Rare Earth Complex Eu Research Articles

Waterborne rare earth complexes/polyurethane systems with UV shielding and tunable fluorescence for anti-counterfeiting

Fluorescent polymer materials integrated with rare-earth complexes demonstrate promising multifunctional capabilities. However, their complex synthesis procedures and prohibitive cost currently constrain large-scale utilization. Herein, rare earth complexes Eu(PBA)3Phen and Tb(PBA)3Phen were synthesized by coordinating Eu3+, Tb3+ with p-hydroxybenzoic acid and phenanthroline, which were then physically incorporated into waterborne polyurethane (WPU) to obtain Eu-WPU and Eu/Tb-WPU composites. The as-prepared Eu/Tb-WPU had tunable fluorescence, whose fluorescent colors from green to red were achieved under ultraviolet excitation. Compared to Eu(PBA)3Phen (0.27 ms; 0.22 %), the Eu-WPU exhibited a prolonged fluorescence lifetime(1.08 ms) and high fluorescence quantum yield (10.7 %). In addition, Eu-WPU had a wider UV shielding range of 200–289 nm than WPU (200–222 nm). The prepared Eu/Tb-WPU exhibited rich fluorescent emission colors and can be used for information security encryption. Therefore, these Eu-WPU and Eu/Tb-WPU have good application prospects in ultraviolet shielding and fluorescence anti-counterfeiting.

Improving light converting properties with wettability of polyethylene film by rare earth complex Eu(GI)3Phen

ABSTRACT Modern agriculture needs multifunctional greenhouse films to meet different needs. A novel method for improving light converting properties and wettability of polyethylene film was developed in this paper. Glycerin monostearic acid itaconic acid diester (GI) with a carboxyl group and double band was synthesized. Rare earth complex Eu(GI)3Phen with Eu3+ as central ion has been obtained. Subsequently, a simple strategy of grafting it onto LLDPE backbone was employed to delay the migration of Eu(GI)3Phen. The fluorescence spectrum indicated that the modified film emitted red light. Meanwhile, the accelerated dripping time of modified film was extended to 12 days.

Properties of Ultraviolet‐Shielding Composite Film Prepared from Cellulose Acetate with Eu(III) Complex

AbstractThe ultraviolet shielding composite films were prepared from cellulose acetate (CA) modified by grafting rare earth complexes Eu(MAA)3phen‐APS (MMA: Methacrylic Acid, APS: (3‐Aminopropyl)trimethoxysilane). The composite films possessed high optical transmittance and exhibited excellent ultraviolet (UV) absorption property. It exhibited bright red emission centered at 615 nm under UV excitation. The thermal analysis showed that the stability of the composite film is similar to that of pure CA. However, the glass transition temperature gradually disappeared with the increasing amount of Eu(MAA)3phen‐APS (Eu(III)‐complex) owing to the crosslinking reaction. The morphology analysis showed that the Eu(III)‐complex microdomains dispersedly was filled in the matrix of CA and a good interfacial adhesion was achieved. The size of the Eu(III)‐complex formed in the CA matrix is the main factor to effect the transparency of composite films.

Preparation of Eu(Avobenzone)3TPPO by precipitation method and its luminescence performance

Using Eu2O3 as raw material, anhydrous ethanol as solvent system, 1-(4-Methoxyphenyl)-3-(4-tert-butylphenyl)-1,3-propanedione (Avobenzone) as first ligands and triphenylphosphane oxide (TPPO) as second ligands, the rare earth complex Eu(Avobenzone)3TPPO has been successfully prepared by precipitation method. The Eu(Avobenzone)3TPPO were characterized by fluorescence spectrum analysis (FS), Fourier transform infrared spectroscopy(FT-IR) and color coordinate calculation. The thermal stability of Eu(Avobenzone)3TPPO was studied by thermogravimetry differential scanning calorimetry (TG-DSC). The results showed that Eu(Avobenzone)3TPPO emitted strong red characteristic fluorescence, the optimal excitation wavelength was 397nm, the characteristic emission wavelength was 612 nm, and the color coordinates were (0.66, 0.34). Eu(Avobenzone)3TPPO decomposes at about 200°C it shows good thermal stability.

Preparation and luminescence of rare earth complex Eu(DBM)3(TPPO)

Using Eu2O3 as source of europium, anhydrous ethanol as solvent system, methylene benzoyl(DBM) as first ligands, triphenyl phosphine (TPPO) as second ligands, the europium(III) ternary rare earth complex Eu(DBM)3TPPO has been successfully prepared. The samples were characterized by fluorescence spectrum(FS), Fourier transform infrared spectroscopy(FT-IR), thermogravimetry differential scanning calorimetry(TG-DS) and scanning electron microscope(SEM). The influence of TPPO on luminescence intensity, color temperature, color coordinates, morphology and thermal stability of the samples were analyzed. The results showed that the addition of second ligand could enhance the luminescence intensity of Eu(DBM)3TPPO. Eu(DBM)3TPPO can emit strong red fluorescence when excited by 395nm ultraviolet light. The color coordinate of Eu(DBM)3(TPPO) is (0.63, 0.36). The Eu(DBM)3TPPO is a kind of red luminescent material with wide application prospect.

Emulsifier-free emulsion polymerized poly(MMA-HEMA-Eu(AA)3Phen)/Fe3O4 magnetic fluorescent bifunctional nanospheres for magnetic resonance and optical imaging

Integration of biocompatibility with superparamagnetic Fe3O4 nanoparticles and luminescence rare earth complexes Eu(AA)3Phen was carried out to form bifunctional nanospheres for using in bioimaging applications. The nanospheres Poly(MMA-HEMA-Eu(AA)3Phen)/Fe3O4 exhibit magnetic and fluorescent properties that are favorable for the use in drug delivery, magnetic separation and MR imaging for biomedical research. The TEM and SEM studies reveal that the bifunctional nanospheres have core-shell structure, in a spherical shape with a size ranging from 140 nm to 180 nm. In MRI experiments, a clear negative contrast enhancement in T2 images and the r2 reaches 568.82 (mmol·L-1)-1·s-1. In vivo magnetic and fluorescence resonance imaging results suggest the nanospheres are able to preferentially accumulate in liver and spleen tissues to allow dual-modal detection of cancer cells in a living body.

Red emissive nanoclay hybrids in transparent aqueous dispersion—towards optical applications in biophotonics

Hydrophobic guest molecules like organic dyes and metal–ion complexes can be introduced into aqueous media via adsorption onto inorganic nanoclay host materials such as nm-sized laponite. Dispersions of these organic–inorganic hybrid materials show several advantageous properties like minimum light scattering due to their small size in the nanometer regime, ease of modification, low cost, low toxicity, and long-term stability, making them perfect candidates as signaling units and optically active materials in photonics and biotechnology. In this study, we summarize first findings on the easy-to-make, but chemically and optically fairly complex behavior of nanoclay hybrids for biotechnological applications. The latter includes the preparation of nanomaterials, which are colloidally stable in buffers and in the presence of biomolecules like proteins, and methods to control their surface chemistry. For this purpose, we used two red emitting fluorophores, the small organic dye Nile Red and the rare earth complex Eu(ttfa)3(topo)2, and evaluated the interaction of the red nanoclay hybrids with two model proteins, bovine serum albumin and β-lactoglobulin. We were able to monitor the formation of the protein corona around these hybrids using absorption and luminescence spectroscopy.

Generation of amplified spontaneous emission from rare-earth complexes dispersed in phenol + AOT self-assembled organogels

The rare-earth complex Eu(hfa)3(phen) is dispersed in the self-assembled organogel of p-chlorophenol and surfactant AOT. The time profiles of the emission intensity observed from the complex–organogel system suggest the possible generation of amplified stimulated emission when excited with a strong excitation pulse. As the host material, the organogel can support eight times as much of the complex along with better emission quantum yield. A theoretical estimation of the laser gain factor of the complex–organogel also suggested that this system might have application in laser systems.

Synthesis and luminescence properties of the europium quaternary complexes nanoparticles

In this paper, the nanometer-sized (200 nm) quaternary rare-earth complex Eu(BA)(TTA)2phen was successfully prepared by using the method of optimizing chemical precipitation. The characterizations of these nanoparticles were performed by using elemental analysis, thermogravimetric analysis, infrared spectroscopy, fluorescence spectroscopy, transmission electron mi-croscopy and luminescence quantum-yield. The results indicate that they are better than common ternary complexes at light-emitting performance, luminescence properties, thermal stability, uniformity and particle size; they can also be further mixed with a suitable polymer to form functional rare earth polymers. Compared to the common solid materials, the quaternary complex has better and unique characteristics such as nanoparticle size effect and surface effect. A foundation had been laid for the further expansion of its application in the field of light-emitting and magnetic materials.

Synthesis and Characterization of [Eu(DBM)3phen]Cl3@SiO2–NH2 Composite Nanoparticles

Fluorescent rare earth complex Eu(DBM)3(phen)]Cl3@SiO2-NH2 nanoparticles were synthesized by combination of solvent precipitation method and Stöber method. The morphologies, structure, surface and optical properties of the samples were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and fluorescence spectrophotometer (FS). The observation from FE-SEM images indicate that the obtained samples are spherical and uniform nanoparticles with a tunable average sizes from 140 nm to 300 nm. TEM results verify a core-shell structure of the nanoparticles. The FTIR spectrum confirms the characteristic vibration absorption peaks of the complex [Eu(DBM)3(phen)]Cl3@SiO2-NH2. TGA result indicates that the complex is stable below 200 degrees C. The photoluminescence analysis shows that the complex has Eu3+ characteristic red luminescence and broader excitation peak from 200 nm to 450 nm that can meet the demands of fluorescent confocal imaging. The amino groups are directly introduced to the [Eu(DBM)3(phen)]Cl3@SiO2-NH2 nanoparticles surface by using APS (3-aminopropyl triethoxysilane). This makes the surface modification and bioconjugation of the nanoparticles easier. The nano-sized spheres could be provided a basis for further expansion of its application in biomedical imaging, biological detection and fluorescent nanoprobes.

Cationic Lanthanide Luminescent Copolymer: Design, Synthesis and Interaction with DNA

Polymerizable rare earth complex Eu(AA)3Phen was synthesized by complexion of europium ion, acrylic acid (AA), and 1,10-phenanthroline (Phen). The structure and fluorescence properties of the complex were studied by elemental analysis, 1H-NMR spectroscopy, and fluorescence spectroscopy. Eu-containing copolymer poly(PEGMA-co-MMA-co-METAC-co-Eu(AA)3Phen) (PPMMEu) was then synthesized by free radical copolymerization of Eu(AA)3Phen and other functional monomers including poly(ethylene glycol) methyl ether methacrylate (PEGMA) and [2-(Methacryloyloxy) ethyl] trimethylammonium chloride (METAC). 1H-NMR spectroscopy and fluorescence spectroscopy were used to characterize the copolymer and the interactions between the copolymer and DNA was investigated by TEM, fluorescence spectroscopy, and agarose gel electrophoresis. The desired luminescent cationic copolymer was successfully obtained. The copolymer can form micelles in water solution and can efficiently bind to DNA molecules through electrostatic interaction. The results suggest the potential use of PPMMEu in bioprobes and gene vectors.

Synthesis and emission analysis of novel rare earth complex Eu(TTA) 3(2NH 2-Phen)

The rare earth ternary complex of Eu 3+ with thenoyltrifluoroacetone, and 4, 7-2NH 2 phenanthroline was synthesized and well characterized by UV, fluorescent, IR spectrometry and X-ray diffractometry (XRD) as well as elemental analysis. The results show that the complex of Eu(III) emits strong red luminescence when excited by UV light, and Eu(TTA) 3(2NH 2-Phen) has the higher sensitized luminescent efficiency and longer lifetime than Eu(TTA) 3(Phen). In device of ITO/PVK/Eu(TTA) 3(2NH 2-Phen)/Al, the spectra of Eu(TTA) 3(2NH 2-Phen) with different ratios for spin-cast film were monitored. The main emitting peak at 614 nm can be attributed to the transition of 5D 0→ 7F 2 of Eu 3+ and this process results in the enhancement of red emission from electroluminescence device. The effect and mechanism of the ligands on the luminescence properties of europium complex were discussed. The results show that the luminescence intensity of the title complexes greatly increases in comparison with that of their corresponding complexes, revealing that the second ligands form very good synergistic effect with the first ligands. The title complexes possess excellent thermal stability properties, and are hopefully developed into fine PL and EL red materials.

Luminescent property of a novel rare earth complex Eu(TTA)(2NH 2-Phen) 3

Rare earth ternary complex of Eu 3+ with 4,7-2NH 2 Phenanthroline and HTTA was synthesized, and it contents and structures were postulated based on elemental analysis, FT-IR spectra and UV–vis spectra. Results show that the complex of Eu(III) emit strong red luminescence when excited by UV light. Eu(TTA)(2NH 2-Phen) 3 has the higher sensitized luminescent efficiency and longer lifetime. In device ITO/PVK/Eu(TTA)(2NH 2-Phen) 3/Al, Eu 3+ may be excited by intramolecular energy transfer from ligands as observed by electroluminescence. The main emitting peak at 614 nm can be attributed to the transition of 5D 0 → 7F 2 of Eu 3+ ion and this process results in the enhancement of red emission from electroluminescence device.

Synthesis of Eu(TTA)<sub>3</sub>phen•H<sub>2</sub>O-PVP Composite Film and Study of their Luminescence Properties

We obtained the Eu(TTA)3phen•H2O-PVP composite film by rare earth complexes Eu(TTA)3 phen•H2O was doped intentionally in polyvinylpyrrolidone(PVP), and the factors of effect it’s luminous intensity were investigated. The results indicate that the luminous effect of sample was best when the water and the alcohol proportion is 1: 4 in the resolver, the aggregation-time reached 12 h and the doping concentration of europioun ion reached 0.6%. The infrared spectrum analyses of sample indicate that there is an interaction between Eu(TTA)3phen•H2O and PVP. In addition, the fluorescence spectra and ultraviolet spectrum analyses of sample indicate that polymer materials can not only fix rare earth ions to enhance its luminescence intensity, but also avoid the quenching effect to rare earth caused by water molecule, through the replacement of PVP ligand to water molecule in the complex. The luminous intensity of the rare earth complexes can be greatly enhanced, and the composite film contained high amount of rare earth complexes is obtained, which laid a foundations for further study the film formation properties of rare earth complexes luminous materials.

Enhanced luminescence of novel rare earth complexes Eu(3,5-DNBA) 3Phen in nano-TiO 2

Eu 3+ (or Tb 3+) of 3,5-dinitrobenzoic acid and 1,10-phenanthroline ternary rare earth complexes were synthesized and characterized by thermal analysis , infrared spectroscopy, elemental analysis and fluorescence spectroscopy. In this study an organic–inorganic combined device indium tin oxide/poly( N-vinylcar-bazole):RE(3,5-DNBA) 3Phen:TiO 2/Al was fabricated. The nano-TiO 2 has been used in the luminescence layer to change the electroluminescence property of RE(3,5-DNBA) 3 Phen (RE = Eu 3+or Tb 3+).

Study on Luminescence Properties of a Novel Rare Earth Complex Eu(TTA) 2 (N-HPA)Phen

A novel rare earth complex Eu (TTA) 2(N-HPA) Phen (TTA = thenoyltrifluoroacetone, N-HPA = N-pheny-lanthranilic acid, and phen = 1, 10-phenathroline), which contains three different ligands, was synthesized. The Eu complex was blended with poly N-vinylcarbazole (PVK) in different weight ratios and spin coated into films. The luminescence properties of films were investigated and energy transfer between PVK and the complex was discussed. Multilayer structural devices consisting of ITO/PVK: Eu(TTA) 2(N-HPA) phen/BCP/Alq 3/Al were fabricated with PVK: Eu (TTA) 2(N-HPA) as light-emitting layer. Increasing the concentration of Eu in the PVK thin film would inhibit the emission of PVK to different degrees. Finally, the pure red luminescence of europium (III) was observed when the doping weight ratio was approximately 1:5, which indicated an effective energy transfer from PVK to rare earth complex.

Synthesis and Luminescence of Eu Complex Incorporated MCM-41 Mesoporous Molecular Sieves

Rare earth complex Eu(phen)2Cl3·2H2O synthesized by precipitation method was incorporated into MCM-41 mesoporous molecular sieves which were synthesized via a hydrothermal method. Hybrid inorganic/organic mesoporous luminescent material Eu(phen)2/MCM-41 has been characterized by XRD, TEM, IR, UV-visible spectra and fluorescence spectra. Results indicated that the hybrid mesoporous material has typical structure of MCM-41 and retains the same pore structure as MCM-41 after the assembly process. The fluorescence spectra of these materials present a series of narrow lines assigned to 5D0 → 7F0,1,2,3,4 transitions. The high emission intensity observed is a promising property for application of the rare earth complex in technological luminescent devices.

Electroluminescence Based on Eu 0.5La 0.5(TTA) 3phen Doped Poly N-Vinylcarbazole

A novel rare earth complex Eu 0.5La 0.5(TTA) 3phen, displaying electroluminescent property, was synthesized, and monolayer and double-layer devices were fabricated by doping it into poly N-vinylcarbazole. The characteristics of these optimized devices were investigated, and the emitting mechanism was explained through the energy band diagram. Optimized double-layer devices with a turn-on voltage of 6.5 V were achieved. At the current density of 68.48 mA·cm −2, the maximum brightness and the current efficiency of the device reached 238.4 cd·m −2 and 0.35 cd·A −1, respectively.

Preparation and Fluorescent Property of Eu(TTA)3Phen Incorporated in Polycarbonate Resin

Rare earth complex Eu(TTA)3Phen was synthesized with a new method. The product was characterized by element analysis, IR, UV, TGA and fluorescence spectra. The strong fluorescence and high thermal stability of Eu(TTA)3Phen were used for modification of resin. Eu(TTA)3Phen-PC composite was prepared at 220 °C for 30 min under stirring. The fluorescence spectra showed that the prepared Eu(TTA)3Phen-PC composite materials retained the fluorescent characteristic and strong red fluorescence emission of Eu3+ complex and its fluorescence intensity was found to be increased with increase in the mass fraction of Eu(TTA)3Phen in PC resin.

The photoluminescent and electroluminescent properties of a new Europium complex

A new rare earth (RE) complex Eu(BSA) 3phen was synthesized. A narrow emission band from a device structure of ITO/PVK: RE complex/LiF/Al was observed, in which poly N-vinylcarbazole (PVK) was used to improve the film-forming and hole-transporting property of the Eu(BSA) 3phen. Excitation, photoluminescence (PL) and electroluminescence (EL) characteristics of the device were studied and an energy transfer from PVK to europium complex was proposed. Effects of doping ratios of Eu(BSA) 3phen on the device performance were also studied.