Dy2O3 Concentration Research Articles

Spectroscopic, calorimetric, and radiation shielding analysis of lead-free transparent dysprosium-doped phosphate glasses

Eco-friendly phosphate glasses with 50P2O5-(50 – x)BaO-xDy2O3 (x = 0, 0.5, 1.0, 2.0, 3.0, 4.0 mol %) compositions were prepared and studied focusing on their potential for radiation attenuation and shielding applications. The glasses were synthesized by melting and subsequently characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, densitometry, refractive index, optical absorption, and differential scanning calorimetry (DSC). XRD confirmed the amorphous nature of the glasses, while FT-IR spectra indicated that the glass structure was preserved upon Dy2O3 inclusion. It was observed that both the density and refractive index generally increased with higher Dy2O3 content. Optical absorption data showed a linear increase in Dy3+ ion absorption with Dy2O3 concentration, confirming the effective incorporation of Dy3+ ions. Tauc and Urbach plots were also employed to analyze the absorption edges of the glasses. DSC thermograms revealed that the glass transition temperatures increased while glass stability improved with higher Dy2O3 content. The radiation shielding properties were assessed by evaluating parameters such as mass attenuation coefficients, linear attenuation coefficients, tenth value layer, mean free path, effective conductivity, and effective electron density against gamma-ray photons. Dysprosium doping was found to enhance gamma-ray shielding (from 1 keV to 100 GeV) based on theoretical methods. Additionally, the 3 mol % Dy2O3 doped sample exhibited greater fast neutron removal cross-sections. However, the undoped barium phosphate host demonstrated better stopping potential and lower projected ranges against ions (protons and carbon). Photon trajectories and dose attenuation properties were also investigated using the Particle and Heavy Ions Transport System (PHITS) Monte Carlo code, indicating that the Dy3+ doped lead-free transparent glass protects against ionizing radiation. Hence, the barium phosphate host and Dy3+-doped counterparts are attractive for use in ionizing radiation and nuclear facilities, such as hospitals, research centers, and industries.

Magneto-optic properties of highly Dy3+-doped GeO2-B2O3 glasses for NIR optical applications

Recent progress in the development of optical communication and high power laser systems in the near-infrared (NIR) region (1.5 to 2.0 μm) increased the demand for magneto-optic (MO) devices employing MO materials. These MO materials are required with lower optical absorption coefficients and higher Verdet constants at spectral range of interest. In this study, two series of highly Dy3+-doped GeO2–B2O3 glasses with and without P2O5 were fabricated using a simple melt-quenching technique. The glasses were characterized through various techniques (Raman, UV–VIS-NIR, and DTA) for the evaluation of characteristic properties with respect to the Dy2O3 concentration and glass composition. Faraday rotation measurement was carried out at 1550 nm to quantify the Verdet constant of the glasses. The Verdet constant values were found to increase linearly with increasing Dy3+ concentration for both the glass systems. The increase in Dy3+ concentration and, consequently, the number of unpaired electrons, leads to an increase in the Verdet constant. The GeO2-B2O3 glass doped with 30 mol% of Dy2O3 exhibited the highest Verdet constant of −5.36 rad/(T⋅m) at 1550 nm. The glasses exhibited a good optical transparency (>70 %) in the region covering from 400 to 2400 nm. The thermo-physical, optical, and polarizability properties of both glass systems were also investigated. The results indicate that the highly Dy3+-doped glasses are attractive for magneto-optics at 1550 nm.

Thermal, and radiation shielding properties of SrO–B2O3–TeO2–ZnO–Bi2O3 glasses doped with Dy2O3

The newly proposed materials demonstrated outstanding and effective radiation shielding capabilities and promising mechanical properties. A series of (20-x) SrO-(73)B2O3-(5)TeO2-(1)ZnO-(1)Bi2O3 doped with x-Dy2O3 have been produced employing the traditional melt-quench process, with the concentration of Dy2O3 varying from 0.05 to 1.5 mol%. This research examined glass samples' structural stability, mechanical and thermal characteristics, and radiation shielding capabilities. All of the glasses were amorphous, as confirmed by the X-ray examination, and the glass with the label SBTZBD6 had the maximum density because of the higher Dy2O3 content. The insert of Dy2O3 into the glass composition increased density values from 2.94 to 3.04 g/cm3 for SBTZBD1 and SBTZBD6 and improved mechanical properties such as Poisson ratio and elastic moduli. The hardness Vickers showed the maximum value at 1095.7 HV corresponding to Dy2O3 1 mol%, indicating the influence of Dy2O3 addition on the mechanical properties. The ability of the generated samples to shield against several forms of radiation, such as alpha, proton, neutron, and gamma radiation, was examined using SRIM and Phy-X software. The lowest HVL is 0.009 cm for SBTZBD6 at 0.02 MeV, the highest HVL was observed at 15 MeV with a value equal to 7.066 cm for the same sample. Dy2O3 was used instead of SrO, significantly increasing the μ/ρ values and improving radiation shielding. However, it was discovered that fast neutron shielding experienced a reduction in energy loss per unit mass (mass stopping power) when SrO was replaced with Dy2O3. However, the substitution also reduced energy loss per unit mass for alpha and protons and fast neutron shielding. To sum up, this study's glass samples are highly recommended for ionizing radiation shielding.

Luminescence properties and thermal stability of Dy2O3/Sm2O3 doped glass ceramics containing NaBi(WO4)2

Dy2O3–Sm2O3 co-doped transparent glass ceramics (GCs) containing NaBi(WO4)2 crystalline phase were prepared by melt-curing-crystallization method. The optimal heat treatment condition is 580 °C/2 h. The optimum incorporation concentration of Dy2O3 is 0.4%, exceeding which a quenching phenomenon dominated by quadrupole-quadrupole interactions emerges. Meanwhile, when the concentration of Dy2O3 was fixed, the chromaticity coordinate of the sample moved the cool white light region to the warm white light region as the concentration of Sm2O3 increased. The temperature-dependent emission spectra of the 0.4% Dy2O3-0.7% Sm2O3 co-doped GC samples show that emission intensity at 575 nm at 185 °C still reaches 80% of the room temperature. The thermal quenching activation energy was 0.1537 eV and the activation energy after the addition of Mo6+ was 0.1957 eV. This study indicates that Dy2O3–Sm2O3 co-doped GCs containing NaBi(WO4)2 crystalline phase can achieve light-color tunable emission, which is potentially valuable for solid-state color rendering and illumination applications.

Elucidating the impact of Dy2O3 substitution on structure, optical, photoluminescence and mechanical properties of borosilicate glass

This work aims to investigate the changes in characteristics seen in the composition 60B2O3+ (30–x) BaO + 10SiO2 + xDy2O3 where x is 0.0, 1.0, 2.0, and 3.0 mole% glass samples. Melt-quenching technique was used to prepare the glass samples. A variety of analytical techniques were employed to characterize the prepared glasses, such as x-ray, Raman, photoluminescence, and UV-vis-NIR spectroscopy. XRD spectra verified the glassy nature. The glasses’ compactness was studied using structural properties such as density, molar volume, and oxygen packing density. Makishima-Mackenzie’s (M-M) method was used to determine mechanical parameters such as elastic moduli, Poisson’s ratio, and hardness, and it was found that these properties decreased with increasing Dy2O3 concentration. Glass absorption spectra showed eleven distinct peaks in the range 300–2000 nm, resulting from Dy3+ electronic transitions. Urbach energy, refractive index, and optical band gap energy were determined. The optical parameters, such as molar refraction, molar polarizability, reflection loss, optical transmission, metallization, and optical electronegativity, were estimated. The photoluminescence spectra revealed five distinct peaks in the 400–800 nm wavelength range under excitation at 325 nm.

Optical and radiation shielding characteristics of Dy2O3 doped B2O3–TeO2–BaO glasses

Glass samples with varying compositions was prepared by standard approach. The composition of the samples was (50-x) B2O3–25TeO2–25BaO-xDy2O3, with x ranging from 0 to 1.25 mol%. XRD profiles confirmed that the samples were amorphous, as there were no long-range lattice arrangements observed. The successful preparation of amorphous samples was further confirmed by the absence of sharp lines & peaks. The optical properties of the obtained samples were analyzed. That a decrease in Eopt values resulted in a higher value of the refractive index (n) for the glasses. However, when the concentration of Dy2O3 exceeded certain levels (0.75, 1, and 1.25 mol%), the refractive index (n) decreased due to an increase in Eopt values. Experimental measurements using a NaI(Tl) detector were conducted to determine the radiation shielding parameters (LAC and MAC), as well as the (HVL), (TVL), & (MFP) of the glasses against gamma rays emitted by 137Cs and 60Co isotopes at energies of 0.662, 1.173, and 1.333 MeV. Excellent agreement was observed when comparing the experimental results with theoretical calculations using Phy-x/PSD software program. This suggests that the fabricated glasses have great potential for various applications in the field of optics and can effectively shield against radiation.

Examination of the ionizing radiation shielding behavior of the zinc boro-tellurite glasses doped with dysprosium oxide

A set of zinc boro-tellurite glasses (xDBTZ) is prepared by the melt-quenching technique. The glasses are investigated to evaluate the shielding effectiveness. The glass stability is proven higher for the glass containing 2% Dy. The 2DBTZ glass owns higher oxygen packing density and lower molar volume of oxygen among the prepared glasses, and the behaviour specifies that the atoms in the glass lattice are aligned to be tightly packed. The structural and mechanical features suggested the applicability of the 2DBTZ glass in radiation-shielding applications. The Monte-Carlo simulation was also applied to evaluate the γ-ray attenuating aptitude for the manufactured zinc boro-tellurite glasses. The obtained data shows that including 2 wt% of Dy2O3 concentration improves the linear attenuation coefficient of the as-prepared zinc boro-tellurite glasses. The linear attenuation coefficient enhancement affected the half values thickness of the manufactured zinc boro-tellurite glasses, where the half values decreased by 32.78%, 22.21% and 21.57% for γ-ray energies of 0.059, 0.551 and 2.506 MeV correspondingly. Additionally, adding the Dy2O3 to the glasses enhances the radiation-protection efficiency accompanied by a reduction in the transmission factor of the fabricated composites. Therefore, the fabricated samples can be used as an alternative lead-free shielding material.

Influence of dysprosium oxide on physical and optical characteristics of zinc boro-tellurite glasses for optoelectronic device application

Glasses with compositions [(50-X) TeO2 − 20 B2O3 − 30 ZnO − x Dy2O3] where X = 0, 1, 2, 3, 4 and 5 mol% were synthesized by melt quenching method. X-ray diffraction (XRD) measurements confirmed the amorphous nature of the as-prepared glasses. UV–Vis absorption and PL spectroscopy studied the optical properties of the glass samples. High absorption of glass samples observed up to 3 mol% of Dy2O3, and then increasing the concentration of Dy2O3 reduces the absorption. The increasing concentration of Dy2O3 formed the glass sample containing 4 and 5 mol% Dy2O3 acts as a UV band-cutting filter. CIE achromatic color coordinates and CCT results for visible transitions confirm the ability of the glass samples under study as potential materials for white light-emitting diodes and laser application. The studies suggest that these materials are suitable for optoelectronic application.

Tailoring Variations in the Microstructures, Linear/Nonlinear Optical, and Mechanical Properties of Dysprosium-Oxide-Reinforced Borate Glasses

Hybrid dysprosium-doped borate glassy samples [B-Gly/Dy]HDG (Borate Glass/Dysprosium)Hybrid Doped Glass were prepared in this study via the melt-quenching method. Its linear/nonlinear optical, photoluminescence, hardness indentation, and micro-creep properties were analyzed. The amorphous structure for all the prepared samples was confirmed from the XRD patterns. In addition, density functional theory (DFT), optimized by TD-DFT and Crystal Sleuth, was used to study the structure and crystallinity of the [B-Gly/Dy]HDG as isolated molecules and agreed with the peaks of experimental XRD patterns. Additionally, theoretical lattice types were studied using Polymorph, a content studio software, and orthorhombic Pc21b (29) and triclinic P-1 (2) structures were provided. Both mechanical and optical properties were responses to different concentrations of Dy2O3 in the glassy borate system. It was found that the length of indentation increases by increasing the load time, and the hardness decreases by increasing the load time. The stress exponent value also increased from 4.1 to 6.3. The indentation strain increases by increasing the load time. The direct optical band gap was evaluated using the Davis–Mott relation. Urbach energy and its connection to the disorder degree in materials were studied depending on the Dy2O3 concentration. The acquired optical parameters were also analyzed to determine the nonlinear refractive index as well as the linear and third-order nonlinear optical susceptibility of the investigated glass samples. The photoluminescence emission spectra were recorded, and their attributed transitions were studied. The mechanical studies showed that the hardness values increased by increasing Dy2O3 concentrations from 4160.54 to 5631.58 Mpa. The stress exponent value also increased from 4.1 to 6.3. Therefore, the higher value of stress exponent (S) is more resistant to indentation creep.

Mechanism of enhanced critical fields and critical current densities of MgB2 wires with C/Dy2O3 co-additions.

A series of monofilamentary powder-in-tube MgB2 wires were fabricated with 2 mol. % C doping and co-additions of 0-3 wt. % Dy2O3. Irreversibility fields (μ 0 Hirr ), upper critical fields (μ 0 Hc 2), and transport critical currents were measured, and from these quantities, anisotropies and electronic diffusivities were estimated. The addition of 1 wt. % Dy2O3 to already optimally C-doped MgB2 wires produced higher Hc 2//ab , Hc 2//c , and Hirr values at 4.2 K. In addition, the critical current density, Jc , increased with Dy2O3 concentration up to 1 wt. % where non-barrier Jc reached 4.35 × 104 A/cm2 at 4.2 K, 10 T. At higher temperatures, for example, 20 K and 5 T, co-additions of 2 mol. % C and 2 wt. % Dy2O3 improved non-barrier Jc by 40% and 93% compared to 2 and 3 mol. % C doping, respectively. On the other hand, measurements of Tc showed that C/Dy2O3 co-additions increase interband scattering rates at a lower rate than C doping does (assuming C doping levels giving similar levels of low-T μ 0 Hc 2 increase as co-addition). Comparisons to a two-band model for μ 0 Hc 2 in MgB2 allowed us to conclude that the increases in Hc 2//ab , Hc 2//c , and Hirr (as well as concomitant increases in high-field Jc ) with Dy2O3 addition are consistent with increases primarily in intraband scattering. This suggests C/Dy2O3 co-addition to be a more promising candidate for improving non-barrier Jc of MgB2 at temperatures above 20 K.

Na2O-Gd2O3-Al2O3-P2O5 glass scintillator doped with Dy3+: X-rays and proton responses

Dy3+:Na2O-Al2O3-Gd2O3-P2O5 (Dy:NAGP) glasses were fabricated to investigate the capability for radiation responses. The influence of Dy2O3 concentration on glass properties was studied. The density and effective atomic number of glass increased with the addition of Dy2O3 content. The glasses absorbed the photons in the ultraviolet, visible light, and near-infrared region. In photoluminescence (PL) spectra, the obvious yellow emission at 574 nm and blue emission at 482 nm of Dy3+ were both generated by the direct excitation and the Gd–Dy energy transfer. The PL decay time of glasses was in the millisecond order. There was thermal quenching observed in temperature-dependent luminescence (TDL). The radioluminescence (RL) and protonluminescence (PrL) represented the emission pattern of Dy3+ similarly to PL spectra. The concentration quenching caused 0.50Dy:NAGP glass with the highest PL and RL emission intensity. The X-ray imaging of developed glass using a synchrotron light source was successfully imaged for the first time.

Radio and photo luminescence properties of Dy3+ ion doped bismuth barium gadolinium borate glass

Investigations on physical, optical and photo – radio luminescence properties of dysprosium doped bismuth barium gadolinium borate glass (BiBaGdBDy) have been prepared for the melt at 1200 °C and rapidly cooling in the casting process. The glasses were doped by Dy2O3 with six concentrations which varied from 0.00 to 1.50 mol%. The cut and polished glass samples were measured density and refractive index at room temperature. The absorption spectra show at the wavelength 802, 891, 1083, 1265 and 1679 nm that that are matched with the transition of Dy3+ from 6H15/2 (ground state) to various excited state 6F5/2, 6F7/2, 6F9/2, 6F11/2 and 6H11/2 respectively. The 387 nm flash lamp was used to excite the sample lead to display the five emission bands at 481, 576, 661 and 753 nm which matched with the emission transitions 4F9/2→6HJ (J = 15/2, 13/2, 11/2 and 9/2) respectively. The prominent blue light from 4F9/2→6H15/2 and yellow light from 4F9/2→6H13/2 emissions was combined and produces white light emission, which is confirmed by the CIE chromaticity diagram. The certain Lifetime of important laser-level is 4F3/2, which shows a decreasing trend with the increase of Dy2O3 concentration. The Judd-Ofelt (J-O) intensity parameters found the trend Ω2 > Ω4 > Ω6. The branching ratios (βR) transition probabilities (AR) and stimulated emission cross-sections (σe) were estimated for 4F9/2→6H13/2 transition they are the radiative properties that were used to figure out the potential benefit of these glasses for laser action in the visible region along these lines suggests that the present Dy3+ doped bismuth barium gadolinium borate glasses are suitable for white light applications and scintillator material.

Optical, luminescence, and energy transfer studies of Gd3+/Dy3+ doped potassium gadolinium borophosphate glasses

The K2O–Gd2O3–B2O3–P2O5 glass doped with Dy2O3 (Dy:KGPB) were synthesized by the melt-quenching technique. These glasses were subjected to characterize the physical, structure, optical and luminescence properties. It was observed that the density, molar volume and refractive index of glass increased with increasing Dy2O3 concentration. The FTIR result confirmed the main glass network of BOB and POP linkages those were degraded by adding Dy2O3 modifier. Glasses absorbed photons in ultraviolet, visible light and near-infrared region. The photoluminescence under direct Dy3+ excitation performed the strong emissions at 574 and 482 nm corresponding to 4F9/2 → 6H13/2 and 4F9/2 → 6H15/2 transition, respectively. The Gd3+ excitation also caused strong emission of Dy3+ by the Gd3+-Dy3+energy transfer. Glass doped with 1.00 mol% of Dy2O3 owned the highest emission intensity due to the concentration quenching. The lifetime of 4F9/2 level was found to decrease with addition of Dy2O3 content via dipole-diploe interaction between Dy3+ ion. Judd-Ofelt (J-O) intensity parameters were initially calculated and applied to evaluate the radiative parameters such as branching ratios, radiative transition probabilities, and stimulated emission cross-sections. The radioluminescence of glass was also investigated and found the scintillation efficiency around 15.6%, compared to BGO scintillator. The Dy:KGPB glass has an interesting potential for solid-state laser, LED and X-ray detection applications.

Effect of Mg2+/Sr2+ addition on luminescence properties of Dy3+ doped glass ceramics containing Ca2Ti2O6

Dy2O3-doped transparent glass-ceramics containing Ca2Ti2O6 crystal phase were synthesized by melting crystallization method. The optimum heat treatment condition was determined to be 710 °C/1.5 h by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmittance curves. The optimal doped concentration of Dy2O3 is 0.4 mol%. The effects of doping with different concentrations of Mg2+ and Sr2+ on the fluorescence intensity of glass-ceramics were discussed. In comparison to Sr2+, the addition of Mg2+ effectively increased the luminescence intensity of 0.4 mol% Dy2O3-doped glass-ceramics. Since Mg2+ has a smaller ionic radius, it has a larger Coulomb potential and is more attractive to O2−, which makes the three-dimensional skeleton of BO6 tilt, and the symmetry of the structure deteriorates, resulting in enhanced luminescence. Comparison of 0.4 mol%Dy2O3-doped glass-ceramic and 8 mol%MgF2-0.4 mol%Dy2O3 co-doped glass-ceramic, the fluorescence intensity increased by 56.8% at 484 nm and 83.5% at 577 nm, the optical band gap value was reduced from 2.7824 eV to 2.4341 eV. The findings suggest that Dy3+-doped glass-ceramics containing Ca2Ti2O6 crystal phase will be used in white light-emitting diodes (W-LEDs).

Synthesis and characterization of B2O3–Bi2O3–SrO–Al2O3–PbO–Dy2O3 glass system: The role of Bi2O3/ Dy2O3 on the optical, structural, and radiation absorption parameters

In the present study, a number of glass samples with the chemical signature: 70B2O3+(10-x)Bi2O3+5SrO+10Al2O3+5PbO+xDy2O3 were prepared and investigated for their structural, physical, optical, and radiation (gamma rays and fast neutron absorption) properties. The optical absorption data was used to measure the optical bandgap and Judd-Ofelt parameters. Based on photoluminescence decay spectral features stimulated emission cross-section and quantum efficiency were measured. The mass attenuation coefficient and the effective atomic number of the glass samples were observed to increase with the addition of Dy2O3. The addition of Dy2O3 also played a positive role in the charged particles absorption capacity of the glasses. In addition, the fast neutron removal cross-section of the glass samples increased from 0.0669 to 0.0713 cm−1 as molar concentration of Dy2O3 was increased from 0.1 to2.5 mol%. The synthesized glasses showed key characteristics that made them attractive for optical as well as radiation protection applications.

White emission from Dy3+ doped Gd2O3-B2O3 glass for WLEDs encapsulation

Novel bell-shaped glasses were fabricated to study the electro-luminescence properties of the glasses for LED applications. The physical and optical properties of Dysprosium (Dy3+) doped Gd2O3-B2O3 glasses were synthesised using the standard melt quenching procedure with compositions of 27.5Gd2O3-(72.5-x)B2O3-xDy2O3 (where x = 0.05, 0.1, 0.5, 1.0, and 1.5 mol%). The highest emission intensity of Dy3+ doped Gd2O3-B2O3 glasses was found to be at 0.5 mol% (by 275 nm excitaiton of Gd3+ ion) and 1.5 mol% (by 350 nm excitation of Dy3+ ion) of Dy2O3 concentration. A bright yellow emission corresponding to the transition F9/2→H13/2 (at 576 nm) was found in the emission spectra. This emission band was a mix of blue, yellow, and red. Furthermore, the CIE chromaticity diagram for glass 0.5 mol% Dy2O3 with color coordinates x = 0.368, y = 0.405, and shows white emission. The decay profiles were investigated for 575 emission and values show decreasing trend with increase in Dy2O3 content. Encapsulation of fabricated glasses were made to embed on top of the LED to investigate electro-luminescence spectra. From all results, this glasses could be used for LED encapsulation.

Luminescence and Judd-Ofelt analysis of gallium aluminum gadolinium yttrium borate scintillating glass doped with Dy3+

In this work, Dy3+:B2O3–Ga2O3–Al2O3–Gd2O3–Y2O3 glasses system were prepared by melt quenching technique. The physical, chemical groups, optical, photoluminescence and radioluminescence properties of glasses were investigated. The density and refractive index tended to increase with increasing Dy2O3 concentration. The Dy3+ doped glasses absorbed photon in UV, VIS and NIR region in the absorption spectra. For photoluminescence study, the 276 and 351 nm wavelength owned the strong excitation peak, so they were used to measure the emission spectra. The main emission peak of Dy3+ showed at 487 and 575 nm with 4F9/2 → 6H15/2,13/2 transition due to both direct excitation and the Gd–Dy energy transfer. The luminescence lifetime of Dy3+ was in the milliseconds order that shortened with adding Dy2O3 content. The PL emission intensity at 100 K was around 1.48 times compared to its value at room temperature (∼300 K). The Judd-Ofelt theory was used to analyse the radiative properties of glass and its result performed the quantum efficiency around 63.75%. The X-rays induced optical luminescence represented the highest intensity in 0.50 mol% Dy2O3-doped glass similarly to the photoluminescence under 351 nm excitation. The X-rays scintillation efficiency of this glass is 14% compared with BGO crystal. The developed glass in this work owns the potential for X-rays detection material with integration mode usage, and is also interesting for white light source and laser medium applications.

White Emission from Dy3+ Doped in ZnO – CaO – B2O3 for WLEDs Material Application

The Dy3+ ions doped CaO-ZnO-B2O3 glasses were synthesis by the melt quenching technique with various Dy2O3 concentrations to investigation physical and optical properties. The results showed that the density and the molar volume trend to be increased along with increased Dy3+ concentration. The absorption spectra showed characteristic absorption peaks in the visible and near infrared regions. Judd–Ofelt (JO) intensity parameters have been obtained from the optical absorption spectra. The emission spectra of the glasses are illustrated the highest emission intensity at 574 nm wavelength, which corresponding to Dy3+ transition 4F9/2→6H13/2 level. The decay time value decreased as the concentration of Dy2O3 increased. The CIE 1931 chromaticity investigation showed that Dy3+ doped glasses emitted light with white color.

Preparation and luminescence properties of Dy3+ doped BaO-Al2O3-SiO2 glass ceramics

Dy3+ doped transparent glass ceramics containing Ba0.808(Al1.71Si2.29)O8 crystal phase are successfully prepared by the melting crystallization method. Through differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscope (SEM), the optimum heat treatment condition is determined to be 680 ℃/1.5 h. The absorption spectra of the glass and glass-ceramic samples are used to calculate their indirect allowable optical band gaps. It is found that the optical band gap of glass ceramics narrowed. The emission spectrum shows three emission peaks at 484 nm, 576 nm, and 669 nm, corresponding to the blue, yellow, and red emission of Dy3+. The optimal doping concentration of Dy2O3 is 0.45 mol% , the Correlated Color Temperature (CCT) of 4540 K, and the CIE chromaticity coordinates of (0.3642, 0.3924), which is close to warm white light. The reason for the concentration quenching is the electrical multipolar interaction between Dy3+.

Spectroscopic properties of P2O5–MgO–Na2O:Dy2O3 glasses for the applications of W-LEDs

P2O5–MgO–Na2O glasses with varied concentrations of (RE) Dy3+ ions (Dy2O3: 0.5, 1.0, 1.5, and 2.0 mol percent) were prepared by melt quenching technique. The prepared glass samples have been characterized using XRD and SEM techniques and the amorphous nature of the samples was ensured. Optical absorption and photoluminescence spectra and also decay characteristics were recorded. Using absorbance spectra, the J-O parameters Ω2, Ω4, and Ω6 were calculated for the glass doped with 1.0 mol % of Dy2O3. Several radiative parameters such as radiative probability, AR, radiative lifetime τR, branching ratio, βR, emission cross-section, σEP for Dy2O3 doped glasses were evaluated and reported using the emission spectra. The quantum efficiency of 1.0 mol% Dy2O3 doped glass was determined to be 86%, which is observed to be the largest when compared to that of all other glasses. The color chromaticity co-ordinates were observed to move towards white region as the concentration of Dy2O3 is increased. The quantitative analysis of these data in commination with results of infrared spectral investigations, revealed that the 1.0 mol % of Dy3+ ions is optimal concentration for achieving the highest luminescence efficiency.