Luminescent Materials Based on Tb- and Eu-Containing Layered Double Hydroxides (original) (raw)
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The Mg 3 /Al and Mg 3 /Al 0.99 Eu 0.01 layered double hydroxides (LDHs) were fabricated using a sol-gel chemistry approach and intercalated with different anions through ion exchange procedure. The influence of the origin of organic anion (oxalate, laurate, malonate, succinate, tartrate, benzoate, 1,3,5-benzentricarboxylate (BTC), 4-methylbenzoate (MB), 4-dimethylaminobenzoate (DMB) and 4-biphenylacetonate (BPhAc)) on the evolution of the chemical composition of the inorganic-organic LDHs system has been investigated. The obtained results indicated that the type and arrangement of organic guests between layers of the LDHs influence Eu 3+ luminescence in the synthesized different hybrid inorganic-organic matrixes. For the characterization of synthesis products X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy, fluorescence spectroscopy (FLS), and scanning electron microscopy (SEM), were used.
Intercalation of luminescent Europium(III) complexes in layered double hydroxides
Optical Materials, 2009
Anionic Europium(III) complexes EuL1, EuL2 and EuL3 (L1 = tris (dipicolinate), L2 = diethylenetriaminepentaacetate, L3 = disulfonated bathophenanthroline tris(dibenzoylmethanate) were intercalated in Zn 2 Al(OH) 6 Cl, nH 2 O and Zn 4 Al(OH) 10 Cl, nH 2 O layered double hydroxides (LDHs). Intercalation was confirmed by X-ray diffraction, vibration spectroscopy and photoluminescence measurements, using Eu(III) as a local structural probe. Information on host-guest interactions in the hybrid materials were deduced by analyzing the intensity parameter X 2 , the energy position of the 5 D 0-7 F 0 transition and the emission decay profile of the prominent hypersensitive red 5 D 0-7 F 2 emission.
The acetate intercalated layered double hydroxides of Zn and Mn, have been synthesized by chimie douce method. The materials were characterized by XRD, TGA, CHN, IR, XPS, SEM-EDX and UV-visible spectroscopy. The photoluminescence properties was also studied. The optical properties of layered hydroxides are active transition metal ion dependent, particularly d 1À10 system plays an important role. Simultaneously the role of host e guest orientation has been considered the basis of photoluminescence. Acetate ion can be exchanged with iodide and sulphate ions. The decomposed product resulted the pure phase Mn doped zinc oxide are also reported.
Inorganic Chemistry, 2005
The synthesis of a new ligand (1) containing a single phenanthroline (phen) chromophore and a flexibly connected diethylenetriamine tetracarboxylic acid unit (DTTA) as a lanthanide (Ln) coordination site is reported [1 is 4-[(9methyl-1,10-phenantrol-2-yl)methyl]-1,4,7-triazaheptane-1,1,7,7-tetraacetic acid]. From 1, an extended series of watersoluble Ln‚1 complexes was obtained, where Ln is Eu(III), Tb(III), Gd(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III). The stoichiometry for the association was found 1:1, with an association constant K A g 10 7 s -1 as determined by employing luminescence spectroscopy. The luminescence and photophysical properties of the series of lanthanide complexes were investigated in both H 2 O and D 2 O solutions. High efficiencies for the sensitized emission, φ se , in air-equilibrated water were observed for the Ln‚1 complexes of Eu(III) and Tb(III) in the visible region (φ se ) 0.24 and 0.15, respectively) and of Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III) in the vis and/or near-infrared region [φ se ) 2.5 × 10 -3 , 5 × 10 -4 , 3 × 10 -5 , 2 × 10 -5 , 2 × 10 -4 , 4 × 10 -5 , and (in D 2 O) 4 × 10 -5 , respectively]. For Eu‚1 and Tb‚1, luminescence data for water and deuterated water allowed us to estimate that no solvent molecules (q) are bound to the ion centers (q ) 0). Luminescence quenching by oxygen was investigated in selected cases.
Journal of materials science, 2000
Microporous silica gel has been prepared by the sol-gel method utilizing the hydrolysis and polycondensation of tetraethylorthosilicate (TEOS). The gel has been doped with the luminescent ternary europium complex Eu(TTA) 3 ·phen: where HTTA = 1-(2-thenoyl)-3,3,3-trifluoracetone and phen = 1,10-phenanthroline. By contrast to the weak f-f electron absorption bands of Eu 3+ , the complex organic ligand exhibits intense near ultraviolet absorption. Energy transfer from the ligand to Eu 3+ enables the production of efficient, sharp visible luminescence from this material. Utilizing the polymerization of methyl methacrylate or ethyl methacrylate, the inorganic/polymer hybrid materials containing Eu(TTA) 3 ·phen have also been obtained. SEM micrographs show uniformly dispersed particles in the nanometre range. The characteristic luminescence spectral features of europium ions are present in the emission spectra of the hybrid material doped with Eu(TTA) 3 ·phen. C 2000 Kluwer Academic Publishers
Chemistry of Materials, 2003
This study focuses on luminescent materials based on the antenna effect and prepared by the sol-gel method. These materials are composed of a Eu(III) complex (luminescence center) entrapped in a xerogel matrix. Luminescence properties of the lanthanide-based emitting materials depend on the efficiency of energy transfer from the absorption center (ligand) to the emission center (central ion) and on the concentration of quenchers (O-H oscillators) surrounding the central ion. In this study, such luminescence properties as * lifetime and quantum yield were improved by modifying the coordination environment of the central ion and changing anion groups and matrixes. The results of the experiments on the composition of the coordination sphere show that a cryptand ligand with aromatic groups and an aromatic coligand efficiently initiate the antenna effect, thus isolating the central ion from every efficient quencher, e.g., water molecules. Luminescence properties also depend on the anion in the Eu(III) complex salt, the type of matrix material, and the concentration of water and OH groups in the matrix. These luminescent materials have been tested for their photochemical stability under continuous UV irradiation.
New Journal of Chemistry, 2004
Lanthanide-doped sol-gel-derived materials are an attractive type of luminescent materials that can be processed at ambient temperatures. However, the solubility of the lanthanide complexes in the matrix is a problem and it is difficult to obtain a uniform distribution of the complexes. Fortunately, these problems can be solved by covalently linking the lanthanide complex to the sol-gel-derived matrix. In this study, luminescent Eu 31 and Tb 31 bipyridine complexes were immobilized on sol-gel-derived silica. FT-IR, DTA-TG and luminescence spectra, as well as luminescence decay analysis, were used to characterize the obtained hybrid materials. The organic groups from the bipyridine-Si moiety were mostly destroyed between 220 and 600 1C. The luminescence properties of lanthanide bipyridine complexes anchored to the backbone of the silica network and the corresponding pure complexes were comparatively investigated, which indicates that the lanthanide bipyridine complex was formed during the hydrolysis and co-condensation of TEOS and modified bipyridine. Excitation at the ligand absorption wavelength (336 nm for the hybrid materials and 350 nm for the pure complexes) resulted in strong emission of the lanthanide ions:
Layered double hydroxides: noble materials for the development of multi-functional nano- hybrids
Layered double hydroxides (LDH), auch als anionische Tonmineralien bekannt, werden seit längerem in der Katalysetechnik und in verschiedenen biologischen und medizinischen Anwendungen eingesetzt. Die Nutzung von LDH als multifunktionelle Nanofüllstoffe ist in den letzten Jahren in der Polymerforschung forciert worden. Dazu trugen die positive Ladung der Hydroxidschichten, die im Gegensatz zu den weit verbreiteten Schichtsilicaten eine anionische Modifizierung erfordert, die chemische Aktivität, die eine Kopplung organischer Moleküle an die anorganische Oberfläche ermöglicht, die hohe einstellbare Ionenaustauschkapazität und die Wasserabspaltung bei höheren Temperaturen besonders bei. Mg-Al-LDH wurden hergestellt, modifiziert und in polymerer Matrix nanoskopisch verteilt. Für unpolare Matrices (z.B. PE) zeigte sich, dass ein Verstärkungseffekt aufgrund des hohen Modifikatorbedarfs nicht erreicht werden konnte, der bei polaren Matrices wie carboxyliertem Nitrilbutadienkautschuk (XNBR) deutlich nachgewiesen werden kann. Gezeigt werden konnte, dass LDH ein effektiver Co-Flammhemmer in Polyolefinen mit einer Metallhydroxid-Basisflammhemmung ist.