Luminescence of Eu(DBM)3Phen-doped in azobenzene-containing copolymers—Effects of absorption overlapping of two components

Poly(N-isopropylacrylamide)-b-poly{6-[4-(4-methylphenyl-azo)phenoxy]hexylmethacrylate} (PNIPAM₃₂-b-PAzoMM₈) and poly(N-isopropylacrylamide)-b-poly{6-[methyl(4-nitrophenyldiazenyl)phenyl]aminohexylmethacrylate} (PNIPAM₃₂-b-PAzoNO₁₀) were prepared by reversible addition–fragmentation chain transfer (RAFT) radical polymerization. The optical properties of Eu(DBM)₃Phen (Eu, Europium; DBM, dibenzoylmethide; Phen, 1,10-phenanthroline)-doped azobenzene-containing copolymer vesicle solutions were studied by UV–vis and fluorescence spectroscopy. When the electronic transition bands of azobenzene and Eu(DBM)₃Phen overlapped at about 350 nm in PNIPAM₃₂-b-PAzoMM₈, the fluorescent emission intensity at 612 nm of Eu(DBM)₃Phen could be modulated by irradiation with UV and visible light. However, when the absorption of the azobenzene-moiety red-shifted to 477 nm in PNIPAM₃₂-b-PAzoNO₁₀, the luminescence intensity of Eu(DBM)₃Phen was not affected any longer. The difference between these two systems was possibly caused by the energy allocation in the luminescence process, which was discussed in detail.     

方酸作桥联配体的双核铕螯合物的电致发光

利用方酸作为桥联配体合成了一种双核铕鳌合物Eu_2（DBM）_4（Sq）Phen_2 ．用TPD作空穴传输材料、Eu_2（DBM）_4（Sq）Phen_2作发光材料和载流子传输材料、 8-羟基喹啉和铝（AlQ）作电子传输材料，设计了不同电致发光电特性，结果表明 Eu_2（DBM）_4（Sq）phen_2是一种同时具有空穴和电子传输能力的红色电致发光 材料，在器件结构为ITO/TPD,50nm/Eu_2（DBM）_4（Sq）Phen2，20nm/ALQ，50nm/LiF， 1nm/Al,200nm时，获得了在16V,6.9mA下有最大亮度91cd／m~2的电致发光器件.     

UV-Vis, NMR, and time-resolved spectroscopy analysis of photoisomerization behavior of three- and six-azobenzene-bound tris(bipyridine)cobalt complexes

The photoisomerization properties of tris(bipyridine)cobalt complexes containing six or three azobenzene moieties, namely, [Co(II)(dmAB)3](BF4)2 [dmAB = 4,4'-bis[3'-(4'-tolylazo)phenyl]-2,2'-bipyridine], [Co(III)(dmAB)3](BF4)3, [Co(II)(mAB)3](BF4)2 [mAB = 4-[3' '-(4' '-tolylazo)phenyl]-2,2'-bipyridine], and [Co(III)(dmAB)3](BF4)3, derived from the effect of gathering azobenzenes in one molecule and the effect of the cobalt(II) or cobalt(III) ion were investigated using UV-vis absorption spectroscopy, femtosecond transient spectroscopy, and 1H NMR spectroscopy. In the photostationary state of these four complexes, nearly 50% of the trans-azobenzene moieties of the Co(II) complexes were converted to the cis isomer, and nearly 10% of the trans-azobenzene moieties of the Co(III) complexes isomerized to the cis isomer, implying that the cis isomer ratio in the photostationary state upon irradiation at 365 nm is controlled not by the number of azobenzene moieties in one molecule but rather by the oxidation state of the cobalt ions. The femtosecond transient absorption spectra of the ligands and the complexes suggested that the photoexcited states of the azobenzene moieties in the Co(III) complexes were strongly deactivated by electron transfer from the azobenzene moiety to the cobalt center to form an azobenzene radical cation and a Co(II) center. The cooperation among the photochemical structural changes of six azobenzene moieties in [Co(II)(dmAB)3](BF4)2 was investigated with 1H NMR spectroscopy. The time-course change in the 1H NMR signals of the methyl protons indicated that each azobenzene moiety in [Co(II)(dmAB)3](BF4)2 isomerized to a cis isomer with a random probability of 50% and without interactions among the azobenzene moieties.     

Rectification of excitation with bathochromic shift induced by intense absorption of organic ligands during emission measurement of Eu(III) complex

Bathochromic shift in excitation spectrum was observed during emission measurement of Eu(DBM)(3)Phen containing dilute solution in methyl methacrylate (MMA). Detailed analysis shows that the reason of bathochromic shift is not the formation of molecule aggregation. It is caused by the intense absorption of ligands in the complex. Based on this model, a new method has been established to rectify excitation spectra before emission measurement of systems with different concentration. There exists a critical value of the absorption strength, which is 0.87 from calculation. Higher absorption than this value will cause the bathochromic shift of excitation peak. The wavelength whose absorbance is 0.87 will be the position of the strongest excitation peak. With 200 ppm and 500 ppm Eu(DBM)(3)Phen as the standard sample, relations between relative concentration and wavelength of excitation peak in Eu(DBM)(3)Phen system were deduced and plotted. Theoretical curves are in good agreement with experiment data except extra-dilute concentration, for partial decomplexation of the beta-diketonate and phenanthroline ligands.     

Electroluminescent properties of three ternary europium complexes with different phenanthroline derivatives

In the past decade a number of lanthanide com-plexes have been designed and synthesized for organic electroluminescent (EL) devices owing to their ex-tremely sharp emission bands and potentially high internal quantum efficiency[113]. This characteristic made the lanthanide complexes one kind of promising candidates for full color flat-panel displays which re-quire pure red, green and blue emissions. So far, how-ever, the devices based on lanthanide complexes as emitters have not demonstrated v…     

Combinatorial study of cofluorescence of rare earth organic complexes doped in the poly(methyl methacrylate) matrix

The luminescence enhancement effect of different kinds and contents of rare earth complexe (RE(DBM)3Phen, RE = Dy, La, Gd, Sm, Y; DBM = dibenzoylmethane; Phen = 1,10-phenanthroline) sensitized Eu(DBM)3Phen doped in poly(methyl methacrylate) (PMMA) matrix was investigated using the combinatorial method. The efficiency of the luminescence enhancement increases with a decrease in the weight percentage of the Eu(DBM)3Phen and an increase in the molecular weight of the PMMA in the systems. Among these sensitization ion complexes, La(DBM)3Phen shows the highest sensitization efficiency. At the optimal content of 5 wt % Eu(DBM)3Phen and 350,000 g/mol weight average molecular weight (Mw) of PMMA, the maximum sensitization efficiency of La(DBM)3Phen is approximately 20 times. We believe that the PMMA with high molecular weight enwraps the rare earth complexes and keeps the donors and acceptors close, which results in the effective intermolecular energy transfer and, consequently, the high sensitization efficiency.     

Synthesis and photoluminescence properties of novel europium complexes of 2'-hydroxyacetophenone and 4,6-diacetylresorcinol

Novel europium (III) complexes of the formulae Eu(OHAP)(3).2H2O, Eu(OHAP)(3)Phen, Eu2(DAR)(3).4H2O and Eu2(DAR)(3)Phen2 (HOHAP=2'-hydroxyacetophenone, H2DAR=4,6-diacetylresorcinol, Phen=1,10-phenanthroline) have been designed and synthesized in this paper. These complexes were characterized by elemental analysis, FT-IR, and UV-vis. Based on these observations, the ligands are coordinated to Eu(III) via the acetyl and phenolic oxygens, and H2DAR is concluded to be bis-bidentate donor. Photoluminescence studies showed that the several complexes emitted red luminescence. Thermo-gravimetric analysis showed that the complexes possess good thermal stability. Also, it was found that Phen as a synergic ligand, coordinated to Eu(III) in a composite system like 2'-hydroxyacetophenone and 4,6-diacetylresorcinol, could enhance the complexes luminescence intensity, quantum yield and lifetime.     

Nona-coordinated chiral Eu(III) complexes with stereoselective ligand-ligand noncovalent interactions for enhanced circularly polarized luminescence

Circularly polarized luminescence (CPL) of chiral Eu(III) complexes with nona- and octa-coordinated structures, [Eu(R/S-iPr-Pybox)(D-facam)(3)] (1-R/1-S; R/S-iPr-Pybox, 2,6-bis(4R/4S-isopropyl-2-oxazolin-2-yl)pyridine; D-facam, 3-trifluoroacetyl-d-camphor), [Eu(S,S-Me-Ph-Pybox)(D-facam)(3)] (2-SS; S,S-Me-Ph-Pybox, 2,6-bis(4S-methyl-5S-phenyl-2-oxazolin-2-yl)pyridine), and [Eu(Phen)(D-facam)(3)] (3; Phen, 1,10-phenanthroline) are reported, and their structural features are discussed on the basis of X-ray crystallographic analyses. These chiral Eu(III) complexes showed relatively intense photoluminescence due to their (5)D(0) → (7)F(1) (magnetic-dipole) and (5)D(0) → (7)F(2) (electric-dipole) transition. The dissymmetry factors of CPL (g(CPL)) at the former band of 1-R and 1-S were as large as -1.0 and -0.8, respectively, while the g(CPL) of 3 at the (5)D(0) → (7)F(1) transition was relatively small (g(CPL) = -0.46). X-ray crystallographic data indicated specific ligand-ligand hydrogen bonding in these compounds which was expected to stabilize their chiral structures even in solution phase. CPL properties of 1-R and 1-S were discussed in terms of transition nature of lanthanide luminescence.     

Bright and monochromic red light-emitting electroluminescence devices based on a new multifunctional europium ternary complex

A novel europium(III) complex, tris(dibenzoylmethanato)(2-4'-triphenylamino)imidazo[4,5-f]1,10-phenanthroline)europium(III), Eu(DBM)3(TPIP), is synthesized. The light-emitting center, hole-transporting triphenylamine and electron-transporting phenanthroline fragments are integrated into one molecule. A single-layer device of ITO/Eu(DBM)3(TPIP) (60 nm)/Mg0.9Ag0.1/Ag exhibits Eu(III)-based pure red emission with a maximum brightness of 19 cd m(-2) at 13.5 V and 280 mA cm(-2), and an onset driving voltage of 8 V. A four-layer device of ITO/TPD (20 nm)/Eu(DBM)3(TPIP) (40 nm)/BCP (20 nm)/AlQ(40 nm)/Mg0.9Ag0.1/Ag gives a maximum Eu(III)-based pure red emitting luminance of 1305 cd m(-2) at 16 V and 255 mA cm(-2) with an onset driving voltage of 6 V; the maximum external quantum yield and luminous yield are estimated to be 0.85% and 1.44 lm W(-1), respectively, at 7.5 V and 0.25 mA cm(-2).     

Tuning the reactivity in classic low-spin d6 rhenium(I) tricarbonyl radiopharmaceutical synthon by selective bidentate ligand variation (L,L'-Bid; L,L'= N,N', N,O, and O,O' donor atom sets) in fac-[Re(CO)3(L,L'-Bid)(MeOH)]n complexes

A range of fac-[Re(CO)(3)(L,L'-Bid)(H(2)O)](n) (L,L'-Bid = neutral or monoanionic bidentate ligands with varied L,L' donor atoms, N,N', N,O, or O,O': 1,10-phenanthroline, 2,2'-bipydine, 2-picolinate, 2-quinolinate, 2,4-dipicolinate, 2,4-diquinolinate, tribromotropolonate, and hydroxyflavonate; n = 0, +1) has been synthesized and the aqua/methanol substitution has been investigated. The complexes were characterized by UV-vis, IR and NMR spectroscopy and X-ray crystallographic studies of the compounds fac-[Re(CO)(3)(Phen)(H(2)O)]NO(3)·0.5Phen, fac-[Re(CO)(3)(2,4-dQuinH)(H(2)O)]·H(2)O, fac-[Re(CO)(3)(2,4-dQuinH)Py]Py, and fac-[Re(CO)(3)(Flav)(CH(3)OH)]·CH(3)OH are reported. A four order-of-magnitude of activation for the methanol substitution is induced as manifested by the second order rate constants with (N,N'-Bid) < (N,O-Bid) < (O,O'-Bid). Forward and reverse rate and stability constants from slow and stopped-flow UV/vis measurements (k(1), M(-1) s(-1); k(-1), s(-1); K(1), M(-1)) for bromide anions as entering nucleophile are as follows: fac-[Re(CO)(3)(Phen)(MeOH)](+) (50 ± 3) × 10(-3), (5.9 ± 0.3) × 10(-4), 84 ± 7; fac-[Re(CO)(3)(2,4-dPicoH)(MeOH)] (15.7 ± 0.2) × 10(-3), (6.3 ± 0.8) × 10(-4), 25 ± 3; fac-[Re(CO)(3)(TropBr(3))(MeOH)] (7.06 ± 0.04) × 10(-2), (4 ± 1) × 10(-3), 18 ± 4; fac-[Re(CO)(3)(Flav)(MeOH)] 7.2 ± 0.3, 3.17 ± 0.09, 2.5 ± 2. Activation parameters (ΔH(k1)(++), kJmol(-1); ΔS(k1)(), J K(-1) mol(-1)) from Eyring plots for entering nucleophiles as indicated are as follows: fac-[Re(CO)(3)(Phen)(MeOH)](+) iodide 70 ± 1, -35 ± 3; fac-[Re(CO)(3)(2,4-dPico)(MeOH)] bromide 80.8 ± 6, -8 ± 2; fac-[Re(CO)(3)(Flav)(MeOH)] bromide 52 ± 5, -52 ± 15. A dissociative interchange mechanism is proposed.     

含铕荧光两亲接枝共聚物的制备及胶束化行为

以丙烯酸(AA)、 苯甲酸(BA)和邻菲啰啉(Phen)为配体, Eu³⁺为中心离子, 制备了可聚合荧光配合物单体, 并以此单体为功能单体, 聚乙二醇单甲醚甲基丙烯酸酯(MPEGMA)和甲基丙烯酸六氟丁酯(HFMA)为共聚单体, 通过溶液聚合制备出含铕两亲荧光接枝共聚物P-[HFMA-co-Eu(AA)(BA)₂Phen]g-PEG. 利用红外光谱(FTIR)和核磁共振波谱(¹H NMR和¹⁹F NMR)对共聚物的结构进行表征; 采用表面张力法测定共聚物的临界胶束浓度(cmc)为0.20 g/L; 通过透射电子显微镜(TEM)和动态光散射仪(DLS)观察胶束的形貌及其胶束化行为, 发现该共聚物可以形成大小均一的球形胶束, 且随着共聚物浓度的提高, 胶束粒径相应增大; 在溶液浓度达到临界胶束浓度时, 溶液荧光出现强度突变.     

Photo-and Electro-luminescence of the New Ternary Europium(III) Complex

In recent years, the interest in developing luminescent lanthanide complexes has been greatly stimulated by their potential use in electroluminescent displays1. Europium complexes appear most attractive in view of the high photoluminescent efficiency and the high monochromatic red light that are widely exploited in full-color displays2. It has been approved that the second ligand plays an important role in europium complexes, the synergistic complexation of the second ligand can not only lead …     

含有电子传输基团的双齿配体及铕配合物Eu(DBM)3(DPOP)的制备与发光性能的研究

1, 3, 4-oxadiazole-contanining ligand DPOP(DPOP=2-(11-dipyrido[3, 2-a: 2′, 3′-c]phenazine)-5-p-tolyl-1, 3, 4-oxadiazole) was synthesized by a convenient method and characterized by elemental analysis, IR, ¹H NMR. Then, corresponding Eu(Ⅲ) complex [Eu(DBM)₃(DPOP)] (DBM=1, 3-diphenyl-1, 3-propanedionate) was prepared and characterized by elemental analysis, IR. The photophysical properties of ligand and its europium complex were investigated. The ligand emitted at 443 nm. There were different PL spectra in solid state and in solution of Eu(DBM)₃(DPOP). There are two fluorescent peaks at 614 nm, 400 nm in dichloromethane solution of Eu(DBM)₃(DPOP), but in solid state only red emission was observed. This result indicated that efficient energy tranfer could take place from DPOP ligand to europium ion in Eu-complex solid.     

掺钕聚甲基丙烯酸甲酯的光学特性

Nd(DBM)3Phen-doped (DBM is dibenzoylmethane and Phen is phenanthroline) polymethyl methacrylate (PMMA) is prepared. Optical absorption, excitation and emission spectra were analyzed for Nd3+ in Nd(DBM)3Phen-doped PMMA. Using the Judd-Ofelt theory, the absorption spectrum was analyzed. The Judd-Ofelt(J-O) intensity parameters of Nd(DBM)3Phen-doped polymethyl methacrylate were calculated to be Ω2 = 20.97 × 10-20 cm2, Ω4 = 3.42 × 10-20 cm2, Ω6 = 2.90 × 10-20 cm2. The radiative lifetime (631 μs)of the excited 4F3/2 level is given. The stimulated emission cross-sections and the fluorescence branch ratios for the 4F3/2 →4 IJ/ transitions are also evaluated. Analysis reveals that Nd(DBM)3Phen-doped PMMA is promising for application in polymer optical fibers and planar waveguides.     

基于稀土配合物的有机光盲型紫外探测器

使用二苯甲酰甲烷-二苯菲罗啉-铕(Eu(DBM)3BPhen)作为电子给体和[6,6]-苯基-C61-丁酸酸甲酯([60]PCBM)作为电子受体制备了一种新型的有机光盲型紫外探测器.在光强为2.1 mW cm-2且波长为360 nm的紫外光照射下,获得了26 mA W-1的响应度和9.1%的外量子效率,这是由于Eu(DBM)3BPhen的强紫外光吸收能力和长达300μs的激子寿命使得给受体界面处具有较高的激子解离率.在把[60]PCBM掺入Eu(DBM)3BPhen后,观察到了明显的光致发光猝灭和光电导现象.由于材料较低的载流子迁移率和受陷激子的缓慢释放,在紫外光照射关闭后,观察到了较强的持续光电导现象.     

Eu(DBM)3超微粒子的光谱特性

The colloids of Eu(DBM)3 and ultrafine particles Eu(DBM)3 were perpared. The particle sizes determined by X-ray and by TEM measurements were in 7-30nm range. Their UV absorption and fluorescence spectra were compared with each other and with those of the solid sample. It was shown that the 5D1→7 F1,2 transition was observed in the colloids of Eu(DBM)3 at room temperature. The increase of the excited-state S1 and T1 energy, the peak positions of UV absorption shifted to shorter wavelength, the changes of the absoprtion coefficient with decreasing size were observed.     

A single red InGaN-based light-emitting diode with a europium (III) ternary complex as mono-phosphor

A novel europium (III) ternary complex, Eu(TPBDTFA)(3)Phen, was designed and synthesized. Photoluminescence measurements show that the energy absorbed by the organic ligands was efficiently transferred to the central Eu(3+) ions, and the complex exhibits strongly red emission due to the (5)D(0)-(7)F(j) transitions of Eu(3+) ions with appropriate CIE (Commission Internationale de l'Eclairage, International Commission on Illumination) chromaticity coordinates (x=0.66, y=0.33) under 310-420 nm light excitation. The luminescence quantum yield for the Eu(3+) complex is 0.18. Thermogravimetric analysis (TGA) confirms a high thermal stability of the complex with a decomposition temperature of 341 degrees C. All the characteristics indicate that the Eu(3+) complex is a highly efficient red phosphor suitable to be excited by near UV light. An intense red-emitting LED was fabricated by combining the mono-phosphor Eu(TPBDTFA)(3)Phen with a approximately 395 nm emitting InGaN chip.     

含Eu(DBM)_3·H_2O纳米微晶的光学树脂的制备及性能研究

稀土β二酮的配合物因其具有Antenna效应,发光强度明显增强;而且它的激光性质也被证实[1] ,是应用价值极大的配合物.稀土配合物与高分子的复合,获得了兼具二者优良性能的功能材料,有很好的应用前景.通常二者的复合多采用直接掺杂、机械共混和熔融等方法.但由于二者的相容性较差,并且存在着浓度淬灭现象,使获得高稀土含量、分散均匀的聚合物发光材料非常困难.以往,杨柏小组分别采用直接掺杂和原位复合的方法制备了含稀土配合物的光学树脂[2 ,3 ] ,但稀土配合物含量受到限制.本文在文献[4,5 ]的基础上,采用化学沉淀的方法,制备了30～30 0nmEu…     

High performance oxygen sensing nanofibrous membranes of Eu(III) complex/polystyrene prepared by electrospinning

In this paper, we report the synthesis, characterization, crystal structure, and photophysical properties of a Eu(3+) complex of Eu(TTA)(3)Phen, where TTA=2-thenoyltrifluoroacetonate, and Phen=1,10-phenanthroline. Its elementary application for oxygen-sensing application is also investigated by doping it into a polymer matrix of polystyrene (PS). Experimental data suggest that the 3wt% doped Eu(TTA)(3)Phen nanofibrous membrane exhibits a high sensitivity of 3.4 towards oxygen with a good linear relationship of R(2)=0.996. In addition, the 3wt% doped Eu(TTA)(3)Phen nanofibrous membrane owns a quick response of 9s towards molecular oxygen, along with its excellent atmosphere insensitivity and photobleaching resistance. All these results suggest that both Eu(TTA)(3)Phen and Eu(TTA)(3)Phen/PS system are promising candidates for oxygen-sensing optical sensors.     

稀土—β—二酮配合物LB膜和三线态能量转移研究

在胶束体系中，Eu3+的发光强度可通过加入La3+－TTA－Phen（TTA：噻吩甲酰三氟丙酮；Phen：邻菲咯琳）而大大增强，这种发光增强作用被认为是由配体TTA经过三线态向EU3+的共振能级转移能量所致[1]．本文利用LB技术将这种Eu3+增强的发光转移到有序排列的LB膜中，研究了La（TTA）3Phen对Eu3+的发光增强作用，并用LB方法探讨了这种分子间的能量转移过程，发现这种能量转移距离小于3um，属经由三线态的短程交换能量转移过程．同时，用荧光光谱和低角X衍射对这种混合稀土配合物LB膜进行了表征．1实验部分配合物La（TTA）3Phen和Eu…