complexes as well as the observation of the extractability of Eu(III) with the Hpta and the phosphonates and of the luminescence spectra of the complexes, it was confirmed that the extraction of Eu(III) was remarkably enhanced with a β-diketonate and a strong Lewis base, and also the ternary complex that was formed as the extracted species, showed luminescence enhancement. This phenomenon may be due the formation of a strong bond between the Eu(III) and the strong Lewis base leading to more hydrophobicity in the extracted species and also to more effective energy transfer from the Lewis base to the Eu(III). It was not significant whether the donor atoms were N or O.     

Preparation and Long Persistence Red Luminescence of M0.2Ca0.8TiO3∶Pr3+(M=Mg2+,Sr2+,Ba2+,Zn2+)

M0.2Ca0.8TiO3∶Pr3 (M=Mg2 , Sr2 , Ba2 , Zn2 ) long persistence red phosphors were prepared by solid state reaction. The influence of the partially replacing Ca2 in CaTiO3 with Mg2 , Sr2 , Ba2 , Zn2 on the excitation spectra, the emission spectra and the long persistence properties were studied. The results suggest that certain quantity of Mg2 , Sr2 , Ba2 , Zn2 which partially replace Ca2 can enhance the luminescent intensity and prolong the afterglow persistence of the samples. The intensity of Mg0.2Ca0.8TiO3∶Pr3 is above all of the samples. Take Mg0.2Ca0.8TiO3∶Pr3 as the basic sample, the influence of Pr3 concentrations(C(Pr3 )) on the long afterglow properties were also studied. The results suggest that when the C(Pr3 ) is 0.10%(mol fraction) the intensity of the sample is the highest. The excitation spectra of all these samples show broad band spectra ranging from 300～500 nm peaking at about 342 nm. The emission spectra also exhibit a broad band peaking at 613 nm(CaTiO3∶Pr3 is 612 nm). XRD research indicates that the crystalline phases change due to the replacement of divalent metal ions.The research on the thermoluminescence spectra of Mg0.2Ca0.8TiO3∶Pr3 indicates that the peak is at 107.35 ℃ and the depth of the trap energy is about 0.852 eV.     

Preparation and Long Persistence Red Luminescence of M0.2Ca0.8TiO3 ： Pr^3＋ （M = Mg^2＋ , Sr^2＋ , Ba^2＋ , Zn^2＋）

M0.2Ca0.8TiO3 : Pr^3 (M = Mg^2 , Sr^2 , Ba^2 , Zn^2 ) long persistence red phosphors were prepared by solid state reaction. The influence of the partially replacing Ca^2 in CaTiO3 with Mg^2 , Sr^2 , Ba^2 , Zn^2 on the excitation spectra, the emission spectra and the long persistence properties were studied. The results suggest that certain quantity of Mg^2 , Sr^2 , Ba^2 , Zn^2 which partially replace Ca^2 can enhance the luminescent intensity and prolong the afterglow persistence of the samples. The intensity of Mg0.2Ca0.8TiO3: Pr^3 is above all of the samples. Take Mg0.2Ca0.8TiO3:Pr^3 as the basic sample, the influence of Pr^3 concentrations (C (Pr^3 )) on the long afterglow properties were also studied.The results suggest that when the C (Pr^3 ) is 0.10% (tool fraction) the intensity of the sample is the highest. The excitation spectra of all these samples show broad band spectra ranging from 300 - 500 nm peaking at about 342 nm. The emission spectra also exhibit a broad band peaking at 613 nm (CaTiO3: Pr^3 is 612 nm). XRD research indicates that the crystalline phases change due to the replacement of divalent metal ions. The research on the thermoluminescence spectra of Mg0.2Ca0.8TiO3:Pr^3 indicates that the peak is at 107.35℃ and the depth of the trap energy is about 0.852 eV.     

Synthesis of novel europium complexes and their photoluminescence properties

Two novel luminescent Eu(III) complexes with the formulas(NIP)Eu(DBM)3 1 and(ENIP)Eu(DBM)3 2(NIP=2-(naphtha-len-1-yl)-1H-imidazo [4,5-f] [1,10] phenanthroline,ENIP=1-ethyl-2-(naphthalen-1-yl)-1H-imidazo [4,5-f] [1,10] phenanthroline,DBM= dibenzoylmethanato) were successfully synthesized and characterized by IR and elemental analysis.The UV-vis absorption spectra and pho-toluminescence properties of the complexes were investigated,and the irradiation at the absorption band between 300-400 nm of europium complexes either in solution or in the solid state led to the emission of a sharp red band at ~610 nm,a characteristic Eu3+ emission due to the transition of 5D0→7F2.Furthermore,the weak emission bands around 587 and 595 nm attributed to 5D0→7F0 and 5D0→7F1 transition were also displayed in the emission spectra.These results demonstrated that the Eu(III) ion was sensitized efficiently by the ligand and displayed photoluminescence with high intensity,narrow half-peak width,and monochromic light.The excited-state lifetimes of 1 and 2 were in the microsecond time scale,but the photoluminescence quantum yield of 2(0.03) was two times higher than that of 1(0.01) which should be at-tributed to the effect of the ethyl substituting in ENIP.     

Preparation of Eu （ TTA ）2 phen （ MA ）/SiR Fluorescent Materials under High Mechanical Blending Temperature

Eu（TTA）2（phen）（MA） complexes were synthesized, in which MA was introduced as the acidic ligand to increase the fluorescent intensity of the complexes. The complexes were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and fluorescent spectra, respectively. Different amounts of rare earth complexes were blended with silicon rubber over the melting point of Eu （TTA） 2 （phen） （MA）. Next, a definite amount of 2,5-dimethyl-2, 5-di （tert-butylperoxy） hexane was added as a cross linker to the composite, to get the uncured composites. Subsequently, the composites were vulcanized at 160℃, and silicon rubber-based composites with different contents of the complexes were prepared and their fluorescent properties were observed. The contents of rare earth complexes were 0.96 %, 2.83 %, 4.63 % and 6.36 % （mass fraction）, respectively. Moreover, the composites of Eu （TTA） 2 （phen） （ MA ）/SiR were measured by SEM, XRD, and fluorescent spectra. The measurement result shows that the fluorescent intensity of uncured rubber is similar to one of the pure rare earth complexes. However, there is no marked change of fluorescent intensity in the uncured rubber when the content of rare earth complexes continues to increase.     

Fabrication and photoluminescent characteristics of one-dimensional La202S：Eu3＋ nanocrystals

One-dimensional La2O2S:Eu3+ nanowires(NWs) were fabricated with a simple hydrothermal method.The structures were characterized by X-ray diffraction and transmission electron microscopy(TEM).The photoluminescent properties including excitation and emission spectra were studied.The results indicated that in excitation spectra there existed charge transfer(CT) absorption of both O2-→Eu3+ and S2-→Eu3+,and f-f transitions absorption in NWs and corresponding sub-meter materials(SMs).The relative intensity of CT absorption of O2-→Eu3+ to S2-→Eu3+ in both samples clearly changed.The strong yellow and red emissions of Eu3+ ions in NWs were observed.     

Luminescent properties of red phosphors K2Ba（MoO4）2：Eu3＋ for white light emitting diodes

K2Ba(MoO4)2:Eu3+ phosphors were synthesized by solid-state reaction. The emission and excitation spectra of K2 Ba(MoO4)2:Eu3+ phosphors exhibited that the phosphors could be effectively excited by near ultraviolet (394 nm) and blue (465 nm) light, and emitted red light at 616 nm. The influence of Eu3+concentration, sintering temperature and charge compensators (K+, Na+ or Li+ ) on the emission intensity were investigated. The results indicated that concentration quenching of Eu3+ was not observed within 30mol.% Eu 3+, 600 oC was a suitable sintering temperature for preparation of K2 Ba(MoO4)2:Eu3+phosphors, and K+ ions gave the best improvement to enhance the emission intensity. The CIE chromaticity coordinates of K2 Ba(MoO4)2:0.05Eu3+phosphor were calculated to be (0.68, 0.32), and color purity was 97.4%.     

红色Sr1-2xNaxWO4∶Eux3+荧光体的制备与发光性能

采用传统高温固相法,以钨酸锶为基质材料,掺杂稀土Eu3+制备了可被紫色光有效激发的红色荧光粉Sr1-2xNaxWO4∶Eu3x+。通过测定与分析样品Sr1-2xNaxWO4∶Eu3x+的激发和发射光谱,发现激发光谱在395nm处吸收值最大,发射光谱的发射主峰位于613nm处,属于Eu3+的5D0→7F2特征跃迁。不同的Eu3+掺杂浓度下样品发光强度不同,当x=0.07时发光强度最佳。电荷补偿剂Na+对样品发光强度的影响很大,主要原因是Na+的加入会影响基质的晶体结构,当Na+的含量与Eu3+含量相同时样品发光强度最好,Na+含量增加到一定程度后基质结晶不完善,荧光体的发光强度急剧下降。     

Solvothermal fabrication and luminescent properties of Eu2＋/Ce3＋ doped barium lithium fluoride

Phosphors of BaLiF3 doped with Eu or/and Ce were solvothermally prepared at 200°C for 5d and characterized by means of X-ray powder diffraction (XRD) and environment scanning electron microscopy (ESEM). The excitation and emission spectra of the rare earth ions doped BaLiF3 were measured by fluorescence spectroscopy and the effects of Ce3+ ions on the luminescence of Eu2+ ions were investigated. In the codoped Eu2+ and Ce3+ system, the emission intensity of Eu2+ ion gradually increased with the Ce3+ concentration increasing, and the enhancement of Eu2+ fluorescence was due to efficient energy transfer from Ce3+ to Eu2+ in the host.     

Preparation and photoluminescence of Eu-doped oxyfluoride borosilicate glass ceramics

Eu-doped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared by controlling crys-tallization of melt-quenched glass fabricated under a reductive atmosphere.In the oxyfluoride borosilicate glass ceramics,the mean crystal size of Ba2GdF7 nanocrystals was about 30 nm,which could be observed by X-ray diffraction(XRD) and transmission electron microscopy analysis.The photoluminescence spectra of the samples excited at 392 nm showed that,besides the characteristic sharp emissions of Eu3+ ions,a very intense broadband emission of Eu2+ ions centered at 450 nm appeared.The photoluminescence intensity of Eu3+ and Eu2+ ions in the glass ceramics was much stronger than that in the as-made precursor.The long decay lifetimes of Eu3+ and Eu2+ ions evidenced the partitions of Eu3+ and Eu2+ ions into the Ba2GdF7 nanocrystals.The energy transfer from Gd3+ ions to Eu3+ and Eu2+ ions was confirmed by the excita-tion and emission spectra.     

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 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…     

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.     

Luminescence investigation of Eu~(3+)-Bi~(3+) co-doped CaMoO_4 phosphor

A series of Eu3+-Bi3+ co-doped CaMoO4 red phosphors were synthesized via the solid-sate reaction method. The crystal structures of the obtained samples were identified by X-ray powder diffraction (XRD). The photoluminescence property was investigated, and the results showed that the intensity of excitation spectra and emission spectra could be changed with different doping ratios of Bi3+/Eu3+. The proposed explanation of these changes was from the energy transfer between Bi3+ and Eu3+ and the unbalanced cha...     

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.