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A correction to the article "Luminescent characteristics of layered yttrium oxide nano-phosphors doped with europium," by L. Mariscal-Bercerra and colleagues published in the April 17, 2019 online issue is presented.

White and yellow light were obtained from ZrO2:Dy3+ nanocrystals which were synthesized by the solvent evaporation technique. The crystalline structure was studied by X-ray diffraction, resulting in a tetragonal and monoclinic mixture phases of ZrO2 when the powders were annealed at 600 °C and the zirconia monoclinic phase when they were thermal treated at 1000 °C. By means of atomic force microscopy images was observed that the synthesized powders are constituted by nanocrystals about 20 nm for the samples annealed at 600 °C, whereas samples annealed at 1000 °C were constituted by crystals about 135 nm, these features were confirmed by TEM images. Luminescence properties were analyzed by means of photo and cathodoluminescence; exhibiting emissions in the white light region of the chromatic diagram. In the case of photoluminescence white-warm color (x = 0.35, y = 0.37) was observed, which is close to pure white color; while for cathodoluminescence the emission was yellowish with coordinates (x = 0.39, y = 0.39) in the chromatic diagram. PL decay time measurements were carried out; a lifetime of 0.66 ms was found. In addition, the PL quantum efficiency was measured; the obtained value was as high as 45%. [ABSTRACT FROM AUTHOR]

In this paper, the photo and cathodoluminescent properties of HfO2 films optically activated with different atomic concentrations of Tb3+ and Eu3+ ions, deposited by the Pyrosol technique, are reported. These films were deposited at temperatures from 400 to 600 °C, using chlorides as raw materials. The surface morphologies of all deposited films were rough and dense. X-ray diffraction analysis showed that the films deposited at 600 °C were polycrystalline exhibiting the HfO2 monoclinic phase. The tuning by the means of the excitation wavelength generates photoluminescence spectra, for co-doped films, in several emissions from blue to yellow (including white light) due to the characteristic electronic transitions of Tb3+ (green), Eu3+(red) ions and the violet-blue emission associated to the host lattice (HfO2). According to the chromaticity diagram, the best white light is reached for the sample S2 excited with 382 nm ( x = 0.3343, y = 0.3406). The cathodoluminescence emission spectra for co-doped films showed emissions from green to red (including yellow, orange and other intermediate emissions). The averaged quantum efficiency values of the sample labeled as S2 resulted between 47 and 78% depending on the excitation wavelength. In addition, XPS, TEM, SEM and decay times were performed to characterize these films. [ABSTRACT FROM AUTHOR]

Zinc phosphate glasses codoped at various compositions of Mn2+ and Eu3+ were successfully prepared. All samples were highly transparent. All samples were characterized with absorption, excitation, emission and mean life time measurements. The Mn2+ ion presents double green and red emissions due to a simultaneous four and six folded coordination. An energy transfer is shown to happen by exciting the 6A 1 (S) → 4E(D) transition of the Mn2+ ion to the 7F 0 →5D 1 and 7F 0 →5D 0 levels of Eu3+ that increase the emission efficiency of the later and this is proved in the Mn2+ reduced and non-exponential decay. An energy diagram is presented to show the mechanism of this energy transfer. • Mn2+ can transfer his energy to Eu3+. • Mn2+ presents dual green-red emissions in zinc phosphate glass. • Matrix fourfold coordination favors the energy transfer efficiency. • An efficient energy transfer could be possible by exchange interactions. [ABSTRACT FROM AUTHOR]

ZrO[sub 2]:Mn, Cl luminescent powders have been synthesized at temperatures ranging from 250 to 500 °C. X-ray diffraction measurements indicate changes in the crystallinity of the material as a function of the processing temperature. The photoluminescence spectra show bands associated with transitions from the [sup 4]T[sub 1] level to the [sup 6]A[sub 1] levels of the Mn[sup 2+] ions. An impurity concentration quenching is observed with the Mn contents. In addition, the presence of Cl in the synthesized material has been found to have an important role on the photoluminescence intensity emission. Preliminary results on cathodoluminescent emission are also reported. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Hafnia is a novel material for optoelectronic applications, fabrication methods are focused to obtain hafnium oxide nanomaterials included thin films and nanoparticles. HfO 2 nanoparticles synthesized and studied in this work are crystalline without subsequent heat treatment and were processed by hydrothermal method at 200 °C during 1.3, 2 and 4 h. SEM and TEM analysis revealed the presence of spherical and oval nanoparticles, with range size from 60 to 70 nm and 90–110 nm for spherical and oval nanoparticles, respectively. Raman spectroscopy and X-ray diffraction confirmed that nanoparticles exhibit a stable monoclinic phase. Crystal growth is typical with the presence of the characteristic monoclinic plane (1 ‾ 11) but for reaction times of 2 and 4 h and pH over 12 it turns in the plane (220) which is perpendicular to typical growth. Cathodoluminescence measurements revealed strong blue emission intensity showing a broadband in all visible range and a maximum peak at 460 nm. The presences of V O3 and V O4 in HfO 2 crystalline structure are responsible for this inherent CL emission corroborated by photoluminescence studies. [ABSTRACT FROM AUTHOR]

Zirconium oxide powders doped with terbium, synthesized by hydrothermal route from a highly basic solution, were used to determine the role of the basic agent (NaOH, KOH or LiOH) utilized to carry out the hydrothermal synthesis on their morphology, crystalline structure, photoluminescent or cathodoluminescent properties. The synthesized powders showed an amorphous/polycrystalline nature with tetragonal phase crystallites of ZrO 2 . The ratio of material undergoing the transformation from amorphous to crystalline is highly influenced by the kind of stabilizing agent used. As for the photoluminescence (PL) and cathodoluminescence (CL) results, the samples present the characteristic emission lines corresponding to inter electronic energy levels transitions for Tb 3+ ions ( 5 D 4 → 7 F J ( J  = 3–6) transitions). The photoluminescence excitation spectra present a broad peak centered at 250 nm for all samples, however the sample prepared with LiOH as basic agent presented an additional peak at 290 nm which much likely is related to localized centers introduced by Li + ions into the ZrO 2 crystallites. [ABSTRACT FROM AUTHOR]

Here, the up-and down-conversion emissions enhancement in Er3+/Yb3+/Li+ co-doped Y 4 O(OH) 9 NO 3 and Y 2 O 3 nanoparticles was studied in function of the calcination temperature. Tri-doped Y 4 O(OH) 9 NO 3 nanophosphors were synthesized by the hydrothermal method and then calcined to yield Y 2 O 3 nanocrystalline structures. The phase evolution from Y 4 O(OH) 9 NO 3 to Y 2 O 3 was investigated by XRD analysis, and the quantification of Li + species in the nanoparticles lattice was done by FTIR. Both techniques allow explaining the photoluminescence enhancement in terms of the calcination temperature required to achieve optimum lithium incorporation. SEM analysis was used to monitor changes in the morphology with the thermal treatment temperature. The resulting photoluminescence emission spectra of the Er3+/Yb3+ doped Y 4 O(OH) 9 NO 3 and Y 2 O 3 nanocrystals were composed of emission bands associated with the Er3+2H 11/2 , 4S 3/2 → 4I 15/2 (green), 4F 9/2 → 4I 15/2 (red), and 4I 13/2 → 4I 15/2 (infrared) intraelectronic transitions, and its relative contribution was found to be sensitive to the calcination temperature. Thus, tunable color emission from yellowish-orange to yellow-green light with a color temperature of 2581–4433 K upon 980 nm excitation, respectively, was observed. [ABSTRACT FROM AUTHOR]

The structural and optical characteristics of Nd3+-Yb3+ doped CaF 2 phosphors with and without the addition of Li+ ions are described in this work. The phosphors synthetized by hydrothermal and co-precipitation methods showed near-infrared (NIR) luminescence emission associated with inter-electronic transition of the Yb3+ ion in the range of 900–1050 nm via energy transfer process from Nd3+ ions under visible light excitation. The addition of Li+ to these phosphors resulted in an improvement of the NIR luminescence intensity by a factor up to 5. The effect of the incorporation of Li+ ions into the CaF 2 crystallite structure, the reduction of luminescence quenching states, as well as the energy transfer mechanism involved are discussed. [ABSTRACT FROM AUTHOR]

The deposition of high-quality metal-organic framework (MOF) films is still challenging but offers potential applications in gas storage, catalysis, sensing, lighting, and solar energy harvesting. This work reports a single-step, simple, fast and inexpensive method for in situ synthesis and deposition of crystalline luminescent Tb 2 (BDC) 3 (Tb = terbium) (BDC = 1,4-benzenedicarboxylate) MOF films using ultrasonic spray deposition on top of several types of substrates including glass slides, metal oxides films, filter paper, and polyimide sheets. The glass supported films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), profilometry, infrared (IR), and luminescence spectroscopies. As expected, the emission spectra present high-intensity characteristic emission bands of the sensitized terbium luminescence for all the films. Nevertheless, the temperature of the substrate, during deposition, plays a crucial role in the final structural and morphological characteristics of the MOFs, which in turn, dramatically modifies the excitation features. The MOF-film synthesis/deposition method here reported can be extended to other MOF structures and substrates. Image 1 [ABSTRACT FROM AUTHOR]

SrAl 2 O 4 , SrAl 2 O 4 :Tb 3+ and SrAl 2 O 4 :Eu 3+ :Eu 2+ films were synthesized by means of the ultrasonic spray pyrolysis technique. These samples, characterized by X-Ray Diffraction, showed the monoclinic phase of the strontium aluminate. Images of the surface morphology of these films were obtained by SEM and the chemical composition was measured by EDS and XPS. The photoluminescence and cathodoluminescence characteristics of the films were studied as a function of the terbium and europium concentrations. The optimal PL emission intensities were reached at 8 at% for terbium doped films and 6 at% for europium doped samples. The CL emission spectra for europium doped films showed the typical bands of Eu 3+ ions and also a broadband centered at 525 nm which is attributed to Eu 2+ ions. XPS measurements confirm the presence of Eu 3+ and Eu 2+ in europium doped SrAl 2 O 4 films, without having been subjected to a reducing atmosphere. Chromatic diagrams exhibited green color for SrAl 2 O 4 :Tb 3+ films, red and yellow colors for SrAl 2 O 4 :Eu 3+ :Eu 2+ films. The PL decay curves were also obtained: the averaged decay time was 2.7 ms for SrAl 2 O 4 :Tb 3+ films and 1.9 ms for SrAl 2 O 4 :Eu 3+ films. Similar results were obtained by the stretched exponential model. [ABSTRACT FROM AUTHOR]

Visible and near-infrared upconversion luminescence from Y 2 O 3 co-doped with Er 3+ , Yb 3+ and Li + phosphors under continuous excitation with 1532 nm light are reported. The upconversion emissions at 530–570 nm (green light emission region), and 640–700 nm (red light emission region) correspond to transitions from the 4 S 3/2 to 4 I 15/2 and ( 4 F 9/2 + 4 I 9/2 ) to 4 I 15/2 electronic energy levels of the Er 3+ ions respectively. The near infrared emissions at 900–1100 nm region correspond to inter-electronic energy levels transitions from 4 I 11/2 to 4 I 15/2 of Er 3+ ions and 2 F 5/2 to 2 F 7/2 of Yb 3+ ions. The role of Li + and Yb 3+ ions were to enhance the luminescence emission of these phosphors around 9, 7 and 11 times, respectively in comparison with only-erbium doped samples. The luminescence spectra of these phosphors remain unchanged when dispersed in deionized water, cholesterol and in bovine serum. [ABSTRACT FROM AUTHOR]

Polycrystalline HfO 2 and HfO 2 :Al3+ coatings were synthesized by the spray pyrolysis technique. The photoluminescence and cathodoluminescence characteristics of the coatings were studied as a function of the synthesis parameters; the temperature of deposition and the dopant content (Al3+ions). A blue, bluish-white and warm white emission was found in the coatings, depending on the substrate temperature, doping concentration and excitation wavelength. The photoluminescence emission was enhanced with the increment of the deposition temperature and a quenching effect was also observed with the dopant concentration. The CIE chromatic coordinates: (0.3067, 0.3462), (0.3091, 0.3502) and (0.3073, 0.3498), were close to the ideal white emission. CCT values for some of the coatings make them potentially useful in white lighting systems. The structural characterization was also carried out by X-ray diffraction, SEM, HRTEM and EDS elemental composition. • Polycrystalline HfO 2 and HfO 2 :Al3+ coatings were synthesized by the spray pyrolysis technique. • A blue, bluish-white, and warm white emission was found in the coatings, depending on the substrate temperature, doping concentration, and excitation wavelength. • The photoluminescence emission was enhanced with the increment of the deposition temperature. • The photoluminescence emission a quenching effect was also observed with the dopant concentration. [ABSTRACT FROM AUTHOR]

The luminescent and structural properties of Zn 3 (PO 2 ) 4 :Y 2 O 3 /Eu 3 + glasses synthesized by melting method at a temperature of 1000 °C are described; the doping was performed with Y 2 O 3 :Eu 3 + powders which were synthesized by the simple evaporation method at 1100 °C with a concentration of 4.3% Eu 3 + as determined by EDS. These glasses have a transparency above 90% within the range 400–700 nm, they present an intense luminescence that is associated with characteristic intra-electronic energy levels of Eu 3 + ion transitions. The dominant emission peak is at 613 nm, corresponding to the 5 D 0 to 7 F 2 transition and the dominant excitation peak is at λ exc = 395 nm. The XRD results indicate that they remain amorphous even when they are doped with different masses of the powders Y 2 O 3 :Eu 3 + ; the CIE diagram shows that the luminescence of these glasses Zn 3 (PO 2 ) 4 :Y 2 O 3 /Eu 3 + and Y 2 O 3 :Eu 3 + powders lies in the red region. [ABSTRACT FROM AUTHOR]

In this work, the optical and morphological properties of HfO 2 : Tb 3+ , Eu 3+ thin films deposited by the Ultrasonic Spray Pyrolysis technique from metal-organic precursors are reported. The films showed optical average transmittance values in the visible region greater than 90%, with surface roughness lower than 3.9 nm. The films deposited at 500 °C showed the lowest average roughness with a value of 0.9 nm, and the smallest thickness was 35 nm for sample deposited at 500 °C during 45 s. XRD measurements indicate a hafnium oxide monoclinic phase for films deposited at substrate temperatures higher than 500 °C. All films deposited showed the luminescent emissions (PL and CL) characteristic of Tb 3+ and Eu 3+ ions. A luminescence concentration quenching was observed for both Tb 3+ and Eu 3+ ions. The HfO 2 : Tb 3+ (5 at%) and HfO 2 : Eu 3+ (10 at%) films deposited at 500 °C, showed the highest PL and CL emission intensity. Quantum Efficiency measurements (up to about 35%) were measured for these films which have a refractive index between 1.97 and 2.04 and band gap of 5.4 eV. The chemical composition of the films as measured by XPS is also reported. In addition, decay time measurements were performed on some HfO 2 : Tb 3+ , Eu 3+ samples. [ABSTRACT FROM AUTHOR]

Up-conversion (UC) luminescence in hafnia powder (HfO 2 ) doped with Er 3+ , Yb 3+ and Li + was studied under continuous wave excitation at 980 nm. Powder samples were prepared by the simple evaporation technique and incorporated into polyester films (by spin coating technique). They were characterized using x-ray diffraction, electron microscopy, IR spectroscopy and UV–vis. A study of UC emission from Er 3+ ions was performed including the analysis of the spectral and temporal behavior. The effect of Yb 3+ co-doping concentration was found to change the intensity ratio of the Er 3+ green and red characteristic emissions which allows for a color tuning of the UC emission. The mechanisms contributing to the UC luminescence are discussed as well. [ABSTRACT FROM AUTHOR]

The incorporation of Bi 3+ and Li + as co-dopants in Eu 3+ -doped aluminum oxide films deposited by the ultrasonic spray pyrolysis technique and its effect on the luminescence characteristics of this material are described. Both Bi 3+ and Li + do not introduce new luminescence features but affect the luminescence intensity of the Eu 3+ related emission spectra as well as the excitation spectra. The introduction of Bi 3+ generates localized states in the aluminum oxide host that result in a quenching of the luminescence intensity, while Li + and Bi 3+ co-doping increase the luminescence intensity of these films. [ABSTRACT FROM AUTHOR]

Spectroscopic parameters of a novel Nd 3+ -activated barium borate (BBONd) glass have been analyzed for broadband laser amplification. The Judd–Ofelt (JO) intensity parameters were determined through a systematic analysis of the absorption spectrum of Nd 3+ ions in the BBONd glass. High values of the JO intensity parameters reveal a great centro-symmetrical loss of the Nd 3+ sites and high covalency degree of the ligand field. The very high Ω 6 intensity parameter value makes evident both a great structural distortion of the Nd 3+ sites and a strong electron–phonon coupling between Nd 3+ and free OH − ions, which is consistent with the phonon energy maximum (3442.1 cm −1 ) recorded by Raman spectroscopy. This strong electron–phonon coupling favors high effective bandwidth and gain bandwidth values of the laser emission ( 4 F 3/2 → 4 I 11/2 ) of Nd 3+ ions. The electric-dipole oscillator strengths of all the Nd 3+ absorption transitions, and in particular that of the hypersensitive transition ( 4 I 9/2 → 4 G 5/2 ), are enhanced by this great structural distortion of the host. Broadband laser amplification of the 4 F 3/2 → 4 I 11/2 emission (1062 nm) of Nd 3+ ions in the BBONd glass pumped at 805 nm ( 4 I 9/2 → 4 F 5/2 + 2 H 9/2 ) is evaluated through the main fluorescent parameters in competition with non-radiative processes. In general, the BBONd glass exhibits spectroscopic parameters comparable with those reported in the literature for broadband laser amplification into the IR region. [ABSTRACT FROM AUTHOR]

The luminescent properties of Al 2 O 3 :Tb 3+ powders embedded in polyethylene terephthalate (PET) films have been studied. Luminescent Al 2 O 3 :Tb 3+ polycrystalline powders were synthesized by a simple evaporation method. The powder embedded films were obtained by the spray pyrolysis technique. The photoluminescence and cathodoluminescence emission spectra from these samples show, in both cases, luminescence peaks associated with transitions within the electronic energy levels of Tb 3+ ions. The dominant peak is at 544 nm corresponding to the 5 D 4 to 7 F 5 transition. In the case of the powder embedded films, the CIE coordinates depend on the excitation wavelength because there is a blue emission contribution from the PET host. UV–Vis% transmission measurements on these films show that they are transparent (∼80% and 95% T). [ABSTRACT FROM AUTHOR]

ZrO 2 , ZrO 2 :Dy 3+ and ZrO 2 :Dy 3+ , Gd 3+ films were synthesized using the Pyrosol technique. These films have a ZrO 2 -metastable tetragonal crystalline structure, which is better defined as the deposition temperature increases. Photoluminescence and cathodoluminescence properties of these films were studied as a function of deposition parameters such as substrate temperature and Dy 3+ and Gd 3+ relative concentrations. All luminescent emission spectra showed the typical electronic transitions 4f → 4f of the Dy 3+ ions at 480, 574 and 655 nm. The luminescent intensity is observed to increase with the Dy 3+ ion concentration up to 7 at.% in the spraying solution (1.8 at.% inside films), higher concentration result in an inhibition of the luminescence. Incorporation of Gd 3+ ions in ZrO 2 :Dy 3+ films produced a marked increase in the luminescent emission intensity (approximately 15 times). The elemental composition and surface morphology of these films are also reported. [ABSTRACT FROM AUTHOR]

In this work Sm 3+ (0–2.0 at%) and Bi 3+ (0–2.0 at%) doped Y 2 O 3 luminescent powders were prepared by a sol–gel method from yttrium acetylacetonate, samarium and bismuth nitrates as metal sources. The as prepared powders (chemical composition is close to stoichiometric Y 2 O 3 ) present the cubic structure from 700 °C, and at 900 °C are characterized by the presence of rounded particles with heterogeneous size of 42.9 nm. Luminescent effect of ions of Sm 3+ and Bi 3+ into Y 2 O 3 host as was studied on heat treated powders from 800 to 1100 °C. The combination of the red luminescence from the Sm 3+ ions and the bluish from Bi 3+ , makes the synthesized phosphors candidates to be used in fabrication of phosphor-converted light-emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

ZrO 2 :Dy 3+ and ZrO 2 :Dy 3+ + x Li + films were synthesized by an ultrasonic spray pyrolysis process. X-Ray Diffraction studies, as a function of the deposition temperature, indicate a meta-stable tetragonal crystal structure of the zirconia, as the substrate temperature was increased. Photoluminescence and cathodoluminescence characteristics of the films were studied as a function of deposition parameters such as the substrate temperature and the dysprosium and lithium concentrations. For an excitation wavelength of 286 nm, all the luminescent emission spectra show peaks located at 485, 584, 670 and 760 nm, which are the characteristic 4f→4f intra-transitions of Dy 3+ ions and they correspond to electronic transitions 4 F 9/2 → 6 H 15/2 , 4 F 9/2 → 6 H 13/2 , 4 F 9/2 → 6 H 11/2 and 4 F 9/2 → 6 H 9/2 , respectively. The lithium incorporation in the ZrO 2 :Dy 3+ films produced an improvement in the intensity of the luminescent emission. As the deposition temperature is increased, a rise of the luminescence intensity is observed. Also, it is noted, a quenching of the luminescence, with increasing doping concentration. The elemental chemical composition of the layers, as determined by energy dispersive spectroscopy, is reported as well. In addition, the surface morphology characteristics of the films, as a function of the deposition temperature, are presented. [ABSTRACT FROM AUTHOR]

In this work, the photoluminescent (PL), cathodoluminescent (CL) and thermoluminescent (TL) properties of hafnium oxide films doped with trivalent dysprosium ions are reported. The films were deposited on glass substrates at temperatures ranging from 300 to 600 °C, using chlorides as precursor reagents. The surface morphology of films showed a veins shaped microstructure at low deposition temperatures, while at higher temperatures the formation of spherical particles was observed on the surface. X-ray diffraction showed the presence of HfO 2 monoclinic phase in the films deposited at temperatures greater than 400 °C. The PL and CL spectra of the doped films showed the highest emission band centered at 575 nm corresponding to the transitions 4 F 9/2 → 6 H 13/2 , which is a characteristic transition of Dy 3+ ion. The greatest emission intensities were observed in samples doped with 1 atomic percent (at%) of DyCl 3 in the precursor solution. Regarding the TL behavior, the glow curve of HfO 2 :Dy +3 films exhibited spectrum with one broad band centered at about 150 °C. The highest intensity TL response was observed on the films deposited at 500 °C. [ABSTRACT FROM AUTHOR]

Abstract: The luminescent characteristics of Dy3+-doped Y2O3 nanopowders synthesized using the polyol method are reported. The Y2O3 nanoparticles presented a cubic phase crystalline structure of Y2O3 after an annealing treatment in oxygen ambient at temperatures above 600°C. The averaged crystallite size determined from the X-ray diffraction peaks width was in the 20–32nm range depending on the annealing temperature. Scanning and transmission electron microscopy studies indicate the formation of nanoparticle aggregates up to 175nm in diameter. Photoluminescence and cathodoluminescence measurements show a predominant emission at 573nm, which is attributed to the 4F9/2→6H13/2 of the Dy3+ ion. The luminescence emission dependence with the dopant concentration and post-annealing temperatures is discussed. [Copyright &y& Elsevier]

Abstract: Rutherford backscattering (RBS) with 4He energies from 2 to 6MeV has been used to study the properties of thin amorphous photoluminescent Al2O3:Ce,Mn films grown by spray pyrolysis on Corning 7059 glass substrates. The source solutions were AlCl3, CeCl3 and MnCl2 dissolved in deionized water. Different molar concentrations (Ce 10%; Mn 1%, 3%, 5%, 7% and 10%) were investigated under the same deposition conditions at a substrate temperature of 300°C. The RBS spectra show a homogeneous depth profile of both Ce and Mn within the films, and the measured quantities are consistent with the original solution concentrations. An important amount of Cl, which plays a significant role in luminescent properties, was detected, in both the doped and undoped samples. [Copyright &y& Elsevier]

The Continuous Wavelength Optically Stimulated Luminescence (CW-OSL) and Linear Modulation Optically Stimulated Luminescence (LM-OSL) of ZrO2 after irradiation with beta particles were studied. A typical OSL decay of light intensity showed a dependence on illumination time. The LM-OSL curve showed a maximum approximately at 41 s of illumination time. The LM-OSL curve of ZrO2 showed an initial peak followed by a long tail one. The OSL signal showed more than one component. Plotted data as a function of absorbed dose showed linear behavior from 10 to 200 Gy from 90Sr/90Y beta source.The present work summarizes the experimental results obtained for the OSL characteristics of ZrO2 after beta irradiation in order to use it as a beta particles detector. A comparison between CW-OSL and LM–OSL characteristics are also presented. [Copyright &y& Elsevier]

The 10BaO–20ZnO–20LiF-(50- x)B 2 O 3 - x Er 2 O 3 (x = 0, 0.1, 0.5, 0.7, and 1.0 mol %) glass system was studied for green emission device, NIR laser, and optical amplifier applications. The impact of Er3+ doping was assessed through structural, optical, and thermal properties. The Er3+ ions behaved as network modifiers and decreased the network rigidity by the transformation of [BO 4 ] → [BO 3 ] and Non-Bridging Oxygens. This was consistent with the decrease in the glass transition temperature. Ten absorption peaks of Er3+ ion equivalent to transitions from 4I 15/2 to various excited levels were quantified through their oscillator strengths. Through broadband impedance spectroscopy, the insulating property of the glass system was authenticated by the persistence of dc-conductivity in the order of 10−10 Scm−1 up to 523 K. With 378 nm excitation, a violet emission (2H 9/2 → 4I 15/2) and two intense green emissions (2H 11/2 → 4I 15/2 , 4S 3/2 → 4I 15/2) were noticed. The NIR emission (4I 13/2 → 4I 15/2) was observed at 1531 nm with 378 and 980 nm excitations and the corresponding decay curves were recorded. The Inokuti-Hirayama model indicated the increase in the energy transfer and reduction in critical distance amid the Er3+ ions with doping leading to energy migration through cross-relaxations and lifetime quenching. The laser parameters were determined from Fuchtbauer-Ladenburg theory. The color coordinates of the samples were lying in the green region, with purity >89% and CCT >6000 K. The gain coefficient from McCumber theory was positive for a population inversion >50%, with a wide gain between 1460 and 1565 nm, extending the application of the glass system as an optical amplifier in the S + C communication window. [Display omitted] • Spectroscopic study of BaO–ZnO–LiF–B 2 O 3 –Er 2 O 3 glass system. • Good thermal stability for optical fiber-drawing. • CIE coordinates in green region, color purity >89%, and CCT >6000 K. • NIR emission (4I 13/2 → 4I 15/2) at 1531 nm, decay time 0.57–0.37 ms with Er 2 O 3 doping. • Wide gain in the S + C communication window for optical amplifier application. [ABSTRACT FROM AUTHOR]

This contribution exhibits the luminescence properties of BaHfO 3 : Tb3+ perovskite ceramics. The main objective is to know the effect on the luminescent properties of the trivalent Terbium ion (Tb3+), when it is introduced into a crystalline structure of high symmetry such as perovskite, where it can occupy any of two sites available in the lattice. The synthesis of these nanocrystal powders was conducted by hydrothermal route. X-ray diffraction pattern showed crystallized cubic perovskite type structure with space group Pm -3m. Luminescence spectra showed emission peaks which are associated to the 5D 4 →7F J (J = 2, 3, 4, 5, 6) typical transitions of trivalent terbium ion. Photoluminescence features were obtained as a function of Tb3+ doping concentration, being the sample doped with Tb3+ (5 at.%) the one presented the highest intensity peak emission. Also, some characteristics of the decay time, surface morphology, crystallite size and chemical composition of the studied powders, are shown. • Trivalent rare earth ions can present intense emissions in highly symmetrical cristal structures. • The hydrothermal technique allows obtaining nanostructured crystalline materials in short times. • The BaHfO3:Tb compound, has the highest luminescent emission with Tb (5% at.). [ABSTRACT FROM AUTHOR]

In this paper, luminescent properties of Europium trivalent ion in the matrix with unbalanced charge of barium hafnate under UV radiation, with special emphasis on the 5D 0 → 7F 0 transition are reported. The synthesis was conducted by the hydrothermal route at 200 °C with a reaction time of 90 min using chlorides as raw materials. In order to determinate the luminescent quenching concentration, the samples were doped with different amounts of Europium trivalent ions being the sample doped with 1 and 3% at of Eu3+ which shows the highest luminescent emission. X-ray diffraction analysis showed that the material crystallize in the cubic perovskite structure with space group Pm-3m. The Energy Dispersive Spectroscopy (EDS) shows there are not elements other those that Ba, Hf, O and Eu in the synthesized material. Photoluminescent emission spectra show peaks of emission associated with the 5D 0 → 7F J (J = 0,1,2,3,4) transitions, characteristics of europium ion. The 5D 0 → 7F 0 transition centered at 580 nm showed an unusual great intensity when it was excited with the wavelength associated with the charge transfer band (272 nm). Finally the decay time was measured in the 5D 0 → 7F J (J = 0,1,2,3,4) transitions using the sample doped with Eu3+ (3% at). • Powders of Eu doped BaHfO 3 were synthesized. • Effect of Eu dopant concentration was studied. • UV radiation effect in BaHfO 3 :Eu was discussed. • Decay time of 5D 0.→ 7F 0 transition was measured [ABSTRACT FROM AUTHOR]