Addition Of Eu3 Research Articles

Red luminescence CaSiO3:Eu3+ eco-friendly nontoxic phosphor derived from biomass for display and latent finger print applications

Red luminescent Eu3+ activated CaSiO3 phosphor has been prepared by facile green synthesis hydrothermal route using biomass. Future technologies will be required to synthesize on a massive scale using quick, easy, and affordable ways. The current study deals with the preparation of CaSiO3:Eu3+ using egg shell and rice husk ash. The synthesized powders had a single phased monoclinic structure with space group P1 21/C1. It has been found that addition of Eu3+ ion dopant causes decrease in the optical energy band gap. The phosphor exhibits the intense peak at 612 nm corresponds to 5D0 → 7F2 of the Eu3+ anions upon excitation at 392 nm. The lifetimes ranged from 1.90 to 3.53 ms. With an increase in Eu3+ concentration, emission was tuned towards the red area of the CIE diagram. In order to detect hidden fingerprints on flat surfaces using the powder dusting approach, the CaSiO3:Eu3+ effectiveness was also evaluated. The nontoxicity of CaSiO3:Eu3+ was validated by carrying out a cell viability test on MG 63 cell lines. These outcomes demonstrated that the luminescent CaSiO3:Eu3+ can be used as potential material for display, security encoding, and latent fingerprint applications.

Rare-earth (Eu3+) substitution impact on the structural, morphological, magneto-dielectric, and electrochemical properties of Cd0.45Co0.55Fe2−y Eu y O4 spinel nanoferrites

A series of Cd0.45Co0.55Fe2−yEuyO4 (y = 0.0, 0.1, 0.2, 0.3) spinel nanoferrites (SNFs) were synthesized using a self-igniting process and employed as electrode materials for supercapacitor applications. The results demonstrated the formation of a single SNFs phase, as shown by the XRD data. The crystallite size lies between the range of 29.30–51.12 nm. The porosity percentage is within the range of 31.37%–32.99%. Rietveld refinement of XRD and Raman analysis revealed the pure spinel phase and no secondary phase was observed. The saturation magnetization and magnetic anisotropy were also decreased with the addition of Eu3+ in Cd–Co SNFs. The high coercive field was enhanced for Eu3+ doping as compared to pure Cd–Co SNFs. The dielectric constant was improved with the substitution of Eu3+ in Cd–Co SNFs. The dielectric tangent loss was reduced with the doping of Eu3+. The electrochemical performance of the Eu3+ doped Cd–Co SNFs achieved an impressive maximum specific capacitance at a lower scan rate. Based on these findings, the outstanding electrochemical performance of the Eu3+ doped Cd–Co SNFs suggests their potential as promising materials for high-frequency, magnetic ferrofluid, and supercapacitor electrodes.

Effect of Li+ on luminescence properties and thermal stability of glass ceramics containing SrMoO4

Dy3+, Eu3+ co-doped glass ceramics (GCs) containing SrMoO4 crystalline phase were prepared by melt-curing-crystallization method. The most favorable heat treatment conditions for the glass ceramics were found to be 610 °C/2 h by differential scanning calorimetry (DSC), ultraviolet spectrophotometer (UV–Vis), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The best doping concentrations of Dy3+ and Eu3+ in this glass ceramic were 0.8 % and 0.6 %, concentration quenching caused by dipole-dipole interactions occurs when the content of rare earth ions in GCs continues to increase. The chromaticity coordinates of the Dy3+- Eu3+ co-doped glass ceramics changed from cool white light to warm white light with the addition of Eu3+ concentration. At the optimal doping concentration (0.8 % Dy3+-0.6 % Eu3+), the chromaticity coordinate of glass ceramics is (0.3972, 0.3331), and the related color temperature is 3047 K. The luminescence intensity can still reach about 80 % of room temperature at 180 °C, and its thermal quenching activation energy is 0.233 eV. This suggests that glass ceramics have excellent thermal stability. After adding an appropriate amount of Li+, the crystalline phase of the glass ceramics remained unchanged and the luminous intensity of the glass ceramics increased by a factor of about 1.4 in the same environment. The thermal quenching activation energy of the glass ceramic doped with 0.2 % Li+-0.8 % Dy3+-0.6 % Eu3+ was 0.344 eV. The experimental results indicate that GCs has potential application prospects in the field of solid-state lighting.

A Spectroscopic Correlative Analysis of Eu3+‐Substituted Zn1‐xSnO3 Nano Phosphors for Anticounterfeiting Applications

AbstractA series of orange–red phosphors Zn1‐xSnO3:xEu3+ synthesized using a sol–gel combustion process is used to study the modified local crystal structure by site‐selective substitution of Eu3+ ions. XRD with the Rietveld refinement analysis reveals an orthorhombic ZnSnO3 structure with a space group 61. SEM and TEM with EDAX analyses confirm the flower‐like morphology of Zn1‐xSnO3:xEu3+ nanorods. Photoluminescence (PL) spectroscopy gives substantial confirmation for the inclusion of Eu3+ ions into the ZnSnO3 host. Judd‐Ofelt analysis confirms the substitution of Eu3+ ion in an asymmetric environment in ZnSnO3, which is responsible for orange–red emission at 615 nm. UV–vis–DRS analysis shows that the addition of Eu3+ ions (1% to 17% in phases of 4%) results in the formation of confined energy states with an increased band gap from 2.78 to 3.29 eV. The ability of ZnSnO3 to host Eu3+ ions signifies that it can be used as an effective luminescent material. Cyclic voltammetry analysis reveals the enhanced charge separation in Zn1‐xSnO3:xEu3+(13%) nanophosphor. The optimized Zn1‐xSnO3:xEu3+(13%) nano phosphor mixed with silicone investigated for the generation of anti‐counterfeiting patterns indicates its potential to generate high‐resolution image patterns on various surfaces under monochromatic UV or visible‐LASER LED illumination.

Luminous properties of highly moisture-resistant Dy3+-Tm3+-Eu3+ co-doped phosphate glasses for W-LED

In this study, the high-temperature melt quenching method was used to create Dy3+-Tm3+-Eu3+ co-doped P2O5–CaO–K2O–ZnO series glasses (abbreviated PCKZ glasses). The samples were then subjected to various analyses such as X-ray diffraction, thermo-temperature property analyses, chemical stability analysis, Raman spectroscopy analysis, absorption spectroscopy, photoluminescence spectroscopy, fluorescence decay lifetime and CIE chromaticity coordinates to determine the structure and luminous properties of the glass. The sample’s density was determined, and the molar volume was calculated. The results reveal that the PCKZ series glasses prepared in this study are structurally stable and resistant to moisture. Following the addition of Eu3+ to the glass, the emission spectra revealed red emission from Eu3+ at 613 nm. The emission bands of Dy3+ and Tm3+ were enhanced as the concentration of Eu3+ increased, indicating an energy transfer between Eu3+ and Dy3+-Tm3+. The energy was fitted using the Inokuti-Hirayama (I–H) model resulting in energy transfer in dipole-dipole mode. Notably, the glass prepared in this study shows good moisture resistance and chemical stability, as well as emitting bright warm white light when exposed to 350 nm UV light excitation. Under UV simulation at 350 nm, the glass with the composition 50P2O5– 12CaO– 5K2O– 33ZnO-0.5Dy2O3-0.6Tm2O3-0.09Eu2O3 produces white light with a white colour temperature of 4954 K, colour coordinates of (0.3498, 0.3744), a long fluorescence lifetime of 0.498 ms, the quantum yield is 6.86 %, and it has good thermal stability. Therefore, it is considered that PCKZ: DTE (1, 2, 3) series glasses can be used in high humidity-resistant W-LEDs.

Luminescence and spectroscopic studies on Eu3+-doped borate and boro-phosphate glasses for solid state optical devices

An addition of Eu3+ ions in Borate glasses (7TiO2 + 3Al2O3 + (60−x)B2O3 + xEu2O3 + 5LiCO3 + 25SrCO3) (where x = 0.05, 0.10, 0.15, and 0.20 mol%) and Boro-phosphate glasses (40B2O3 + 3Al2O3 + (10−x)P2O5 + xEu2O3 + 7ZnO + 5LiCO3 + 10H6NO4P + 25SrCO3) (where x = 0.10 and 0.20 mol%) containing heavy metals, alkali, and alkaline were prepared using a conventional melt quenching technique. The complementary study of the FT-IR and FT-Raman spectroscopic studies proposed the conversion of BO3 ⇔ BO4 in the borate glass network, and the exchange of the PO3 ⇔ PO2 in the boro-phosphate glass network by increasing the Eu3+ ion concentration. The optical characteristics including absorption, linear refractive index (n), Urbach energy (Eu), direct and indirect band gap energies of the prepared glasses were examined and discussed. Judd-Ofelt (JO) theory was used to determine radiative spectroscopic properties such as radiative transition probability (AR), luminescence branching ratio (βR) and stimulated emission cross-section (σPE). Theoretically, the optical gain parameter and gain bandwidth were calculated, which shows their vital role in laser applications. Using CIE chromaticity coordinates, the reddish orange light emission was observed as a proportion of the increase in Eu3+ ions concentration in both glass networks. The measured colour coordinates were utilised to evaluate the correlated colour temperature (CCT), colour purity (Pc), and excitation purity (Pe) of the studied glasses.

Color tuneability behaviour and energy transfer analysis on Dy3+-Eu3+ co-doped glasses for NUV-WLEDs application

A series of Dy3+ and Eu3+ co-doped zinc aluminoborosilicate (ZABS) glasses were synthesized by a high-temperature melt-quenching method. Visible and NIR transitions of Dy3+-Eu3+ ions are observed through absorption spectra. A reverse trend in the optical band gap values and Urbach energy are seen with addition of Eu3+ ions. Photoluminescence studies recorded under different excitation wavelengths showed a variation in the emission intensities and prevailed the color tuneability behaviour of dopants. The energy transfer between Dy3+ and Eu3+ ions are studied through emission profiles, energy level diagram, and decay curves. The type of multipolar interaction between Dy3+ and Eu3+ are understood via Inokuti-Hirayama (IH) model and Dexter energy model. The CIE chromaticity coordinates, and correlated color temperature (CCT) values suggest that the prepared glasses can be used for light emitting diode application when excited at near-ultraviolet region.

Luminescent and magnetic behavior of Eu3+-doped lanthanum manganite after slow cooling

In this study, the effect of Eu3+ on the magnetic, optical, and structural behavior of the slow-cooled La0.7Sr0.3MnO3 and La0.4Eu0.3Sr0.3MnO3 manganites was investigated using magnetization measurements as a function of the applied field, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, FTIR measurements, and photoluminescence tests. The results showed that the addition of Eu3+ decreases the saturation magnetization of the manganite. An additional europium compound was identified after the slow cooling. The photoluminescence properties of this manganite showed to be dependent on the excitation wavelength, being more effective through the charge transfer band which transfers energy from the matrix to the Eu3+ ions. Two-lifetime constants were determined from photoluminescence experiments.

Smartphone-assisted miniature device based on nitrogen and sulfur co-doped carbon dots for point-of-care testing of tetracycline

A miniature device was design for the point-of-care testing (POCT) of tetracycline (TC) including a ratio fluorescence test strip, a sample slot, a UV lamp and a smartphone. The nitrogen and sulfur co-doped carbon dots (N, S-CDs) and Eu3+ were dropped onto the filter paper to construct the ratio fluorescence test strips for the specific detection of TC. Under the excitation at 390 nm, the fluorescence emission of N, S-CDs at 530 nm decreases through inner filter effect (IEF) after addition of Eu3+. When the further addition of TC, the emission of N, S-CDs at 530 nm kept unchanged while the emission of Eu3+ at 616 nm was obviously enhanced for the antenna effect (AE) between Eu3+ and TC. The ratio changes of the two-fluorescence emission realized the quantitative detection of TC. In addition, the test strips with different concentrations of TC showed different fluorescence color from green to red under a 365 nm UV lamp. The miniature device was designed as a fluorescence photo reader with the merits of the powerful functions of smartphones and the portability of test strips. The smartphone camera takes a fluorescent color image of the test strips and the photos are recognized by a color recognizer on the smartphone to obtain RGB (red–greenblue) values which reflect the concentrations of the analytes. Therefore, we established a fast, sensitive and efficient POCT of TC. In particular, the proposed nanomaterial-based POCT platform will open a new route towards the development of ratio fluorescence probe for TC analysis for environment samples.

Stable Fluorescence of Eu3+ Complex Nanostructures Beneath a Protein Skin for Potential Biometric Recognition.

We designed and realized highly fluorescent nanostructures composed of Eu3+ complexes under a protein coating. The nanostructured material, confirmed by photo-induced force microscopy (PiFM), includes a bottom fluorescent layer and an upper protein layer. The bottom fluorescent layer includes Eu3+ that is coordinated by 1,10-phenanthroline (Phen) and oleic acid (O). The complete complexes (OEu3+Phen) formed higher-order structures with diameter 40–150 nm. Distinctive nanoscale striations reminiscent of fingerprints were observed with a high-resolution transmission electron microscope (HRTEM). Stable fluorescence was increased by the addition of Eu3+ coordinated by Phen and 2-thenoyltrifluoroacetone (TTA), and confirmed by fluorescence spectroscopy. A satisfactory result was the observation of red Eu3+ complex emission through a protein coating layer with a fluorescence microscope. Lanthanide nanostructures of these types might ultimately prove useful for biometric applications in the context of human and non-human tissues. The significant innovations of this work include: (1) the structural set-up of the fluorescence image embedded under protein “skin”; and (2) dual confirmations of nanotopography and unique nanofingerprints under PiFM and under TEM, respectively.

Preparation and Performance of Eu3+-Doped BaSnF4-Based Solid-State Electrolytes for Room-Temperature Fluoride-Ion Batteries

Fluoride-ion batteries are promising “next-generation” electrochemical energy storage devices, and thus, the room-temperature rechargeable fluoride-ion batteries (FIBs) have attracted tremendous attention due to their high theoretical volume energy density and high safety. However, a series of problems including high interface impedance and poor ionic conductivity at room temperature prevent further development and commercial application of FIBs. Herein, rare-earth element Eu3+-doped BaSnF4 solid solutions [Ba1–xEuxSnF4+x (0 ≤ x ≤ 0.06)] are designed and prepared to improve the performance of BaSnF4 solid electrolytes for room-temperature FIBs. It has been found that the as-prepared Ba0.98Eu0.02SnF4.02 solid-state electrolyte can achieve a better ionic conductivity of 3.8 × 10–4 S cm–1 at room temperature after a calcination process at 300 °C for 2 h, which is the improvement of an order of magnitude in comparison with the original samples. In addition, the FIBs based on Ba1–xEuxSnF4+x (0 ≤ x ≤ 0.04) solid-state electrolytes (Sn/Ba0.98Eu0.02SnF4.02/BiF3) show a discharge capacity of 106 mAh g–1 at 1st cycle and 72 mAh g–1 at 20th cycle. Moreover, the Sn/Ba1–xEuxSnF4+x/BiF3 (0 ≤ x ≤ 0.04) batteries also exhibit good cycling stability and rate performance. Therefore, the addition of Eu3+ can better improve the ionic conductivity of the original solid electrolyte material, which provides a new strategy for the preparation and modification of fluoride-ion electrolytes in FIBs chracterization chracterization.

Multicolor emission leading by energy transfer between Dy3+ and Eu3+ in wolframite InNbTiO6

Exploring new color-tunable phosphors is of significance for light-emitting applications. In this work, multicolor-emitting InNbTiO6:Dy3+,Eu3+ phosphors were formulated and synthesized using the classic solid-state reaction technique. Phase identification indicates the pure wolframite crystal structure of as-prepared samples. According to the Rietveld refinement, dopants have been confirmed to occupy the In3+ site in the InNbTiO6 matrix. The phosphors exhibit strong absorption around 385 and 394 nm, due to the dominated transitions of 4F9/2->6H13/2 in Dy3+ and 5D0->7F2 in Eu3+, respectively, well matching the emissions from the commercial UV LED chips. In single doped phosphors, activators Dy3+ and Eu3+ under the UV light excitation respectively present their unique emission lines. As for the codoped phosphors, the co-activation and sensitization between Dy3+ and Eu3+ have been elucidated under a 394 nm excitation. The addition of Eu3+ into InNbTiO6:0.06Dy phosphor leads to the emission tuning from grass-green to orange-red crossing the warm-white region. The energy transfer can be proved through analyzing the PLE and PL profiles of the co-activated phosphors and evaluating the decay process for Dy3+ ions. According to the Dexter's theory and Reisfield's approximation, the mechanism of coupling effect has been identified to be the electric d-d (dipole-dipole) interaction. When the sum of dopants concentration equals to 0.09, the energy transfer efficiency reaches the maximum value 40.5. Moreover, the thermal stability of a representative InNbTiO6:0.06Dy3+,0.015Eu3+ phosphor have been investigated, which presented and a emission intensity maintenance of 42% at 423 K relative to room temperature 298 K. Besides, the quantum yields of InNbTiO6:0.06Dy3+, 0.04Eu3+ within the luminescence range 603–620 nm are measured to be 33.4% under the ultraviolet radiation of 394 nm. These results demonstrate that these new type phosphors have promising applications in UV LED based white light-emitting devices.

Photoluminescence properties of ZnTiO3:Eu3+ phosphor with enhanced red emission by Al3+ charge compensation

This paper reports the charge compensation effects of Al3+ incorporated ZnTiO3:Eu3+ as a co-dopant ion. The structural and morphological characterization show that the addition of Eu3+ and Al3+ does not affect the phase formation and the surface morphology of the host. There was an improvement in the luminescence emission intensity of Eu3+ ions for an optimal concentration of 2 mol% under 395 nm excitation, after incorporating Al3+ charge compensator. The energy level diagram showing the charge compensation mechanism was proposed for the co-doped system.

Luminescence tuning of Tb/Eu Co-doped zinc aluminoborosilicate glasses for white LED applications

Tb3+/Eu2+,3+-doped zinc aluminoborosilicate glasses were prepared using a conventional high temperature melt-quenching method. Infrared spectra and physical properties of as-prepared glasses verified that the addition of Tb/Eu causes structural weakness in the glass. Tuning of blue, green, and red emission bands achieves white light for the zinc aluminoborosilicate glasses. The broad blue emission band is attributed to the 5d-4f transition of Eu2+ due to partial reduction of Eu3+ during calcination in ambient atmosphere. The reduction of Eu3+ is related to the formation of EuZn• and VZn'' defects and host alkalinity decreases with the addition of Eu3+. Emission spectra and decay curves confirm energy transfer from Tb3+ to Eu3+ in the zinc aluminoborosilicate glasses, and relative intensities of green and red luminescence can be tuned through concentrations changes of Tb3+ and Eu2+,3+. When the concentrations of Tb3+ and Eu2+,3+ are equal to 6% and 1.2%, respectively, a neutral white light emitting glass is obtained. Furthermore, the white-emitting glass shows very high thermal stability compared to a commercial Y3Al5O12:Ce3+ phosphor. Therefore, luminescence tuning of glasses through changing activator concentrations and energy transfer is expected to achieve high-powered white LEDs.

Luminescent properties of Eu3+-doped silica nanophosphors derived from rice husk

Rice husk nanosilica (RH-SiO2) doped with europium (RH-SiO2: Eu3+) was produced by the sol-gel method. X-ray Diffraction patterns show amorphous silica with increased crystallinity as the concentration of Eu increases. Phase transformation occurred with the addition of Eu3+ ion due to the presence of oxygen vacancy as well as strain in the lattice imposed by the larger size of the dopant ion in the lattice. The quartz structure emerged at a relative low concentration (1 mol%) and increased with Eu3+ content and at 3 mol% doping, the cristabolite phase emerged. No Eu3+ phase was observed. Scanning Electron Microscopy review agglomerates of nano-sized particles and Transmission Electron Microscopy show dispersed spherical nanoparticles measuring an average size of 35 nm. Fourier Transform Infra-red spectroscopy confirms the presence of SiO2. The surface area of the nanophosphor measured by Brunauer-Emmett-Teller is 189.64 m2/g. Photoluminescence (PL) analysis shows Eu3+ ion transitions leading to red emission. The asymmetry ratio and Judd-Ofelt intensity parameters indicate a low symmetry environment for the Eu3+ in the RH-SiO2 nanophosphors. The Ω2 values increase with increasing Eu3+ concentration, suggesting an increase in structural deformation or transformation of SiO2. The International Commission on Illumination (CIE) chromaticity coordinates values are close to the national television standard committee (NTSC) standards for red phosphors, which confirms the suitability of these red nanophosphors for display applications.

Tm3+-Dy3+-Eu3+ tri-doped transparent glass-ceramics containing NaY(MoO4)2 crystal phase: Preparation, energy transfer, warm white light emitting

Tm3+-Dy3+ co-doped and Tm3+-Dy3+-Eu3+ tri-doped glass-ceramics (dGCs) containing NaY(MoO4)2 crystal phase were prepared. The crystal phase of the GCs was determined to be NaY(MoO4)2 by XRD, and the optimal heat treatment condition of GCs was determined to be 670 °C/2.5 h by DSC, SEM, and transmittance curves. Under 362 nm light excitation, the chromaticity coordinates of the Tm3+-Dy3+ co-doped GCs were tuned from blue to white region by adjusting the Dy3+ concentration. The energy transfer (ET) mechanism from Tm3+ to Dy3+ was a dipole-dipole interaction, and the ET efficiency was as high as 56.3% when the concentration of Dy3+ was 1.1%. When the concentration of Dy3+ exceeds 1.1%, concentration quenching caused by interaction between nearest-neighbor ions can be observed. With the addition of Eu3+, the chromaticity coordinates shifted from cool white to warm white region. These GCs were expected to be used in white LEDs.

Warm white-light phosphor based on a single-phase of Ag+/Eu3+/Zn2+ loading SOD zeolites with application to white LEDs

Single-phase white-light phosphors are still much preferred materials for easily manufacturing white LEDs with excellent properties such as improved stability and color reproducibility. Herein, we report a new white emitting phosphor upon the incorporation of Ag+ into the Zn2+ containing SOD zeolites and achieve a series of warm white emitting phosphors by an addition of Eu3+. Under the ultraviolet excitation of 395 nm, the material of Ag10Eu displays the white light with CIE chromaticity coordinate of (0.33, 0.34), the quantum efficiency of 22%, appropriate CRI of 85 and CCT value of 5838 K. In addition, such material with the advantages including appropriate excitation wavelengths, good emission performance and high thermal stability is highly desirable for WLEDs. The as-fabricated warm WLEDs show the appropriate CIE chromaticity coordinates of (0.37, 0.35), with a lower CCT of 4041K, a higher Ra of 87, which match with the traditional incandescent light quality benchmarks. This new single-component warm white emitting phosphors point interesting applications for UV-LED chip excited white LEDs.

P.143 Relationship of alexithymia and aggression with internet addiction symptom severity among university students

In this study, a series of Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+ white-emitting phosphors were prepared using the sol-gel method, and Eu3+ were co-doped in Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+ for excellent luminescence properties such as low CCT. The effects of synthesis temperature and Dy3+/Eu3+ concentrations on the crystal structure and luminescence properties of Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+, Eu3+ phosphors were investigated. The X-ray diffraction results indicated that the Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+, Eu3+ samples had a standard CaTiO3 structure. Under the excitation of 390 nm, Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+ phosphors exhibited a white emission consisting of two emission peaks at 488 nm and 582 nm, which corresponded to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ions, respectively. With the addition of Eu3+, a red emission appeared and significantly improved via the energy transfer from Dy3+ to Eu3+ ions, and a lower CCT value was achieved. Overall, Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+, Eu3+ phosphors have potential applications in warm white light-emitting diodes as a single-component phosphor.

Synthesis and luminescence properties of Eu3+ codoped Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+ white-emitting phosphor through sol-gel method

In this study, a series of Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+ white-emitting phosphors were prepared using the sol-gel method, and Eu3+ were co-doped in Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+ for excellent luminescence properties such as low CCT. The effects of synthesis temperature and Dy3+/Eu3+ concentrations on the crystal structure and luminescence properties of Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+, Eu3+ phosphors were investigated. The X-ray diffraction results indicated that the Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+, Eu3+ samples had a standard CaTiO3 structure. Under the excitation of 390 nm, Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+ phosphors exhibited a white emission consisting of two emission peaks at 488 nm and 582 nm, which corresponded to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ions, respectively. With the addition of Eu3+, a red emission appeared and significantly improved via the energy transfer from Dy3+ to Eu3+ ions, and a lower CCT value was achieved. Overall, Ca0.7Y0.3Ti0.7Al0.3O3:Dy3+, Eu3+ phosphors have potential applications in warm white light-emitting diodes as a single-component phosphor.

Chemical alteration of 238Pu-loaded borosilicate glass under saturated leaching conditions

Abstract Highly radioactive 238Pu-doped and non-radioactive samples of borosilicate glass with chemical compositions and synthesis routine similar to SON68 glass were studied under static saturated leaching conditions in distilled water at 90 °C. Dramatic differences in behavior of the radioactive and model glasses were observed. On time scale of 4 months the radioactive glass is fully covered by mechanically unstable alteration layer, possibly consisting of aluminum hydroxides with small fraction of a separate secondary Pu bearing phase. The model glass remains virtually pristine. Addition of Eu3+ into the glass allowed examination of the glass radio- and photoluminescence and to assess changes or REE3+ impurity local environment during self-irradiation and leaching. Photoluminescence spectra suggest more ordered local environment of europium ions in the alteration “gel” than in the bulk glass. Peculiar behavior of the photoluminescence spectra excited at different laser power is observed for the alteration layer and is ascribed to optical bleaching of color centers.