ABSTRACT
Given the lack of timely evaluation of the well-received selenium fortification, a neat lateral-flow chromatographic solution was constructed here by using the recently identified urinary selenosugar (Sel) as a strongly indicative marker. As there are no ready-made receptors for this synthetic standard, phenylboronic acid (PBA) esterification and Dolichos biflorus agglutinin (DBA) affinity joined up to pinch and pin down the analyte into a sandwich-type glycol complex. Pilot lectin screening on homemade glycan microarrays verified such a new pairing between dual recognizers as PBA-Sel-DBA with a firm monosaccharide-binding constant. To quell the sample autofluorescence, europium nanoparticles with efficient long-life afterglow were employed as conjugating probes under 1 µs excitation. After systematic process optimizations, the prepared Sel-dipstick achieved swift and sensitive fluorometry over the physiological level of the target from 0.1 to 10 µM with a detection limit down to 0.06 µM. Further efforts were made to eliminate matrix effects from both temperature and pH via an approximate formula. Upon completion, the test strips managed to quantify the presence of Sel in not just imitated but real human urine, with comparable results to those in the references. As far as we know, this would be the first in-house prototype for user-friendly and facile diagnosis of Se nutrition with fair accuracy as well as selectivity. Future endeavors will be invested to model a more traceable Se-supplementary plan based on the rhythmic feedback of Sel excretion.
Subject(s)
Metal Nanoparticles , Selenium , Humans , Europium , Point-of-Care Systems , ChromatographyABSTRACT
The attenuation of bacterial metabolism provides an adjunct to the treatment of bacterial infections. To develop a bacterial eradication agent, a bioactivatable material (BP@Eu-TCPP) was designed and synthesized by coordination and reduction of europium(III) with thin-layer black phosphorus (BP) and tetrakis (4-carboxyphenyl) porphyrin (TCPP). The existence of the P-Eu bond and Eu2+ 3d5/2 in X-ray photoelectron spectroscopy confirmed the successful synthesis of BP@Eu-TCPP. This material showed high fluorescence sensitivity to l-Arginine (l-Arg) and the main binding ratio of BP@Eu-TCPP to l-Arg was ca. 1:2 or 1:3, with the limit of detection of 4.0 µM. The material also showed good photothermal properties and stability, with a photothermal conversion efficiency of 37.3%. Although metal coordination has blocked the generation of 1O2, the addition of l-Arg to BP@Eu-TCPP can restore 1O2 generation upon red light-emitting diode (LED) light irradiation due to the formation of water-soluble Arg-TCPP species. Additionally, BP@Eu-TCPP was enabled to change the bacterial membrane and interfered with the bacterial iron absorption that effectively contributes to bacterial eradication. Such BP@Eu-TCPP is promised to be a novel material for the detection of l-Arg and l-Arg-activated photodynamic therapy.
Subject(s)
Europium , Porphyrins , Arginine , Partial Thromboplastin Time , PhosphorusABSTRACT
A europium-based metal organic framework (Eu-TFPA-MOF) was used for the fluorescence detection of fipronil in green tea and oolong tea for the first time. The red fluorescence of Eu-TFPA-MOF could be quenched significantly by low concentration (0.24 mM) of fipronil, and the "turn off" process exhibited quick response time (2 min), high sensitivity and selectivity, low detection limits (4.4 nM) and wide linear range (0-0.15 mM). The mechanism of fluorescence quenching was mainly attributed to static quenching process and the competitive absorption of excitation energy. Besides, the spiked and recovery test indicated that Eu-TFPA-MOF could be used in the fluorescence detection of fipronil in real green tea and oolong tea sample and the process had the advantages of simple pretreatment and satisfactory recoveries (98.33-106.17 %). More importantly, a simple, portable and low-cost smartphone-assisted test strip were designed for the visual detection of fipronil in real tea samples. The detection platform will be beneficial for tea quality safety and human heath, and is expected to be applied in other agricultural product safety field.
Subject(s)
Europium , Metal-Organic Frameworks , Humans , Fluorescent Dyes , Spectrometry, Fluorescence , Tea , Limit of DetectionABSTRACT
This paper reports a sequence of a Ca3 YAl3 B4 O15 :xEu3+ red phosphor prepared using a high-temperature solid-state reaction. At the excitation of 396 nm, the samples emitted intense red emission centred at ~623 nm, which could be attributed to the 5 D0 â7 F2 transition of the Eu3+ ion. The results showed that the optimum Eu3+ doping concentration of Ca3 YAl3 B4 O15 :Eu3+ phosphor was x = 80 mol%, and the concentration quenching mechanism of Ca3 YAl3 B4 O15 :Eu3+ red phosphor belonged to the exchange coupling between Eu3+ ions. The Commission Internationale de l'éclairage (CIE) coordinates and colour purity of Ca3 Y0.2 Al3 B4 O15 :0.8Eu3+ were calculated as (0.6375, 0.3476) and 95.5%, respectively. Moreover, the red emission of the obtained phosphor Ca3 YAl3 B4 O15 :0.8Eu3+ exhibited a low thermal quenching behaviour with an intensity retention rate of 92.85% at 150°C. The above results manifest that the Eu3+ -activated Ca3 YAl3 B4 O15 phosphor is predicted to be a promising red luminescent component for white light-emitting diodes.
Subject(s)
Luminescent Agents , Europium , Phosphorus , Luminescence , SorbitolABSTRACT
In this work, we synthesize stable europium ion modified black phosphorus quantum dots (Eu-BPQDs) using a microwave irradiation technique, which can react with organic amines exhibiting unique chemiluminescence (CL). The mechanism of the Eu-BPQDs/organic amines CL system accounting for the efficient CRET is induced by the chelation of organic amines with the surface functionalized europium.
Subject(s)
Quantum Dots , Amines , Europium , Luminescence , PhosphorusABSTRACT
The synthesis of two new tetra- and penta-phenycyclopentadienyldiphenylphosphine pro-ligands which readily undergo selective C-P bond cleavage has allowed for the facile synthesis of bulky divalent octa- and deca-phenylmetallocenes of europium, ytterbium and samarium.
Subject(s)
Lanthanoid Series Elements , Carbon/chemistry , Europium , Lanthanoid Series Elements/chemistry , Phosphorus , SamariumABSTRACT
Trivalent europium-based monochromatic red light-emitting phosphors are an essential component to realize high-performance smart lighting devices; however, the concentration and thermal quenching restrict their usage. Here, we report a series of efficient Eu3+-substituted Li3Y3BaSr(MoO4)8 red-emitting phosphors based on a stratified scheelite structure with negligible concentration and thermal quenching. All of the host and phosphor compositions crystallize in monoclinic crystal structure (space group C2/c). All of the phosphor compositions produce narrow-band red emission (FWHM â¼6 nm), which is highly apparent to the human eyes, and lead to exceptional chromatic saturation of the red spectral window. Concurrently, detailed investigations were carried out to comprehend the concentration and thermal quenching mechanism. Absolute quantum yields as high as 88.5% were obtained for Li3Y0.3Eu2.7BaSr(MoO4)8 phosphor with virtuous thermal stability (at 400 K, retaining 87% of its emission intensity). The light-emitting diodes were constructed by coupling Li3BaSrY0.3Eu2.7(MoO4)8 red phosphor with a near-UV LED chip (395 nm) operated at 20 mA forward bias, and the hybrid white LED (an organic yellow dye + red Li3Y3BaSr(MoO4)8:Eu3+ phosphor integrated with an NUV LED chip) showed a low CCT (6645 K), high CRI (83) values, and CIE values of x = 0.303; y = 0.368, which indicated that the synthesized phosphors can be a suitable red component for white LEDs. In addition, we have systematically investigated the Sm3+ and Sm3+, Eu3+ activation in Li3Y3BaSr(MoO4)8 to display the latent use of the system in plant growth applications and establish that the phosphor exhibits orange red emission with an intense deep-red emission (645 nm (4G5/2 â 6H9/2)). The phytochrome (Pr) absorption spectrum well matched the fabricated deep-red LED (by integrating a NUV LED + Li3Y3BaSr(MoO4)8:Sm3+ and Eu3+ phosphor) spectral lines.
Subject(s)
Color , Light , Luminescent Agents/pharmacology , Plants/drug effects , Barium/chemistry , Barium/pharmacology , Europium/chemistry , Europium/pharmacology , Humans , Lithium/chemistry , Lithium/pharmacology , Luminescent Agents/chemistry , Luminescent Measurements , Molybdenum/chemistry , Molybdenum/pharmacology , Phosphorus/chemistry , Phosphorus/pharmacology , Samarium/chemistry , Samarium/pharmacology , Strontium/chemistry , Strontium/pharmacology , TemperatureABSTRACT
It is vital to remove residual tumor cells after resection to avoid the recurrence and metastasis of osteosarcoma. In this study, a mineral nanomedicine, europium-doped calcium fluoride (CaF2:Eu) nanoparticles (NPs), is developed to enhance the efficacy of adjuvant radiotherapy (i.e., surgical resection followed by radiotherapy) for tumor cell growth and metastasis of osteosarcoma. In vitro studies show that CaF2:Eu NPs (200 µg/mL) exert osteosarcoma cell (143B)-selective toxicity and migration-inhibiting effects at a Eu dopant amount of 2.95 atomic weight percentage. These effects are further enhanced under X-ray irradiation (6 MeV, 4 Gy). Furthermore, in vivo tests show that intraosseous injection of CaF2:Eu NPs and X-ray irradiation have satisfactory therapeutic efficacy in controlling primary tumor size and inhibiting primary tumor metastasis. Overall, our results suggest that CaF2:Eu NPs with their osteosarcoma cell (143B)-selective toxicity and migration-inhibiting effects combined with radiotherapy might be nanomedicines for treating osteosarcoma after tumor resection.
Subject(s)
Antineoplastic Agents/therapeutic use , Calcium Fluoride/therapeutic use , Europium/therapeutic use , Metal Nanoparticles/therapeutic use , Osteosarcoma/drug therapy , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/toxicity , Calcium Fluoride/chemistry , Calcium Fluoride/toxicity , Cell Line, Tumor , Cell Movement/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Combined Modality Therapy , Europium/chemistry , Europium/toxicity , G2 Phase Cell Cycle Checkpoints/drug effects , Humans , Metal Nanoparticles/chemistry , Metal Nanoparticles/toxicity , Mice , Radiotherapy, AdjuvantABSTRACT
A novel perovskite CaLa4Ti4O15:Eu3+ red-emitting phosphor was synthesized via a sol-combustion method, and Gd3+ was further co-doped into structure to improve the luminescence performance. The effects of Eu3+ doping and Gd3+ co-doping concentrations on the microstructure and luminescence properties were investigated. The red emission peaks of as-prepared phosphors originate from the 5D0â7Fj electron transitions of Eu3+ ions. Under 273 nm excitation, the luminescence intensity of Eu3+ was significantly enhanced through the energy transfer between Gd3+ and Eu3+ in CaLa4Ti4O15, and the luminescence intensity was also improved even under the excitation of 394 nm. By combining red-emitting CaLa4Ti4O15:Eu3+, Gd3+ phosphor with commercial blue and green phosphors on n-UV chip (λ = 395 nm), an eye-friendly w-LEDs with appropriate correlated color temperature (4761 K) and high color rendering index (Ra = 93.1) has been realized. The electroluminescence spectrum of the packaged red LED have an excellent match with the PR absorption of plants. In addition, when introducing CaLa4Ti4O15:Eu3+, Gd3+ phosphor into a commercial w-LED with YAG:Ce3+, the adjustable chromaticity parameters like CCT and CRI values can be obtained. These results demonstrated that the as-prepared CaLa4Ti4O15:Eu3+, Gd3+ phosphor is an outstanding candidate as the red component for the application of w-LEDs and plants lighting.
Subject(s)
Europium , Luminescence , Calcium Compounds , Lighting , Oxides , Phosphorus , TitaniumABSTRACT
Herein, a novel adsorbent based on carbon-modified zirconia/spinel ferrite (C@ ZrO2/Mn0.5Mg0.25Zn0.25Fe2O4) nanostructures were chemically prepared to remove 60Co and 152+154Eu radionuclides from liquid media using batch experiments. The XRD pattern confirms the successful preparation of the C@ZrO2/MnMgZnFe2O4 composite. Also, SEM and TEM images confirmed that the composite owns a heterogeneous morphology in the nanoscale range. The optical band gap value of Mn0.5Mg0.25Zn0.25Fe2O4, ZrO2, and the composite samples was 1.45, 2.38, and 1.54â¯eV, respectively. Many parameters have been studied as the effect of time, solution pH, and initial ion concentration. The kinetics models for the removal process of 152+154Eu and 60Co radionuclides were studied. The second-order kinetic equation could describe the sorption kinetics for both radionuclides. The Langmuir monolayer capacity for 60Co was 82.51â¯mg/g and for 152+154Eu was 136.98â¯mg/g. The thermodynamic parameters such as free energy ΔGo, the enthalpy ΔHo, and the entropy ΔSo were calculated. The results indicated that the sorption process has endothermic nature for both two radionuclides onto C@ZrO2/MnMgZnFe2O4 composite.
Subject(s)
Nanostructures , Water Pollutants, Chemical , Adsorption , Aluminum Oxide , Carbon , Cobalt , Europium , Ferric Compounds , Hydrogen-Ion Concentration , Kinetics , Magnesium Oxide , Solutions , Temperature , Thermodynamics , Water Pollutants, Chemical/analysis , ZirconiumABSTRACT
Effects of Al content on the formation and the photoluminescence properties of CaAlSiN3:Eu2+ phosphor (CASIN) were investigated by a combustion synthesis method. XRD (X-ray diffraction), combined with PL (photoluminescence), TEM-EDS (transmission electron microscope equipped with an energy-dispersive X-ray spectroscope), and SAED (selected area electron diffraction) measurements, show that the bar-like CASIN gives a stronger emission than the plate-like and agglomerated fine particles. The emission intensity increases as the Al content increased from Al = 0.2 to Al = 0.8, which resulted from the extent of formation of CASIN increases. Then, the emission intensity decreases as the Al content is increased from Al = 0.8 to Al = 1.5, which resulted from the transformation of morphology of CASIN and a large amount formation of AlN. In addition, the extent of formation of CASIN increases with increasing Al from Al = 0.2 to Al = 1.2 and begins to decrease as Al is further increased to 1.5, and thus the peak emission wavelength increases from 647 nm to 658 nm as the Al molar ratio is increased from 0.2 to 1.2 and begins to decrease when further increasing the Al molar ratio to 1.5, which resulted from the large amount of AlN formed.
Subject(s)
Aluminum/metabolism , Calcium/chemistry , Carbazoles/chemistry , Europium/chemistry , Luminescence , Luminescent Agents/chemistry , Phosphorus/chemistry , Aluminum/analysisABSTRACT
GQDs decorated with europium (Eu), silver (Ag) and selenium (Se) at molar ratios of 0.1%, 0.3% and 0.5% were produced for the first time at different temperatures of 180 °C, 200 °C and 220 °C. Surface passivation was carried out with polyethylene glycol (PEG) to increase the intensity of photoluminescence (PL) of the produced samples. The prepared quantum dots were characterized by X-Ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), transmission electron microscopy (TEM), PL and ultraviolet-visible spectroscopy. GQDs synthesized at 180 °C and decorated with Se (0.3%) had maximum PL intensity along with long lasted afterglow over 90 min compared with other samples. Excitation wavelength at 360 nm produced maximum emission at 600-900 nm and resulted in high singlet oxygen (1O 2) generation which makes it a good candidate for photodynamic therapy applications.
Subject(s)
Graphite/chemistry , Photochemotherapy , Photosensitizing Agents/chemistry , Quantum Dots/chemistry , Europium/chemistry , Photosensitizing Agents/chemical synthesis , Reactive Oxygen Species/analysis , Selenium/chemistry , Silver/chemistryABSTRACT
Gd2 (MoO4 )3 :Eu3+ red phosphors assigned to different crystal systems were prepared using a sol-gel method with ammonium molybdate, Gd2 O3 , and Eu2 O3 as starting materials. X-ray diffraction (XRD) patterns showed that when annealing temperature was 700°C or 800°C, Eu3+ doping concentration was the main factor affecting sample structure. When the Eu3+ doping concentration was 0-2.00 mol%, samples had a monoclinic structure, but when the Eu3+ doping concentration was increased to 4.00-10.00 mol%, the samples changed to a mixed crystal structure (with existence of both monoclinic and orthorhombic structures). When the annealing temperature was increased to 900°C, annealing temperature became the main factor affecting sample structure, that is sample structure did not change with change in Eu3+ doping concentration, and all samples could be assigned to the orthorhombic system. Change in structure also affected the luminescence properties of the samples. Gd2 (MoO4 )3 :Eu3+ phosphors with different crystal systems could be effectively excited by blue light (466 nm wavelength); red light at 614 nm wavelength gave better colour purity and color stability, corresponding to the Eu3+5 D0 â7 F2 transition. Finally, when Eu3+ concentration was 0.02 mol, the luminescence intensity of the orthorhombic system was higher than that of the monoclinic system; when the concentration was 0.04 mol, the luminescence intensity of the mixed system was almost the same as that of the orthorhombic system.
Subject(s)
Europium , Luminescence , Color , Phosphorus , X-Ray DiffractionABSTRACT
Experiments conducted over a period of 6 weeks using Brassica napus callus cells grown in vitro under Eu(III) or U(VI) stress showed that B. napus cells were able to bioassociate both potentially toxic metals (PTM), 628 nmol Eu/gfresh cells and 995 nmol U/gfresh cells. Most of the Eu(III) and U(VI) was found to be enriched in the cell wall fraction. Under high metal stress (200 µM), cells responded with reduced cell viability and growth. Subsequent speciation analyses using both metals as luminescence probes confirmed that B. napus callus cells provided multiple-binding environments for Eu(III) and U(VI). Moreover, two different inner-sphere Eu3+ species could be distinguished. For U(VI), a dominant binding by organic and/or inorganic phosphate groups of the plant biomass can be concluded.
Subject(s)
Brassica napus , Uranium , Water Pollutants, Radioactive/analysis , Europium , Plant CellsABSTRACT
Oxide based highly efficient narrow band red emitting phosphors are still a bottleneck in white LED applications. Trivalent europium ion based phosphors could be a better choice, however their weak oscillator strength restricts their use in white light emitting diodes (LEDs). Herein, we report a novel red emitting NaSrEu(MoO4)3 (NSEuM) phosphor with zero concentration quenching (non-layered crystal structure). The phosphors (NaSrY1-xEux(MoO4)3, x = 0.1-1, in increments of 0.1) were synthesized through a traditional solid-state reaction and their phase formations were analyzed by powder X-ray diffraction (PXRD) followed by Rietveld refinement. Under 395 nm excitation, all the phosphors showed sharp emission at 616 nm (full width at half maximum, FWHM â¼4-5 nm) owing to the 5D0â7F2 electric dipole transition of the Eu3+ ion. A concentration dependent photoluminescence (PL) study revealed that there is no concentration quenching of the systems, leading to them having superior emission characteristics over those of commercial red phosphors as well as a reported Eu3+ phosphor with a layered structure. The color purity of the synthesized phosphor was observed to be 96.32% and it shows excellent thermal stability at 423 K, retaining 64.6% of the emission intensity of its initial room temperature. The NSEuM phosphor shows a high absolute quantum yield of 79.7%. Besides this, a red LED (near UV (NUV) LED chip with the NaSrEu(MoO4)3 phosphor) as well as a hybrid white LED (NUV LED chip with an organic yellow dye + red NSEuM phosphor) were fabricated and their optical properties were studied. After the inclusion of the red phosphor in the hybrid white LED, the color rendering index (CRI)/correlated color temperature (CCT) were improved significantly (60/9333 K vs. 79/6004 K, respectively). In addition, to show the potential use of the system in plant growth application, we systematically investigated the Sm3+ activation in NaSrY(MoO4)3 and found that the phosphor shows orange red emission with an intense deep red emission (645 nm (4G5/2â6H9/2)). We fabricated a hybrid red/deep red LED by integrating a NUV LED with a mixed Sm3+ and Eu3+ phosphor and the spectral lines were well matched with the phytochrome (Pr) absorption spectrum. The presently investigated phosphor showed potential in a white LED as well as a deep red/orange-red LED for plant growth.
Subject(s)
Europium/chemistry , Light , Luminescent Agents/chemistry , Phosphorus/chemistry , Molybdenum/chemistry , Oxygen/chemistry , Plant Development , Samarium/chemistry , Sodium/chemistry , Strontium/chemistry , Yttrium/chemistryABSTRACT
Luminescent lanthanide downconversion nanoparticles (DCNPs) provide a combination of high luminescence intensity, sharp emission peaks with narrow bandwidth and a large Stokes' shift, leading to high-performance biomedical applications mainly for imaging. The purpose of this study is to present a nanotoxicological study of DCNPs Y2 O3 codoped with Eu3+ and functionalized with folic acid (FA). These assessments include cytotoxicity, genotoxicity, hemocompatibility, and in vitro inflammatory studies. We demonstrated by flow cytometry and confocal microscope the internalization of FA-DCNPs in breast cancer and melanoma cells. They were synthesized by sol-gel method and coated with a thin silica shell to make them biocompatible; also they were functionalized with amino groups and FA ligands that bind to the folate receptors (FR) located on the surface of the cancer cells studied. This functionalization enables the DCNPs to be internalized into the cancer cells via endocytosis by the conjugation FA-FR. The DCNPs were characterized with transmission electron microscope, Fourier transform infrared spectroscopy and photoluminescence. The nanotoxicological assessments demonstrated that both nanoparticles (bare and functionalized) are no cytotoxic and no genotoxic at the tested concentrations (0.01-20 µg/mL) in three cell lines (breast, skin cancer, and osteoblasts). Also they are hemocompatible and do not exert nitric oxide production in vitro by macrophages. The FA-DCNPs were clearly localized into the cell cytoplasm with bright red luminescence. Thus, herein we present a complete nanotoxicological study of FA-DCNPs Y2 O3 codoped with Eu3+ and we conclude that these nanoparticles are biocompatible and can be further used for cancer cells bioimaging.
Subject(s)
Aluminum Oxide/toxicity , Diagnostic Imaging/methods , Europium/chemistry , Folic Acid/chemistry , Luminescent Agents/chemistry , Nanoparticles/toxicity , Nanostructures/toxicity , Neoplasms/pathology , Animals , Biocompatible Materials , Carcinogenicity Tests , Cell Line, Tumor , Cell Survival , Folate Receptor 1/metabolism , Humans , Macrophages/drug effects , Mice , Mutagenicity Tests , Nitric Oxide/metabolism , RAW 264.7 Cells , Silicon Dioxide/toxicity , Yttrium Radioisotopes/toxicityABSTRACT
In this paper, the Eu3+ -Eu2+ (4%, molar ratio)-doped xAl2 O3 -ySiO2 (x = 0-2.5, y = 1-5) and xAl2 O3 -zMgO (x = 0-1.5, z = 0-3) composites phosphors with different Al2 O3 to SiO2 (A/S) and Al2 O3 to MgO (A/M) ratios were prepared using a high-temperature solid-state reaction under air atmosphere. The effects of the A/S and A/M on luminescence properties, crystal structure, electron spin resonance, and Commission Internationale de l'Eclairage chromaticity coordinates of the samples were systematically analyzed. These results indicated that the different A/S and A/M ratios in the matrix effectively affected the crystal phase, degrees of self-reduction of Eu3+ , and led the relative emission intensity of Eu2+ /Eu3+ to change and adjust.
Subject(s)
Aluminum Oxide/chemistry , Europium/chemistry , Luminescent Agents/chemistry , Magnesium Oxide/chemistry , Silicon Dioxide/chemistry , Luminescent MeasurementsABSTRACT
A facile approach for possible industrial production of long-persistent phosphorescence, continuing to emitting light for a long time period, smart cobbles were developed toward photoluminescent hard surfaces. The inorganic strontium aluminium oxide pigment doped with rare earth elements was added to a synthetic organic epoxy in the presence of polyamine as a hardener to make a phosphor-loaded viscous fluid that can then be hardened in a few minutes. The transparency of the solid cobbles can be accomplished easily using homogeneous dispersion of the phosphor in the epoxy resin fluid before the addition of a hardener to avoid pigment aggregation. This pigment-epoxy formula can be easily applied industrially onto flagstones surfaces under ambient conditions. The photoluminescent cobblestones demonstrated an optimum excitation wavelength at 366 nm and an emission band at 521 nm with a long-persistent phosphorescence cobble surface. The development of a translucent white colour under normal daylight, bright green under ultraviolet (UV) irradiation, bright white colour after 30 sec in the dark, and phosphorescent green colour after 75 min in the dark was indicated using Commission Internationale de l'Eclairage (CIE) Laboratory coloration measurements. The luminescent hard composite cobble exhibited a highly durable and reversible long-persistent phosphorescence light. Photoluminescence, morphological, and hardness properties as well as the elemental composition of the prepared cobbles were explored.
Subject(s)
Aluminum Oxide/chemistry , Epoxy Resins/chemistry , Europium/chemistry , Luminescence , Strontium/chemistry , Luminescent Measurements , Particle Size , Photochemical Processes , Surface PropertiesABSTRACT
Aluminium oxide (Al2 O3 ) has widely been used for catalysts, insulators, and composite materials for diverse applications. Herein, we demonstrated if γ-Al2 O3 was useful as a luminescence support material for europium (Eu) (III) activator ion. The hydrothermal method and post-thermal treatment at 800°C were employed to synthesize Eu(III)-doped γ-Al2 O3 nanofibre structures. Luminescence characteristics of Eu(III) ions in Al2 O3 matrix were fully understood by taking 2D and 3D-photoluminescence imaging profiles. Various sharp emissions between 580 to 720 nm were assigned to the 5 D0 â7 FJ (J = 0, 1, 2, 3, 4) transitions of Eu(III) activators. On the basis of X-ray diffraction crystallography, Auger elemental mapping and the asymmetry ratio, Eu(III) ions were found to be well doped into the γ-Al2 O3 matrix at a low (1 mol%) doping level. A broad emission at 460 nm was substantially increased upon higher (2 mol%) Eu(III) doping due to defect creation. The first 3D photoluminescence imaging profiles highlight detailed understanding of emission characteristics of Eu(III) ions in Al oxide-based phosphor materials and their potential applications.
Subject(s)
Aluminum Oxide/chemistry , Luminescent Agents/chemistry , Luminescent Measurements , Nanofibers/chemistry , Europium/chemistry , Particle Size , Photochemical Processes , Surface PropertiesABSTRACT
The thermoluminescence (TL) spectra and dose responses of strontium sulphate doped with rare earth ions show that the SrSO4:Eu2+ phosphor might reasonably be assumed a isoelectronic trap sample which has unique TL characteristics: there is only one obvious glow peak at 385 nm, 489 K in the TL 3D emission spectra and its TL dose response is linear-sublinear. However, there are several elementary glow peaks in the TL 3D emission spectra and their TL dose responses are linear-supralinear for SrSO4:RE3+ (RE = Dy, Tm). These TL peaks occurred from low to high temperature indicate that the traps are distributed in different energy levels. When a suitable amount of other impurities co-doped into these SrSO4:RE3+, such as phosphorus, the relative intensities of these elementary glow peaks are changed significantly, especially the TL peak ~500 K is enhanced while the peaks at lower temperature are suppressed. The enhanced peak of SrSO4:RE3+,P is attributed to the deep traps. Their dose responses remain in nonlinearity when co-doped phosphorus. The above results and the luminescence properties of other sulphate doped rare earths impurities illustrate that the TL characteristics depend on the structure of defect complexes which can be assumed the basic elements in the TL multi-stage processes.