Luminescent properties of Lu_2MoO_6:Eu^(3+) red phosphor for solid state lighting

The Eu^3＋ activated Lu2MoO6 phosphors were synthesized by high-temperature solid-state reaction method. The X-ray diffraction （XRD）, excitation spectra, emission spectra and decay lifetime of the phosphors were measured to characterize the structure and luminescent properties. The XRD results show that all the prepared phosphors can be assigned to the monoclinic structure. The experimental results indicate efficient absorption of near ultraviolet light from the Mo^6＋O^2- group followed by intensive emission in the visible spectral range. The optimal content of Eu3＋ is 10% （mole fraction）. The critical distance Rc and energy transfer mechanism were also discussed in detail. This red emitting material may be applied as a promising red phosphor for the near ultraviolet excited white light emitting diodes.

Synthesis and luminescent properties of Ln^(3+) (Ln^(3+)=Eu^(3+),Dy^(3+))-doped Bi_2ZnB_2O_7 phosphors

The new phosphors Bi2ZnB2O7:Ln3+ (Ln3+=Eu3+,Dy3+) were synthesized by solid-state reaction technique.The obtained phosphors were investigated by means of X-ray powder diffraction (XRD),photoluminescence excitation and emission spectra with the aim of enhancing the fundamental knowledge about the luminescent properties of Eu3+ and Dy3+ ions in the Bi2ZnB2O7 host lattice.XRD analysis shows that all these compounds are of a single phase of Bi2ZnB2O7.The excitation and emission spectra of Bi2ZnB2O7:Ln3+ (Ln3+=Eu3+,Dy3+) at room temperature show the typical 4f-4f transitions of Eu3+ and Dy3+,respectively.The hypersensitive transitions of 5D0→7F2 (Eu3+) and 4F9/2→6H13/2 (Dy3+) are relatively higher than those of the insensitive transitions in Bi2ZnB2O7.It is conceivable that the Bi2ZnB2O7 structure provides asymmetry sites for activators (Eu3+,Dy3+).The optimum concentrations of Eu3+ and Dy3+ ions in Bi2ZnB2O7 phosphors are both x=0.05.

Intercalation Assembly, Characterization and Luminescent Properties of Novel Supramolecular Composite Materials, Tb(Ⅲ) Complex with Tetrapodal Ligand-Montmorillonite

Two kinds of Tb（ Ⅲ ） complexes with tetrapodal ligand, [TbL（NO3）]^3＋ and [TbL]^3＋ （L： 1,1, 1＇, 1＇-tera （ 2-pyridinecarboxylester ）-di （ trimethylpropane）） were intercalated into the interlayer space of montmorillonite （MT） by ion exchange and coordination reaction of L with the Tb^3＋ ion existing in the interlayer space of Tb-MT respectively. The obtained luminescent supramolecular composite materials, [ TbL （NO3） ]^2＋-MT and [TbL]^3＋-MT were characterized by elemental analysis, XRD, FT-IR, UV-vis and thermal analysis. At the same time, the luminescent properties of the materials were also studied. The results show that the intercalated materials with regular layered structure, good thermal stability and the interlayer spacing （d001） approximates to the size of the complex ions which are located in the interlayer space of MT in the form of a monolayer.

Preparation, Characterization and Luminescent Properties of MCM-41 Type Materials Impregnated with Rare Earth Complex

Hybrid materials incorporating Eu-(TTA)(3). 2H(2)O (7hereafter designated as Eu-TTA, with TTA: thenoyltrifluoroacetone) in unmodified or modified MCM-41 by 3-aminopropyl-triethoxysilane (APTES) were prepared by impregnation method. The obtained materials were characterized using X-ray diffraction (XRD), IR and diffuse reflectance spectroscopy and luminescence spectra. All the hybrid samples exhibited the characteristic emission bands of EU3+ under UV light excitation at room temperature, and the excitation spectra showed significant blue-shifts compared to the pure rare-earth complex. Although the red emission intensity in the modified hybrid was almost the half of the red emission intensity in the pure Eu-TTA complex at room temperature, the hybrid showed a much higher thermal stability due to the shielding character of the MCM-41 host.

Synthesis of Long Afterglow Phosphors MAl_2O_4∶Eu^(2+), Dy~ (3+)(M=Ca, Sr, Ba) by Microemulsion Method and Their Luminescent Properties

Long afterglow phosphors MAl2O4：Eu^2＋ , Dy^3＋ （M = Ca, Sr, Ba） were synthesized by microemulsion method, and their crystal structure and luminescent properties were compared and investigated. XRD patterns of samples indicate that phosphors CaAl2O4：Eu^2＋, Dy^3＋ and SrAl2O4 ： Eu^2＋, Dy^3＋ are with monoelinie crystal structure and phosphor BaAl2O4：Eu^2＋ , Dy^3＋ is with hexagonal crystal structure. The wide range of excitation spectrum of phosphors MAl2O4： Eu^2 ＋ , Dy^3＋ （M = Ca,Sr, Ba） indicates that the luminescent materials can he excited by light from ultraviolet ray to visible light and the maximum emission wavelength of phosphors MAl2O4：Eu^2＋ , Dy^3＋ （M = Ca, Sr, Ba） is found mainly at λem of 440 nm （M = Ca）, 520 nm （M = Sr） and 496 nm （M = Ba） respectively, the corresponding colors of emission light are blue, green and eyna-green respectively. The afterglow decay tendency of phosphors can he summarized as three processes： initial rapid decay, intermediate transitional decay and very long slow decay. Afterglow decay curves coincide with formula I = At^ - n, and the sequence of afterglow intensity and time is Sr 〉 Ca 〉 Ba.

Synthesis and Luminescent Properties of Ce^(3+), Tb^(3+) Co-Doped Zn_4B_6O_(13)

Green-photoluminescence material Zn4B6O13: Ce3+, Tb3+ was first synthesized by spread method of high temperature and solid state reaction, which is cubic crystal system with lattice parameters: a(0) = 0.7472 nm, V = 0.4172 nm(3), and structural properties are investigated by XRD. The excitation and emission band of Ce3+ ion single-doped in Zn4B6O13 transfer longer spectra 2.38 similar to 4.94 kk than in other matrices. Emission band of Ce3+ ion better overlaps with the F-7(6)-->(5)G(2),D-5(1),H-5(7) absorption band of Tb3+. It shows that emission of Tb3+ ion is sensitized by Ce3+. In Zn4B6O13:Ce3+, Tb3+, it is due to the energy transfer mechanism, resonance transfer of electric multipolar interaction of the dipole-dipole between Ce3+-->Ce3+ and Ce3+-->Tb3+. The color coordinates of Zn4B6O13: X 0.281, gamma = 0.619. The mean diameter of the particles is 0.23 mum.

A Two-dimensional Anthracene-9,10-dicarboxylate Zinc(Ⅱ) Coordination Polymer Based on Binuclear [Zn_2Cl_2] Nodes: Synthesis, Characterization and Luminescent Properties

A two-dimensional（2D） 44 topological ZnⅡ coordination polymer {[Zn2Cl2（L）（4bpy）2]}∞（H2L = anthracene-9,10-dicarboxylic acid, 4bpy = 4,4ˊ-bipyridine） based on binuclear [Zn2Cl2] nodes has been synthesized and characterized by IR, elemental analysis, X-ray powder diffraction and single-crystal X-ray diffraction analysis. Moreover, the luminescent properties of the correspon- ding compound have been briefly investigated.

Syntheses,Crystal Structures and Luminescent Properties of Lead(Ⅱ) and Cadmium(Ⅱ) Coordination Polymers Constructed from Biphenyl-2,5,3′-tricarboxylate

Two coordination polymers, namely [Pb（Hbtc）（phen）]n（1） and {[Cd3（btc）2（H2O）4]·2H2O}n（2, H3btc = biphenyl-2,5,3＇-tricarboxylic acid, phen = 1,10-phenanthroline）, were assembled. Single-crystal X-ray diffraction studies show that compound 1 possesses a zigzag chain 1D coordination network, which is further extended into a 3D supramolecular architecture via O–H···O hydrogen bonds and π-π packing interactions. Compound 2 features a 3D open framework based on a tricadmium（II） subunit, generating a trinodal 4,4,6-connected net with the 4,4,6T24 topology defined by the point symbol of（44·62）3（46·69）2. Thermal stability and luminescent properties of both compounds were studied and discussed.

6,8-Di-tert-butyl-3-(2,4-dimethyl-quinolin-7-yl)-3,4-dihydro-2H-benzo[e][1,3]oxazine: Synthesis, Crystal Structure and Luminescent Properties

6,8-Di-tert-butyl-3-（2,4-dimethyl-quinolin-7-yl）-3,4-dihydro-2H-benzo[e][1,3]oxa- zine（1） was obtained by one-pot reaction starting from 2,4-di-tert-butylphenol, 7-amino-2,4- dimethyl-quinoline and paraformaldehyde. The compound was structurally characterized by NMR, IR and single-crystal X-ray diffraction along with the elemental analysis. Compound 1 crystallizes as solvate with chloroform. The solvate 1·CHCl3（C28 H35 Cl3 N2 O, Mr = 521.93） belongs to the triclinic system, space group P1 with a = 10.852（2）, b = 11.352（2）, c = 13.050（3）, α = 101.95（3）, β = 92.94（3）, γ = 114.64（3）o, V = 1412.4（5）3, Z = 2, Dc = 1.227 g/cm3, F（000） = 552, μ = 0.347 mm–1, R = 0.0959 and wR = 0.2725（I 〉 2？（I））. The chloroform molecule displays a rotational disorder as one chloro atom can be located at two different positions. The packing of 1·CHCl3 was further stabilized by intramolecular C–H…O interactions, intermolecular C–H…N interactions, C–H…π interactions, and π…nteractions. The luminescent properties of compound 1 in both methylene chloride solution and the solid state were studied.

Electronic and luminescent properties of Cr-doped cadmium sulfide nanowires

Cr-doped CdS nanowires were synthesized in large scale through thermal co-evaporation of CdS and metal Cr powders. General morphology, detailed microstructure and optical properties were characterized using various techniques. Devices consisting of individual Cr-doped CdS nanowire were fabricated and they exhibited remarkable rectifying characteristics. Ⅰ-Ⅴ curves of individual Cr-doped CdS nanowire devices demonstrate that the present nanowires are n-type doped and have high conductivity （10.96 Ω^-1cm^-1）, indicating great potential applications in nanoscale electronic and optoelectronic devices.

Synthesis, Crystal Structure and Luminescent Properties of a Novel 2D Sheet Cd(Ⅱ) Coordination Polymer [Cd(Cpna)(Py)]_n

A coordination polymer, [Cd（cpna）（py）]n （H2cpna = 5-（2＇-carboxylphenyl） nicotic acid, py -- pyridine） 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, fluorescence spectra and single-crystal X-ray diffraction. Colorless crystals crystallize in the monoclinic system, space group P21/c with a = 8.589（2）, b = 13.047（3）, c = 14.940（4） A, fl = 96.001（2）°, V = 1664.9（7） A3, C18H12CdN204, Mr = 432.70, Dc = 1.726 g/cm3, F（000） = 856, Z = 4, p（MoKa） = 1.337 mm^-1, the final R = 0.0396 and wR = 0.0891 for 2422 observed reflections （1 〉 2a（I））. Complex I exhibits a two-dimensional （2D） sheet structure, which further builds a three-dimensional （3D） supramolecular architecture via C-H...O hydrogen-bonding interactions.

Synthesis,Crystal Structure and Luminescent Properties of a 1D Loop-chain Coordination Polymer [Ag(3,3-pybz)(3,3-Hpybz)]_n

A new coordination polymer, [Ag（3,3-pybz）（3,3-Hpybz）]n （1, 3,3-Hpybz = 3-pyri- din-3-yl-benzoic acid）, has been synthesized and characterized by elemental analysis, IR spectra, PXRD, and single-crystal X-ray diffraction. In complex 1, the Ag（1）ions are linked by the paired 3,3-pybz ligands to generate an infinite 1D loop chain, and further through π-π stacking interactions to form a 2D supramolecular architecture. Crystal data for 1： triclinic, space group P1, a = 10.2635（17）, b = 10.3041（12）, c = 10.8060（13） A, V= 1679.1（5）A3, α = 62.028（11）, β = 80.325（15）, γ = 78.738（14）°, Z = 2, C24H17AgN2O4, Mr = 505.27, Dc= 1.698 g/cm3, μ= 1.058 mm--, F（000） = 506, S = 1.012 and T = 293（2） K. The final R = 0.0293 and wR = 0.0667 for 3435 observed reflections with I〉 2a（/）, and R = 0.0350 and wR = 0.0688 for all data.

Syntheses,Crystal Structures and Luminescent Properties of Two Lanthanide Coordination Polymers Based on Bifunctional Ligand

Two lanthanide coordination polymers, [Eu（HL）（L）（H2O）2]n（1） and [Tb（H0.5L）2]n（2）, based on bifunctional 5-（1H-imidazol-1-yl） isophthalic acid（H2L）, are hydrothermally synthesized and characterized by both single-crystal and powder X-ray diffraction analyses, and FT-IR. In compound 1, the basic inorganic building unit of the coordination network is the dinuclear [Eu2（COO）6] cluster. Each [Eu2（COO）6] cluster connects four HL^- ligands and each HLligand links two [Eu2（COO）6] clusters, resulting in a 2D coordination layer. The adjacent 2 D layers are further connected via neighboring inter-layer hydrogen bonds to give a 3D supramolecular structure. In compound 2, the Tb^3＋ is coordinated to six oxygen atoms. Each Tb^3＋ ion connects six ligands and each ligand links three Tb^3＋ ions, leading to a 3D coordination polymeric network which exhibits remarkably high thermal stability up to 500℃. Furthermore, due to the successful incorporation of Tb^3＋, compound 2 displays characteristic luminescent emission in the solid state at room temperature. The combination of high thermal stability and fluorescent property of compound 2 would make it as a promising light-emitting material.

Alternating Double Trinucleate[Yb_3(μ_3-OH)_2O]_2 Chain Bridged byμ_3-OH Mode in a 3D Yb^(3+)-CP and Its Near Infrared Luminescent Properties

A new 3D coordination polymer,namely,[Yb_3（μ_3-OH）_3（μ_2-OH）（DDLA）_（2.5）（BIPY）]（1,H_2DDLA = 2,2-dipyridyl-4,4-dicarboxylic acid,BIPY = 2,2？-bipyridine）,has been synthesized via solvothermal method. The complex crystallizes in triclinic,space group P1 with a = 7.7339（4）,b = 15.6699（8）,c = 17.2221（9） ？,α = 68.8630（10）,β = 88.1890（10）,γ = 88.1740（10）°,V = 1945.27（17） ？~3,Z = 2,D_c = 2.296 g·cm^3,μ（MoKα） = 1.075 mm^（-1）,F（000） = 1268,S = 1.068,R = 0.0263 and wR = 1.067 for 5176 observed reflections with I 〉 2σ（I）. Compound 1 contains a unique alternating double trinucleate {[Yb_3（μ_3-OH）_2OH]_2}_n chain,in which Yb^（3＋） is bridged through μ_3-OH and μ_2-OH two coordination modes. The alternating double trinucleate chains are further extended into a 3D structure through DDLA^（2-） ligands by different coordination modes. The photoluminescence spectra show 1 is highly sensitized by the characteristic emission of Yb^（3＋） in the NIR region.

Structural Diversity and Luminescent Properties of Metal-organic Frameworks Based on a Rare Sulfonate and Imidazole Co-Ligand System

Four types of luminescent properties of metal-organic frameworks（MOFs） with formulas [Cd（1,2-BIYB）2（H2O）2]n·n（AQ-1,5-DAD）（1）, [Cd（AQ-1,5-DAD）（1,3-BIYB）2]n（2）, [Cd（1,3-BIYB）]n·n（AQ-1,5-DAD）·n H2O（3）, and [Zn（1,4-BIYB）2]n·n（AQ-1,5-DAD）2·6H2O（4）,（Na2AQ-1,5-DAD = anthraquinone-1,5-disulfonic acid disodium, 1,2-BIYB = 1,2-bis（imidazol-1-ylmethyl）benzene, 1,3-BIYB = 1,3-bis（imidazol-1-ylmethyl）benzene, 1,4-BIYB = 1,4-bis（imidazol-1-ylmethyl）benzene） have been synthesized based on a rare sulfonate and imidazole Co-ligand system under different conditions. The structural features of four types of MOFs 1-4 are as follows： MOFs 1 show a 3D supramolecular compound in which the double one-dimensional chains are further cross-linked by hydrogen bonds. 2 exhibits a 2D network constructed by two different 1D chains. 3 features a 2D supramolecular network, in which the 1D chains and AQ-1,5-DAD are arranged alternately through hydrogen bonds. 4 posseses a 3D supramolecular structure constructed by a 2D network and one-dimensional hydrogen bonding chains. All compounds 1-4 are characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The luminescence properties of 1-4 have been investigated.

Syntheses,Structures and Photoluminescent Properties of Cd(Ⅱ)Polymeric Complexes Based on 5-Aminoisophthalic Acid and Bipyridine Co-ligands

Two novel complexes, namely {[Cd（AIP）（4,4＇-bpy）]·1.3DMF}n（1） and [Cd（AIP）（2,2＇- bpy）]n（2）, have been synthesized through solvothermal reaction（H2AIP = 5-aminoisophthalic acid, 2,2＇-bpy = 2,2＇-bipyridine, 4,4＇-bpy = 4,4＇-bipyridine, and DMF = N,N＇-dimethylformamide） and structurally determined by single-crystal X-ray diffraction. Complex 1 shows a three-dimensional（3D） layer-pillar framework with rectangular channels, while complex 2 displays a two-dimensional（2D） wave net architecture. Furthermore, 1 and 2 were characterized by elemental analysis, infrared spectra（IR）, thermal gravimetric analyses（TGA） and fluorescence measurements. The luminescent properties of 1 dispersed in various organic solvents have been investigated systematically, demonstrating high selectivity for acetone via the fluorescence quenching effect.

Synthesis of CaO-SiO_2-B_2O_3∶Sm_2O_3 Glasses and Luminescent Properties of Sm^(3+)

CaO-SiO2-B2O3 ：Sm2O3 glasses were synthesized in air atmosphere with conventional high temperature process. The optimal temperature of synthesis, the absorption spectrum and the luminescent properties of the glasses were studied. The fluorescence spectrum of Sm^3＋ was observed in CaO-SiO2-B2O3 ： Sm2O3 glasses. The fluorescence spectrum of the sample has three major emission bands peaking at 568, 605 and 650 nm respectively. The strongest emission band peak at 605 nm. It is concluded that the emissions were caused by the f-f transition of the 4f electrons of Sm^3＋. The emission bands peaking at 568, 604 and 650 nm correspond to the ^4G5/2→^6H5/2 transition, ^4G5/2→^6H7/2 transition and ^4G5/2→^6H9/2 trasition respectively. The luminescent properties of CaO-SiO2-B2O3 glasses indicate that the glass can convert the ultraviolet in the sunlight into red light, thus increasing the intensity of red light. The luminescent properties of these glasses may be used to make kinds of light-conversion glass for agriculture.

Modification of Luminescent Properties of Red Sulphide Phosphors for White LED Lighting

A kind of sulphide, CaS:Eu2+ , activated by europium ion for white LED lighting was synthesized via solid-state reaction route in reducing atmospheres. The phosphors were then encapsulated with silicone resin. Moreover, chemical structure of the phosphors was characterized by XRD. Microstructure of the powders was observed by SEM. Spectra of excitation and emission for the phosphors were also obtained by a spectrophotometer. Effect of processing parameters on the luminescent properties of the powders was systematically studied to result in the phosphors with good chemical stability and maximal relative luminescent intensity.

Synthesis,Crystal Structure and Luminescent Properties of a Novel Zinc(II) Complex of N-Acetyl-L-glutamic Acid and Imidazole Ligands

A novel complex [Zn（Im）2（A-glu）]-0.5H2O（Im = imidazole, A-glu = N-acetyi- L-glutamic acid） has been synthesized from the reaction of A-glu with Zn（CH3COO）2·2H20 in the presence of Im at 65 ℃, and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in tetragonai, space group P43212 with a = b = 8.9078（6）, c = 43.458（6） A, C26H36N10O11Zn2, Mr = 795.39, V= 3448.3（6） A^3, De = 1.532 g/cm^3, Z = 4,μ（MoKα） = 1.461 mm^-1, F（000） = 1640, the final R = 0.0453 and wR = 0.0992. X-ray analysis reveals that the crystal structure is constructed by mixed iigands. A-glu adopts the bis-monodentate coordination mode linking two adjacent metal ions to form a one-dimensional chain. Zinc（Ⅱ） ions are four-coordinated with a distorted tetrahedral geometry. Luminescent properties of the complex have been inves- tigated.

Synthesis,Structure and Luminescent Properties of [Zn(btzb)_2Cl_2]·2H_2O [btzb=1,2-Bis(5-tetrazolyl)benzene]

The title compound [Zn（btzb）2Cl2]·2H2O （1·2H2O, btzb = 1,2-bis（5-tetrazolyl）ben- zene） was synthesized in situ by the [2＋3] cycloaddition reaction of phthalonitrile with NaN3 in water in the presence of ZnCl2 under refluxing conditions. 1·2H2O crystallizes in the monoclinic system, space group P2 1/c with a = 9.0119（18）, b = 7.5566（15）, c = 18.076（5）A, β= 114.67（2）°, V= 1118.6（4）A^3, Z = 2, Dc = 1.784 g/cm^3, T= 223（2） K, C16H16N16O2Cl2Zn, Mr = 600.74, F（000） = 608, μ（MoKα） = 1.393 mm^-1, S = 1.081, R = 0.0306 and wR = 0.0669 for 1896 observed reflections with I 〉 2σ（I）. The Zn^2＋ ion of 1 is coordinated by four N atoms from two btzb ligands and two Cl atoms, forming a distorted octahedral coordination geometry. A number of intermolecular hydrogen bon- ding interactions between molecules 1 and/or the solvated water molecules result in a 3D hydrogen-bonded structure. The luminescent property of 1·2H2O was also investigated.