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Optical, structural and luminescence properties of oxyfluoride phosphate glasses and glass-ceramics doped with Yb3+
摘要： The impact of Al2O3 and Y2O3 addition on the structure, Yb3+ luminescence and crystallization is investigated for glasses in the P2O5-SrO-Na2O system. Although the addition of Al2O3 and Y2O3 leads to a more connected phosphate network as evidenced using IR and Raman spectroscopies and increases the glass transition temperature, it does not affect strongly the site of the Yb3+. The addition of Al2O3 and Y2O slightly decreases the rate of the glass crystallization. Surface crystallization occurs upon heat treatment. Crystallization was confirmed by the presence of sharp peaks in the XRD patterns of the glasses. Independently of the glass composition, multiple different crystalline phases precipitate in the glasses upon heat treatment. The precipitation of the Na1O7P2Yb1 crystal phase leads to an increase of the excited state 2F5/2 lifetime of Yb3+ and also of the bandwidth of the Yb3+ emission band centered at 1μm.
关键词： nucleation and growth,Yb3+ doped phosphate glasses,Raman & Infrared spectroscopies,Yb3+ luminescence properties,heat treatment
更新于2025-09-23 15:22:29
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Luminescent hybrid materials based on metal-organic phosphors in PbF2 powder and PbF2-containing glass matrix
摘要： The new hybrid materials (HM's) are based on the phosphors used in OLED technology in inorganic PbF2-containing matrices: PbF2 powders and low melting PbF2-based oxyfluoride glasses, were synthesized. We used highly effective thermostable phosphors: 4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluoro-1- (1-methyl-1H-pyrazol-4-yl) nonane-1,3-dione - (1,10-phenanthroline) europium (III), 8-hydroxyquinoline complexes with metals and the individual organic ligand – 4,4,4-trifluoro-1- (2-naphthyl) butane-1,3-dione. Powdered HM's were prepared by co-precipitation from aqueous solutions. The effect of organic molecules or molecular fragments on dimension and morphology of precipitated PbF2 particles, the luminescence properties of HM's were investigated for the samples obtained directly after the precipitation-drying procedure, and after the powders' calcination procedure. The change in the photoluminescence spectra after the heat treatment of the powders is caused by the proceeding of the exchange reaction between the metal complex and the matrix with the formation of Pb-complexes of different coordination is shown. HM (glasses PbF2eB2O3, PbF2eB2O3eSiO2 or PbF2eB2O3eSiO2eZnO phosphor) were obtained by the melt process in which the phosphor powder was submerged into the melt of the pre-synthesized glasses.
关键词： Lead fluoride,Lead fluoride nanoparticles,Hybrid materials,Luminescence,Organic phosphors
更新于2025-09-23 15:22:29
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Enhanced luminescent properties of Tb3+-doped transparent oxyfluoride glass-ceramics containing YF3 nanocrystals
摘要： Tb3+-doped transparent oxyfluoride glass-ceramics (GC) containing YF3 nanocrystals have been fabricated via a traditional melt-quenching route with appropriate thermal-treatment. The microstructural, luminescent and optical properties of the synthesized material were investigated systematically. The precipitated particles in the glass phase of GC540 are YF3 nanocrystals with a mean size of around 20 nm, which has been confirmed and estimated by XRD and TEM. Compared with the precursor glass (PG), the emission intensity at 545 nm (5D4→7F5) of YF3: Tb3+-doped GC is significantly enhanced (under ultraviolet and X-rays excitation) and the lifetime of GC is longer. It can be confirmed that the preferential enrichment of Tb3+ in the precipitated low-phonon-energy YF3 nanocrystals can effectively reduce non-radiative transitions. The obtained results confirm that such Tb3+-doped YF3 GC might be useful as a novel X-ray scintillating material for slow event detection.
关键词： X-ray excited luminescence spectra,luminescent properties,YF3,Glass-ceramics
更新于2025-09-23 15:22:29
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Effects of sintering temperature on the microstructure and luminescence of LuAG:Pr ceramics
摘要： The effects of the sintering temperature on the microstructure and luminescence of Lu3Al5O12:Pr (LuAG:Pr) ceramics was investigated by density, X-ray diffraction (XRD), scanning electron microscopy (SEM), grain size, attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR), photoluminescence (PL), radioluminescence (RL), and thermoluminescence (TL) measurements. A Czochralski-grown single crystal was used as reference. The increase of the sintering temperature promoted progressive structural modifications toward the characteristics of the single crystal. The presence of an amorphous phase was strongly detrimental to the luminescence of LuAG:Pr, with its elimination leading to enhanced RL and reduced TL emission. Evidence of synergism between the F-related defects and the Pr3+ 4f - 4f and 4f - 5d transitions was also found with the presence of these defects being detrimental to the 4f - 5d scintillation.
关键词： ceramics,sintering temperature,luminescence,microstructure,thermoluminescence,Lu3Al5O12:Pr
更新于2025-09-23 15:22:29
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Continuous In Vivo Monitoring of the Oxygen Concentration in Tissues
摘要： The kinetics of delayed fluorescence and phosphorescence of xanthene dyes in mouse tissues under the pulse-periodic excitation of molecules was studied in vivo and in vitro. The advantages of continuous monitoring of oxygen content in tissues by the kinetics of delayed fluorescence caused by singlet–triplet annihilation of singlet oxygen with triplet excitation of fluorophore are demonstrated. A method is proposed for determining the time of recovery of the concentration of oxygen consumed in tissues in vivo and in vitro during photodynamic processes.
关键词： delayed luminescence,singlet oxygen,tissues,xanthene dyes
更新于2025-09-23 15:22:29
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Changes of Optically Stimulated Luminescence Dosimeter Sensitivity with High Dose
摘要： We investigated the effect of high dose on the sensitivity of optically stimulated luminance dosimeters (OSLDs) on Co-60 gamma rays and used a commercial OLSD (Landauer, Inc., Glenwood, IL). New OSLDs were chosen arbitrarily and were irradiated with 1 Gy repeatedly. We confirmed the change in the radiation sensitivity after repeated irradiation. The OSLD sensitivity increased up to 3% after irradiating for seven times and decreased continuously after the eighth time. It dropped by approximately 0.35 Gy per irradiation. Finally, after irradiating for 30 times, the OSLD sensitivity decreased by approximately 7%. When the OSLDs were irradiated 10 times with 1 Gy after their irradiation using a high dose of 15 Gy and 30 Gy, their sensitivity decreased by 6% and 12%, respectively, compared to that before high-dose irradiation. The change in the OSLD sensitivity with a high dose could be modeled by an exponential equation. We confirmed the radiation sensitivity variation caused by a high dose, and the irradiation history of dosimeters was considered to reuse OSLDs irradiated with a high dose.
关键词： High dose,Co-60,Optically stimulated luminescence dosimeter sensitivity
更新于2025-09-23 15:22:29
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Determination of thiacloprid, thiamethoxam and imidacloprid in tea samples by quenching terbium luminescence
摘要： Consumption of herbal teas, infusions and other plant‐related products has always been popular due to the related health benefits. However, the safety of these products needs to be assessed, for example monitoring the potential presence of contaminants such as pesticides. In this paper, we report an analytical method for determining three neonicotinoid insecticides ? thiacloprid, thiamethoxam, and imidacloprid ? that are widely used worldwide. This method is based on quenching by analytes of the luminescence signal of terbium ions. Terbium presents a time‐resolved luminescence signal at 256/545 nm/nm, which is quenched by the presence of low concentrations of the selected analytes. Detection limits of 0.1, 0.2 or 0.75 μg ml?1 were obtained for thiamethoxam, thiacloprid and imidacloprid, respectively. Recovery experiments in different teas (green tea, black tea, chamomile, peppermint) were performed at concentrations lower than the maximum residue limits established by the European Union and the Codex Alimentarius for tea samples. In all cases, satisfactory recovery yields were observed, and the results were compared with a chromatographic reference method. The proposed method therefore proved suitable for quantifying these insecticides, fulfilling the current legislation.
关键词： luminescence,pesticide,terbium,neonicotinoid,tea
更新于2025-09-23 15:22:29
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Synthesis, crystal structure and luminescence of two barium(II) compounds: from mono- to bis-tetrazole carboxylic acids
摘要： Tetrazole carboxylates are acknowledged as bifunctional ligands for the construction of new coordination architectures. Two new coordination compounds, [Ba(atzpa)2(H2O)3]n·2nH2O (1) and [Ba2(dtzpda)(H2O)]n (2) have been prepared by solvothermal reactions of BaCl2·2H2O with Hatzpa or H4dtzpda, respectively (Hatzpa = 5-aminotetrazole-1-propanoic acid, H4dtzpda = 3,3-di(1H-tetrazol-5-yl)pentanedioic acid). The X-ray diffraction results reveal that compound 1 is a linear chain in which atzpa acts as a tridentate ligand to bridge adjacent Ba2+ ions in a μ1,1,3-COO mode. In contrast, compound 2 is a three-dimensional network where dtzpda4? acts as a dode-dentate ligand to bridge various Ba2+ ions. Furthermore, the luminescence of Hatzpa, H4dtzpda, compounds 1 and 2 in the solid state at room temperature were investigated.
关键词： Hatzpa/H4dtzpda,Crystal structure,Ba(II),Luminescence
更新于2025-09-23 15:22:29
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White-Light-Emitting Decoding Sensing for Eight Frequently-Used Antibiotics Based on a Lanthanide Metal-Organic Framework
摘要： Developing multi-selective luminescence sensing technology to differentiate serial compounds is very important but challenging. White-light-emitting decoding sensing based on lanthanide metal-organic frameworks (Ln-MOFs) is a promising candidate for multi-selective luminescence sensing application. In this work, three isomorphic Ln-MOFs based on H3dcpcpt (3-(3,5-dicarboxylphenyl)-5-(4-carboxylphenl)-1H-1,2,4-triazole) ligand, exhibiting red, blue, and green emission, respectively, have been synthesized by solvothermal reactions. The isostructural mixed Eu/Gd/Tb-dcpcpt is fabricated via the in-situ doping of different Ln3+ ions into the host framework, which can emit white light upon the excitation at 320 nm. It is noteworthy that this white-light-emitting complex could serve as a convenient luminescent platform for distinguishing eight frequently-used antibiotics: five through luminescence-color-changing processes (tetracycline hydrochloride, yellow; nitrofurazone, orange; nitrofurantoin, orange; sulfadiazine, blue; carbamazepine, blue) and three through luminescence quenching processes (metronidazole, dimetridazole, and ornidazole). Moreover, a novel method, 3D decoding map, has been proposed to realize multi-selective luminescence sensing applications. This triple-readout map features unique characteristics on luminescence color and mechanism. The mechanism has been systematically interpreted on the basis of the structural analysis, energy transfer and allocation process, and peak fitting analysis for photoluminescence spectra. This approach presents a promising strategy to explore luminescent platforms capable of effectively sensing serial compounds.
关键词： lanthanide,metal-organic framework,multi-selective luminescence sensing,decoding sensing,white light,antibiotics
更新于2025-09-23 15:22:29
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Synthesis and photoluminescence properties of BaGeTeO6:Eu3+ red-emitting phosphor for n-UV Light Emitting Diodes
摘要： Novel red-emitting phosphors based on germanium tellurate host matrix, BaGeTeO6 doped with Eu3+, were prepared by solid-state reaction. X-ray diffraction analysis revealed that the phosphors consisted of hexagonal structure. The as-prepared BaGeTeO6:Eu3+ phosphors showed strong red emission at 610 nm corresponding to the 5D0–7F2 transition of Eu3+ upon 394 nm near UV wavelength. The optimal doping concentration of BaGeTeO6:xEu3+ was 5% and the critical distance of energy transfer between the Eu3+ ions was estimated to be about 17 ?. Temperature dependence of the Eu3+ emission intensity measured at T = 300–480 K was successfully analyzed. Due to their CIE coordinates with high color purity, BaGeTeO6:Eu3+ phosphors have potential application in the fabrication of WLED.
关键词： germanate,BaGeTeO6:Eu3+,Luminescence,LEDs
更新于2025-09-23 15:22:29