A new disordered langbeinite-type compound, K2Tb1.5Ta0.5P3O12, and Eu3+-doped multicolour light-emitting properties

2019 ◽  
Vol 75 (2) ◽  
pp. 213-220 ◽  
Author(s):  
Ya-Li Xue ◽  
Dan Zhao ◽  
Shi-Rui Zhang ◽  
Ya-Nan Li ◽  
Yan-Ping Fan

For the first time, a new langbeinite-type phosphate, namely potassium terbium tantalum tris(phosphate), K2Tb1.5Ta0.5(PO4)3, has been prepared successfully using a high-temperature flux method and has been structurally characterized by single-crystal X-ray diffraction. The results show that its structure can be described as a three-dimensional open framework of [Tb1.5Ta0.5(PO4)3]∞ interconnected by K+ ions. The TbIII and TaV cations in the structure are disordered and occupy the same crystallographic sites. The IR spectrum, the UV–Vis spectrum, the morphology and the Eu3+-activated photoluminescence spectroscopic properties were studied. A series of Eu3+-doped phosphors, i.e. K2Tb1.5–x Ta0.5(PO4)3:xEu3+ (x = 0.01, 0.03, 0.05, 0.07, 0.10), were prepared via a solid-state reaction and the photoluminescence properties were studied. The results show that under near-UV excitation, the luminescence colour can be tuned from green through yellow to red by simply adjusting the Eu3+ concentration from 0 to 0.1, because of the efficient Tb3+→Eu3+ energy-transfer mechanism.

2015 ◽  
Vol 68 (6) ◽  
pp. 956 ◽  
Author(s):  
Ming-An Dang ◽  
Zi-Feng Li ◽  
Ying Liu ◽  
Gang Li

Three coordination polymers [Sr(p-H2MOPhIDC)2]n (1) (p-H3MOPhIDC = 2-p-methoxyphenyl-1H-imidazole-4,5-dicarboxylic acid), {[Cd2(p-HMOPhIDC)2(4,4′-bipy)]⋅H2O}n (4,4′-bipy = 4,4′-bipyridine) (2), and [Zn(p-HMOPhIDC)(4,4′-bipy)]n (3) have been solvothermally synthesized, and structurally characterized by single-crystal X-ray diffraction. Polymer 1 indicates a three-dimensional framework, which can be simplified as a 6-connected lattice. Polymer 2 is also a three-dimensional framework, and contains mixed bridging ligands HMOPhIDC2– and 4,4′-bipy. Polymer 3 exhibits a sheet structure bearing infinite rectangles. The coordination modes of the p-H3MOPhIDC ligand, and the thermal and solid-state photoluminescence properties of the polymers have been investigated as well.


2016 ◽  
Vol 16 (4) ◽  
pp. 3869-3872 ◽  
Author(s):  
Bitao Liu ◽  
Yuan Chen ◽  
Lingling Peng ◽  
Tao Han ◽  
Hong Yu ◽  
...  

Monodispersed, truncated cube BaMgAl10O17:Eu2+ phosphors were synthesized by the sol–gel process. Scanning electron microscope (SEM), photoluminescence spectrum, powder X-ray diffraction and decay curves were used to evaluate the truncated cubic BaMgAl10O17:Eu2+ phosphors. The crystal growth process and photoluminescence properties were discussed in detail. The results showed that this truncated cubic morphology can be achieved via a simple sinter process. These truncated cubic BaMgAl10O17:Eu2+ phosphors showed acceptable emission intensity and better thermal properties. This result indicates truncated cubic BaMgAl10O17:Eu2+ phosphors would meet the requirements of plasma display panels (PDPs).


2014 ◽  
Vol 69 (9-10) ◽  
pp. 1003-1009 ◽  
Author(s):  
Walter Schnelle ◽  
Reinhard K. Kremer ◽  
Rolf-Dieter Hoffmann ◽  
Ute Ch. Rodewald ◽  
Rainer Pöttgen

Abstract Polycrystalline CeNiIn4 was prepared by arc-melting of the elements and subsequent annealing at 970 K in vacuum. EuNiIn4 and EuCuIn4 were synthesized from the elements by reactions in sealed tantalum tubes. These indium-rich compounds crystallize with the YNiAl4-type structure which was refined for EuCuIn4 from single-crystal X-ray diffraction data: Cmcm, a=450:04(9), b=1698:7(4), c = 740:2(2) pm, wR2 = 0:0606, 495 F2 values, 24 variables. The EuCuIn4 structure is built up from a complex three-dimensional [CuIn4] polyanion (265 - 279 pm Cu-In and 296 - 331 pm In- In) in which the europium atoms occupy distorted hexagonal channels. The Eu-Eu distances within these channels (450 pm) are significantly shorter than the distances between Eu atoms in neighboring channels (552 pm). The magnetic properties and the specific heats of the europium compounds have been investigated. Both europium compounds show the magnetism of divalent Eu ions and antiferromagnetic ordering at low temperatures. EuCuIn4 is magnetically ordered via a surprisingly complex sequence of three transitions


2014 ◽  
Vol 07 (05) ◽  
pp. 1450060 ◽  
Author(s):  
Qun Shi ◽  
Dhia A. Hassan ◽  
Renjie Zeng

Europium-doped Na 1.45 La 8.55-8.55x( SiO 4)6( F 0.9 O 1.1)(0.000 ≤ x ≤ 0.045) phosphors were prepared by a conventional solid-state reaction method at 1200°C and their properties were studied by X-ray diffraction (XRD), and a spectral analysis system. No impurities were observed. The phosphor could be excited at 254 nm, 395 nm and 465 nm to yield a reddish orange emission which was attributed to the 5 D 0 → 7 F j (j = 0–2) transitions of the Eu ion.


2014 ◽  
Vol 70 (11) ◽  
pp. 1025-1028
Author(s):  
Hong Shen

The title CdIIcoordination polymer, [Cd(C10H8O4)(C12H12N6)0.5(H2O)]n, has been obtained by the hydrothermal method and studied by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, IR spectroscopy and fluorescence spectroscopy. The compound forms a novel three-dimensional framework with 3,8-connected three-dimensional binodal {4.52}2{42.510.612.7.83} topology. An investigation of its photoluminescence properties shows that the compound exhibits a strong fluorescence emission in the solid state at room temperature.


2021 ◽  
Author(s):  
P.J. Binu ◽  
S. Muthukumaran

Abstract ZnS, Mn added ZnS (Zn0.97Mn0.03S) and Mn, Cu dual doped ZnS (Zn0.95Mn0.03Cu0.02S) QDs have been prepared using co-precipitation technique. The influence of Mn and Cu addition on the morphology, structure and photoluminescence properties of Mn/Cu incorporated ZnS have been examined. Cubic structure of the synthesized samples was confirmed by X-ray diffraction patterns. The incorporation of Cu in Zn-Mn-S lattice not only decreased the particle/grain size and also generates more defect based luminescent activation centres. The reduced energy gap by Mn addition was explained by sp-d exchange interaction and the elevated energy gap in Cu, Mn dual doped ZnS was expalined by Burstein–Moss effect. The tuning phenomenon of size as well as the energy gap in ZnS by Mn/Cu addition promote these materials for nano-electronic applications. FTIR spectra confirmed the presence of Mn/Cr-Zn-S bondings. The substitution of Mn /Cu provides an effective control over tuning of different emission colours which signifies their applications like light emitting diodes.


Author(s):  
Hong-Tao Zhang ◽  
Xiao-Long Wang

The design and synthesis of metal–organic frameworks (MOFs) have attracted much interest due to the aesthetics of their crystalline architectures and their potential applications as new functional materials. A new twofold interpenetrated three-dimensional (3D) MOF, namely, poly[[triaqua(μ4-(2R,2′R)-2,2′-{[1,4-phenylenebis(carbonyl)]bis(azanediyl)}dipropionato-κ7 O 1:O 1,O 1′:O 4:O 4,O 4′,O 4′′)(μ3-(2R,2′R)-2,2′-{[1,4-phenylenebis(carbonyl)]bis(azanediyl)}dipropionato-κ3 O 1:O 4:O 4)dicadmium(II)] dihydrate], {[Cd2(C14H14N2O6)2(H2O)3]·2H2O} n , (I), has been synthesized by the reaction of Cd(CH3COO)2·2H2O with the synthesized ligand (2R,2′R)-2,2′-{[1,4-phenylenebis(carbonyl)]bis(azanediyl)}dipropionic acid (H2 L). Single-crystal X-ray diffraction analysis reveals that the carboxylate groups from two crystallographically independent L 2− dianions link the cadmium cations into a one-dimensional helical secondary building unit (SBU). The resulting SBUs are extended into a 3D metal–organic framework via the terephthalamide moiety of the ligand as a spacer. In the crystal, two independent MOFs interpenetrate each other, thus producing a twofold interpenetrated 3D architecture, which shows an unprecedented 2-nodal (7,9)-connected net with the point (Schläfli) symbol (37·46·58)(38·411·516·6). MOF (I) was further characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction and thermogravimetric analysis. The photoluminescence properties and UV–Vis absorption spectrum of (I) have also been investigated. The MOF exhibits enhanced fluorescence emission with a high photoluminescence quantum yield of 31.55% and a longer lifetime compared with free H2 L.


2020 ◽  
Vol 76 (1) ◽  
pp. 79-84
Author(s):  
Tong Zhang ◽  
Zhen Zhao ◽  
Yao Tang ◽  
Jing-Si Liu ◽  
Gui-Lin Huang ◽  
...  

Abstract Layer diffusion of 3,5-bis(4-pyridyl)-1H-1,2,4-triazole (BptH) in ethanol on an aqueous solution of cadmium sulfate leads to a novel three-dimensional cadmium sulfate-based inorganic-organic hybrid polymer (IOHP), CdSO4(H2O)(BptH)·1.5H2O (1). Its structure was determined by single-crystal X-ray diffraction (SCXRD), and further characterized by elemental analysis, powder X-ray diffraction (PXRD), infrared spectra (IR), and thermogravimetric (TG) analysis. IOHP 1 exhibits a novel 2-nodal 3,5-connected nanoporous structure formed by BptH ligands connecting 2D neutral inorganic cadmium sulfate layers. Water molecules reside in its nanoporous channels. The thermal stability and solid-state photoluminescence properties of the compound have also been investigated.


2018 ◽  
Vol 74 (9) ◽  
pp. 1053-1057 ◽  
Author(s):  
Qian-Kun Zhou ◽  
Lin Wang ◽  
Yun Xu ◽  
Ni-Ya Li

In recent years, coordination polymers constructed from multidentate carboxylate and pyridyl ligands have attracted much attention because these ligands can adopt a rich variety of coordination modes and thus lead to the formation of crystalline products with intriguing structures and interesting properties. A new coordination polymer, namely poly[[μ2-1,6-bis(pyridin-3-yl)-1,3,5-hexatriene-κ2 N:N′](μ3-naphthalene-1,4-dicarboxylato-κ4 O 1,O 1′:O 4:O 4′)zinc(II)], [Zn(C12H6O4)(C16H14N2)] n , has been prepared by the self-assembly of Zn(NO3)2·6H2O, naphthalene-1,4-dicarboxylic acid (1,4-H2ndc) and 1,6-bis(pyridin-3-yl)-1,3,5-hexatriene (3,3′-bphte) under hydrothermal conditions. The title compound has been structurally characterized by IR spectroscopy, elemental analysis, powder X-ray diffraction and single-crystal X-ray diffraction analysis. Each ZnII ion is six-coordinated by four O atoms from three 1,4-ndc2− ligands and by two N atoms from two 3,3′-bphte ligands, forming a distorted octahedral ZnO4N2 coordination geometry. Pairs of ZnII ions are linked by 1,4-ndc2− ligands, leading to the formation of a two-dimensional square lattice (sql) layer extending in the ab plane. In the crystal, adjacent layers are further connected by 3,3′-bphte bridges, generating a three-dimensional architecture. From a topological viewpoint, if each dinuclear zinc unit is considered as a 6-connected node and the 1,4-ndc2− and 3,3′-bphte ligands are regarded as linkers, the structure can be simplified as a unique three-dimensional 6-connected framework with the point symbol 446108. The thermal stability and solid-state photoluminescence properties have also been investigated.


2021 ◽  
Vol 77 (2) ◽  
pp. 81-83
Author(s):  
Paul Tobash ◽  
Svilen Bobev

Single crystals of dicerium trialuminium tetragermanide, Ce2Al3Ge4, have been synthesized from a high-temperature reaction using an eutectic mixture of Al and Ge as a metal flux. Through single-crystal X-ray diffraction it was established that Ce2Al3Ge4 crystallizes in the centrosymmetric space group Cmce (No. 64) with the Ba2Cd3Bi4 structure type (Pearson code oC36). Five atoms compose the asymmetric unit, i.e. one Ce, two Al, and two Ge atoms, all in special positions with Wyckoff symbols 8f (Ce), 4a and 8e (Al), and 8e and 8f (Ge). The structure can be described as a three-dimensional network of Al and Ge atoms, with Ce atoms occupying the cavities of the framework.


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