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Bioinspired crystallization, sensitized luminescence and cytocompatibility of citrate-functionalized Ca-substituted europium phosphate monohydrate nanophosphors
摘要： Biocompatible nanosystems exhibiting long-lifetime (~millisecond) luminescence features are particularly relevant in the field of bioimaging. In this study, citrate-functionalized calcium-doped europium phosphates nanophosphors of the rhabdophane type were prepared at different synthesis times by a bioinspired crystallization route, consisting in thermal decomplexing of Ca2+/Eu3+ /citrate/phosphate/carbonate solutions. The general formula of this material is Ca?Eu1-?(PO4)1-?(HPO4)?·nH2O, with ??ranging from 0 to 0.58 and n~1. A thorough characterization of the nanoparticles has been carried out by XRD (including data processing with Topas 6.0), HR-TEM, TEM, FTIR, TG/DTA, ICP, dynamic light scattering (DLS), electrophoretic mobility, and fluorescence spectroscopy. Based on these results a crystallization mechanism involving the filling of cationic sites with Ca2+ ions associated to a concomitant adjustment of the PO4/HPO4 ratio was proposed. Upon calcium doping, the aspect ratio of the nanoparticles as well as of the crystalline domains decreased and the relative luminescence intensity (R.L.I.) could be modulated. Neither the pH nor the ionic strength, nor the temperature (from 25 to 37 oC) affected significantly the R.L.I. of particles after resuspension in water, leading to rather steady luminescence features usable in a large domain of conditions. This new class of luminescent compounds has been proved to be fully cytocompatible relative to GTL-16 human carcinoma cells and showed an improved cytocompatibility as the Ca2+ content increased when contacted with the more sensitive m17.ASC murine mesenchymal stem cells. These biocompatible nanoparticles thus appear as promising new tailorable tools for biomedical applications as luminescent nanoprobes.
关键词： Nanophosphors,Citrate-functionalized,Luminescence,Bioimaging,Cytocompatibility,Calcium-doped europium phosphates
更新于2025-09-10 09:29:36
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Synthesis and photophysical properties of europium pentafluorinated β-diketonate complexes
摘要： Two pentafluorinated β-diketone ligands, 4,4,5,5,5-pentafluoro-1-(4-methoxyphenyl)pentane-1,3-dione (PFMP) and 4,4,5,5,5-pentafluoro-1-(4-dimethylaminophenyl)pentane-1,3-dione (PFAP), had been employed to synthesize six novel europium (III) complexes with ancillary ligands 2,2-dipyridine, 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline. The synthesized europium (III) complexes were characterized by FTIR, 1H NMR, UV–Vis, luminescence spectroscopy, elemental analysis and thermogravimetric analysis. The photoluminescence spectra of these complexes showed the typical europium (III) red emissions in solid state and chloroform solution, assigned to 5D0 → 7Fj (j = 0–4) transitions. The higher values of intensity parameter Ω2 indicated that the europium ion was in a highly polarizable ligand field in these complexes. Europium (III) complexes with the β-diketone PFMP exhibited much better photoluminescence properties than complexes with the β-diketone PFAP. Especially, the europium (III) complex of the β-diketone PFMP with the auxiliary ligand 2,2-dipyridine displayed the longest lifetime value, the highest quantum yield and good CIE color coordinates matching the pure red color (x = 0.67, y = 0.33) in these complexes. In addition, the proposed energy transfer mechanisms and the thermal stability of these complexes were also investigated and analyzed.
关键词： Photoluminescence,Europium complex,Quantum efficiency,Luminescent lifetime,Thermal analysis,Pentafluorinated β-diketone
更新于2025-09-10 09:29:36
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Red- and green-emitting nano-clay materials doped with Eu <sup>3+</sup> and/or Tb <sup>3+</sup>
摘要： Trivalent europium (Eu3+) and terbium (Tb3+) ions are important activator centers used in different host lattices to produce red and green emitting materials. The current work shows the design of new clay minerals to act as host lattices for rare earth (RE) ions. Based on the hectorite structure, nano‐chlorohectorites and nano‐fluorohectorites were developed by replacing the OH? present in the hectorite structure with Cl? or F?, thus avoiding the luminescence quenching expected due to the OH? groups. The produced matrices were characterized through X‐ray powder diffraction (XPD), transmission electron microscopy (TEM), FT‐IR, 29Si MAS (magic angle spinning) NMR, nitrogen sorption, thermogravimetry‐differential scanning calorimetry (TGA‐DSC) and luminescence measurements, indicating all good features expected from a host lattice for RE ions. The nano‐clay materials were successfully doped with Eu3+ and/or Tb3+ to yield materials preserving the hectorite crystal structure and showing the related luminescence emissions. Thus, the present work shows that efficient RE3+ luminescence can be obtained from clays without the use of organic ‘antenna’ molecules.
关键词： fluorohectorite,europium,host lattices,terbium,chlorohectorite
更新于2025-09-09 09:28:46
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The luminescent properties comparison of RE2O3:Eu(RE=Lu,Y,Sc) with high and low Eu doping concentrations
摘要： Single crystal scintillators of RE2O3:Eu(RE=Lu, Y, Sc) with high (8%) and low (1%) Eu doping concentration were grown by the optical floating zone method. The luminescence and scintillation properties have been investigated and compared thoroughly. Correlated measurements of afterglow curves, photoluminescence excitation and photoluminescence, photoluminescence decay curves and X-ray excitation curves were performed. Lu2O3:Eu and Y2O3:Eu present significant afterglow intensity decreasing after high Eu concentration doping. While for the Sc2O3:Eu, its afterglow intensity even increases slightly. The luminescence efficiencies of high doping concentration samples are weaker than that of the low concentration ones due to the concentration quenching. The integrated X-ray excitation luminescence reveals the scintillation luminescence efficiencies of samples with the high concentration or the low one both have the following sequence:Lu2O3:Eu＞Y2O3:Eu＞Sc2O3:Eu.
关键词： europium-doped sesquioxide,floating zone method,scintillation properties,afterglow,single crystal
更新于2025-09-09 09:28:46
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The first example of fluorescence of the solid individual compounds of Eu <sup>2+</sup> ion: EuCl <sub/>2</sub> , EuI <sub/>2</sub> , EuBr <sub/>2</sub>
摘要： Fluorescence (FL) from Eu2+ ion solid individual compounds was observed for the first time using the examples EuCl2, EuI2 and EuBr2. Fluorescence was detected at excitation by ultraviolet (UV) light from powdered samples of Eu (II) halides at room temperature (RT) in an argon atmosphere. In air, FL of all Eu2+ compounds studied was stable, and intensity persisted for weeks. Depending on the nature of the halide anion and due to a nephelauxetic effect, the position of the maxima in the FL spectra underwent a red shift in the series: EuCl2 (409 nm) < EuBr2 (428 mm) < EuI2 (432 nm). The lifetimes of the excited states of the Eu2+* ions for EuI2, EuCl2 and EuBr2 were 355, 76 and 54 ns, respectively.
关键词： europium (II),dihalides,fluorescence
更新于2025-09-09 09:28:46
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Raman and fluorescence imaging on polyoxometalate composite agarose films
摘要： Composite agarose films were prepared with Eu(III) containing polyoxometalates, in particular the organic-inorganic hybrid [Eu(W5O18)2(pic)4]13- (Hpic = 3-hydroxypicolinic acid) and a Mo blue Eu(III) derivative. The latter compound shows interesting Eu(III) based photoluminescent properties, firstly described for a molybdenum blue compound. Imaging of the films optical properties and morphology was explored by Raman and fluorescence measurements in a confocal microscopy system, together with the AFM profile. Raman and fluorescence imaging were powerful tools for the characterization of the films, in particular concerning its chemical composition and homogeneity at the micrometric scale.
关键词： Fluorescence imaging,Agarose films,Polyoxometalates,Raman imaging,Europium
更新于2025-09-09 09:28:46
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Eu2+/Eu3+-based Smart Duplicato-responsive of Stimuli and Time-gates Nanohybrid for Optical Recording and Encryption
摘要： With the rapid development of information science, it is urgent that memory devices possessing high security, density, and desirable storage ability should be developed. In this work, a smart duplicato-responsive of stimuli and time-gates nanohybrid based on variable valence Eu2+/Eu3+ co-encapsulated has been fabricated and act as active material in the multi-level and multi-dimensional memory devices. The luminescence lifetime of Eu3+ in this nanohybrid performed a stimuli-response due to the energy level of the coordinated ligand could be modulated. Furthermore, by simply sintered procedure, Eu3+ was partially in situ reduced to Eu2+ with short lifetime in the system. And the in situ reduction ensured both of Eu3+ and Eu2+ ions uniform distribution in the nanohybrid and simultaneous response upon light excitation of variable valence Eu ions. Interestingly, Eu3+ revealed the prolonged lifetime because of the presence of energy transfer effect of Eu2+→Eu3+. Such a nanohybrid had the abundant luminescent properties including the short lifetime of Eu2+, the energy transferring from the Eu2+ to Eu3+ ions, and the stimuli-response of the Eu3+ lifetimes when exposed to acidic or basic vapor, thus giving birth to interesting recording and encryption performance in spatial-temporal dimensions. We believe that this research will point out a new direction for the future development of multi-level and multi-dimensional optical recording and encryption materials.
关键词： variable valence europium,optical recording and encryption,nanohybrid,duplicato-responsive,in situ coordination
更新于2025-09-09 09:28:46
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Electroluminescence of intrashell transitions in Eu doped single ZnO nanowires
摘要： Tunable nanoscale light emitters are essential to accomplish future multifunctional optoelectronic nano-devices. Here, we present an approach for achieving red electroluminescence from single ZnO nanowires implanted with Europium ions. The electroluminescence is emitted mainly from the end facets of ZnO nanowires at room temperature under the application of an AC voltage. The corresponding electroluminescence spectrum is attributed to the radiative intrashell transitions of the Eu ions, while contributions from near band edge or deep level emission of the ZnO remain absent. The total intensity of the electroluminescence is linearly proportional to the length of the nanowires, whereas there is no clear correlation with other morphology factors of the nanowire based device such as the diameter. Furthermore, the underlying excitation mechanism of the electroluminescence is proposed as direct-impact excitation of Eu ions by hot electrons in the ZnO nanowires.
关键词： electroluminescence,Zinc oxide (ZnO),Europium (Eu),nanowires,rare earth elements,ion beam doping
更新于2025-09-09 09:28:46
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Dinuclear Eu(III) complexes with macrocyclic tetraphosphine tetraoxide ligand and their photoluminescence properties
摘要： Dinuclear Eu(III) complexes with macrocyclic tetraphosphine tetraoxide ligand (1, 5, 9, 13-Tetraphosphacyclohexadecane-1, 5, 9, 13-tetraphenyl-1, 5, 9, 13-tetraoxide) that keep the Eu(III) ions apart were synthesized and their photoluminescence properties were investigated. It was found that quantum yield of Eu(III) complex 2 in ethyl acetate was excellent (? =0.54) even at a large concentration (1×10?3 mol/l) and strong photoluminescence was obtained. Macrocyclic TPTO ligand has a function of a “separator” of Eu(III) ions that prevents concentration quenching in the Eu(III) complexes.
关键词： Photoluminescence intensity,Quantum yields,Concentration quenching,Macrocyclic tetraphosphine tetraoxide ligand,Europium complex
更新于2025-09-04 15:30:14
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Selective recognition of salicylic acid employing new fluorescent imprinted membrane functionalized with poly(amidoamine) (PAMAM)-encapsulated Eu(TTA)3phen
摘要： Selective fluorescent molecularly imprinted membrane (FMIM) for salicylic acid (SA) was successfully prepared by phase inversion technique with SA as template molecule, chitosan (CHI) as functional polymer, and Eu(TTA)3phen/PAMAM composed of Eu(TTA)3phen and the dendrimer (PAMAM) as the fluorophore, which was characterized by SEM, AFM, and XPS techniques. The introduction of the hydrophilic Eu(TTA)3phen/PAMAM into FMIM was able to improve the flux and the adsorption capacity of SA with good fluorescent stability. Among the FMIM, the FMIM2 prepared with 2.0% Eu(TTA)3phen/PAMAM in the cast membrane fluid was the optimal fluorescent imprinted membrane for selective detection of SA, which displayed a relatively wider linear range and lower limit of detection (LOD) (24 mg L-1). The imprinted FMIM2 could selectively detect the SA from complicated samples without obvious interference from analogues compared to the non-imprinted FNIM2. Moreover, the FMIM had promising recycling performance. It can be potentially used as an alternative imprinted membrane for selective detection and separation of trace SA in water.
关键词： Salicylic acid,Selective detection and separation,Europium,Dendrimer,Fluorescent molecularly imprinted membrane
更新于2025-09-04 15:30:14