Judd Ofelt Research Articles

Thermal, Optical, and Emission Traits of SM3+-Ion-Doped Fluoride/Chloride/Oxide Glass for Red/Orange Laser Fiber Applications

This study examined spectroscopic, thermal, and other qualities, such as the lasing parameters, of Sm3+-doped glass with the composition 40P2O5–30ZnO–20LiCl–10BaF2. The ellipsometric data were used in a Sellmeier dispersion relation to estimate the refractive index values of the glasses investigated. The measured absorption spectra of the doped glass reveal the presence of various absorption bands assigned to transitions from the 6H5/2 ground state attributed to Sm3+-ion-excited states. We studied the decay of the 4G5/2 level of the Sm3+ ions in the doped glass by analyzing its absorption and emission fluorescence spectra. The Judd–Ofelt hypothesis allowed us to determine that the quantum efficiency of the 4G5/2–6H7/2 transition is high: 96% and 97% for glass doped with 4.05 × 1019 ions/cm−3 and 11 × 1019 ions/cm−3, respectively. Furthermore, this glass exhibits efficient red/orange enhanced spontaneous emission that matches the excitation band of the photosensitizer material used in medical applications.

Dy3+ ions in fluorophosphate glasses for luminescent white light applications

Abstract In this study, a series of fluorophosphate (FP) glasses, activated with Dy3+ ions and displaying concentration dependence, have been prepared and analysed for their suitability in luminescent white light applications. The melt quenching method was utilized to fabricate a set of FP glasses, doped with Dy3+ ions and possessing the composition of (60 − x) P2O5 + 10MgO + 10ZnO + 10BiF3 + 10KF + xDy2O3, where x ranges from 0.1 to 2.0 mol%. The structural properties of the samples were analysed using x-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR), and Raman spectroscopy while the optical properties of the samples were studied using absorption and emission spectra. The amorphous nature of the FP glasses was confirmed through SEM analysis and XRD profiles. Moreover, the presence of elements in their composition was verified using EDX. The FTIR spectra of the FP glasses exhibited vibration bands consistent with the characteristic phosphate groups, which was further supported by Raman analysis. The absorption spectra were used to calculate oscillator strengths (f exp & f cal) and Judd–Ofelt (JO) parameters Ω λ (λ = 2, 4, 6). The values of Ω λ (λ = 2, 4, 6) followed this order: Ω6 > Ω2 > Ω4. The emission spectra displayed three prominent transitions in the UV–visible region: (4F9/2 → 6H15/2) blue, (4F9/2 → 6H13/2) yellow, and (4F9/2 → 6H11/2) red. The peak at 553 nm (4F9/2 → 6H13/2) was the most intense and dominant. Radiative characteristics were evaluated from the emission spectra through the employment of JO intensity parameters and refractive indices. The Y/B intensity ratio values were greater than 1, indicating the high covalency of Dy3+ ions. The colour coordinates (x, y) and correlated colour temperature values of CIE 1931 were situated in the cool white region. The comprehensive analysis suggests that these glasses have the potential to become highly favourable candidates as luminescent components for solid-state white light emitting instruments.

Optical spectroscopy of Nd3+-doped cadmium-rich borate glasses for near-infrared laser applications

AbstractThe structural and spectroscopic properties of Nd3+-activated cadmium-rich borate (inverted) glasses are analyzed for near-infrared laser applications. The evaluation of the optimal glass-emitting sample by the Judd–Ofelt (JO) theory revealed JO parameter values of 4.56 × 10–20 cm2 (Ω2), 2.56 × 10–20 cm2 (Ω4), and 3.84 × 10–20 cm2 (Ω6). The Ω2 value, along with the experimental oscillator strength, suggested that the cadmium-rich borate glass could provide a more asymmetrical Nd3+ environment than other borate glasses like lithium-strontium-zinc, sodium-calcium, and lithium-lead-aluminum. In addition, the quality spectroscopy factor (χ = Ω4/Ω6) of 0.67 suggested that the 4F3/2 → 4I11/2 emission could be more suitable for laser applications. The stimulated emission cross-section (σp), theoretical quantum yield (ηQ), gain bandwidth (σp × Δλem), and optical gain (σp × τrad) laser parameters were close to those reported in sodium-calcium-borate, zinc-aluminum-barium-borate, and bismuth-borate glasses, while the non-radiative rate (WNR) and emission intensity saturation (IS) resulted to be lower. The emission spectra, under 808 nm laser excitation, displayed the featured neodymium 4F3/2 → 4I9/2,11/2,13/2 transitions, being the 4F3/2 → 4I11/2 (1058 nm) transition the more dominant one, in agreement with the χ parameter value. Nd3+ contents higher than 1.4 mol% led to emission quenching due to the increment of the cross-relaxation and/or energy migration rate. Such processes, according to the Inokuti–Hirayama model, were mainly mediated by electric dipole–dipole interactions within Nd–Nd clusters.

Growth and spectroscopy characteristics of Er, Ce:BGSO crystal: A promising material for eye-safe laser applications

Er, Ce co-doped BGSO single crystals were successfully grown by the Bridgman method. The growth parameters, including temperature gradient and growth rate, were optimized to achieve high-quality crystals. The crystal structure and morphology were characterized using X-ray diffraction and scanning electron microscopy. The optical absorption properties of Er, Ce co-doped BGSO single crystals were studied using UV–Vis absorption spectroscopy. The absorption spectrum revealed the absorption edge and the presence of absorption bands related to the presence of Ce dopant, providing valuable insights into the energy transfer processes occurring within the crystal lattice. Furthermore, the luminescence mechanism of BGSO crystals was analyzed using the Judd-Ofelt (J-O) theory, with detailed investigation into the role of ligands in spectral parameters. The photoluminescence spectra and emission decay time of Er, Ce co-doped BGSO single crystals were characterized. A comparative analysis with Er, Ce:BGSO crystals was conducted to investigate the sensitization mechanism of Ce ions on Er emission at 1.5 μm, demonstrating their potential for use as eye-safe laser materials in various applications.

Boosting Photoluminescence of Rare-Earth-Based Double Perovskites by Isoelectronic Doping of ns2 Metal Ions.

Doping of ns2 metal ions as an energy transfer (ET) bridge can significantly elevate the photoluminescence properties. Nonetheless, the fundamental influence of ns2 metal ions on the local lattice structures remains unclear, hindering the advancement of functional materials. Herein, Sb3+ doped rare earth double perovskites is employed as a typical case to demonstrate this issue. It is found that the isoelectronic doping of Sb3+ ions not only enhances the ET efficiency but also changes their localized electronic and lattice structures. Both density functional theory (DFT) and Judd-Ofelt (J-O) theory calculations provide unambiguous evidence that the isoelectronic doping of Sb3+ ions enables a more localized charge density in the [LnCl6]3- (Ln: Lanthanide) octahedron and reduces the symmetry of the environment around the Ln3+, facilitating the radiative transition rates of Ln3+ while enhancing their ET efficiency. Compared with Cs2NaScCl6:Ln3+, the ET efficiency of Cs2NaScCl6:Sb3+/Ln3+ is enhanced by 1.5-fold, reaching up to 98.3%. To the best of available knowledge, this work is the first to unravel the intrinsic mechanism of enhanced ET process enabled by isoelectronic doping via DFT and J-O theory. This research sheds light on understanding the mechanism of photophysics and rational design of the functional perovskite materials.

Spectroscopic Properties of TmF3-Doped CaF2 Crystals.

In this study, we report the growth and comprehensive spectroscopic analysis of TmF3-doped CaF2 crystals, grown using the vertical Bridgman method. The optical absorption and photoluminescence properties of both trivalent (Tm3+) and divalent (Tm2+) thulium ions were investigated. Optical absorption spectra in the UV-VIS-NIR range reveal characteristic transitions of Tm3+ ions, as well as weaker absorption bands corresponding to Tm2+ ions. The Judd-Ofelt (JO) formalism was applied to determine the intensity parameters Ω2, Ω4, and Ω6, which were used to calculate radiative transition probabilities, branching ratios, and radiative lifetimes for the Tm3+ ions. The emission spectra showed concentration-dependent quenching effects, with significant emissions observed for the concentration of 0.1 mol% TmF3 under excitation at 260 nm and 353 nm for Tm3+ ions and at 305 nm for Tm2+ ions. A new UV emission associated with divalent Thulium is reported. The results indicate that higher TmF3 concentrations lead to increased non-radiative energy transfer, which reduces luminescence efficiency. These findings contribute to the understanding of the optical behavior of Tm-doped fluoride crystals, with implications for their application in laser technologies and radiation dosimetry.

Comparative study of spectroscopic properties of Er3+-ion doped K2O/KF-Gd2O3-P2O5 glass systems

The two phosphate glasses with composition 17K2O−17Gd2O3−65P2O5−01Er2O3 and 17KF−17Gd2O3−65P2O5−01Er2O3 composition were synthesized by conventional-melt quenching techniques to study comparatively the spectroscopic, Judd–Ofelt (JO), radiative properties and NIR-luminescent properties. The Urbach energy of K2O−Er and KF-Er samples was 0.3547 and 0.4799 eV. The observed trend is Ω2>Ω4>Ω6 and Ω2>Ω6>Ω4 for JO-intensity-parameters for K2O−Er and KF-Er glasses. Moreover, K2O−Er has higher Ω4 and Ω6 values, thus having more rigidity and viscosity than KF-Er. The measured values of full-width-half-maximum (FWHM) for K2O−Er and KF-Er glasses 54.60 and 58.27, respectively. The measured values of FWHM for K2O−Er and KF-Er glasses were 54.60 and 58.27, respectively. The A R values are 417.61 and 3038 for K2O−Er and KF-Er glasses, respectively. The radiative lifetime (τ R ) for K2O−Er and KF-Er glasses is 2.39 ms and 3.18 ms, respectively. Utilizing McCumber theory the G(λ,β) is positive and population-inversion is more than 0.4 for both glasses. Both samples have flat gain-bandwidth in the range of 1505–1585 nm, which covers the S-, C-, and L-bands of the low-loss optical communication-window. It is evident from all these results that the prepared glass samples have the potential for a low-threshold and high gain NIR laser and optical-fiber amplifier.

Judd-Ofelt analysis and temperature sensing properties of polyethylmethacrylate (PEMA) networks doped with CdNb2O6: Er3+/Yb3+ phosphors

Research on the sensitivity of temperature measurements and optical thermometry involving rare earth ions has been an area of interest in the field of photonics and materials science. Introducing polymer networks as a new host material has an important role due to their properties including a versatile and stable environment for rare earth ions and rapid response in temperature detection. In this work, linear and crosslinked polyethylmethacrylate (PEMA) networks doped with Er3+/Yb3+ (1.5 mol % Er3+, 2 mol% Yb3+) synthesized by free-radical crosslinking polymerization with 0.1 EMA (weight %) at 60 °C were used to investigate direct and indirect optical bandgap energies and Urbach energy from UV–Visible spectra. The Judd-Ofelt (JO) approach was employed to analyze parameters Ωt (t = 2,4,6), spontaneous transition probabilities (Α), branching ratios (β) and radiative lifetimes (τ) as a function of linear and crosslinked PEMA doped nano-crystalline CdNb2O6: Er3+/Yb3+. The stimulated emission cross-sections of the transitions 2H11/2⟶4I15/2, 2S3/2⟶4I15/2 and 2F9/2⟶4I15/2 of Er3+/Yb3+ were calculated by two different methods; Fuchtbauer-Ladenburg formula and modified theory, respectively. The gain bandwidth cross-section product for the 2H11/2⟶4I15/2 was found to be 162.06. 10−28cm3, 260.94. 10−28cm3 and 461.20. 10−28cm3 of Er3+/Yb3+ embedded in linear, low and high crosslinked PEMA samples, respectively. JO parameters and stimulated emission cross-sections increased; therefore, radiative lifetimes decreased by increasing crosslinking content. In addition, the temperature dependence of upconversion (UC) luminescence was monitored under 975 nm excitation. The fluorescence intensity ratio (FIR) method examined the temperature sensing under two thermally coupled levels at 525 and 548 nm. The maximum sensitivities obtained from the FIR technique within the 300–650 K temperature range shifted to lower temperatures with increasing crosslinker content. Hence, linear and crosslinked polymer hosts doped rare-earth ions can be candidates for remote temperature sensors across various fields.

Photoluminescence studies of Sr3P4O13: Eu3+ phosphor prepared by wet chemical method: Structural properties, charge compensation via alkali metal ions and Judd-Ofelt analysis

The Sr3P4O13:Eu3+ phosphors co-doped with alkali metal ions (A+ = Li+, Na+ and K+) were prepared by wet chemical method. The comparison with standard JCPDS data confirmed the formation of a triclinic crystalline phase with P-1(2) space group for the Eu3+ doped Sr3P4O13 phosphor and co-doped with alkali metal ions. The Li+ co-doped Sr3P4O13:Eu3+ phosphor has comparatively sharp and intense XRD patterns. The scanning electron microstructural analysis confirmed the formation of the particles size of 5 -50 μm. The comparative study of photoluminescence properties depicted that the peak positions were similar for all the prepared samples. The photoluminescence analysis of Sr3P4O13:Eu3+ phosphors show the emission in the red-orange region under the excitation of 394 nm (7F0→5L6) wavelength. Further, the charge compensation using alkali metal ions shows the larger photoluminescence intensity observed in the case of the Li+ co-doped Sr3P4O13:Eu3+ phosphors suggesting that the Li+ ion is better charge compensator among the studied alkali metal ions. Further, Judd-Ofelt (J-O) parameters were estimated for the Sr3P4O13:Eu3+ phosphors and co-doped with alkali metal ions in a series of samples. The comparison of Sr3P4O13:Eu3+ phosphors co-doped with alkali metal ions alongwith the J-O estimated parameters have been presented in the article.

Dysprosium ion concentration variations and their comprehensive influence on the physical, structural and optical properties of multi-component borate glasses for luminescence tailoring

A set of Zinc Strontium Lithium Fluoroborate (ZSLFB) glasses with different concentrations of Dysprosium ions (Dy3+) was created using the melt quench technique. The presence of non-crystallinity and various functional groups have been confirmed via X-Ray Diffraction (XRD) and Infrared Fourier Transform FT-IR measurements, respectively. The band gap values obtained from Tauc plot were utilised to analyse the optical characteristics. The photoluminescence (PL) emission spectra display three well-defined intensity peaks at wavelengths of 481, 574, and 664 nm. The intensity of peaks exhibits an ascending trend until a concentration of 0.5 mol% of Dy3+ ions is reached, after which it decreases. The PL intensity maintains up to 82 % at 200° C to room temperature, showing excellent thermal stability. The Judd Ofelt (J-O) parameter values pursue the Ω2 > Ω6 > Ω4 pattern, which shows its asymptotic nature. The CIE coordinates were assessed and determined to fall inside the white region. The interaction in the non-radiative energy transfer process was elucidated by utilizing the Dexter theory and Inokuti-Hiryama (I-H) model.

Multifunctional BiOCl: Sm3+ nanophosphors: A luminescent platform for solid-state lighting applications, optical thermometry, photocatalytic and forensic applications

Rare earth-activated phosphor materials have been widely used as active probes in optical materials for multidimensional applications. Here, we report a series of ultrahigh purity orange-red emitting BiOCl: xSm3+ (x= 0.5- 2.5 mol %) nanophosphors synthesized via conventional solid-state method at relatively low temperatures for various photonic and forensic applications. XRD and Rietveld refinement results confirmed the tetragonal crystal structure of the synthesized phosphor materials with space group P4/nmm. Fourier transform infrared (FT-IR) and Raman spectroscopy were used to perform the functional group analysis. The UV-Vis-NIR spectra were analyzed to determine the Judd-Ofelt (JO) intensity parameters (Ω2, Ω4, Ω6) and to identify the bonding structure and spontaneous emission properties of the samples. The prepared phosphors exhibit intense orange-red emission under 408 nm excitation and beyond 1 mol% doping of Sm3+ ions, the emission intensity decreases due to concentration quenching mechanism via, dipole-dipole interaction between the optically active Sm3+ ions in the phosphor sample. The synthesized BiOCl: Sm3+ nanophosphors possess low correlated color temperature (CCT), admirable high color purity (99.4%) and outstanding internal quantum efficiency (IQE) of 95.27%. The optical thermometry behavior of the optimized sample has been investigated in detail. Moreover, the optimized nanophosphor stains on porous and non-porous surfaces show clear ridge patterns with high sensitivity, efficiency, and minimal background hindrance for latent fingerprints and lip print detection in forensic applications and are used as security ink in anti-counterfeiting applications. Overall, the results revealed the potential prospects of BiOCl: Sm3+ nanophosphors in the field of display applications, optical thermometry, and forensic sciences.

Research on optical performance of Ln2O2S:Er3+/Yb3+ (Ln = La/Gd/Y) phosphors based on different phonon energies.

It is crucial to explore the intrinsic mechanisms that influence thermometric sensitivity. This study investigates the optical performance of materials with the same crystal structure but different phonon energies. Ln2O2S:Er3+/Yb3+ (Ln = La/Gd/Y) phosphors with similar morphology and particle sizes were prepared to systematically study the influence of different phonon energy matrices on optical properties. The intrinsic mechanism was elucidated through the matching degree between the energy gap and phonon energy, Judd-Ofelt (J-O) theory, and quantum dielectric theory. It was ultimately concluded that the combination of high phonon energy with a large Ω2 and a small Ω6 is beneficial for enhancing the sensitivity of temperature sensing materials.

Spectroscopic analysis of La2(WO4)3:Tb3+ phosphor and the delayed concentration quenching of 5D4 →7FJ emission

Trivalent terbium ion doped lanthanum tungstate (La2-xTbx(WO4)3; x = 0.6,1.0,1.4) and terbium tungstate (Tb2(WO4)3) phosphors were successfully synthesized via optimized microwave-assisted co-precipitation technique. The phase purity and crystallinity of the prepared samples were confirmed using the powder XRD technique. The photoluminescence studies revealed a quenching-free emission up to 70 % of Tb3+ doping concentration, even though the emission intensity slightly decreases under host excitation since it becomes less relevant at higher doping concentrations. The experimental and calculated oscillator strengths were evaluated using absorption data and further used to quantify the Judd - Ofelt (JO) intensity parameters, which appeared in a trend of Ω2>Ω4>Ω6 for all samples. As a theoretical approach to assure the excellency of the tungstate host, the radiative parameters were calculated from the emission data using the JO analysis technique. The dominance in the values of stimulated emission cross section and gain bandwidth corresponding to 5D4→7F5 transition of Tb3+ ion of lanthanum tungstate proclaims it as an excellent green phosphor. Hence, the less susceptibility of the tungstate host towards concentration quenching is confirmed in the present work.

First Achievement of Yellow Laser Operation in Dy3+-Doped Borate Crystals.

Continuous-wave (CW) yellow lasers have been demonstrated successfully by using a GaN laser-diode (LD) pumping in borate crystals for the first time. The Dy3+:GdMgB5O10 (Dy:GMB) crystal with dimensions up to 33 × 19 × 15 mm3 is grown by the top-seeded solution growth method, and the polarized spectroscopic properties are investigated systematically at room temperature. The line strengths, Judd-Ofelt (J-O) intensity, spontaneous transition rates, fluorescence branching ratios, and radiative lifetimes are calculated in detail by the Judd-Ofelt theory. Under direct pumping of 452 nm LD, a compact continuous-wave yellow laser with a maximum output power of 628 mW and laser wavelength of 581 nm is generated based on a Y-cut Dy:GMB crystal. To our knowledge, it is not only the highest output power for yellow laser obtained in Dy3+-doped crystals but also the first yellow laser operation achieved by borate crystals under direct LD pumping. The results reveal that the Dy:GMB crystal is an optical material with important application prospects in yellow laser.

Structure and photoluminescence properties of coordination compound [Eu2(o-MBA)6(phen)2] with high quantum yield

An europium(III) coordination binuclear compound [Eu2(o-MBA)6(phen)2] (o-MBA = ortho-methylbenzoate, phen = 1,10-phenantroline) has been synthesized and investigated by X-ray diffraction method, thermogravimetric analysis (TGA), infrared (IR) and photoluminescence (PL) spectroscopy. The single crystal X-Ray diffraction measurements show that the compound crystallizes in the triclinic centrosymmetric space group P-1. The PL excitation spectrum displays a broad band between 300 and 420 nm and a number of sharp transitions between 384 and 590 nm, which can be attributed to the Eu3+ 4f6 intra-shell excitation transitions. The complex exhibits characteristic narrow, metal-centred emission bands, which are determined by the radiative transitions of the Eu3+ ion, from the first excited non-degenerate 5D0 level to the 7FJ (J = 0–4) manifold. The compound shows intense hypersensitive transition 5D0→7F2 which dominates the PL emission spectrum. The dipole strengths of the transitions were determined from the emission spectra in terms of Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4). The high intensity bright-red emission of the complex can be attributed to highly polarizable ligands environment and the low site symmetry (Ci) around the lanthanide ions. We suppose that the J-mixing effect in the Eu(III) ions is responsible for enhanced peak maximum of the 5D0→7F0 transition.

Spectroscopic properties of Pr3+-doped Titania-Silicate glass ceramic for photonic applications

Silicate-Titania (SiTi) glass-ceramics doped with Pr3+ (0.6, 1.6, 2.4 and 3.6 mol%) ions were prepared by sol-gel technique. The materials were characterized by powder XRD, FTIR, TEM, EDX, Optical absorption and Photoluminescence spectroscopy. The identification of non-bridging oxygen (NBO) formation and the removal of OH groups are validated through analysis of the FTIR spectra. Additionally, measurements using XRD and TEM showed that the samples contain nano-sized crystallites. The three phenomenological Judd–Ofelt (J–O) intensity parameters Ω2, Ω4, and Ω6 were obtained and used to analyze different radiative characteristics for the fluorescence levels of Pr3+ in the glass ceramic, including radiative lifetime, branching ratio, radiative transition probability and stimulated emission cross-section. Several emissions were observed in the visible region, among which the 1D2→3H4 in the orange-red region is the most intense. All of these reported branching ratios, stimulated emission cross-sections, and visible emission spectra point to the possibility of employing them as red region lasers. The CIE chromaticity coordinates from all of the emission spectra were also assessed to determine if these materials are suitable for orange-red phosphors. According to CIE chromaticity investigations, 1.6 mol% of Pr3+ ion concentration is ideal for SiTiPr glass-ceramic for use as red phosphors and possibly red lasers.

Prediction of optical properties of rare-earth doped phosphate glasses using gene expression programming

The progression of optical materials and their associated applications necessitates a profound comprehension of their optical characteristics, with the Judd–Ofelt (JO) theory commonly employed for this purpose. However, the computation of JO parameters (Ω2, Ω4, Ω6) entails wide experimental and theoretical endeavors, rendering traditional calculations often impractical. To address these challenges, the correlations between JO parameters and the bulk matrix composition within a series of Rare-Earth ions doped sulfophosphate glass systems were explored in this research. In this regard, a novel soft computing technique named genetic expression programming (GEP) was employed to derive formulations for JO parameters and bulk matrix composition. The predictor variables integrated into the formulations consist of JO parameters. This investigation demonstrates the potential of GEP as a practical tool for defining functions and classifying important factors to predict JO parameters. Thus, precise characterization of such materials becomes crucial with minimal or no reliance on experimental work.

Investigation of growth and polarized spectra of Ho3+ ions heavily doped BaY2F8 crystal

A BaY2F8 (BYF) single crystal heavily doped with Ho3+ ion was grown successfully using the Czochralski (Cz) method. The infrared fluorescence spectra (2–4 μm) and fluorescence lifetime at 3.9 μm were investigated. The detailed polarization absorption properties of Ho:BYF, especially the absorption spectrum in 850–950 nm range, were reported for the first time. The maximum absorption cross-section was at 888.15 nm, σabs = 1.26✕10−21 cm2 (E//c). In comparison, the peak positions of the absorption cross sections in the other two polarization directions were at 885.80 nm and 890.45 nm, respectively, indicating that incident light's polarization direction greatly influences absorption. The spectroscopic parameters were calculated based on the Judd–Ofelt theory.

Microwave melt-quenching technique to synthesize of CuO-doped B2O3–ZnO–Na2O–Sm2O3 scintillating glasses

The new series of CuO-doped samarium sodium zinc borate (SNZB) glasses, with the composition (59.5-x)B2O3:30ZnO:10Na2O:0.5Sm2O3 (x = 0.00–0.10 mol%), were prepared using the microwave melt-quenching technique. These glasses were characterized through XRD, absorption, excitation, photoluminescence (PL), and X-ray luminescence (RL) spectral measurements. The optical absorption analysis revealed a significant increase in the visible Cu2+ absorption band at approximately 770 nm with the addition of CuO at concentrations ranging from 0.00 to 0.10 mol%. From the absorption spectra of SNZBCu-0.00, the Judd-Ofelt (J-O) intensity parameters (Ω2, Ω4, Ω6) were determined. Under 402 nm excitation, the PL spectra exhibited a bright reddish-orange emission at 600 nm. The decay spectral profiles of the 4G5/2 → 6H7/2 (600 nm) luminescence transition were used to measure experimental lifetimes (τg).

Photoluminescent and X-ray photoemission studies of Eu3+-doped kosnarite KZr2(PO4)3 nanophosphor and its Judd–Ofelt analysis

Photoluminescent and X-ray photoemission studies of Eu3+-doped kosnarite KZr2(PO4)3 nanophosphor and its Judd–Ofelt analysis