Luminescence Of Eu3 Research Articles

Recyclable Eu3+ functionalized Hf-MOF fluorescent probe for urinary metabolites of some organophosphorus pesticides

A luminescent metal-organic framework Eu3+ functionalized Hf-MOF (Eu3+@1) is designed through post-synthesis modification (PSM) and utilized as a probe for detecting p-nitrophenol (PNP, the urinary metabolite of parathion, methyl-parathion and EPN) and 3-methyl-4-nitrophenol (PNMC, the urinary metabolite of fenitrothion). The apparent quenching effect in urine is observed from the Eu3+@1 with the addition of organophosphorus metabolites. The fluorescent probe has several appealing merits, such as high selectivity, excellent sensitivity (0.36 μg mL−1 for PNP, 0.41 μg mL−1 for PNMC), fast response time (less than 1 min) and easy preparation. Linear correlation between the fluorescence intensity of Eu3+@1 and the concentration of PNP and PNMC are from 0.005 to 0.15 mg mL−1 and 0.005–0.30 mg mL−1, respectively. Furthermore, this fluorescent material also demonstrated the possibility for recycling. It is a prominent candidate for potential application in personalized monitoring the internal dose of human exposure to some organophosphorus pesticides.

Erratum: First-principles study of the luminescence of Eu2+ -doped phosphors [Phys. Rev. B 96 , 125132 (2017)

Erratum: First-principles study of the luminescence of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi>Eu</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:math> -doped phosphors [Phys. Rev. B <b>96</b> , 125132 (2017)

A luminescent Eu(III)-MOF for selective sensing of Ag+ in aqueous solution

A 3D open structure FeIII(OH)[C6H2(CO2)2(CO2H)2]·xH2O(MIL-82) with carboxyl-rich groups is designed as a parent metal-organic framework (MOF). A stable lanthanide fluorescent MOF was successfully constructed by doping the Eu3+ cation on the coordination site of MIL-82. The intense luminescence of Eu3+ incorporated MIL-82 indicates that uncoordinated carboxyl group is an efficient framework for accommodating and sensitizing Eu3+ cations. The luminescent MOF can be developed as a chemical sensor for Ag+ in aqueous solution. The sensor also displays high selectivity towards Ag+, excellent sensitivity with a relatively low detection limit (0.09 μM) and fast response time within 3 min. In addition, the framework has excellent water stability and thermal stability, which provides a rare method for detecting Ag in daily water samples.

Sensitized Mechanoluminescence Design toward Mechanically Induced Intense Red Emission from Transparent Polymer Films

Mechanoresponsive polymers with intense red emission are highly desirable in view of the strong penetrability and high resolution of red luminescence. Herein we introduce the sensitized luminescence of rare-earth Eu(III) complexes into the mechanochemiluminescence from polymeric dioxetane in a covalent way. By controlling the energy-transfer process from mechanically broken dioxetane to the Eu(III) center, bright red emission from transparent poly(methyl acrylate) films was achieved for the first time. Importantly, mechanoluminescence sensitivity is greatly improved, enabling the location and timing of bond scission with high resolution. A sensitive stretchable device with the polymer film as an emissive layer was fabricated by a facile surface-engineering method, which can emit patterned red light upon deformation. This sensitized mechanoluminescence design thus expands the useful space of luminescent stress probes.

Luminescence of Eu3+ Ions in a Matrix of a Fluorinated Yttrium–Aluminum Composition

We studied the optical spectra of fluorinated yttrium–aluminum compositions activated by Eu3+ ions. The compositions were synthesized by thermal decomposition at 800°C of fluorine-containing complexes of yttrium, europium, and aluminum nitrate, isolated as sols from ethyl acetate (EA). The main phases of the compositions are (Y1 – xEux)OF and (Y1 – xEux)AlO3. Photoluminescence is associated with 5D1, 2 → 7F0, 1, 2 and 5D0 → 7F0, 1, 2, 3, 4 electronic transitions of 4f electrons of Eu3+ ions replacing yttrium ions in oxide and oxyfluoride. The dependences of luminescence on the composition and synthesis conditions of the compositions, the wavelength of the excitation radiation, and other factors are found.

Sensitivity of a solid Eu(III) complex towards acetonitrile vapor: Structural and spectroscopic characterization

The Eu(III) nitrate complex of the meso- N,N′-bis(2-pyridylmethylene)-1,2-(R,S)-cyclohexanediamine ligand was synthesized and characterized by single crystal and powder X-ray diffraction. The crystal lattice of the complex is capable of absorbing and desorbing selectively acetonitrile molecules, at 293 K upon an acetonitrile vapor pressure of ∼0.1 × 105 Pa. This process, which is partially reversible, can be easily followed by both powder X-ray diffraction (P-XRD) and Eu(III) luminescence spectroscopy. The acetonitrile molecule, located in the outer coordination sphere of the metal ion, does not affect the radiative transition probability of 5D0 level of Eu(III) and also it does not activate further non-radiative channels from this level. On the other hand, this molecule is capable of affecting the energy position and intensities of the crystal field components of the 5D0→7F2 transition. The complex in solid form can be considered a promising material for the optical sensing of acetonitrile vapors.

Selective sensing of Fe3+ ions in aqueous solution by a biodegradable platform based lanthanide metal organic framework.

As a significant metal ion in the environmental and biological systems, excess or shortage of Fe3+ from the organism can cause a host of diseases. So it is very urgent to explore an explicit, rapid and recoverable method for the detection of Fe3+ ions. Herein, a novel and flexible ligand containing 12 carboxyl groups (BHM-COOH) is used for the structure of a series of luminescent Eu3+/Tb3+-metal-organic frameworks (MOFs). A reliable and convenient luminescent detection platform is constructed by combining polylactic acid (PLA) film with Eu0.24Tb0.76-BHM-COOH. More importantly, the luminescent platform can highly sensitive to sense Fe3+ ions through fluorescence quenching (Stern-volmer constant Ksv = 1.27 × 104 M-1 for Fe(NO3)3), and detection limit can be as low as 4.47 μM. The sensing mechanism is ascribed to the fluorescence quenching caused by the competitive absorption between Eu0.24Tb0.76-BHM-COOH and Fe3+ ion. At the same time, the sensor can be reused many times. These exciting results indicate that Eu0.24Tb0.76-BHM-COOH film can serve as a promising multi-responsive luminescent sensor for environmental pollutant monitoring.

A responsive supramolecular-organic framework: Functionalization with organic laser dye and lanthanide ions for sensing of nitrobenzene

A anionic supramolecular-organic framework, namely [(NH4)4·[Zn (bpdo)3]2·[Zn(bpdo)2·2H2O]·[(p-sulfonatocalix[4]arene)2]·H2O SOF-1 has been synthesized, which exhibited highly efficient adsorption of organic laser dye (4-[p-(dimethylamino)styryl] -1-methylpyridinium, DSM). In addition, we prepared a responsive luminescent Eu3+@ SOF-1 by postsynthetic incorporation of Eu3+ cations into the SOF-1 framework, which can serve as a platform for the recognitions of nitrobenzene.

A study on temperature sensing performance based on the luminescence of Eu3+ and Er3+ co-doped YNbO4.

Eu3+ and Er3+ co-doped YNbO4 powder phosphors were synthesized by a traditional high-temperature solid-state reaction method. A laser of 487.6 nm wavelength was selected to be the excitation source which can pump Eu3+ ions from its thermally populated low-lying 7F2 ground state to the excited state 5D2 and lift the Er3+ ions from their 4I15/2 to 4F7/2 states. Fluorescence intensity ratio (FIR) between the 5D0 → 7FJ emissions of Eu3+ and 4S3/2 → 4I15/2 emissions of Er3+ ions is remarkably dependent on temperature because of the dramatic increase of Eu3+ luminescence against a slight quenching of Er3+ luminescence with the rise of temperature. This temperature sensitive FIR can be favorably employed for temperature sensing, owing to this novel scheme of 5D2 excitation, instead of 5D0, from 7F2 and utilizing Er3+ luminescence as a reference for FIR measurements. This sample is also prominent for its excellent signal-to-noise ratio and is a promising candidate for an optical temperature sensor.

Preorganized helical chirality controlled homochiral self-assembly and circularly polarized luminescence of a quadruple-stranded Eu2L4 helicate.

β-Diketones are one of the most widely used ligands for sensitizing the luminescence of lanthanide complexes due to their excellent sensitization abilities. However, the difficulties in introducing chiral groups to take part in the electronic transitions of conjugated systems limit their application in lanthanide circularly polarized luminescence (CPL) materials. In view of the inherent chirality of the helical structure, herein, a pair of homochiral quadruple-stranded helicates, Eu2L4, is assembled based on chiral bis-β-diketonate ligands, wherein the two point chirality centers in the spacer preorganize the helical conformation of the ligand (3S,4S)/(3R,4R)-3,4-bis(4,4'-bis(4,4,4-trifluoro-1,3-dioxobutyl)phenoxyl)-1-benzylpyrrolidine, LSS/LRR. X-ray crystallographic analyses reveal that the R,R configurations of the chiral carbons in the spacer induce the M helical sense of the ligand, while the S,S configurations induce the P helical sense. Through the comprehensive spectral characterization in combination with semiempirical geometry optimization using the Sparkle/RM1 model, it is confirmed that the preorganized ligands successfully control the homochirality of the helicates. Moreover, the mirror-image CD and CPL spectra and NMR measurements confirm the formation of enantiomeric pairs and their diastereopurities in solution. Detailed photophysical and chiroptical characterization studies reveal that the helicates not only exhibit intense circularly polarized luminescence (CPL) with |glum| values reaching 0.10, but also show a high luminescence quantum yield of 34%. This study effectively combines the helical chirality of the helicates with the excellent sensitization ability of the β-diketones, providing an effective strategy for the syntheses of chiral lanthanide CPL materials.

Electronic strain effect on Eu(iii) complexes for enhanced circularly polarized luminescence.

Luminescent Eu(iii) complexes with point-chiral phosphine oxide ligands, [Eu(hfa)3((R,R)-B2QPO)] (hfa: hexafluoroacetylacetonato, B2QPO: 2,3-bis(tert-butylmethylphosphine oxide)quinoxaline) and [Eu(hfa)3((R)-B3QPO)] (B3QPO: 2-tert-butylmethylphosphine oxide-3-(di-tert-butylphosphineoxide)quinoxaline), are reported for the investigation of the electronic strain effect on the coordination sphere. Single crystal X-ray crystallography reveals the strong structural strain of the hfa ligands in [Eu(hfa)3((R,R)-B2QPO)]. The emission quantum yields of [Eu(hfa)3((R,R)-B2QPO)] in solution (55%) and solid (63%) are comparable to those of previously reported bright luminescent Eu(iii) complexes. The chiroptical properties of [Eu(hfa)3((R,R)-B2QPO)] and [Eu(hfa)3((R)-B3QPO)] were characterized using circular dichroism (CD) and circularly polarized luminescence (CPL) spectra. The dissymmetry factor of [Eu(hfa)3((R,R)-B2QPO)] was estimated to be 0.08. The chiroptical phenomena of the Eu(iii) complexes are closely related to their structural (geometry) and electronic (LMCT: ligand-to-metal charge transfer) strains.

Luminescent Chemosensor Properties of Eu(III) Complex Compounds

Luminescent chemosensor properties of Eu(III) carboxylate dibenzoylmethanates are observed. It is shown that the interaction of Eu(III) complexes with ammonia or methylamine vapors leads to an increase in the Eu(III) luminescence intensity. An optical response mechanism related to the interaction between the analyte and Eu(III) complex molecules and to suppression of luminescence quenching is proposed.

Solvatochromic dual luminescence of Eu–Au dyads decorated with chromophore phosphines

Chromophore-containing phosphines produce highly solvatochromic gold(i) fluorophores. Their combination with red-emitting Eu centers offers a facile approach to dual emissive complexes with widely tunable luminescence characteristics.

A luminescent pH-sensitive lysosome targeting Eu(iii) probe

A pH-responsive, water soluble luminescent Eu(iii) probe is designed to target lysosomes via intrinsic f–f emission from the Eu(iii) centre.

A luminescent Eu coordination polymer with near-visible excitation for sensing and its homologues constructed from 1,4-benzenedicarboxylate and 1H-imidazo[4,5-f][1,10]-phenanthroline

Ln-CPs were constructed to achieve luminescent Eu-CP excited at a wide excitation band including the visible region for sensing.

Thermal and Crystallographic Investigation of Luminescent Eu(III) Coordination Polymers with Dithiane and Dioxane Hexyl Rings

The steric structures of luminescent compounds play a key role in controlling the thermal and optical properties. In order to improve the thermal properties of a strong luminescent Eu(III) coordina...

Synthesis of Fluorescent Eu-Doped InVO₄ Nanocrystals by Using In(OH)₃ Templates with Controlled Morphologies.

In this study, In(OH)₃ nanocrystals with three morphologies including rods, cubes and spheres were synthesized through a hydrothermal method. The morphology and crystalline were manipulated by controlling the growth speed and the addition of ascorbic acid. The InVO₄ nanocrystals were obtained by a process sacrificing In(OH)₃ templates. The phase transformation of rods and cubes generated size-controllable products, whereas that of nanospheres formed hollow micro-spheres. InVO₄ nanocrystals display a brilliant yellow emission band with the peak at 517 nm. Intriguingly, luminescent rare-earth Eu ions with red emission could be doped into InVO₄ nanocrystals during the phase transformation. Excitation and the emission spectra indicated an excitation energy transfer from the vanadate to the rare-earth ions.

Microscopic Imaging of Chiral Amino Acids in Agar Gel through Circularly Polarized Luminescence of EuIII Complex.

We recently found that [Eu(pda)2 ]- (pda: 1,10-phenanthroline-2,9-dicarboxylic acid), which has an achiral structure in crystals, exhibits circularly polarized luminescence (CPL) in aqueous solutions containing chiral amino acids such as arginine and histidine. CPL measurements were performed for agar gel, which includes an aqueous solution of [Eu(pda)2 ]- and chiral arginine or histidine. The spectral shape, concentration, and pH dependences on CPL intensity in the agar gels were very close to those in aqueous solutions, indicating that the CPL of the EuIII complex in the agar gels was induced by mechanism similar to that in aqueous solutions. We performed spatially resolved CPL measurements using a laboratory-built microscopic CPL spectroscopic system for agar-gel samples, where d- and l- amino acids were separately dispersed. We successfully recorded CPL imaging maps showing spatial dispersions of d- and l-amino acid in the agar gels.

Study of the luminescence of Eu2+ and Eu3+ states in Ca3Ga2Ge3O12:Eu garnet using synchrotron radiation excitation

The work is dedicated to the investigation of Eu2+ and Eu3+ luminescence centers in the Ca3Ga2Ge3O12 garnet using synchrotron radiation excitation. The luminescence of Eu2+ and Eu3+ states was observed in the emission spectra of Ca3Ga2Ge3O12:Eu ceramics under excitation with energies in the exciton range and the range above band gap of this garnet. The luminescence of Eu2+ ions Ca3Ga2Ge3O12 host is observed in the band peaked at 450–460 nm with decay time in the ten ns range and excited in the two wide bands peaked at 5.04 and 6.05 eV, related to the allowed 4f-5d transitions of Eu2+ ions. The Eu3+ luminescence can be excited via the Eu2+ luminescence. We have also found the energies of formation of excitons bound with Eu2+ and Eu3+ ions in Ca3Ga2Ge3O12, being equal to 7.64 and 6.95 eV, respectively, and the onset of interband transitions in this garnet which is equal to 7.83 eV at 8 K. Strong increase of the luminescence intensity of Eu2+ and Eu3+ centers is observed under excitation above 21 eV due to multiplication of electronic excitation in Ca3Ga2Ge3O12 host.

Luminescence behaviour of Eu3+ in hot-compressed silicate glasses

Abstract This paper aims to explore density-driven effects on the luminescence of Eu3+ doped silicate glasses. For this, mildly densified samples were fabricated by quasi-isostatic hot compression at up to 2 GPa from melt-quenched precursor materials. As a result of compression, both density and glass transition temperature of the blank (Eu free) and doped compositions increase. Raman spectroscopy indicates a slight increase in the intensity of vibrational modes assigned to small silicate rings and Si-O-Si bridges. Photoluminescence experiments reveal the creation of new paths of de-excitation, reducing the relative intensity of the transitions in the excitation spectra and the lifetime of the 5D0 → 7F2 emission line. Meanwhile, the luminescence intensity remains unchanged due to enhanced oscillator strength and refractive index at uniform electron-phonon coupling strength. Luminescence spectra also show a slight expansion of some of the energy levels of Eu3+, together with an increase of the bandwidth of the 5D0 → 7F2 emission line due to the crystal-field influence and growing electron population of the lower Stark sub-levels. Finally, increasing symmetry of Eu3+ sites was detected with increasing degree of compaction, resulting in a reduction of the intensity of the forced electric dipole transition of 5D0 → 7F2 relative to the magnetic dipole transition of 5D0 → 7F1.