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Synthesis and characterization of Er3+/Cu+-codoped fluorophosphate glasses
摘要： NaPO3-ZnF2 binary fluorophosphate glasses doped with trivalent erbium and monovalent copper were synthesized by the conventional melting and casting method using ErF3 and CuCl as starting materials. The samples were systematically investigated using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. X-ray powder diffraction patterns confirmed that the as-prepared compounds were all amorphous. The glass transition temperature (Tg) was observed around 230°C by DSC analysis, while the thermal stability range (?T) was estimated to be between 90 and 140 °C. The measured value of the refractive index (n) was measured as 1.502 at a wavelength of 632.8 nm. Thermal annealing of the samples was performed at different temperatures above Tg for various heat-treatment times. During these steps, monovalent copper and sodium ions were expected to be reduced, forming metallic nanoparticles. This transformation lead to coloration changes, depending on the annealing time and temperature, with respect to the transparency of the glasses. These spectroscopic changes are related to the plasmonic effects induced by the presence of both Cu and Na metallic nanoparticles, which promote red shift due to absorption. The VIS-NIR absorption spectra of the prepared glasses were investigated in the frame work of standard Judd-Ofelt (J-O) theory, which was used to determine the J-O intensity parameters, radiative transition probabilities and branching ratios for Er3+ ions embedded in the glasses. The calculated intensity parameters (Ω2,4,6) were compared to those obtained for Er3+ in several other glasses.
关键词： Nanoparticles,Fluorophosphate glasses,Absorption,Judd-Ofelt theory,Optics
更新于2025-10-22 19:40:53
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Comparative study of Sm3+ ions doped phosphate based oxide and oxy-fluoride glasses for solid state lighting applications
摘要： The physical and luminescent properties of Sm3+-doped oxide and oxy-fluoride phosphate glasses were investigated. The glass samples with chemical composition of 69P2O5-10BaO-10ZnO-10Gd2O3-1Sm2O3 and 69P2O5-10BaO-10ZnO-10GdF3-1Sm2O3 were prepared by conventional melt quenching technique. The prepared glass samples were characterized with density, molar volume, refractive index, FTIR, UV-Vis-NIR, photoluminescence, radio luminescence, decay time profile, and CIE diagram. The density and refractive index of the oxide glass have higher values as compared to the oxy-fluoride glass. The FTIR spectra show the reduction of O-H group in oxy-fluoride glass. The characteristic peaks of Sm3+ are observed at 360, 372, 402, 438, 419, 473, 944, 1077, 1227, 1373, 1474, 1529 and1585 nm in UV-VIS-NIR spectra. These peaks are related respectively to the transitions from ground state 6H5/2 to 4D3/2, 6P7/2, 6P3/2, 4I11/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2, 6F3/2, 6H15/2 and 6F1/2 excited states. From photoluminescence and radio-luminescence it is observed that the oxy-fluoride glass samples show better emission intensity than the oxide glass. The Judd-Ofelt theory (J-O theory) was used to find J-O intensity ?λ (λ=2,4 and 6) parameters and radiative properties such as transition probability, stimulated emission cross section and branching ratios for titled glasses. The trend observed in the J-O parameters is ?4 >?2 >?6. The transition probability, emission cross section and branching ratio have the highest values for the 4G5/2→6H7/2 transition. The CIE coordinates of the prepared glass samples are positioned in the orange region and the CCT value is 3776.105 for oxide and oxyfluoride glass. The oxy-fluoride glass has shorter decay time as compared to the oxide glass and it is recorded to be 1.62 and 1.32 ms for oxide and oxy-fluoride respectively. According to the results obtained in this work, it is obvious that these glass samples can be good candidate materials for producing cool orange light.
关键词： Judd-Ofelt theory,Oxy-fluoride glass,Rare earths,Photoluminescence,CIE coordinates
更新于2025-09-23 15:23:52
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Up-conversion Luminescence Properties of Er3+/Yb3+ Co-Doped Oxyfluoride Glass Ceramic
摘要： Er3+/Yb3+ co-doped glass ceramic samples were prepared by melt-quenching method utilizing nominal composition 52SiO2-8Na2CO3-16Al2O3-33NaF-3LuF3-0.15Yb2O3-0.03Er2O3 (in mol%). The spectral characteristic was studied based on Judd-Ofelt theory. Spectrum intensity parameters Ωλ(λ=2,4,6) were calculated on the basis of the absorption spectrum. The theoretical and experimental oscillator strengths were calculated according to the spectrum intensity parameters, and the root mean square deviation (δrms) of glass ceramic sample was 4.28x10-6. The parameters such as transition probability, decay branching ratios and level lifetime of Er3+ were obtained. Lifetimes of metastable level 4I13/2 and 4I11/2 in as-prepared samples are respectively 11.64 and 13.61ms which are suitable for up-conversion intermediate levels. Decay branching ratio of 4I13/2→4I15/2 is nearly 100% in Er3+/Yb3+ co-doped oxyfluoride glass ceramic samples which can be used to produce 1543nm laser. Under the excitation of 980 nm diode laser, up-conversion luminescence is observed at the wavelength of 549nm and (653, 664) nm, corresponding to the radiative transitions of Er3+: 4S3/2→4I15/2 and 4F9/2→4I15/2, respectively. The numbers of absorbed photons in the transition process of Er3+/Yb3+ co-doped oxyfluoride glass ceramic samples are estimated at 1.99 and 2.06 respectively according to the relationship between the up-conversion transmitting power and the 980 nm LD laser power. It is determined that the transition process of Er3+/Yb3+ co-doped oxyfluoride glass ceramic samples is two-photon absorption process.
关键词： Glass ceramic,Two-photon absorption,Up-conversion,Judd-Ofelt theory
更新于2025-09-23 15:23:52
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Up-conversion characteristic and Judd-Ofelt calculation of BaGd2ZnO5:Er3+/Yb3+ microcrystalline powder
摘要： Er3+/Yb3+ co-doped BaGd2ZnO5 microcrystalline powder are prepared through high-temperature solid phase method. Absorption spectrum are obtained and spectral characteristic are analyzed through Judd-Ofelt theory. The calculated spectrum intensity parameters are Ω2 = 3.01 × 10?20 cm2, Ω4 = 3.76 × 10?20 cm2 and Ω6 = 0.43 × 10?20 cm2, respectively. The transition probability, branching ratio and energy level lifetime of Er3+ ion in BaGd2ZnO5 microcrystalline host are calculated. Up-conversion spectrum under 980 nm excitation are measured, The analyzed results indicates that three peaks of up-conversion luminescence, located at 533 nm, 553 nm and 670 nm, all belong to two photon absorbing process.
关键词： Judd-ofelt theory,BaGd2ZnO5,Up-conversion luminescence
更新于2025-09-23 15:22:29
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A novel Nd <sup>3+</sup> -doped MgO-Al <sub/>2</sub> O <sub/>3</sub> -SiO <sub/>2</sub> -based transparent glass-ceramics: towards excellent fluorescence properties
摘要： Generally, glass-ceramics have superior properties compared to their parent glasses. Here, we prepared a novel Nd3+-doped MgO-Al2O3-SiO2-based transparent glass-ceramics with excellent fluorescence properties. The effects of Nd2O3 content on the structure and properties of glass-ceramics were studied, aiming to provide a key guidance for preparing this transparent glass-ceramics. The results revealed that the glass stability increased originally and then decreased with increasing Nd2O3 content, so did the variation of wavenumbers in infrared spectra. And these glass-ceramics are mainly composed of cordierite with residual glassy phase. The three phenomenological intensity parameters (Ω2,4,6) and radiative properties were estimated by Judd-Ofelt theory, and the values of Ω2 first decreased and then increased with increasing Nd2O3 content. Three main emission peaks ascribed to the transitions from 4F3/2 to 4I9/2, 4I11/2, 4I13/2 at 898, 1057, 1330 nm were observed, respectively. The branching ratios for 4F3/2→4I11/2 transition increased as the Nd2O3 content raised, and the fluorescence lifetimes of the 4F3/2 level were found to increase first and then decrease with Nd2O3 content (from 181 to 726 μs). The excellent fluorescence properties indicate that this novel glass-ceramics can be used as a potential solid-state optical functional material for 1.06 μm laser emission.
关键词： MgO-Al2O3-SiO2,Judd-Ofelt theory,Nd3+-doped,Transparent glass-ceramics,Solid-state optical functional materials
更新于2025-09-23 15:22:29
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Synthesis, structure and optical properties of Erbium-doped Lithium Barium Phosphate
摘要： Li2BaP2O7 activated with Er3+ ions was prepared by the classic ceramic method and characterized by X-ray diffraction technique, IR, Raman and photoluminescence (PL) spectroscopies. The Li2BaP2O7: Er phosphors exhibited a monoclinic single phase structure with C2/c space group. A green and red emission lines dominate the spectrum upon excitation at 400 nm. The CIE-coordinate (x = 0.308, y = 0.512) were found in green light. Free ion parameters of the Er3+ ions in Li2BaP2O7 and the Judd–Ofelt parameters were calculated and they were used to explore the radiative parameters such as transition probability (AT), and branching ratios (β) related to the Er3+ emission transitions. The calculated 4S3/2 radiative life time around 0.198 ms is compared with the experimental value. The calculated quantum efficiency is about 42 %. Li2BaP2O7: Er can be considered as a novel green phosphor.
关键词： Erbium,green phosphor,Judd-Ofelt theory,optical spectroscopy
更新于2025-09-19 17:15:36
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Near-infrared and upconversion luminescence of Tm3+ and Tm3+/Yb3+-doped oxyfluorosilicate glasses
摘要： Oxyfluorosilicate glasses-doped with different concentrations of Tm3+ and Tm3+/Yb3+ ions have been synthesized and characterized their absorption, photoluminescence, luminescence decay and upconversion properties. The Judd-Ofelt intensity parameters have been obtained from the absorption spectrum of Tm3+ single-doped glass and are in turn used to calculate radiative properties such as transition probabilities, branching ratios and lifetimes for the fluorescent levels of Tm3+ ions. Visible and near-infrared emission spectra of Tm3+ and Tm3+/Yb3+-doped glasses have been measured under 473 nm laser excitation. The quenching of emission intensities at higher concentrations of Tm3+ ions has been found to be due to cross-relaxation mechanisms. The Tm3+/Yb3+ co-doped glasses show upconverted emissions under 975 nm laser excitation. The mechanism of upconversion has been explained based on the pump power dependence of upconversion luminescence. The results reveal that the co-doped glasses are promising for optical fiber amplifiers operating at the relatively low-loss wavelength regions.
关键词： Glasses,Optical properties,1.2 μm emission,Upconversion,Judd-Ofelt theory,Tm3+ and Tm3+/Yb3+
更新于2025-09-19 17:15:36
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Synthesis of intense red light-emitting β-Ca2SiO4:Eu3+ phosphors for near UV-excited light-emitting diodes utilizing agro-food waste materials
摘要： The sugarcane baggage ash and chicken shells are the abundant by-products of agro-food waste materials. These waste materials have hazardous impact on environment and thus require proper utilization to get valuable products. The present report is a detailed study to use these materials to fabricate intense red light-emitting Eu-doped Ca2SiO4 (C2S) phosphors via conventional solid-state method. For this purpose, silica (SiO2) is extracted from sugarcane baggage ash at 600 °C via alkali extraction followed by acid precipitation method. The raw eggshells were washed, dried, and calcined in furnace at 900 °C in order to get calcium oxide (CaO). The structural, morphological, elemental, optical, and luminescent properties were characterized via X-ray diffraction, scanning electron microscopy, energy dispersed X-ray spectroscopy, transmission electron microscopy, UV–Visible spectroscopy, Fourier transform infrared spectroscopy, and photoluminescence techniques. The effect of Eu concentration (0.1 to 0.5 mol%) on the structural, optical, and luminescent properties of Ca2SiO4 has been studied in detail. The agro-food waste-derived phosphors exhibited intense emission at 625 nm corresponding to 5D0 → 7F2 transitions of Eu3+ ions under near-UV light excitation at 393 nm. The quenching mechanism and type of energy transfer interactions involved are studied via Blasse and Dexter’s theory. The photometric parameters such as CIE coordinates, CCT values, and color purity are calculated from emission spectra. Judd–Ofelt (?4) and other spectral parameters (radiative rates, branching ratio, radiative lifetime, and radiative cross-sectional area) are calculated as a probe to investigate the luminescent environment of Eu3+ ions in the Ca2SiO4 host lattice. The present agro-food waste-derived phosphors are expected to be promising candidates for UV-excited white light-emitting diodes in solid-state lightning and optoelectronic devices.
关键词： Judd–Ofelt theory,Ca2SiO4:Eu3+,Agro-food waste,Luminescence,Phosphors
更新于2025-09-16 10:30:52
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Standard and modified Judd-Ofelt theories in Pr3+-doped calcium aluminosilicate glasses: A comparative analysis
摘要： The small energy difference between the fundamental level and the first opposite parity configuration of Pr3+-doped hosts is particularly challenging for the characterization of radiative transitions using the Judd-Ofelt theory, although modified versions of the theory have been proposed in the past for the investigation of praseodymium doped materials. Here, we present a detailed spectroscopic investigation on two sets of calcium aluminosilicate glasses, with 34 wt.% of SiO2 (CAS) and with 7 wt.% of SiO2 (LSCAS), doped with different concentrations of Pr3+ (0.5, 1.0 and 2.0 wt.%). We use the standard Judd-Ofelt theory to characterize the glasses and the results and derived spectroscopic quantities — such as transition probabilities, radiative lifetimes and branching ratios — are compared to results obtained by the modified Judd-Ofelt theories. The analysis showed that the modified theories could lead to smaller values of root mean square deviations. However, a better agreement between experimental data and the standard theory was achieved when the derived spectroscopic quantities are taken into account. Moreover, the branching ratios of the 3P0 → 3H4 and 1D2 → 3H4 transitions were over 60% for both glass hosts, suggesting its potential use as solid-state laser devices.
关键词： Standard Judd-Ofelt theory,Aluminosilicate glass,Modified Judd-Ofelt theory,LSCAS:Pr3+,CAS:Pr3+
更新于2025-09-10 09:29:36
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Encyclopedia of Spectroscopy and Spectrometry || Optical Spectroscopy of Rare-Earth Ions in the Solid State
摘要： The birth of optical spectroscopy as science can be considered from the time when in 1672 Isaac Newton published his famous paper describing the results of experiments where, using a glass prism, he decomposed a beam of sunlight into its optical spectral components ranging from blue to red. Since that time, scientists and engineers studied a broad range of phenomena associated with the interaction of light with matter, using the fact that light actually contains different spectral components. Within a field of optical spectroscopy, it is hard to underestimate the importance of optical spectroscopy of different optical centers in solid-state materials because of numerous scientific and industrial applications of such optical systems. These applications range from studying fundamental properties of impurity centers in solids, solid-state material properties, up-conversion devices, scintillators, and Faraday rotators to a creation of solid-state lasers.
关键词： rare-earth ions,Fu¨chtbauer–Ladenburg theory,optical spectroscopy,Judd–Ofelt theory,McCumber theory,electron–phonon coupling,Franck–Condon principle,solid state
更新于2025-09-10 09:29:36