Luminescence Properties Of Dy3 Research Articles

Luminescence properties of Dy3+ doped B2O3–CaMg(CO3)2 – TeO2 glasses: A promising host for solid state lighting devices

In this work, a novel series of 30B2O3–15CaMg(CO3)2–(55–x)TeO2–x Dy2O3(0.2≤x≥1.3 mol%) glasses coded as BDT x Dy are fabricated via conventional melt quenching procedure. The structure and luminescence properties of the as-produced glasses were explored through experimental and theoretical analyses. Through X-Ray profile, the amorphous status of the glasses was verified. FTIR spectra and N4 ratio analyses affirmed that Dy2O3 could act as a network modifier, transforming BO3→ BO4 and TeO3→ TeO4 units. Moreover, tthe characteristics of Dy3+ bond forming with O2−ion, oscillator strengths, band gap energies as well as Judd-Ofelt intensity units were deduced from the absorption spectra. Under 350 nm excitation wavelength, theemission spectra disclosed three f-f transitions situated around 482 nm, 575 nm and 662 nm attributed to 4F9/2→6H15/2, 6H13/2 and 6H11/2, respectively, wherein 4F9/2→6H11/2 transition, presentstrongest emission and better radiative properties. According to CIE 1931 chromaticity diagram, the current glasses radiate light, closer to the standard white light zone. To conclude, BDT x Dy glasses, due to their robust quantum efficiency (up to 97.97 %), boosted branching ratio (70 %) and remarkable stimulated emission cross section (≥ 10.15 × 10-22cm2) are promising for white light source and laser medium applications.

White Light Emission and Judd-Ofelt Analysis of Dy3+ Doped Mixed Alkali Borate Glass for W-LEDs Material

The Dy3+ doped lithium sodium potassium borate glasses with white light-emitting were prepared by the melt quenching technique. In this work, optical, photoluminescence properties and Judd-Ofelt analysis of borate glasses have been investigated. For optical properties, Dy3+ doped glasses showed the absorption in visible and near-infrared region, which originate from 6H15/2 ground state to higher state. While the luminescence properties of Dy3+ doped glasses, the emission spectra were presented more intense at 484 nm (blue light) and 574 nm (yellow light) which are essential for white light emitting materials, whilst decay time decrease with an increase of Dy2O3 contents. The emission intensity of Dy3+ doped glasses were enhanced by adding Dy2O3 concentrations until 0.5 mol%, after that the emission intensities were decreased due to the concentration quenching effect. Judd-Ofelt is analyzed by using the absorption and photoluminescence results, The stimulated emission cross-section has been investigated in this work. The CIE 1931 chromaticity investigation shows that Dy3+ doped glass emitted light with white color. Hence, these glasses may be suitable candidates for use in W-LEDs material.

Structural, luminescence and thermometric properties of LaVO4:Ln3+ nanopowders (Ln = Dy and Sm)

Lanthanide-doped materials have been intensively studied for optical thermometry due to their unique luminescence properties. However, the engineering of high-resolution multimode nanopowders for high-sensitivity thermometry is still a big challenge. Here, we study the structural and luminescence properties of Dy3+- and Sm3+-doped LaVO4 concentration series to find the suitable candidates for possible application as a temperature sensor. The synthesized nanocrystalline phosphors have successfully demonstrated multimode thermal sensing in the wide temperature range based on the temperature-induced red shift of the charge transfer band. The proposed sensing strategies were compared in terms of thermal sensitivity and temperature resolution. The best thermometric performances of Sr = 2.07 % K−1 and ΔT = 0.2 K at room temperature were found for LaVO4:Sm3+ 2 at% sample. The studies testify that Ln3+-doped LaVO4 materials are promising in multimode high-sensitivity optical thermometry.

Structural, optical, and luminescence properties of Dy3+ -activated potassium calcium silicate phosphor for white light-emitting diodes.

A dysprosium (Dy3+ )-activated potassium calcium silicate (K4 CaSi3 O9 ) phosphor was prepared using a solid-state synthesis route. The phosphor had a cubic structure with the space group Pa as confirmed using X-ray diffraction (XRD) measurements. Details of surface morphology and elemental composition of the as-synthesized undoped KCS phosphor was obtained using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. The chemical structure as well as the vibrational modes present in the as-prepared KCS phosphor was analyzed using Fourier transform infrared (FT-IR)spectroscopy. Diffuse reflectance spectra (DRS) were used to determine the optical bandgap of the phosphors and were found to be in the optical range 3.52-3.71 eV. Photoluminescence (PL) spectra showed intense yellow emission corresponding to the 4 F9/2 →6 H13/2 transition under 350 nm excitation. Commission International de l'Eclairage colour chromaticity coordinates were evaluated using the PL spectral data lie within the white region. Dexter theory and the Inokuti-Hirayama (I-H) model were applied to study the nature of the energy transfer mechanism in the as-prepared phosphors. The relatively high activation energy of the phosphors was evaluated using temperature-dependent PL (TDPL) data and confirmed the high thermal stability of the titled phosphor. The abovementioned results indicated that the as-prepared KCS:Dy3+ phosphor was a promising candidate for n-UV-based white light-emitting diodes.

Synthesis and luminescence properties of Dy3+ ions doped KMgPO4 phosphor for eco-friendly solid-state lighting

Synthesis and luminescence properties of Dy3+ ions doped KMgPO4 phosphor for eco-friendly solid-state lighting

Effect of dopant concentration on photoluminescence properties of Dy3+ doped Gd2O3 nanophosphors under different excitation wavelengths

In this work, the role of dopant Dy3+ concentration and excitation wavelength on luminescence properties of Dy3+ doped Gd2O3 nanophosphors prepared by chemical precipitation method were studied. The phosphors were characterized by X-ray diffraction (XRD), Energy dispersive analysis of X-ray (EDAX) and photoluminescence spectroscopy. The crystallite sizes of the phosphors were found to be in the range of 11–17 nm. The profile of the emission spectra for the phosphors was independent of dopant concentration as well as excitation wavelengths. The photoluminescence emission peaks were observed at 486 nm and 574 nm corresponding to 4F9/2-6H15/2 and 4F9/2-6H13/2 transitions respectively. The optimum concentration of Dy3+ for maximum emission intensity was found to be 2 at.% of Dy3+ which was independent of excitation wavelength. The emission intensity of all prepared phosphors under 234 nm excitation wavelength was found to be stronger than that of 278 nm. This showed the energy transfer due to host absorption was more efficient. The color emission of different concentration of Dy3+ doped Gd2O3 nanophosphors under different excitation wavelengths were studied from calculated CIE coordinates and was found to be shifted towards the blue region with the increase of dopant concentration.

Structure and luminescence properties of Dy3+ doped quaternary tungstate Li3Ba2Gd3(WO4)8 for application in wLEDs.

Quaternary tungstates with the composition Li3Ba2Gd3(WO4)8 doped with different concentrations of Dy3+ (from 0.5 to 10 at%) were prepared by the solid-state reaction method at 900 °C. Their structural, spectroscopic and optical properties were studied systematically in this work. X-ray diffraction analysis confirmed the crystallization of Li3Ba2Gd3(WO4)8 to have a monoclinic structure (sp. gr. C2/c); the lattice constants for 1 at% doping concentration of Dy3+ are a = 5.2126(2) Å, b = 12.7382(1) Å, c = 19.1884(3) Å, Vcalc = 1273,40(4) Å3 and β = a × c = 91.890(9)°. The first principles calculations for the undoped crystal revealed a direct bandgap of 2.45 eV, which is very close to the experimental one. The identified broad, and strong excitation peak at 450 nm indicates that Li3Ba2Gd3(WO4)8:Dy3+ phosphors are suitable to be pumped by a blue laser diode (LD). Under excitation at 445 nm, the phosphor showed a stronger luminescence peak at 575 nm which corresponds to the Dy3+:4F9/2 → 6H13/2 transition, and three weaker emissions peaks at 477, 661, and 750 nm. Meanwhile, the effect of different Dy3+ contents on the luminescence properties was investigated. The optimum concentration to minimize the quenching effect was 4 at% and the critical distance is 31.209 Å. The phosphor emitted strong greenish-yellow light situated at (0.425, 0.472) in CIE coordinates with a color temperature of 3652 K. All the measured luminescence lifetime curves exhibited a single-exponential nature. Excellent thermal stability was found for this tungstate phosphor (the activation energy is 0.352 ± 0.01 eV). The measured absolute photoluminescence quantum yield was around 10.5%. The results presented in this work show that Li3Ba2Gd3(WO4)8:Dy3+ phosphors with strong yellow emission are promising candidates for white-light emitting LED (wLED) applications.

Synthesis and luminescence properties of Dy3+-doped Mg2InSbO6 yellow-emitting phosphors with abnormal thermal quenching performance for w-LEDs

Synthesis and luminescence properties of Dy3+-doped Mg2InSbO6 yellow-emitting phosphors with abnormal thermal quenching performance for w-LEDs

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).

Structural, thermal, optical and luminescence properties of Dy3+ ions doped Zinc Potassium Alumino Borate glasses for optoelectronics applications

Zinc Potassium Alumino Borate (ZnKAlB) glasses doped with dysprosium (Dy3+) ions of different concentrations were synthesized through the process of melt quenching which is commonly used in solid-state lighting (SSL) and laser systems, to comprehend their viability. This article evaluates and analyzes the physical, structural, thermal and optical properties of Dy3+ ions doped glasses by X-ray diffraction (XRD), Infrared Fourier Transform (FT-IR), differential scanning calorimetry (DSC), UV absorption and photoluminescence (PL) spectra to explain their utilization in optoelectronic devices such as lasers and white light-emitting diodes (w-LEDs). The physical parameters viz. density, refractive index, inter-ionic distance, molar volume, polaron radius, field strength, optical electronegativity, dielectric constant, reflection loss and metallization were computed by following the expressions reported in the literature. Glasses are non-crystalline materials and the non-crystallinity of an un-doped Zinc Potassium Alumino Borate glass was proven by the absence of high-pitched peaks in the XRD spectra. FT-IR spectroscopy was used to identify the presence of different functional groups and their bond nature in Dy3+ ions doped ZnKAlB glasses. The transition temperature (Tg), melting temperature (Tm) and thermal stability was calculated by monitoring DSC thermograms of all glasses. Further, the bonding parameters (δ) and nephelauxetic ratio (β) were estimated to explore the bonding nature of Dy3+ ions in its neighborhoods by using UV-absorption data. The optical direct-indirect band gap energy (Eopt) and Urbach's energy (∆E) were enumerated from the absorption spectrum to elaborate electrical properties of as-prepared glasses. Judd-Ofelt theory was employed to find oscillator strengths from absorption spectra and for further calculation of radiative parameters such as the radiative lifetimes (τR), radiative transition probability (AR), total radiative transition probability (AT) and branching ratio (βR) to understand the quantum efficiency (η). Furthermore, the colorimetric parameters such as correlated color temperature (CCT), CIE coordinates and yellow to blue (Y/B) ratio were estimated from the PL emission data. The multipole-multipole interaction was confirmed by Dexter approximation to explain concentration quenching. This work primarily explains the essential features of borate glasses with Dy3+ ions doping to explain their potential use in tricolor w-LEDs and lasers.

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+.

Influence of Zn2+ concentration on the luminescence properties of Dy3+ ions doped zinc strontium alumino-telluroborate glasses for light emitting applications

Incorporation of Zn2+ ions in the place of Sr2+ ions in a glass network and their concentration effect on the structural and spectroscopic properties of novel Dy3+ doped glass with composition (30−x)SrO+xZnO+39.5B2O3+25TeO2+5Al2O3+0.5Dy2O3, (where x = 0, 5, 10, 15 and 20 wt %) have been investigated. The structural, bonding and spectroscopic changes due to the replacement of Sr2+ by Zn2+ ions were inspected through conventional routes such as FTIR, optical absorption, photoluminescence and lifetime measurements. Inclusion of Zn2+ ions into the glass medium affects the strength of Dy3+-ligand bonds and the Dy−O bonds becomes less ionic with their surrounding ligands while increasing the Zn2+ ions concentration. Radiative properties of the Dy3+ ions emission transitions were derived using Judd-Ofelt (JO) theoretical framework and the increasing magnitude of Ω2 parameters as increasing the Zn2+ ions concentration indicates that the symmetry around the Dy3+ ion sites in the glass network gets collapsed owing to the infusion of Zn2+ ions. Luminescence decay profile of the 4F9/2 metastable state of the Dy3+ ions demonstrate the non-exponential nature and the same is fitted with Inokut-Hirayama (IH) model to identify the nature of interaction between the activators. It is found that the dipole-dipole interaction dominates between Dy3+ ions. Chromaticity color coordinates and CCT (color correlated temperature) values of the prepared glasses suggests that the current glasses are promising candidate for neutral white light emitting applications such as luminescence solar concentrators and bright white light emitting devices.

Bright white light emission from (Gd3+ /Dy3+) dual doped transparent lithium aluminum borate glasses for W- LED application

The improving optical and luminescence properties of Dy3+ and Gd3+ dual doped lithium aluminum borate glasses with composition 25Li2O-5.0Al2O3-2.5Gd2O3-(67.5-X)B2O3-XDy2O3 glasses were successfully developed. The as-synthesis composite used conventional melt-quenching processes. All glass samples doped with Dy2O3 show an enhanced emission intensity (photo and radioluminescence spectra) with increasing the concentration of Dy2O3 up to 1.0 mol%, and beyond that, concentration quenching has occurred for all samples. The experimental decay times calculated from the decay profiles have been gradually declined with an increase in Dy3+ ion concentration. The chromaticity coordinates (CIE 1931) were located in the white light region of the color chromaticity diagram. The Dy-doping glasses synthesized show the prevalent presence of Dy3+also, the presence of the trivalent oxidation state in the glasses series. Therefore, the results confirm that the Dy3+-doped glasses could be useable for white-LEDs applications.

Synthesis and luminescence properties of Dy3+ and Tb3+ doped Y2Mg3Ge3O12 phosphors with excellent thermal stability and color tunable emission

A series of Y2-x-yMg3Ge3O12: xDy3+, yTb3+ samples were manufactured by high temperature solid phase method. XRD test and Rietveld refinement clarified the phase purity of the samples. When the excitation wavelength is 352 nm, the energy transfer efficiency is 57.74%, and q-q interaction is the main energy transfer mechanism of Dy3+-Tb3+ co-doped samples. In addition, we tested the thermal stability of Y1.94Mg3Ge3O12:0.05Dy3+, 0.01 Tb3+ sample, and found that its luminous intensity at 423 K could still reach 93.86% of that at 303 K. By changing the concentrations of Tb3+, the luminescent color of the samples could also be changed from blue-white light to yellow-green light. These results indicate that Y2Mg3Ge3O12 co-doped with Dy3+ and Tb3+ is expected to be applied in the field of white light LEDs.

Effect of anionic group [SiO4]4\u2212/[PO4]3\u2212 on the luminescence properties of Dy3+-doped tungstate structural compounds

Novel scheelite structures of Li2Ca(WO4)2, Li2Ca2(WO4)(SiO4), and LiCa2(WO4)(PO4) fluorescent materials were successfully prepared using a high-temperature solid-phase process. The compounds were characterized by X-ray diffraction and energy dispersive spectroscopy. The tests revealed that the substitution of [WO4]2− by [SiO4]4− or [PO4]3− tetrahedron in tungstate had no significant influence on the crystal structure of the Li2Ca(WO4)2. When Dy3+ ions were introduced as an activator at an optimum doping concentration of 0.08 mol%, all of the as-prepared phosphors generated yellow light emissions, and the emission peak was located close to 576 nm. Replacing [WO4]2− with [SiO4]4− or [PO4]3− tetrahedron significantly increased the luminescence of the Li2Ca(WO4)2 phosphors. Among them, the LiCa2(WO4)(PO4):0.08Dy3+ phosphor had the best luminescence properties, decay life (τ = 0.049 ms), and thermal stability (87.8%). In addition, the as-prepared yellow Li2Ca(WO4)2:0.08Dy3+, Li2Ca2(WO4)(SiO4):0.08Dy3+, and LiCa2(WO4)(PO4):0.08Dy3+ phosphor can be used to fabricate white light emitting diode (LED) devices.

Structural and luminescence properties of Dy3+-doped La2(MoO4)3 phosphors

Structural and luminescence properties of Dy3+-doped La2(MoO4)3 phosphors

Hydrothermal synthesis and luminescence properties of Dy3+ doped SrMoO4 nano-phosphor

Dysprosium (Dy3+) doped SrMoO4 nanophosphors were synthesized by hydrothermal method. The characterization of synthesized samples was done by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), High Resolution Transmission Electron Microscope (HR-TEM), Energy Dispersive Spectra (EDS), Ultraviolet–Visible microscope (UV), Fourier Transform Infrared (FT-IR) techniques and Photoluminescence (PL). The results reveal that the constituted SrMoO4 phosphor has a single phase scheelite structure with tetragonal symmetry and crystalline size is in the range of 10–50 nm. The formation of crystalline Nano rod nature of the sample has been confirmed by the TEM. Photoluminescence spectra show blue emission at 485 nm and bright yellow emission at 576 nm monitored at 353 nm excitation. The optimum concentration of Dy3+ doped SrMoO4 was found to be 6 mol %.

Influence of Ag nano particles on spectroscopic and luminescence properties of Dy3+ doped borate glasses

Dy3+ doped lithium zinc borate glasses with silver (Ag) nanoparticles (NPs) were synthesized by the conventional melt quenching method. Impact of silver NPs on the luminescence properties of 59B2O3: 20ZnO: 10Na2O: 10Li2O: 0.5SnO: 0.5Dy2O3 glasses doped with Dy3+ions were investigated. Ag+ ions have been reduced and nucleated to AgNPs by thermochemical redox method. Amorphous characteristics of the glasses were confirmed by XRD measurements. Raman and Fourier transform infrared spectra were used to estimate structural and vibrational bands of the glass samples. Localized surface plasmon resonance (LSPR) band is observed at 419 nm for 0.3 mol% of Ag along with three absorption bands of dysprosium were observed. Luminescence studies were performed on these glasses and found that three emission bands at 484, 575, and 665 nm when excited with wavelength of 349 nm, which corresponds to 4F9/2 to 6H15/2, 4F9/2 to 6H13/2, and 4F9/2 to 6H11/2 transitions of Dy3+ ions.

Preparation and luminescence properties of Dy3+ doped BaAlBO3F2 glass ceramic phosphor for solid state white LEDs

A series of BaAlBO3F2 glass ceramics (GC) phosphor with different Dy3+ concentration were prepared by melt quenching method followed by sintering process. The BaALBO3F2:xDy3+(x = 0.01,0.03,0.05,0.07,0.09 mol%) samples were characterized using X-ray diffraction (XRD), Differential Scanning Caloriemter (DSC) UV–vis diffuse reflectance spectroscopy (DRS), Transition Electron Microscope(TEM), Energy Dispersive X-ray studies (EDX), and Photoluminescence (PL).The phase formation of the prepared GC phosphor was characterized by powder X-ray diffraction (PXRD). The optimum heat treatment condition (550℃/4 h) was determined by DSC curve. The nano crystalline nature and the elemental analysis of the prepared samples were done by TEM and EDX. The absorption wavelength and the band gap value was found from the DRS spectrum. The luminescence Properties of Dy3+ in BaAlBO3F2 host were systematically studied using excitation and emission spectrum profile. Commission International de l’Eclairage (CIE) was used to study the chromatic nature of the GC phosphors. The calculated values of chromaticity coordinates were found to be located within the white light region. In addition to it, the CCT value was confirmed in the day light region. Hence the prepared materials find vast applications as white light LEDs

Luminescence properties of Dy3+ doped glass ceramics containing Na3Gd(PO4)2

Dy3+ doped precursor glass (PG) was prepared by melt-quenching, the glass ceramics (GCs) containing Na3Gd(PO4)2 phase were obtained via heating treatment. The heat treatment regime, luminescence properties of the samples were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence spectrum (PL), respectively. Finally, heat treatment system of glass ceramics is 660°C, 2 h. Emission spectra show that there are two mainly peaks at 483 nm and 577 nm, emitting blue and yellow light. The optimal doping concentration of Dy2O3 was determined to be 0.7%, and the reason for the concentration quenching is electrical multipolar interaction. According to the chromaticity coordinates (CIE), it indicated that with the change of Dy2O3concentration, the luminescence color changed from blue light to warm white light. The result shows that the Dy3+ doped GCs containing Na3Gd(PO4)2 have potential application value in white light-emitting diode (W-LED).