Relevant bibliographies by topics / Eu3+ / Journal articles

To see the other types of publications on this topic, follow the link: Eu3+.

Journal articles on the topic 'Eu3+'

Author: Grafiati

Published: 4 June 2021

Last updated: 18 June 2025

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Eu3+.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

Zinchenko, Viktor, Ganna Volchak, Nataliia Chivireva, et al. "Solidified Salt Melts of the NaCl–KCl–CeF3–EuF3 System as Promising Luminescent Materials." Materials 17, no. 22 (2024): 5565. http://dx.doi.org/10.3390/ma17225565.

Full text

Abstract:

This study presents the results of investigating the interaction between the CeF₃–EuF₃ system and the NaCl–KCl salt melt using spectroscopic methods. It was found that CeF₃ ions undergo no significant changes upon dissolution in the NaCl–KCl melt. In contrast, the dissolution of EuF₃, both individually and within the CeF₃–EuF₃ system, is accompanied by redox reactions leading to the formation of Eu2⁺. The diffuse reflectance spectra of both the bottom (insoluble sediment) and upper parts of the solidified salt melt in the UV range indirectly indicate photoluminescence excitation from Ce3⁺ and Eu2⁺ ions. In addition, absorption bands in the near-IR region (1900–2300 cm⁻1) confirm the retention of some Eu3⁺ ions in the salt melt. The study explored the effects of various factors—including sample composition, excitation wavelength, prior and subsequent heat treatment, and medium composition—on the excitation and emission spectra of the samples. Intense 5d-4f luminescence of Ce3⁺ and Eu2⁺ ions (at 330 and 430 nm, respectively) was observed predominantly in the upper part of the salt melts, along with much weaker 4f-4f luminescence from Eu3⁺ ions. Certain parameters were optimized to reduce the luminescence contribution from Ce3⁺ and especially Eu3⁺ ions while enhancing the luminescence of Eu2⁺ ions. Solidified salt solution-melts of the NaCl–KCl–CeF₃–EuF₃ system show promise as materials for developing solar ultraviolet radiation detectors.

APA, Harvard, Vancouver, ISO, and other styles

Zhu, Yuhan, Yu Pan, Wenjun Wang, et al. "Chemical bond parameters, bond energy and the local crystal sites of Eu3+ in Ca5(BO3)3F:1% Eu3+ phosphor." RSC Advances 8, no. 56 (2018): 32325–32. http://dx.doi.org/10.1039/c8ra06357e.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Li, Liping, Guangshe Li, Jipeng Miao, Wenhui Su, and Hiroshi Inomata. "Valence variations in titanium-based perovskite oxides by high-pressure and high-temperature method." Journal of Materials Research 16, no. 2 (2001): 417–24. http://dx.doi.org/10.1557/jmr.2001.0063.

Full text

Abstract:

Typical titanium-based perovskite oxides Eu1−xBaxTiO3 (x = 0.6−0.8), Eu1−xKxTiO3 (x = 0.2,0.32), and La0.7 (Na,K)0.3TiO3 were synthesized by high pressure and temperature using RE2O3 (RE = La,Eu), TiO2, alkaline, or alkaline earth carbonates as the starting materials. X-ray diffraction data analysis showed that there was a structural transformation in Eu1−xBaxTiO3 by varying Ba content [i.e., from cubic (x = 0.6,0.7) to tetragonal (x = 0.8)], and that samples Eu1−xKxTiO3 and La0.7(Na,K)0.3TiO3 crystallized in the cubic perovskite structure. 151Eu Mössbauer spectroscopy and electron paramagnetic resonance measurements revealed mixed valence of Eu2+/Eu3+ in samples Eu1−xBaxTiO3 and Eu1−xKxTiO3, while Ti ions were present in pure Ti4+ state. Cubic Eu1−xKxTiO3 was metastable, which decomposed into a mixture of perovskite and pyrochlore phases at high temperatures as accompanied by an oxidation process from Eu2+ to Eu3+. For samples La0.7 (Na,K)0.3TiO3, Ti3+ signals were clearly observed. The reduction mechanisms for Eu ions at A site and Ti ions at B site in the perovskite oxides are discussed in terms of the chemical nature of the framework ions and substitution ions under high pressure and temperature.

APA, Harvard, Vancouver, ISO, and other styles

You, Hong Peng, Tomokatsu Hayakawa, and Masayuki Nogami. "Spectral Hole Burning in Sol-Gel-Derived Eu³⁺-Doped Al₂O₃-B₂O₃-SiO₂ Glass." Advanced Materials Research 11-12 (February 2006): 201–4. http://dx.doi.org/10.4028/www.scientific.net/amr.11-12.201.

Full text

Abstract:

Al2O3-B2O3-SiO2 glass containing europium ions was prepared by a sol-gel method. The excitation spectrum of the Eu3+ ions in the glass consists of the charge transfer and f-f transition absorptions of the Eu3+ ions. The emission spectrum indicates the coexistence of the Eu2+ and Eu3+ ions. The formation of some reducing agents in the heat-treatment process should be responsible for the reduction from Eu3+ to Eu2+ ions. The fluorescence line-narrowing spectra reveal that there are two different environments for the Eu3+ ions. Persist spectral hole was burned in the excitation of the 5D0-7F0 transition of the Eu3+ ions. We suggested a possible mechanism on the persistent spectral hole burning of the Eu3+ ion in the glass.

APA, Harvard, Vancouver, ISO, and other styles

Liu, Lei, Xianying Shao, Zhenyuan Zhang, Jiayu Liu, Yuebo Hu, and Chaofeng Zhu. "Spectral properties and self-reduction of Eu³⁺ to Eu²⁺ in aluminosilicate oxyfluoride glass." RSC Advances 13, no. 34 (2023): 23708–15. http://dx.doi.org/10.1039/d3ra03689h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Ruan, Wenke, Renrong Zhang, Qi Zhong, Yan Fu, Zhiwei Yang, and Mubiao Xie. "Preparation and wide band emission characteristics of Eu²⁺/Eu³⁺ co-doped Ba₃P₄O₁₃ phosphors." RSC Advances 12, no. 23 (2022): 14819–26. http://dx.doi.org/10.1039/d2ra02478k.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Sipina, Elena V., Dmitry A. Spassky, Nataliya R. Krutyak, et al. "Abnormal Eu3+ → Eu2+ Reduction in Ca9−xMnxEu(PO4)7 Phosphors: Structure and Luminescent Properties." Materials 16, no. 4 (2023): 1383. http://dx.doi.org/10.3390/ma16041383.

Full text

Abstract:

β-Ca3(PO4)2-type phosphors Ca9−xMnxEu(PO4)7 have been synthesized by high-temperature solid-phase reactions. The crystal structure of Ca8MnEu(PO4)7 was characterized by synchrotron X-ray diffraction. The phase transitions, magnetic and photoluminescence (PL) properties were studied. The abnormal reduction Eu3+ → Eu2+ in air was observed in Ca9−xMnxEu(PO4)7 according to PL spectra study and confirmed by X-ray photoelectron spectroscopy (XPS). Eu3+ shows partial reduction and coexistence of Eu2+/3+ states. It reflects in combination of a broad band from the Eu2+ 4f65d1 → 4f7 transition and a series of sharp lines attributed to 5D0 → 7FJ transitions of Eu3+. Eu2+/Eu3+ ions are redistributed among two crystal sites, M1 and M3, while Mn2+ fully occupies octahedral site M5 in Ca8MnEu(PO4)7. The main emission band was attributed to the 5D0 → 7F2 electric dipole transition of Eu3+ at 395 nm excitation. The abnormal quenching of Eu3+ emission was observed in Ca9−xMnxEu(PO4)7 phosphors with doping of the host by Mn2+ ions. The phenomena of abnormal reduction and quenching were discussed in detail.

APA, Harvard, Vancouver, ISO, and other styles

Uehara, Akihiro, Osamu Shirai, Takayuki Nagai, Toshiyuki Fujii, and Hajimu Yamana. "Spectroelectrochemistry and Electrochemistry of Europium Ions in Alkali Chloride Melts." Zeitschrift für Naturforschung A 62, no. 3-4 (2007): 191–96. http://dx.doi.org/10.1515/zna-2007-3-412.

Full text

Abstract:

In order to investigate the redox equilibrium of europium ions in molten NaCl-2CsCl, UV-Vis absorption spectrophotometry measurements were performed for Eu2+ and Eu3+ in molten NaCl- 2CsCl at 923 K under simultaneous electrolytic control of their ratio. Molar absorptivities of EuCl3 and EuCl2 in NaCl-2CsCl at 923 K were determined to be (420±21) M −1cm−1 at 31200 cm−1 and (1130±56) M−1cm−1 at 30300 cm−1, respectively. The formal redox potential of the Eu2+/Eu3+ couple in NaCl-2CsCl melt at 923 K was determined to be (−0.941 ±0.004) V vs. Cl2/Cl− by electromotive force measurements on varying concentration ratios of Eu2+ and Eu3+, which were performed using a technique based on the combination of electrolysis and spectrophotometry. Cyclic voltammetry was also carried out in order to examine the characteristics of the voltammograms for the Eu2+/Eu3+ couple in NaCl-2CsCl melt. The formal redox potential of the Eu2+/Eu3+ couple determined by a spectroelectrochemical method agreed with that determined by cyclic voltammetry [(−0.946±0.008) V vs. Cl2/Cl−]. The effects of temperature on the redox potential of the Eu2+/Eu3+ couple in NaCl-2CsCl, NaCl-KCl, LiCl-KCl, and CsCl melts were studied by cyclic voltammetry in the range from 923 to 1123 K.

APA, Harvard, Vancouver, ISO, and other styles

Elkholy, Hagar, Hosam Othman, Ibrahim Hager, Medhat Ibrahim, and Dominique de Ligny. "Europium-Doped Tellurite Glasses: The Eu2+ Emission in Tellurite, Adjusting Eu2+ and Eu3+ Emissions toward White Light Emission." Materials 12, no. 24 (2019): 4140. http://dx.doi.org/10.3390/ma12244140.

Full text

Abstract:

Europium-doped magnesium tellurite glasses were prepared using melt quenching techniques and attenuated total reflection (ATR) spectroscopy was used to study the glass structure. The glass transition temperature increased with increasing MgO content. Eu2+ and Eu3+ emissions were studied using photoluminescence spectroscopy (PL). The broad emission of Eu2+ ions centered at approximately 485 nm was found to decrease in intensity with increasing MgO content, while the Eu3+ emission was enhanced. The Eu3+ emission lay within the red orange range and its decay time was found to increase with increasing MgO content. Different excitation wavelengths were used to adjust Eu2+ to Eu3+ emissions to reach white light emission. The white light emission was obtained for the sample with the lowest MgO content under excitation in the near-UV range.

APA, Harvard, Vancouver, ISO, and other styles

Rasadujjaman, Md, Jinming Zhang, Alexey S. Vishnevskiy, Jing Zhang, and Mikhail R. Baklanov. "Structural and Luminescence Properties of Eu-Doped PMO Films with Ethylene Bridge and Methyl Terminal Groups." Coatings 13, no. 9 (2023): 1656. http://dx.doi.org/10.3390/coatings13091656.

Full text

Abstract:

Eu-doped periodic mesoporous organosilicate (PMO) films with terminal methyl and ethylene bridging groups have been synthesized using sol-gel technology and spin-coating, employing evaporation-induced self-assembly (EISA), on silicon wafers. Eu doping is achieved by the dissolution of Eu(NO3)3·6H2O in the precursor solution. The deposited films are characterized using Fourier transform infrared (FTIR) spectroscopy, ellipsometric porosimetry (EP), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy. It is observed that Eu doping reduces the concentration of terminal methyl groups, makes the films more hydrophilic and reduces the pore size and open porosity. The reduction reaction Eu3+ → Eu2+ occurs in the pores of organosilicate glass (OSG) films, which was confirmed by the depth profiling XPS. Eu3+ was still present on the top surface of the films. The presence of Eu3+ and Eu2+ gives luminescence emission in the range of 600–630 nm (Eu3+) and 290–400 nm (Eu2+). The Eu2+/Eu3+ concentrations ratio depends on CH3 groups concentration in the films. The concentration of Eu2+ ions in the pores can be reduced by exposure to inductively coupled (ICP) oxygen plasma. The observed shift in the luminescence spectra towards the UV region, in comparison to previously reported Eu-doped organosilicate films, can be attributed to the energy transfer occurring between the host material and Eu2+ ions.

APA, Harvard, Vancouver, ISO, and other styles

CARRILLOCABRERA, W., J. THOMAS та G. FARRINGTON. "The Eu3+→Eu2+ reduction process in Eu3+ β″-alumina". Solid State Ionics 18-19 (січень 1986): 645–52. http://dx.doi.org/10.1016/0167-2738(86)90235-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Nikiforov, Ivan V., Dmitry A. Spassky, Nataliya R. Krutyak, et al. "Co-Doping Effect of Mn2+ and Eu3+ on Luminescence in Strontiowhitlockite Phosphors." Molecules 29, no. 1 (2023): 124. http://dx.doi.org/10.3390/molecules29010124.

Full text

Abstract:

A new series of Sr-based phosphates, Sr9−xMnxEu(PO4)7, were synthesized using the high-temperature solid-state method in air. It was found that these compounds have the same structure as strontiowhitlockite, which is a β-Ca3(PO4)2 (or β-TCP) structure. The concentration of Mn2+ ions required to form a pure strontiowhitlockite phase was determined. An unusual partial reduction of Eu3+ to Eu2+ in air was observed and confirmed by photoluminescence (PL) and electron spin resonance (ESR) spectra measurements. The PL spectra recorded under 370 nm excitation showed transitions of both 4f5d–4f Eu2+ and 4f–4f Eu3+. The total integral intensity of the PL spectra, monitored at 395 nm, decreased with increasing Mn2+ concentration due to quenching effect of Eu3+ by the Mn2+ levels. The temperature dependence of Eu2+ photoluminescence in a Sr9−xMnxEu(PO4)7 host was investigated. The conditions for the reduction of Eu3+ to Eu2+ in air were discussed.

APA, Harvard, Vancouver, ISO, and other styles

Prat, Maxime, Mélanie Jeanneau, Ignace Rakotoarivony, et al. "Virulence and transmission vary between Usutu virus lineages in Culex pipiens." PLOS Neglected Tropical Diseases 18, no. 6 (2024): e0012295. http://dx.doi.org/10.1371/journal.pntd.0012295.

Full text

Abstract:

Usutu virus (USUV) is a zoonotic arbovirus infecting mainly wild birds. It is transmitted by ornithophilic mosquitoes, mainly of the genus Culex from birds to birds and to several vertebrate dead-end hosts. Several USUV lineages, differing in their virulence have emerged in the last decade and now co-circulate in Europe, impacting human populations. However, their relative transmission and effects on their mosquito vectors is still not known. We thus compared the vector competence and survival of Culex pipiens mosquitoes experimentally infected with two distinct USUV lineages, EU2 and EU3, that are known to differ in their virulence and replication in vertebrate hosts. Infection rate was variable among blood feeding assays but variations between EU2 and EU3 lineages were consistent suggesting that Culex pipiens was equally susceptible to infection by both lineages. However, EU3 viral load increased with viral titer in the blood meal while EU2 viral load was high at all titers which suggest a greater replication of EU2 than EU3 in mosquito. While their relative transmission efficiencies are similar, at least at low blood meal titer, positive correlation between transmission and blood meal titer was observed for EU3 only. Contrary to published results in vertebrates, EU3 induced a higher mortality to mosquitoes (i.e. virulence) than EU2 whatever the blood meal titer. Therefore, we found evidence of lineage-specific differences in vectorial capacity and virulence to both the vector and vertebrate host which lead to balanced propagation of both viral lineages. These results highlight the need to decipher the interactions between vectors, vertebrate hosts, and the diversity of arbovirus lineages to fully understand transmission dynamics.

APA, Harvard, Vancouver, ISO, and other styles

Lin, Tzu-Chiao, and Xiaoding Qi. "Cation Valences and Multiferroic Properties of EuTiO3 Co-Doped with Ba and Transition Metals of Co/Ni." Materials 15, no. 19 (2022): 6652. http://dx.doi.org/10.3390/ma15196652.

Full text

Abstract:

Eu1−xBaxTi1−yMyO3 (M = Co or Ni) was sintered at 1400 °C under a reduction atmosphere. X-ray photoelectron spectroscopy revealed the mixed valences of Eu2+/Eu3+ and Ti4+/Ti3+ in EuTiO3 and Eu0.7Ba0.3TiO3, as well as some oxygen vacancies required to keep the charge neutrality. The co-doping of Co2+/Ni2+ in Eu0.7Ba0.3TiO3 resulted in the disappearance of oxygen vacancies, as a result of a reduction in Ti3+ numbers and an increase in Eu3+ numbers. On the other hand, Ba2+ doping led to an increased lattice parameter due to its larger ionic size than Eu2+, whereas the Co2+/Ni2+ co-doping resulted in smaller lattice parameters because of the combined effects of ionic size and variation in the oxygen-vacancy numbers. Eu0.7Ba0.3TiO3 exhibited a clear ferroelectricity, which persisted in the Co2+/Ni2+ co-doped samples until the doping levels of y = 0.05 and 0.10, respectively. Eu0.7Ba0.3TiO3 remained to be antiferromagnetic with a reduced transition temperature of 3.1 K, but co-doping of Co2+/Ni2+ turned the samples from antiferromagnetic to ferromagnetic with transition temperatures of 2.98 K and 2.72 K, respectively. The cause for such a transition could not be explained by the larger lattice volume, oxygen vacancies and mixed valences of Eu2+/Eu3+, which were proposed in previous works. Instead, it was more likely to arise from a large asymmetric distortion of the Eu–O polyhedron introduced by the aliovalent doping, which promotes the admixture of Eu 5d and 4f states.

APA, Harvard, Vancouver, ISO, and other styles

Lapraz, D., H. Prévost, and A. R. Lakshmanan. "Instability of Eu2+/Eu3+ photoluminescence in X-irradiated CaSO4:Eu3+." physica status solidi (a) 201, no. 3 (2004): 596–601. http://dx.doi.org/10.1002/pssa.200306743.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Tanner, Peter A., and Lixin Yu. "Photoluminescence of ZnO:Eu3+ Nanoflowers." Journal of Nanoscience and Nanotechnology 8, no. 3 (2008): 1307–11. http://dx.doi.org/10.1166/jnn.2008.18187.

Full text

Abstract:

The synthesis of ZnO:Eu3+ nanoflowers by a low-temperature hydrothermal route is described. Characterization of the materials was performed by ESEM, XRD and FTIR spectra. The 355 nm excited photoluminescence spectra at 10 K do not indicate the presence of Eu2+ or the ZnO defect states which give rise to green or red broadband emission. Excitation into the ZnO conduction band at low temperature does not give emission from Eu3+. Selective excitation of the Eu3+ emission shows that Eu3+ ions occupy a variety of different sites, of which one of them is similar to Eu3+ in C-type Eu2O3.

APA, Harvard, Vancouver, ISO, and other styles

Xie, Mubiao, Guoxian Zhu, Rongkai Pan, and Wei Xie. "Optical properties of Eu2+ /Eu3+ mixed valence phosphor Ca2 SiO2 F2 :Eu2+ /Eu3+." Luminescence 32, no. 7 (2017): 1169–73. http://dx.doi.org/10.1002/bio.3305.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Zaitoun, M. A., D. M. Goken, L. S. Bailey, T. Kim, and C. T. Lin. "Thermoanalysis and Emission Properties of Eu3+/Eu2+in Eu3+-Doped Xerogels." Journal of Physical Chemistry B 104, no. 2 (2000): 189–96. http://dx.doi.org/10.1021/jp991873m.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Block, Theresa, Ryosuke Numakura, Masashi Kosaka, Shinji Michimura, and Rainer Pöttgen. "Magnetic hyperfine field splitting in the Zintl phase Eu2Mg4Si3." Zeitschrift für Naturforschung B 74, no. 5 (2019): 451–54. http://dx.doi.org/10.1515/znb-2019-0055.

Full text

Abstract:

AbstractEu2Mg4Si3 ≡ (2Eu2+)(4Mg2+)(3Si4−) is an electron-precise Zintl phase. Its Hf2Co4P3-type structure contains three crystallographically independent europium sites. The divalent state of europium was manifested through 151Eu Mössbauer spectroscopy. In the paramagnetic regime (T = 78 K) the isomer shifts range from −9.16 to −11.29 mm s−1. Eu2Mg4Si3 shows complex magnetic hyperfine field splitting at T = 5.7 K with a superposition of three subspectra with magnetic hyperfine fields of 5.4 (Eu2), 20.4 (Eu1) and 22.4 (Eu3) T.

APA, Harvard, Vancouver, ISO, and other styles

Sun, Jia Yue, Liu Han, Qiu Mei Di, and Qi Guang Xu. "Synthesis and Luminescence Properties of Na₃YSi₂O₇:Sm³⁺, Eu³⁺ Phosphor." Applied Mechanics and Materials 633-634 (September 2014): 306–9. http://dx.doi.org/10.4028/www.scientific.net/amm.633-634.306.

Full text

Abstract:

Novel Na3YSi2O7: Sm3+, Eu3+phosphors for white light-emitting diodes were prepared by high-temperature solid-state reaction. The photoluminescence excitation and emission spectra, energy transfer from Eu2+to Tb3+are investigated in detail. The current research suggests that Na3YSi2O7: Sm3+, Eu3+phosphor is a potential candidate for application in Phosphor-converted LEDs.

APA, Harvard, Vancouver, ISO, and other styles

Namkhai, Purevdulam, and Kiwan Jang. "Co-Doping Effect on the Optical Properties of Eu(2+/3+) Doped in BaSiO3." Materials 15, no. 19 (2022): 6559. http://dx.doi.org/10.3390/ma15196559.

Full text

Abstract:

To investigate the effect of co-doping on the optical properties of Eu(2+/3+) doped in Ba0.98SiO3:0.02Eu, the series of Ba0.96SiO3:0.02Eu, 0.02R+/3+ (R+ = Li+, K+ or Na+, R3+ = La3+ or Y3+) phosphors were synthesized using a solid-state reaction method. The excitation efficiency due to the charge transfer band (CTB) was enhanced via co-doping of R+ and the emission intensity due to Eu3+ was thus increased by 3.7 times compared with that of the single-doped Ba0.98SiO3:0.02Eu3+. However, the co-doping of R+ does not increase the emission intensity of Eu3+ via the direct 7F0→5L6 excitation of Eu3+, but rather decreases it. On the other hand, the emission intensities due to Eu2+ were decreased via the co-doping of R+ but increased via the co-doping of La3+. The present work reveals that the optical properties of Eu3+ or Eu2+ doped in BaSiO3 depend not on the charge state (+ or 3+) of the co-doped ions, but on the co-doped element itself.

APA, Harvard, Vancouver, ISO, and other styles

Kolesnik, Stefaniia S., Nikita A. Bogachev, Ilya E. Kolesnikov, et al. "Microcrystalline Luminescent (Eu1-xLnx)2bdc3·nH2O (Ln = La, Gd, Lu) Antenna MOFs: Effect of Dopant Content on Structure, Particle Morphology, and Luminescent Properties." Molecules 29, no. 2 (2024): 532. http://dx.doi.org/10.3390/molecules29020532.

Full text

Abstract:

In this work, three series of micro-sized heterometallic europium-containing terephthalate MOFs, (Eu1-xLnx)2bdc3·nH2O (Ln = La, Gd, Lu), are synthesized via an ultrasound-assisted method in an aqueous medium. La3+ and Gd3+-doped terephthalates are isostructural to Eu2bdc3·4H2O. Lu3+-doped compounds are isostructural to Eu2bdc3·4H2O with Lu contents lower than 95 at.%. The compounds that are isostructural to Lu2bdc3·2.5H2O are formed at higher Lu3+ concentrations for the (Eu1-xLux)2bdc3·nH2O series. All materials consist of micrometer-sized particles. The particle shape is determined by the crystalline phase. All the synthesized samples demonstrate an “antenna” effect: a bright-red emission corresponding to the 5D0-7FJ transitions of Eu3+ ions is observed upon 310 nm excitation into the singlet electronic excited state of terephthalate ions. The fine structure of the emission spectra is determined by the crystalline phase due to the different local symmetries of the Eu3+ ions in the different kinds of crystalline structures. The photoluminescence quantum yield and 5D0 excited state lifetime of Eu3+ are equal to 11 ± 2% and 0.44 ± 0.01 ms, respectively, for the Ln2bdc3·4H2O structures. For the (Eu1-xLux)2bdc3·2.5H2O compounds, significant increases in the photoluminescence quantum yield and 5D0 excited state lifetime of Eu3+ are observed, reaching 23% and 1.62 ms, respectively.

APA, Harvard, Vancouver, ISO, and other styles

Huang, Yuan Ming, Qing Lan Ma, and Bao Gai Zhai. "Luminescent Properties of Eu²⁺, Eu³⁺ and Dy³⁺Co-Activated SrAl₂O₄ Nanocrystals." Key Engineering Materials 538 (January 2013): 15–21. http://dx.doi.org/10.4028/www.scientific.net/kem.538.15.

Full text

Abstract:

By the control of the reducing atmospheres in the one-pot combustion reactions, Eu2+, Eu3+ and Dy3+ co-activated strontium aluminate oxide were synthesized. X-ray diffraction confirmed the formation of monoclinic SrAl2O4 nanocrystals. The photoluminescence spectra of the phosphors were measured. It is found that three sharp emissions at 483, 570 and 615 nm were superimposed onto the broad green emission band at about 520 nm. The origins of the broad green luminescent band, the sharp blue at 483 nm, and sharp yellow emissions at 570 nm and the sharp red emissions at 615 nm can be attributed to the 4f65d1→4f7 transitions of Eu2+ ions, the 4F9/2→6H15/2 transition of Dy3+ ions, the 4F9/2→6H13/2 transition of Dy3+ ions, and the 5D0–7F2 transition of Eu3+ ions in the SrAl2O4 nanocrystals, respectively. The results indicate that the white light emitting phosphors are possible by tuning the relative molar percentages of Eu2+, Eu3+ and Dy3+ in the phosphors.

APA, Harvard, Vancouver, ISO, and other styles

Chen, Yuhui, Pu Fan, Xiao He, Xiaoguang Liu, and Ling Li. "The Broadband Emitting and Lattice Occupation Analysis of Eu²⁺, Eu³⁺ and Ce³⁺ co-doped K₃YSi₂O₇ Phosphors." Journal of Physics: Conference Series 2548, no. 1 (2023): 012012. http://dx.doi.org/10.1088/1742-6596/2548/1/012012.

Full text

Abstract:

Abstract Eu3+, Eu2+ and Ce3+ doped K3YSi2O7 phosphors are synthesized under reducing atmosphere. Photoluminescence properties show K3YSi2O7:1%Ce, 1%Eu at 330 nm excitation (FWHM = 211 nm, where FWHM stands for the full width at half maximum) can produce broadband emission. The preferential occupation sites of Ce and Eu ions in K3YSi2O7 are calculated using the bond energy theory. Eu2+, Eu3+, Ce3+ ions preferentially occupy K3, Y2, K1 sites, respectively. The broadband emission of the phosphor is caused by the dopant ions’ selective site occupancy.

APA, Harvard, Vancouver, ISO, and other styles

Зюзин, А. М., та Д. А. Салкин. "Влияние рентгеновского излучения на валентное состояние Eu в люминофоре Y-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- : Eu-=SUP=-3+-=/SUP=-". Физика твердого тела 61, № 10 (2019): 1849. http://dx.doi.org/10.21883/ftt.2019.10.48259.352.

Full text

Abstract:

The effect of X-rays on the valence state of Eu ions in a Y2O3 matrix has been studied by the EPR method. The effect of charge exchange of Eu ions (Eu3 + → Eu2 + → Eu3 +) in the Y2O3 structure has been found. The mechanism of europium reduction to the divalent state under the action of X-ray irradiation has been described.

APA, Harvard, Vancouver, ISO, and other styles

Zhu, Hongliang, Enze Zhu, Hong Yang, et al. "Hydrothermal Synthesis and Photoluminescence of Eu2−xSmxSn2O7 (x = 0–2.0) Nanophosphors." Journal of Nanoscience and Nanotechnology 8, no. 3 (2008): 1427–31. http://dx.doi.org/10.1166/jnn.2008.18209.

Full text

Abstract:

Eu2–xSmxSn2O7 (x = 0, 0.1, 0.5, 1.0, 1.5, and 2.0) solid solutions were successfully synthesized by a simple, mild hydrothermal process. The crystal structure, particle size, and chemical composition of the solid solutions were characterized by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. X-ray diffraction patterns and transmission electron microscopy images reveal that all the products were cubic pyrochlore-type Eu2–xSmxSn2O7 nano-crystals with the diameter of ∼20 nm. Due to efficient energy transfer from Sm3+ to Eu3+, the Eu2–xSmxSn2O7 (x = 0.1, 0.5, 1.0, and 1.5) nanocrystals exhibited strong 5D0 → 7F1 photoluminescence emission of Eu3+. The dominant 5D0 → 7F1 transition revealed good monochromaticity and low distortion of the Eu2–xSmxSn2O7 nanophosphors.

APA, Harvard, Vancouver, ISO, and other styles

Niida, H., M. Takahashi, T. Uchino, and T. Yoko. "Spontaneous reduction of europium ions below 250 °C in organic–inorganic hybrid low-melting phosphite glasses." Journal of Materials Research 18, no. 1 (2003): 1–3. http://dx.doi.org/10.1557/jmr.2003.0001.

Full text

Abstract:

Europium-doped organic–inorganic hybrid low-melting phosphite glass was prepared from SnCl2, Me2SiCl2, and H3PO3 (phosphonic acid) through the nonaqueous acid–base reaction process. The europium-doped glass melted at 250 °C showed fluorescence with a broad peak at 373 nm due to the 4f6 5d1 → 4f7 transition of Eu2+ ions, whereas no fluorescence from the Eu3+ ions was observed. Almost all of the Eu3+ ions incorporated into the glasses could be successfully reduced to Eu2+ ions at a temperature as low as 250 °C by the strong reducing power of H3PO3.

APA, Harvard, Vancouver, ISO, and other styles

White, Frankie, та Richard E. Sykora. "Crystal structure of di-μ-benzato-κ4O:O′-bis[aqua(benzato-κO)(benzato-κ2O,O′)(2,2′:6′,2′′-terpyridine-κ3N,N′,N′′)europium(III)]–benzoic acid (1/2)". Acta Crystallographica Section E Structure Reports Online 70, № 9 (2014): m328—m329. http://dx.doi.org/10.1107/s1600536814018182.

Full text

Abstract:

The title compound, [Eu2(C7H5O2)6(C15H11N3)2(H2O)2]·2C7H6O2, is a co-crystalline compound containing a dinuclear EuIIIcoordination complex with inversion symmetry co-crystallized with benzoic acid in a 1:2 ratio. The Eu3+ions within the dimer are nine-coordinate, containing one tridentate terpyridine, one water, and four benzoate ions, two of which bridge the Eu3+ions. Of the four benzoate ligands coordinating to each Eu3+position, three distinct coordination modes [monodentate, bidentate–chelating, and bidentate–bridging (twice)] are observed. Within the crystal, there are two additional uncoordinating benzoic acid molecules per dinuclear complex. Within the dimer, the water bound to each Eu3+ion participates in intramolecular hydrogen bonding with a coordinating benzoate. Additionally, the carboxylic acid group on the benzoic acid participates in intermolecular hydrogen bonding with a benzoate ligand bound to the dimer complex.

APA, Harvard, Vancouver, ISO, and other styles

Sahu, Muskan, and R. K. Verma. "Luminescence of Eu3+/Eu2+ In PVA Film: Transitions from the 5D0 Level and its Lifetime Measurement." Prabha Materials Science Letters 4, no. 2 (2025): 170–78. https://doi.org/10.33889/pmsl.2025.4.2.016.

Full text

Abstract:

We have synthesized Eu3+ doped poly vinyl alcohol (PVA) polymer film by the solution-casting method. The vibration features of the film are analyzed by using the FTIR spectrum. In the FTIR spectrum, many peaks are observed and correlate with different branches of vibrations. On excitation of 325 nm, Eu3+ ions emit at 579 nm, 592 nm, 615 nm, 649 nm, 698 nm through transitions 5D0→7F0, 5D0→7F1, 5D0→7F2, 5D0→7F3, 5D0→7F4 respectively. These peaks are verified with the help of Eu3+ energy level diagram. In addition, we observed a broad peak of Eu2+ in the range 450 nm to 550 nm centered at 500 nm. Some stark splitting also has been observed in transitions 5D0 →7F0 and 5D0→7F4. The micron - second lifetime of the 5D0 level of Eu3+ is observed and correlated with the emission spectrum.

APA, Harvard, Vancouver, ISO, and other styles

Du, Xi-Gang, Jun Zhang та Jia-Jia Li. "Poly[tetraaquabis(μ4-thiophene-2,5-dicarboxylato)(μ2-thiophene-2,5-dicarboxylato)dieuropium(III)]". Acta Crystallographica Section E Structure Reports Online 68, № 8 (2012): m1024. http://dx.doi.org/10.1107/s1600536812029546.

Full text

Abstract:

The three-dimensional coordination polymer, [Eu2(C6H2O4S)3(H2O)4]n, has been synthesized under hydrothermal conditions. The asymmetric unit comprises one Eu3+cation, two aqua ligands and one and a half thiophene-2,5-dicarboxylate anions (the half-anion being completed by a twofold rotation axis). The Eu3+cation is eight-coordinated in a distorted dodecahedral geometry. The crystal structure features O—H...O hydrogen bonds.

APA, Harvard, Vancouver, ISO, and other styles

Jakubcová, Petra, Dirk Johrendt, Peter Sebastian, Sudhindra Rayaprol, and Rainer Pöttgen. "Structure, Magnetic Properties and 151Eu, 119Sn Mössbauer Spectroscopy of Eu5Sn3S12 and Eu4LuSn3S12." Zeitschrift für Naturforschung B 62, no. 1 (2007): 5–14. http://dx.doi.org/10.1515/znb-2007-0102.

Full text

Abstract:

Eu5Sn3S12 and Eu4LuSn3S12 were synthesized and their structures refined from single crystal data (Pmc21, Eu5Sn3S12: a = 3.908(1), b = 20.115(4), c = 11.451(2) Å ; wR2 = 0.0519 for 3048 F2 and 122 parameters; Eu4LuSn3S12: a = 3.920(1), b = 20.132(4), c = 11.459(2) Å ; wR2 = 0.0737 for 3298 F2 and 122 parameters). The structures contain one-dimensional chains of edge-sharing SnS2S4/2 octahedra and corner-sharing SnS3S2/2 trigonal bipyramids, running parallel to [100]. Five europium sites are seven- or eightfold coordinated by sulfur atoms. Lutetium atoms in Eu4LuSn3S12 show a strong site preference for one of the two Eu3+ positions of Eu5Sn3S12 and no structural disorder was observed. Both compounds show static mixed valence according to Eu2+3 Eu3+2 Sn4+3 S2−12 and Eu2+3 Eu3+Lu3+Sn4+3 S2−12 , which was confirmed by temperature dependent magnetic susceptibility measurements. The experimental magnetic moments of 14.6(1) (Eu5Sn3S12) and 14.1(1) (Eu4LuSn3S12) μB/f.u. indicate that each of the two sulfides contains three divalent europium atoms per formula unit. Magnetic ordering for Eu5Sn3S12 and Eu4LuSn3S12 sets in below 5 and 3 K, respectively. Both sulfides show metamagnetic or spin-flip transitions in the magnetization curves at 3 K (2 K) with full saturation of the europium magnetic moments at 3 K (2 K) and 80 kOe. 151Eu Mössbauer spectra fully confirm the Eu2+ and Eu3+ site occupancies. At 4.2 K an increase in line width indicates small hyperfine fields at the europium nuclei.

APA, Harvard, Vancouver, ISO, and other styles

Szyszka, Katarzyna, Adam Watras, and Rafal J. Wiglusz. "Strontium Phosphate Composite Designed to Red-Emission at Different Temperatures." Materials 13, no. 20 (2020): 4468. http://dx.doi.org/10.3390/ma13204468.

Full text

Abstract:

Eu3+-doped Sr10(PO4)6(OH)2–Sr3(PO4)2 (SrHAp-TSP) composites were obtained via the microwave-stimulated hydrothermal method and post-heat-treated from 750 to 950 °C. Concentration of the Eu3+ ions was set to be 0.5, 1, 2, 3, 5 mol% in a ratio of the strontium ions molar content. The structural and morphological properties were investigated by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FT-IR) techniques. The average particle size of the studied materials annealed at 750, 850 and 950 °C were counted about 100, 131 and 173 nm, respectively. The luminescence properties depending on the dopant ion concentration, heat-treatment temperature, excitation wavelength and temperature were investigated. In the emission spectra, a broad peak corresponding to the 4f65d1 → 4f7 (8S7/2) emission of Eu2+ ions as well as narrow 4f-4f transitions typical for Eu3+ ions can be observed. The luminescence intensity of the 1 mol% Eu3+:Sr10(PO4)6(OH)2–Sr3(PO4)2 was measured depending on the ambient temperature in the range of 80–550 K. The CIE 1931 (International Commission on Illumination) chromaticity diagram was determined from emission spectra measured in 80, 300 and 550 K. The reduction mechanism of the Eu3+ to the Eu2+ was explained by the charge compensation mechanism based on the Kröger–Vink-notation. The decay times were measured and the Judd–Ofelt (J–O) theory was applied to analyze the observed structural and spectroscopic features.

APA, Harvard, Vancouver, ISO, and other styles

Kim, Sung Hoon, Hong Seop Yun, Hyun Kyung Yang, et al. "Hydrogen Plasma Process to Reduce the Eu-Doped Sr₂SiO₄ Thin Films." Solid State Phenomena 124-126 (June 2007): 335–38. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.335.

Full text

Abstract:

As-grown Sr2SiO4:Eu thin films on Si (100) substrates have been reduced by hydrogen plasma reaction which was carried out by using radio frequency plasma enhanced chemical vapor deposition system. The photoluminescence spectra, the crystal structure and the surface morphologies of the plasma-reduced films were measured and compared with those of the as-grown films. At as-grown state, Eu3+ and Eu2+ ions co-exist so that the photoluminescence spectra of the films reveal several emission bands between 350 and 650 nm. They were due to f-f and f-d transitions within Eu3+ and Eu2+ ions. After the plasma-reduced process, the photoluminescence spectra of the films show a remarkable increase of blue-green emission from the transitions of Eu2+ ions and decrease of red emission from the transitions of Eu2+ ions.

APA, Harvard, Vancouver, ISO, and other styles

Li, Jian, Yanjun Cai, Xiang Yao, Hualing Tian, and Zhi Su. "Europium modified TiO₂ as a high-rate long-cycle life anode material for lithium-ion batteries." New Journal of Chemistry 46, no. 5 (2022): 2266–71. http://dx.doi.org/10.1039/d1nj05560g.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Wang, Guofeng, and Qing Peng. "Synthesis and tunable photoluminescence of NaYF4:Eu/Ba nanocrystals." Journal of Materials Research 25, no. 12 (2010): 2422–25. http://dx.doi.org/10.1557/jmr.2010.0297.

Full text

Abstract:

Sub-10 nm monodispersed NaYF4:Eu/Ba nanocrystals were synthesized by a hydrothermal method. Under 396-nm excitation, in addition to the characteristic emissions of Eu3+ ions, an intense emission band originating from the d–f transition of the Eu2+ ions is also observed, indicating that Eu3+ and Eu2+ coexist in Eu/Ba-codoped NaYF4 nanocrystals. The dependence of the luminescence on the Ba2+ concentration was studied. Tunable photoluminescence of NaYF4:Eu nanocrystals was successfully achieved by codoping with Ba2+ ions. In addition, when the Ba/Ln ratio is 3:7 and 4:1, pure cubic Ba0.92Y2.15F8.29:Eu and tetragonal BaYF5:Eu nanocrystals were obtained, respectively.

APA, Harvard, Vancouver, ISO, and other styles

Kuznetsov, Kirill M., Vadim A. Baigildin, Anastasia I. Solomatina, et al. "Polymeric Nanoparticles with Embedded Eu(III) Complexes as Molecular Probes for Temperature Sensing." Molecules 27, no. 24 (2022): 8813. http://dx.doi.org/10.3390/molecules27248813.

Full text

Abstract:

Three novel luminescent Eu(III) complexes, Eu1–Eu3, have been synthesized and characterized with CHN analysis, mass-spectrometry and 1H NMR spectroscopy. The complexes display strong emission in dichloromethane solution upon excitation at 405 and 800 nm with a quantum yield from 18.3 to 31.6%, excited-state lifetimes in the range of 243–1016 ms at 20 °C, and lifetime temperature sensitivity of 0.9%/K (Eu1), 1.9%/K (Eu2), and 1.7%/K (Eu3). The chromophores were embedded into biocompatible latex nanoparticles (NPs_Eu1–NPs_Eu3) that prevented emission quenching and kept the photophysical characteristics of emitters unchanged with the highest temperature sensitivity of 1.3%/K (NPs_Eu2). For this probe cytotoxicity, internalization dynamics and localization in CHO-K1 cells were studied together with lifetime vs. temperature calibration in aqueous solution, phosphate buffer, and in a mixture of growth media and fetal bovine serum. The obtained data were then averaged to give the calibration curve, which was further used for temperature estimation in biological samples. The probe was stable in physiological media and displayed good reproducibility in cycling experiments between 20 and 40 °C. PLIM experiments with thermostated CHO-K1 cells incubated with NPs_Eu2 indicated that the probe could be used for temperature estimation in cells including the assessment of temperature variations upon chemical shock (sample treatment with mitochondrial uncoupling reagent).

APA, Harvard, Vancouver, ISO, and other styles

Sykora, Richard E. "Synthesis, Structure, and Luminescence of a Molecular Europium Tetracyanoplatinate Incorporating 4,5-Diazafluoren-9-One." Crystals 13, no. 2 (2023): 317. http://dx.doi.org/10.3390/cryst13020317.

Full text

Abstract:

Eu2(Pt(CN)4)3(H2O)12]·4C11H6N2O·6H2O represents a new member to the lanthanide tetracyanoplatinate family of materials. The synthesis, single-crystal X-ray structure, and photoluminescence properties of this compound are reported herein. The compound contains dimeric [Eu2(Pt(CN)4)3(H2O)12] molecules in which the Eu3+ sites are connected with trans-bridging [Pt(CN)4] 2− anions and co-crystallized along with 4,5-diazafluoren-9-one (dafone) and lattice water. Prominent noncovalent interactions that stabilize the structure include H-bonding as well as short stacking interactions involving the planar tetracyanoplatinate anions in conjunction with the planar dafone molecules. Photoluminescence measurements illustrate that Eu2(Pt(CN)4)3(H2O)12]·4C11H6N2O·6H2O contains multiple emitting states and also displays enhanced Eu3+-based emission due to energy transfer within the compound.

APA, Harvard, Vancouver, ISO, and other styles

Zuev, Mikhail G., Vladislav G. Il’ves, Sergey Yu Sokovnin, Andrei A. Vasin, and Elena Yu Zhuravleva. "New amorphous nanophosphors obtained by evaporation of silicates and germanates REE." Pure and Applied Chemistry 89, no. 10 (2017): 1505–20. http://dx.doi.org/10.1515/pac-2016-1118.

Full text

Abstract:

Abstract Amorphous nanophosphors have been produced by pulsed electron beam evaporation of bulk phosphors of rare earth elements (REE) silicates and germanates with oxyapatite structure activated with europium. The processes of crystallization of amorphous nanopowders (NP) have been studied by differential scanning calorimetry and thermogravimetry (40–1400°C) methods. A modification of the Raman and IR spectra of the samples was found when the particle size decreased from bulk to nanostate due to insignificant polymerization of Si(Ge)O4 tetrahedra. The spectral and luminescence characteristics of the bulk samples as well as nanoamorphous samples have been examined. It was established that Eu3+ forms two types of optical centers. Upon the transition of Sr2Gd8(SiO4)6O2:Eu3+ phosphor from bulk state to nanostate during laser excitation, the luminescence intensity of Eu3+ ions increases 10 times. Blue and white amorphous nanophosphors have been obtained for the first time by evaporation of Ca2M8(SiO4)6O2:Eu (M=Y, Gd) and Ca2La8(GeO4)O2:Eu phosphors. Radiation reduction of ions Eu3+→Eu2+ in electron beam has been presumably found.

APA, Harvard, Vancouver, ISO, and other styles

Fujimoto, Yutaka, Yoshisuke Futami, Takayuki Yanagida, et al. "Optical and Scintillation Properties of Eu-Doped Calcium Orthoborate." Key Engineering Materials 508 (March 2012): 235–39. http://dx.doi.org/10.4028/www.scientific.net/kem.508.235.

Full text

Abstract:

Single Crystals of Eu-Doped Calcium Orthoborate Have Been Grown by Micro-Pulling (μ-PD) Technique with Radio Frequency Heating System, and its Transmittance, Photoluminescence and Radiation Responses Were Investigated. In Transmittance Spectra, Eu-Doped Crystal Showed Broad Absorption Band around 200-450 nm, which Is due to the Complex of Charge Transfer (CT) Transition and 4f-4f Transition of Eu3+. Intense Eu2+5f-4f and Eu3+4f-4f Emission Peaks Were Observed when Excited to 265 nm and 385 nm, and the Calculated Decay Times Were 230 ns and 1.5 ms, Respectively.241Am 5.5 Mev α-Ray Excited Radioluminescence Spectra Indicated both Eu2+5f-4f and EuSuperscript text3+ 4f-4f Emission Peaks.

APA, Harvard, Vancouver, ISO, and other styles

Santos, J. F. M., R. F. Muniz, E. Savi, et al. "Broadband downconversion in Eu^2+,3+/Yb³⁺ doped calcium aluminosilicate glasses for solar cells applications." Journal of Applied Physics 133, no. 3 (2023): 033102. http://dx.doi.org/10.1063/5.0131686.

Full text

Abstract:

Novel Eu2+,3+/Yb3+ co-doping calcium aluminosilicate glasses prepared under a vacuum atmosphere were developed and characterized from the spectroscopic point of view, as a potential spectral converter for application in solar cells. The emission of near-infrared photons by downconversion due to cooperative energy transfer (ET) from Eu2+ and Eu3+ to Yb3+ in these glasses was reported. Absorption, excitation, emission, and fluorescence decay measurements were performed to examine the ET processes. The occurrence of cooperative energy transfer from Eu2+ and/or Eu3+ to Yb3+ ions was discussed in detail. The obtained samples have high efficiency and broad absorption in the ultraviolet and visible regions. Under 325 nm excitation, the samples achieve intense near-infrared emission, which increases with Yb2O3 concentration (0 < Yb2O3 < 1.38 mol. %). The energy transfer efficiency from Eu2+,3+ to Yb3+ was evaluated, and a maximum efficiency of ∼85% was obtained (Yb2O3 = 1.38 mol. %).

APA, Harvard, Vancouver, ISO, and other styles

YANG Guo-hui, 杨国辉, 王小军 WANG Xiao-jun, 陈彩花 CHEN Cai-hua, and 梁利芳 LIANG Li-fang. "Research Progress in Eu3+-Eu2+ Coexisting Luminescent Materials Based on The Reduction of Eu3+." Chinese Journal of Luminescence 38, no. 11 (2017): 1475–85. http://dx.doi.org/10.3788/fgxb20173811.1475.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Su, Na, Zi Long Tang, and Zhong Tai Zhang. "Luminescent Properties of Sr₂B₅O₉Cl Phosphor Doped with Eu." Key Engineering Materials 336-338 (April 2007): 625–28. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.625.

Full text

Abstract:

Sr2B5O9Cl:Eu phosphor with high efficient luminescent material was synthesized by solid-state reaction method in air. The result of X-ray diffraction showed that the pure Sr2B5O9Cl phase forms at 900°C. The emission spectrum of Sr2B5O9Cl:Eu under 254nm excitation contained two parts. One part was constituted by a strong peak located at 417nm due to the d→f transition of Eu2+ ion, and the other part contained five weak peaks between 580-660nm due to the 5D0→7FJ(J=1,2,3) of Eu3+ ion. The infrared spectrum revealed that both BO3 unites and BO4 unites coexisted in the resultant product. The Eu2+ was surrounded and protected from being oxidized by the BO4 unites. Both red and blue visible lights were observed under ultraviolet excitation as a result of the coexistence of Eu2+ ion and Eu3+ ion.

APA, Harvard, Vancouver, ISO, and other styles

Secu, Mihail, and Corina Elisabeta Secu. "Processing and Optical Properties of Eu-Doped Chloroborate Glass-Ceramic." Crystals 10, no. 12 (2020): 1101. http://dx.doi.org/10.3390/cryst10121101.

Full text

Abstract:

An europium doped BaO–B2O3–BaCl2 chloroborate glass-ceramic containing a BaCl2 nanocrystalline phase was produced by melt-quenching followed by glass crystallization during annealing. Structural and morphological investigations using x-ray diffraction and scanning electron microscopy have shown fvBaCl2 nanocrystals of about tens of nm size accompanied by a smaller amount of the BaB2O4 crystalline phase. Photoluminescence spectra have indicated the reduction of Eu3+ to Eu2+ during processing in air or a reducing atmosphere. The spectra analysis showed the presence of Eu3+ ions in the borate glass matrix, while the Eu2+ were incorporated in both the BaCl2 nanocrystals and glass matrix. Thermoluminescence properties were due to the recombination of F(Cl) centers and Eu2+ related hole centers produced by irradiation within the BaCl2 nanocrystals. The color impression of the samples and the photoluminescence quantum efficiency were influenced by the glass processing.

APA, Harvard, Vancouver, ISO, and other styles

Yabuta, Ryoto, Norihisa Kobayashi, and Kazuki Nakamura. "Electrofluorochromic Devices Based on Electrochemical Valance Change of Europium Complex in Polyether Matrices." ECS Meeting Abstracts MA2024-02, no. 38 (2024): 2571. https://doi.org/10.1149/ma2024-02382571mtgabs.

Full text

Abstract:

Chromogenic materials, in which optical properties such as luminescence and absorption are altered by external stimuli such as light, heat, and electricity, have potential applications in chemical sensors, biochemical labels, molecular memory, and display devices. Electrofluorochromic (EFC) materials, in which wavelength and/or intensity of their photoluminescence are controlled by electrochemical redox reactions, are innovative materials because they can rapidly and repeatedly convert electrical inputs into visual signals. These EFC phenomena were reported by using small molecules, conjugated polymers, inorganic compounds, and luminescent metal complexes. Among the luminescent metal complexes, the lanthanide(III) complexes are composed of a luminescent center of Ln(III) ions and surrounding antenna ligands with sufficient light-absorbing ability. They have attractive photoluminescence properties such as characteristic and narrow emission bands in the visible-near infrared (Vis-NIR) region, long emission lifetimes, and high transparency in the visible region due to the large pseudo-Stokes shift. In particular, Eu complexes have relatively stable trivalent (Eu3+) and divalent (Eu2+) states. The Eu3+ state is characterized by intense and long-lived red luminescence induced by f–f transitions and is extensively applied to biosensors, light-emitting materials, etc. On the other hand, Eu2+ is known to show broad and blue luminescence induced by d–f transitions, from the excited state of 4f65d1 to the ground level state of 8S7/2 (4f7), and the emission of Eu2+ in inorganic matrices is applicable to various phosphor materials. However, Eu2+ is unstable in common solutions, which complicates the observation of its luminescence in solution state. Therefore, this study aims to control the luminescence between Eu3+ and Eu2+ by electrochemical redox reactions. It is recognized that the blue luminescence of Eu2+ can be stabilized by polyethers, such as crown ethers and polyethylene glycols[1]. By this stabilization, the Eu2+ state was expected to produce stalely and repeatedly by the electrochemical reduction of Eu3+ in polyethylene glycol solutions. Considering the EFC reaction of Eu compounds, this study focuses on the β-diketonate Eu complex that exhibits superior red luminescence properties of the Eu3+ state. The solution was prepared by dissolving the lithium trifluoromethanesulfonate (LiCF3SO3) (500 mM) as the supporting electrolyte, β-diketone type Eu(III) complex (Eu(hfa)3(H2O)2) (10 mM) as the emitting material in polyethylene glycol (MW = 400, PEG400). A three-electrode electrochemical cell with ITO electrode as the working electrode, Pt wire as the counter electrode, and Ag/Ag+ as the reference electrode was prepared using the Eu complex solution, and the electrochemical reaction behavior of the Eu(III) complex and the changes in luminescence properties during the reaction were measured. Then two-electrode electrochemical device was fabricated by sandwiching Eu complex solution between the two ITO electrodes (ITO-ITO device) to evaluate photoluminescence (PL) properties under the application of reduction voltage. When the CV measurement using the constructed three-electrode cell structure, stable Eu2+/3+ reactions were not observed in the common electrochemical solvents (dimethyl sulfoxide, acetonitrile, and propylene carbonate). In contrast, relatively stable Eu2+/3+ changes were observed in the PEG400 electrolyte solution. This indicates that the electrochemically generated Eu2+ is more stable in the PEG400 solution than in the other solvents. The figure shows the emission spectra of the Eu(hfa)3(H2O)2 solution in the two-electrode ITO-ITO device under the application of reduction voltage. When a reduction voltage was applied for working electrode for 60 minutes, the emission bands of Eu2+ (430 nm) in the device significantly increased, and the red emission from Eu3+ (616 nm) simultaneously decreased as electrochemical reduction proceeded. Considering luminescence color, the intensity ratio of Eu2+ emission (430 nm, I 430) to Eu3+ emission (616 nm, I 616) was significantly improved using the two-electrode devices; the I 430 nm: I 616 nm ratio was 1: 100 for the three-electrode cell and 1: 2.5 for the two-electrode devices. Thus, changes in the luminescence color can be recognized by the naked eye after electrochemical reduction (Figure photos). These results show that electrochemical redox reaction of Eu complexes leads to a distinct change in luminescence color in PEG electrolyte by stabilizing Eu2+ state in liquid matrix. Figure 1

APA, Harvard, Vancouver, ISO, and other styles

Rezende, Marcos V. dos S., Paulo J. R. Montes, Felipe M. dos S. Soares, Claudiane dos Santos, and Mário E. G. Valerio. "Influence of co-dopant in the europium reduction in SrAl2O4host." Journal of Synchrotron Radiation 21, no. 1 (2013): 143–48. http://dx.doi.org/10.1107/s1600577513025708.

Full text

Abstract:

Xerogels of strontium chlorate and aluminium chlorate doped with europium (un-co-doped) and co-doped with rare earth ions (Ln = Gd, Dy, Er and Y) were prepared using the proteic sol–gel route. Synchrotron radiation was used to investigate the effect of different co-dopants on the Eu3+→ Eu2+reduction process during the synthesis of the samples. Samples were excited at the EuLIII-edge and the XANES regions were analyzed. The results suggest that some of the Eu ions can be stabilized in the divalent state and that it is difficult to completely reduce Eu3+to Eu2+during thermal treatment. The mechanisms of the Eu reduction processes are explained by a proposed model based on the incorporation of charge-compensation defects.

APA, Harvard, Vancouver, ISO, and other styles

Gomez-Rodriguez, Pilar, Esther Soria, Yu Jin, et al. "Toward white light emission from plasmonic-luminescent hybrid nanostructures." Nanophotonics 10, no. 16 (2021): 3995–4007. http://dx.doi.org/10.1515/nanoph-2021-0336.

Full text

Abstract:

Abstract We study the light emission of plasmonic-luminescent hybrid nanostructures consisting of Ag nanoparticles (NPs) embedded in europium oxide (EuOX). The Ag NPs present a bidimensional organization in the nanostructures and they optically behave as oblate spheroids. The photoluminescence (PL) spectral response of the nanostructures evolves from a narrow red emission characteristic of Eu3+ ions in absence of Ag NPs to a broad blue-green emission band associated with Eu2+ ions when the layer of Ag NPs is present. This behavior is not related to a change in the Eu2+/Eu3+ ratio, which is verified by compositional analysis. Instead, a detailed investigation of the PL emission of the nanostructures suggests that the coupling of the Ag NPs to the Eu2+ ions present in the EuOX layer, which manifests itself in an efficient sensitization of these ions, enhances their broad visible emission. In particular, the longitudinal mode of the Ag NPs surface plasmon is considered to be responsible for the efficient energy transfer for the non-normal incidence excitation PL configuration used. Finally, the use of a capping amorphous Al2O3 layer allows improving the robustness of hybrid nanostructures and further enhances their PL emission. These findings provide a new path to actively control the selective excitation of Eu2+ and Eu3+ ions via a controlled coupling with the surface plasmon resonance modes of the Ag NPs and points to these nanostructures as promising building blocks for the development of integrable white light sources.

APA, Harvard, Vancouver, ISO, and other styles

Serna, Rosalia, Jose Gonzalo, Antonio Mariscal-Jimenez, Pilar Gomez Rodriguez, and Andres Caño. "(Invited) Nanocrystalline Oxide-Based Luminescent Nanophotonic Structures." ECS Meeting Abstracts MA2022-01, no. 20 (2022): 1095. http://dx.doi.org/10.1149/ma2022-01201095mtgabs.

Full text

Abstract:

Light nanoemiters are the cornerstone of photonic integrated applications including displays for consumer products such as phones and smartwatches, and for advanced application such as quantum emitters. In this context it is appealing to have access to a single material platform suitable for tunable wavelength emission, and if possible, that can provide broadband white light emission. Solid state light emitting nanostructures based on Europium ions are a promising solution. When imbedded in a solid they can have two oxidation states Eu3+ or Eu2+ which upon excitation show a either a high purity red emission (associated to the Eu3+ dipole-forbidden intra-4f shell 5D0® 7F2 transition), or a broad emission band in the 450-600 nm spectral region (related to the Eu2+ dipole-allowed 4f6 5d -> 4f7 transitions). Here I will discuss the strategy that our group is following based on europium oxides EuOx, 1/3<x<1, as this approach allows to have a high density of emitters. Moreover, their electric and optical properties can be tuned from the sesquioxide Eu2O3 that is a wide bandgap dielectric that shows the Eu3+ ion related narrow band red emission, to the monoxide EuO that is a semiconductor that shows a wide band white light emission related to the Eu2+ ion. For the nanoemitters we have prepared EuOx nanocrystalline films with high transparency, and in which the coexistence of both oxidation Eu states enables wavelength tunability [1.2]. Finally, recently we have designed 2D hybrid nanoemitters by integrating the EuOx films with metallic metasurfaces in order to induce an enhancement of the emission intensity by selective plasmonic excitation [3]. [1] A. Mariscal, A. Quesada, A. Tarazaga Martín-Luengo, Miguel A. García, A. Bonanni, J.F. Fernández and R. Serna, Appl. Surf. Science 456,980 (2018). [2] A. Mariscal-Jiménez, A. Tarazaga Martín-Luengo, B. Galiana, C. Ballesteros, A. Bonanni, J. Martín-Sánchez, R. Serna, J. Phys. Chem. C. 124, 15434–15439 (2020). [3] P. Gomez-Rodriguez, E. Soria, Y. Jin, A. Caño, I. Llorente, A. Cuadrado, A. Mariscal-Jiménez, A. K. Petford-Long, R. Serna and J. Gonzalo, Nanophotonics. 10, 3995–4007 (2021).

APA, Harvard, Vancouver, ISO, and other styles

Wickleder, Claudia. "A New Mixed Valent Europium Chloride: Na5Eu7Cl22." Zeitschrift für Naturforschung B 57, no. 8 (2002): 901–7. http://dx.doi.org/10.1515/znb-2002-0810.

Full text

Abstract:

The reaction of NaCl, EuCl2 and EuCl3 yields violet crystals of the new mixed valent chloride Na5Eu7Cl22 which crystallizes with a hitherto unknown structure (orthorhombic, Pmmn, Z = 2, a = 2525.9(4), b=846.91(9), c = 781.72(8) pm). The structure contains four crystallographically different europiumions,which can be attributed toEu2+ or Eu3+ with respect to their coordination numbers and Eu-Cl distances. The [EuClx] coordination polyhedra are connected to chains along the [001] direction. Absorption spectra show transitions which can be assigned either to Eu3+ or Eu2+ ions or to intervalence charge transfer transitions (IVCT). The latter are at lower energy compared to other mixed valent europium chlorides. The occurence of IVCT and the number of the crystal field levels of the Eu3+ ions reveal that the sites of the europium ions are occupied for a small amount by ions of the respective other valence.

APA, Harvard, Vancouver, ISO, and other styles

Jiang, Yi, and Su Wen Li. "Fabrication and Luminescent Properties of YVO₄: Eu³⁺/MCM-41 Mesoporous Composites." Applied Mechanics and Materials 707 (December 2014): 102–5. http://dx.doi.org/10.4028/www.scientific.net/amm.707.102.

Full text

Abstract:

The optical functionalized YVO4: Eu3+/MCM-41 mesoporous composites were prepared by hydrothermal method. The structure, morphology, luminescence properties and fluorescence dynamics were studied systemically. The compared studies of the luminescence properties of YVO4: Eu3+/MCM-41 with YVO4: Eu3+ nanocrystal were performed. The results show that the YVO4: Eu3+/MCM-41 retains high ordered mesoporous structure of MCM-41. In YVO4: Eu3+/MCM-41, the intrinsic excitation bands of Eu3+ disappears and the lifetimes of Eu3+ become short. The luminescent efficiency of YVO4: Eu3+/MCM-41 is higher than ones of the YVO4: Eu3+ nanocrystal.

APA, Harvard, Vancouver, ISO, and other styles

Kuznetsova, I. V., D. S. Sugatov, and V. I. Gryzlova. "Technology for obtaining a deposited catalyst based on an aluminosilicate matrix modified with europium oxide." Proceedings of the Voronezh State University of Engineering Technologies 84, no. 1 (2022): 208–13. http://dx.doi.org/10.20914/2310-1202-2022-1-208-213.

Full text

Abstract:

The number of cars used worldwide is constantly growing. In this regard, the problem of combating atmospheric pollutants - exhaust gases of internal combustion engines is of particular relevance. Over the years, automakers have made many improvements to car engine design and fuel systems to meet pollution limits. One of the best solutions to this problem is the use of a so-called catalytic converter (converter) or simply a catalyst with a high content of noble metals, the main function of which is the simultaneous oxidation of unburned hydrocarbons and CO, as well as the reduction of nitrogen oxides. It was found that the addition of rare earth metals to Pd, Pt catalysts improves their properties and reduces the proportion of noble metals in the composition of catalysts. The paper presents the results of a study of complexation in the Eu3+-ligand system, where the ligand is an organic acid, by photocolorimetric and potentiometric methods. In the Eu3+-gallic acid system, a stable complex of the composition MeLnx – 1:2 is formed. In the Eu3+- oxalic acid system, a stable complex of the composition MeLnx – 1:1 is formed. In the Eu3+-valine system, a stable complex of the composition MeLnx – 1:2 is formed. A new technique for obtaining complex compounds is shown, consisting in adding hydrogen peroxide H2O2 to a solution containing solutions of Eu3+ salt and organic acid in an aqueous-alcoholic medium to block the reduction of Eu3+→Eu2+. A technology for obtaining a automotive catalyst has been developed, consisting of successive stages: obtaining complex compounds, applying the obtained complex compounds to ceramic block matrices, drying, applying platinum (palladium) acid, calcination. The presence of the Eu3+ ion in the ceramic matrix is proved by the method of elemental analysis. The technology can be applied to solve the problem of environmental pollution, such pollutants as exhaust gases of cars containing a lot of harmful substances in their composition.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!