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Glasses activated with europium show promising potential for use in applications relating to photonics, in particular solid-state laser generation. In the current work, Eu2O3 incorporated gemanium borate glasses were developed and explored their potentiality towards lasing active medium by probing physical, structural, optical and lasing properties in detail. The physical and structural features of each glass indicated the presence of non-bridging oxygens (NBOs) and an enhancement in network stability on account of the inclusion of europium ions into the GeO2 glass network. Optical energy band gaps, Ed, Eo, no, So, and λo values were obtained by absorption spectra and found to be increased with europium content. The sequence of Judd-Ofelt (JO) intensity parameters (Ω2, Ω4, and Ω6) exhibited the trend Ω2 > Ω4 > Ω6, and it confirmed the covalent nature of the as-developed glasses. 1 mol% Eu2O3 doped glasses exhibited the highest photoluminescence, quantum efficiency and fluorescence intensity ratio (R). The decay profiles showed single exponential nature for 5D0 state of Eu3+ ions and their lifetime values were calculated. The results amply demonstrated the viability of the manufactured glasses as a potential solid-state active laser medium, with the CIE diagram confirming the intense red color emission as seen from the PL spectra.

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Lithium-aluminum-borate glasses doped with single, double, or triple Tm3+, Tb3+, or Eu3+ ions, respectively, at several concentrations were prepared. Structural characterization was performed using optical absorption and luminescence spectroscopy. The transition for the rare earth ions under study was observed in optical absorption and some for-host glass at wavelengths less than 300 nm. The luminescence of Eu3+, Tb3+, and Tm3+ is presented as bright red, green, and blue emissions, respectively. White light was produced by adjusting the excitation wavelength and doping concentration of Tm2O3, Eu2O3, and Tb4O7. The sample doped with triple rare earth ions produced color emissions from Tb and Tm to Eu, which varied in hue based on the excitation wavelengths of 350, 360, and 370 nm. The glass samples under investigation may be promising for optoelectronic devices and security applications such as data encryption.

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The aim of the work is to prepare (51-x)B2O3 + 23CaF2 + 10Li2O + 10Na2O + 6BaO + xEu2O3 glasses with various concentration, analyse the optical/radiative properties and compare with other reported literature. In this work, the Judd-Ofelt analysis was employed to evaluate oscillator strength, JO parameters. Using JO parameters, radiative properties of the prepared samples were evaluated to understand their branching ratios, stimulated emission cross-section and radiative lifetime. The phonon coupling constant was evaluated using phonon sideband and compared with other literatures. The present glasses doped with Eu3+ ions find a potential use in orange red light emitting optical display device applications.

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Inhibiting energy migration between Eu3+ ions in a fixed host to get higher doping concentration is a permanent topic. Herein, a novel non-concentration quenching red-emitting K7SrY2-2xB15O30: xEu3+ (0.1 ≤ x ≤ 1.0) phosphor was synthesized via high-temperature sintering method. XRD measurement, Rietveld refinement results, and radius percentage deviation calculation demonstrated the phase purity and the occupation preference of Eu3+ ions. With continuously increasing doping Eu3+ ions, the absence of concentration quenching could be explained by long distance between two Eu3+ (7.012 Å) and the K7SrEu2B15O30 could exhibit striking photoluminescence performance with the highest emission wavelength centered at 617 nm. Meanwhile, under the radiation of 393 nm, the high internal quantum efficiency ( âˆ¼ 78.71 %), excellent color purity ( âˆ¼ 88.32 %) and robust thermal stability whose emission intensity at 140 °C could still reach âˆ¼ 97.31 % could guarantee its potential application. When coating BaMgAl10O17: Eu2+, (Ba, Sr)2SiO4: Eu2+, and K7SrEu2B15O30 on a near-ultraviolet chip, the bright white light with a low correlated color temperature of 4211 K and CIE color coordinates of (0.3675, 0.3556) could be obtained. Taking the analytic results above, the non-concentration quenching K7SrY2B15O30: Eu3+ compound has great potential to act as a candidate for red-emitting phosphors in solid-state lighting field.

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Eu3+ -doped-bismuth-based phosphate glasses with chemical equation (60 - x)P2 O5 -20Bi2 O3 -10Na2 CO3 -10SrF2 -xEu2 O3 (PBNSEu), (where x = 0, 0.1, 0.5, 1.0, 1.5 and 2 mol%) were fabricated using the melt-quenching method. Obtain X-ray diffraction (XRD), energy-dispersive X-ray (EDAX), and Fourier transform infrared (FTIR) spectra were used to characterize the structure of the prepared PBNSEu glass. The J-O (Judd-Ofelt) intensity parameters (Ω2 , Ω4 ) were estimated using photoluminescence emission spectra. When excited with a xenon lamp at λexc  = 394 nm, the most intense red-emission transition occurred at ~612 nm (5 D0 →7 F2 ). J-O intensity parameters were used to calculate radiative properties, whereas the radiative branching ratio (ßR ), radiative transition probability (AR ), radiative lifetime (τR ), and total radiative transition rate (Aτ ) were calculated for the transitions 5 D0 →7 FJ (where J = 0-4) and were obtained in the emission spectra for europium ion-doped in the current glass. Using the CIE1931 chromaticity coordinates axes, the colours of various concentrations of Eu3+ ion-doped PBNS glass were evaluated using the emission spectra. Temperature-dependent luminescence spectra were recorded for the optimized PBNSEu20 glass to calculate the activation energy. These results strongly suggested red components in w-LEDs and visible display laser applications.

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In this work, Ba2MgWO6: Eu3+ (BMW: Eu3+) ceramic materials with a double perovskite structure were sintered using the High-Pressure Low-Temperature sintering (HPLT) technique. As part of the research, the influence of pressure (CP), sintering temperature (CT), and sintering time (CTS) on the structure and luminescence of the doped BMW were determined. Structural analysis via XRD and SEM + EDS and spectroscopic analysis via emission and excitation spectra, decay time, and absorption spectra of the obtained ceramics were performed. Dense double perovskite ceramics were obtained with a cubic structure with optimal sintering parameters: T = 500 °C, p = 8 GPa, and t = 1 min. The increase in temperature caused an increased extinction of the luminescence due to the diffusion of carbon into the ceramics. The increase in pressure led to the formation of the amorphous phase, which increased the speed of non-radiative transitions and also led to the extinction of the luminescence. The increase in sintering time from 1 to 3 min enhanced the luminescence output, but when the ceramic was sintered for 5 min, the luminescence was quenched, most likely by increasing the rate of the non-radiative process, as evidenced by reduced decay time.

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Glass-ceramic is semi-novel material with many applications, but it is still problematic in obtaining fibers. This paper aims to develop a new glass-ceramic material that is a compromise between crystallization, thermal stability, and optical properties required for optical fiber technology. This compromise is made possible by an alternative method with a controlled crystallization process and a suitable choice of the chemical composition of the core material. In this way, the annealing process is eliminated, and the core material adopts a glass-ceramic character with high transparency directly in the drawing process. In the experiment, low phonon antimony-germanate-silicate glass (SGS) doped with Eu3+ ions and different concentrations of P2O5 were fabricated. The glass material crystallized during the cooling process under conditions similar to the drawing processes'. Thermal stability (DSC), X-ray photo analysis (XRD), and spectroscopic were measured. Eu3+ ions were used as spectral probes to determine the effect of P2O5 on the asymmetry ratio for the selected transitions (5D0 → 7F1 and 5D0 → 7F2). From the measurements, it was observed that the material produced exhibited amorphous or glass-ceramic properties, strongly dependent on the nucleator concentration. In addition, the conducted study confirmed that europium ions co-form the EuPO4 structure during the cooling process from 730 °C to room temperature. Moreover, the asymmetry ratio was changed from over 4 to under 1. The result obtained confirms that the developed material has properties typical of transparent glass-ceramic while maintaining high thermal stability, which will enable the fabrication of fibers with the glass-ceramic core.

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Eu3+ -activated Ba2 V2 O7 (Ba2-x V2 O7 :xEu3+ ) phosphor materials were synthesized using a hydrothermal method and different concentrations of europium (x = 0.01, 0.02, 0.03, 0.04, and 0.05%). Phase purity, structural, morphological, optical, and luminescence characteristics of the as-synthesized phosphors were studied using powder X-ray diffraction (XRD), high resolution scanning electron microscopy, UV-visible spectroscopy, and fluorescence spectrometry. The recorded XRD patterns of the as-synthesized phosphors were indexed and predicted to be a triclinic structure. A cube-like morphology was obtained for the as-prepared samples. Broad absorption in the UV region from 200 nm to 380 nm was observed and the good transparency in the visible region at 400-800 nm originated from the [VO4 ]3- group charge transfer (CT) transition. The broad emission peak centred at 499 nm was due to the CT band of the [VO4 ]3- group. Also, a sharp peak observed at 613 nm was due to the electric dipole transition of 5 D0 →7 F2 of Eu3+ ions that occupied the lattice sites without inversion symmetry for all concentrations. The colour qualities of the as-prepared samples were calculated using Commission International de l'Eclairage coordinates. The colour-rending index (CRI) value was 86 for the Ba1.97 V2 O7 :0.03Eu3+ phosphor. Furthermore, a WLED with a high CRI value of 95 was achieved by coupling the 3 W 356 nm near-UV light-emitting diode (LED) chip with the Ba2-x V2 O7 :xEu3+ phosphor. These results suggested that the as-prepared phosphor materials are potential candidates for fabrication of near-UV chip excited WLEDs.

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In this work, we performed a systematic analysis of the impact of selected chemical reagents used in sol-gel synthesis (i.e., N,N-dimethylformamide) and different catalyst agents (i.e., CH3COOH, HNO3) on the formation and luminescence of Eu3+-doped SiO2-LaF3 nano-glass-ceramics. Due to the characteristic nature of intra-configurational electronic transitions of Eu3+ ions within the 4f6 manifold (5D0 → 7FJ, J = 0-4), they are frequently used as a spectral probe. Thus, the changes in the photoluminescence profile of Eu3+ ions could identify the general tendency of rare earth materials to segregate inside low-phonon energy fluoride nanocrystals, which allows us to assess their application potential in optoelectronics. Fabricated sol-gel materials, from sols to gels and xerogels to nano-glass-ceramics, were examined using several experimental techniques: X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared spectroscopy (IR), and luminescence measurements. It was found that the distribution of Eu3+ ions between the amorphous silicate sol-gel host and LaF3 nanocrystals is strictly dependent on the initial composition of the obtained sols, and the lack of N,N-dimethylformamide significantly promotes the segregation of Eu3+ ions inside LaF3 nanocrystals. As a result, we detected long-lived luminescence from the 5D0 excited state equal to 6.21 ms, which predisposes the obtained glass-ceramic material for use as an optical element in reddish-orange emitting devices.

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One major challenge for application of hydroxyapatite nanoparticles (nHAP) in nanomedicine is the quantitative detection method. Herein, we exploited one quantitative detection method for nHAP based on the Eu(3+) fluorescent labeling via a simple chemical coprecipitation method. The trace amount of nHAP in cells and tissues can be quantitatively detected on the basis of the fluorescent quantitative determination of Eu(3+) ions in nHAP crystal lattice. The lowest concentration of Eu(3+) ions that can be quantitatively detected is 0.5 nM using DELFIA enhancement solution. This methodology can be broadly applicable for studying the tissue distribution and metabolization of nHAP in vivo.

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This paper reports on the effect of concentration of Eu(3+) ions in K2O-Nb2O5-SiO2-Eu2O3 (KNbSiEu) glasses prepared by the melt quenching technique. By using the Judd-Ofelt (JO) theory, the intensity parameters Ωλ (λ=2, 4, 6) have been determined from the absorption and emission spectra of Eu(3+) ions under different constraints. The radiative properties of some of the excited states of Eu(3+) ions have been calculated. The decay curves of (5)D0 level exhibited single exponential for all the Eu(3+) ions concentrations. From these results, it is suggested that the strong red emission at 616 nm corresponding to the (5)D0→(7)F2 transition could be used for the development of optical display devices.

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Pure cubic phase ultra-small α-NaYF4:4 % Eu3+ colloidal nanoparticles were synthesized by thermal decomposition reaction using three various capping ligands, i.e., oleic acid, trioctylphosphine oxide, and hexadecylamine. To expose as many Eu3+ ions as possible to interactions with the surface-bounded ligands, the nanoparticles were fabricated to have the diameters below 10 nm. The geometrical structure and properties of surface ligands needed for qualitative estimation of their influence on spectroscopic features of the investigated Eu3+ doped nanoparticles were obtained from DFT quantum-chemical calculations. Significant changes of luminescence spectra shapes and luminescence lifetime values were observed upon changes in the local chemical environment. We show that the ratio R = 5D0 â†’ 7F1/5D0 â†’ 7F2 of the intensities of the forced electric dipole (J = 2) and magnetic dipole (J = 1) transitions in the synthesized Eu3+ doped nanoparticles is highly sensitive to the type of ligand present on the nanoparticle surface. Similarly, 5D0 luminescence lifetimes are found to be sensitive to the refractive index, and also to the dielectric constant of ligands used during the synthesis to coat nanoparticles surface. We argue that the photophysical and electro-optical properties of colloidal Eu3+ doped inorganic nanoparticles show hyper-sensitive response to the chemical surroundings in the close vicinity of the nanoparticle itself. The behavior of both steady-state luminescence and its kinetics demonstrates the potential suitability of the studied nanoparticles for constructing self-referencing optical nano-sensors.