3d Levels Research Articles

Single Crystal Preparation and Luminescent Properties of Lu2O3:Eu Scintillator by Vertical Bridgman Method

AbstractEuropium‐doped lutetium oxide (Lu2O3:Eu) single crystal is grown by vertical Bridgman method for the first time. Correlated measurements of X‐ray diffraction, X‐ray fluorescence spectra, optical transmittance, photoluminescence excitation, photoluminescence (PL), PL decay, and X‐ray excited luminescence (XEL) spectra are performed. The transmittance of about 80% above 300 nm indicates that the crystal is of good optical quality. By measuring actual Eu3+ concentration, the effective segregation coefficient of Eu3+ in the Lu2O3:Eu crystal is calculated to be 0.75. In the PL spectrum, the dominant emission peaks at 612 and 630 nm originate from the 5D0→7F2 transitions of Eu3+ in C2 site. It is worth mentioning that several emission peaks between 575 and 605 nm mainly ascribe to the transitions of different 5D0 levels to the split 7F1 levels of Eu(C2) or Eu(C3i). PL decay spectra indicate the decay time of 612 nm emission can be determined about 1.0 ms. The decay curve of 582.6 nm emission can be fitted into triple components, and the 5.3 and 1.4 ms components are attributed to Eu3+(C3i) and Eu3+(C2), respectively. The XEL strongest emission of Lu2O3:Eu sample is around 612 nm with a bright red luminescence that matches silicon photodetectors sensitivity.

Comparison between glass and crystal phase of europium 3 + doped Bi2ZnOB2O6

Comparison of optical excitation and emission spectra of trivalent europium (Eu3+) ions in Bi2ZnOB2O6 in both crystal and glass phase was performed. Emission and excitation spectra were studied at low (10 K) and at room temperature. Strong, orange-red emissions of Eu3+ centred at 592 and 615 nm originate mainly from the 5D0 → 7F1 and 5D0 → 7F2 transitions, respectively, both in the crystal as well as in a glass phase of the material. The Ω2,4,6 parameters as well as radiative lifetimes of the 5D0 states were calculated based upon the Judd-Ofelt formalism. The calculated values were compared with the measured values for 5D0 level. The obtained results indicated that Eu3+:BZBO is a promising emitter of orange-red luminescence in a crystal as well as in a glass phase.

Energy Transfer Studies in Tb3+-Yb3+ Co-Doped Phosphate Glasses.

Detailed optical properties of Tb3+-Yb3+ co-doped phosphate glasses were performed based on their emission spectra and decay measurements. Under blue excitation of Tb3+ at 488 nm, the intensity of Yb3+ emissions gradually enhanced upon increasing the Yb3+ content until 1 mol% indicated an energy transfer from Tb3+ to Yb3+. Otherwise, under near infrared excitation of Yb3+ at 980 nm, these glasses exhibit intense green luminescence, which led to cooperative sensitization of the 5D4 level of Tb3+ ions. A cooperative energy transfer mechanism was proposed on the basis of the study on the influence of Yb3+ concentration on up-conversion emission intensity, as well as the dependence of this up-conversion intensity on near infrared excitation power. Moreover, the temporal evolution of the up-conversion emissions have been studied, which was in positive agreement with a theoretical model of cooperative up-conversion luminescence that showed a temporal emission curve with rise and decay times of the involved levels.

Site-Selective Eu3+ Luminescence in the Monoclinic Phase of YSiO2N

Eu3+-doped YSiO2N phosphor was synthesized, and its crystal structure was analyzed by single-crystal X-ray and neutron powder diffraction techniques. The new crystal structure of YSiO2N with the monoclinic lattice (space group C2/c) composed of nonequivalent [YO6N2] dodecahedra was identified, and, in this structure, five different Y3+ sites take Ci or Cn symmetry. Based on the experimentally determined crystal structure, we characterized the luminescence properties of the Eu3+ ions with site-selective and time-resolved spectroscopy. The Eu3+ ions at the Y: Cn sites show intense 5D0 → 7F2 electric dipole luminescence peaking at 626 nm with a short lifetime (0.61 ms) due to the lack of inversion center. In the centrosymmetric Ci sites, the lifetime of the 5D0 level was quite long (5.51 ms), and the strongest three peaks are assigned to the 5D0 → 7F1 magnetic dipole transition instead of 5D0 → 7F2. The anomalous temperature dependence of the long lifetime for Eu3+: 5D0 at this Ci site at low temperatures suggests that the slow radiative rate can be influenced by the thermal distortion of centrosymmetry. The thermal quenching mechanism of the Eu3+: 5D0 luminescence at both sites is considered to be due to the charge transfer states related to the N3– ions in the [Eu3+O6N2] dodecahedra rather than the multiphonon relaxation mechanism. This study shows the potentials of Eu3+ luminescence in oxynitride coordination and provides new insights into the material design guidelines for near-UV excitable red phosphor activated with Eu3+ ions.

Synthesis and enhanced photoluminescence properties of red emitting divalent ion (Ca2+) doped Eu:Y2O3 nanophosphors for optoelectronic applications

This work presents the synthesis of Y2O3:Eu3+,xCa2+ (x = 0 mol%, 1 mol%, 3 mol%, 5 mol%, 7 mol%, 9 mol%, 11 mol%) nanophosphors with enhanced photoluminescence properties through a facile solution combustion method for optoelectronic, display, and lighting applications. The X-ray diffraction (XRD) patterns of the proposed nanophosphor reveal its structural properties and crystalline nature. The transmission electron microscope (TEM) results confirm the change in the shape of the particle and aggregation of particles after co-doping with Ca2+. Fourier transform infrared spectroscopy (FTIR) and Raman vibrations also confirm the presence of Y–O vibration and subsequently explain the crystalline nature, structural properties, and purity of the samples. All the synthesized nanophosphors samples emit intense red emission at 613 nm (5D0→7F2) under excitation with 235, 394 and 466 nm wavelengths of Eu3+ ions. The photoluminescence (PL) emission spectra excited with 235 nm illustrate the highest emission peak with two other emission peaks excited with 466 and 394 nm that is 1.4 times higher than 466 nm and 1.9 times enhanced by 394 nm wavelength, respectively. The emission intensity of Y2O3:Eu3+,xCa2+ (5 mol%) is increased 8-fold as compared to Eu:Y2O3. Doping with Ca2+ ions enhances the emission intensity of Eu:Y2O3 nanophosphors due to an increase in energy transfer in Ca2+→Eu3+ through asymmetry in the crystal field and by introduction of radiative defect centers through oxygen vacancies in the yttria matrix. It is also observed that the optical band gap and the lifetime of the 5D0 level of Eu3+ ions in Y2O3:Eu3+,xCa2+ nanophosphor sample gets changed with a doping concentration of Ca2+ ions. Nanophosphor also reveals high thermal stability and quantum yield as estimating activation energy of 0.25 eV and 81%, respectively. CIE, CCT, and color purity values (>98%) show an improved red-emitting nanophosphor in the warm region of light, which makes this material superior with a specific potential application for UV-based white LEDs with security ink, display devices, and various other optoelectronics devices.

A flexible Eu:Y2O3-polyvinyl alcohol photoluminescent film for sensitive and rapid detection of arsenic ions

The present article reports the synthesis and characterization of Eu:Y2O3 nanophosphor (EYN) and EYN dispersed polyvinyl alcohol (PVA) fluorescent film (EYF), with subsequent studies of sensing behavior for the detection of heavy metal ions particularly arsenic ions (As3+) in real water samples. Various characterization techniques have been employed to confirm the successful phase formation/stability of EYF. The maximum emission peak for EYF with excitation wavelength 394 nm has been obtained as 612 nm and hence picked for the demonstration of PL (Photoluminescence) response with arsenic ions solution in natural pH range (at ∼ 7 pH). Fluorescence intensities of EYF have been found to decrease quickly with As3+ ion contents due to the reduction in the population of Eu3+ ions in the 5D0 level and also due to formation of direct or indirect coordinate bonds with Eu3+. The PL intensity of the EYF nanoprobe has completely been quenched at 260 µg/L concentration of As3+ ions with the limit of detection 57.5 ng/L (=0.057 ppb) for 0–100 µg/L linear range. The selectivity of EYF probe is also investigated for various common cations and ions present in real water samples. Moreover, sensing probe has been examined with different river water samples and shows recovery percent in between 98 and 105 & maximum % RSD value as 5.76 with n = 5 tests. Furthermore, the EYF sensing probe shows a visible color change with the contaminated water under UV–Vis light which useful for the onsite detection of arsenic concentration. Hence, EYF endows a promising pathway for a flexible, portable, low-cost sensing device for the sensitive and selective detection of arsenic ions in real water samples.

Strain modulated luminescence in (Ca,Sr)TiO3:Pr3+ perovskite thin films

We report in-plane strain effect on the photoluminescence property of perovskite phosphor thin films. Epitaxial perovskite thin films of Ca0.6Sr0.4TiO3:Pr3+ phosphor were prepared on perovskite oxide substrates with different lattice constant a, LaAlO3 (LAO, a = 3.815 Å), (LaAlO3)0.3-(SrAl0.5Ta0.5O3)0.7(LSAT, 3.868 Å), and SrTiO3 (STO, 3.905 Å) by a pulsed laser deposition method. From X-ray diffraction, the lattice constants of thin films on LAO, LSAT, and STO substrates were (a, c) = (3.815 Å, 3.956 Å), (3.871 Å, 3.880 Å), and (3.905 Å, 3.865 Å), respectively. Therefore it was confirmed that compressive-strained (∼4%), nearly strain-free, and tensile-strained (∼1%) films were obtained on the LAO, LSAT and STO substrates, respectively. Under N2 laser excitation at 337 nm which is above bandgap energy of thin films, the CSTO film on STO (tensile-strained) and on LSAT (strain-free) substrate showed intense red photoluminescence peaking at 612 nm due to Pr3+:1D2→3H4 transition and no photoluminescence lines from the 3PJ revels were observed at 300 K. On the other hand, the phosphor film on LAO (compressive-strained) showed blue and red luminescence which ascribed to the transitions from the Pr3+:3P0 level below 200 K. These results showed that initial state of photoluminescence can be tuned from the 1D2 level to the 3P0 level by biaxial strain not by composition in the Pr3+ doped perovskite phosphor films. The temperature dependence of photoluminescence was also explained by simplified four-level-model with carrier-trapping-center probably related to Ti center.

Scintillation yield and temperature dependence of radioluminescence of (Lu,Gd)3Al5O12:Ce garnet crystals

The scintillation characteristics of Lu3-xGdxAl5O12:Ce (x = 1, 1.25, 1.75, 2, and 2.25) garnet crystals were investigated. With increasing Gd content, the Ce3+ 5d1 → 4f luminescence band was red-shifted due to an increase in the crystal field splitting of the 5d levels. In addition, both the light yield value and contribution of fast scintillation component increased. We attribute this effect to the reduced electron trapping effects of shallow traps buried in the bottom of the conduction band, the lower-energy shift of which is due to the increasing Gd content. A decrease of scintillation yield at the lowest temperature region observed for all samples, showing large thermoluminescence peaks in the same temperature range, can be caused by the localization of electrons at shallow traps. Afterglow signals observed at 10 K for all samples after X-rays irradiation can be explained by quantum tunneling of electrons from nearby traps towards the holes captured at the Ce3+ recombination centers.

Temperature dependence of red emission in YPO4:Pr3+ nanopowders

In order to compare spectroscopic properties between nanosized and that in single crystal form of YPO4:Pr3+, temperature-dependence of the red emission from 3P0 → 3H4 and 1D2 → 3H4 transitions of YPO4:0.1 at. % Pr3+ nanopowders has been investigated in details. The emission spectra of the sample in size of 20 nm, under selective excitation at 3P2, measured at different temperatures, T = 10, 100, 200 and 300 K have been recorded. The variation of emission intensity of each 3P0 → 3H4 and 1D2 → 3H4 against temperature has been investigated. Several spectral lines constitute 1D2 → 3H4 emission, assigned to transitions between 1D2 and 3H4 Stark levels are observed with no noticeable shifts between them and those observed at the single crystal. It is found that 1D2 → 3H4 emission intensity dominates that of 3P0 → 3H4 transition, pointing out the high efficiency of the multiphonon relaxation (MPR) process from 3P0 to 1D2. Fitting the temperature dependence of 3P0 → 3H4 emission intensity permits to estimate the phonons and their energies involved in non-radiatively transition between 3P0 and 1D2 levels, which are found different from single crystal. Also, fitting the multiphonon relaxation (MPR) rates against temperature, extracted from the measured 1D2 lifetime gives information that seven phonons can be involved to bridge the gap between 1D2 and 1G4. Furthermore, the possibility to use the YPO4: 0.1 at. % Pr3+ in the nano-thermometry application in temperature range T = 10–300 K was investigated.

First-principles study of the Li(Y/Lu)SiO4:Ce3+,Sm3+ storage phosphor

First-principles calculations are carried out to study the native point defects and dopants (Ce3+, Sm3+) in Li(Y/Lu)SiO4 for revealing the mechanism of the optical excitation energy storage properties. The calculated excitation and emission energies, the Stokes shifts as well as the positions of 4f and 5d levels of Ce3+ relative to host band edges show great consistent with the experimental results. The calculated formation energies reveal that the Li vacancies (VLi) and the antisite defects LiY and YLi (or LiLu and LuLi) are always much more energetically favorable than Y or Lu vacancies (VY or VLu) and O vacancies (VO) in Li(Y/Lu)SiO4 under reductive atmospheres. Moreover, according to the calculated charge transition levels of the native point defects and the dopants, the antisite defects YLi (or LuLi) and the dopants Sm3+ (SmY or SmLu) are deemed as electron traps that provide suitable charge transition levels for information storage in Li(Y/Lu)SiO4. Based on our calculations, a mechanism diagram of charge carrier storage and recombination during irradiation and thermal or optical readout is constructed for the storage phosphors Li(Y/Lu)SiO4:Ce3+,Sm3+.

Ultrasound-Assisted Synthesis of Luminescent Micro- and Nanocrystalline Eu-Based MOFs as Luminescent Probes for Heavy Metal Ions

The luminescent coarse-, micro- and nanocrystalline europium(III) terephthalate tetrahydrate (Eu2bdc3·4H2O) metal-organic frameworks were synthesized by the ultrasound-assisted wet-chemical method. Electron micrographs show that the europium(III) terephthalate microparticles are 7 μm long leaf-like plates. According to the dynamic light scattering technique, the average size of the Eu2bdc3·4H2O nanoparticles is equal to about 8 ± 2 nm. Thereby, the reported Eu2bdc3·4H2O nanoparticles are the smallest nanosized rare-earth-based MOF crystals, to the best of our knowledge. The synthesized materials demonstrate red emission due to the 5D0–7FJ transitions of Eu3+ upon 250 nm excitation into 1ππ* state of the terephthalate ion. Size reduction results in broadened emission bands, an increase in the non-radiative rate constants and a decrease in both the quantum efficiency of the 5D0 level and Eu3+ and the luminescence quantum yields. Cu2+, Cr3+, and Fe3+ ions efficiently and selectively quench the luminescence of nanocrystalline europium(III) terephthalate, which makes it a prospective material for luminescent probes to monitor these ions in waste and drinking water.

Enhanced broadband orange-red emission of Eu3+ via Sm3+ co-doping in YAlO3 single crystal

Sm3+/Eu3+: YAlO3 (Sm3+/Eu3+: YAP) single crystal with a size of Ф (25-35) mm × (50-60) mm was successfully grown and analyzed. The use of Sm3+ co-doping to enhance Eu3+: 5D0 → 7F2 orange-red emission has been investigated in the YAP crystal for the first time. Compared with the Eu3+ single-doped YAP crystal, the Sm3+/Eu3+ co-doped YAP crystal possessed a larger fluorescence emission cross section (0.90×10−21 cm2), higher quantum efficiency (78.4%), and comparative fluorescence lifetime (1.74 ms), corresponding to the stimulated emission of Eu3+: 5D0 → 7F2 transition. Moreover, the energy transition efficiency of the energy transition process from the Sm3+: 4G5/2 level to the Eu3+: 5D0 level was calculated to be as high as 47.31%. These results suggest that Sm3+ ion can be used as an efficient sensitizer to enhance the orange-red fluorescence emission and can lead to the expansion of the emission range from 585–640 nm in Sm3+/Eu3+ co-doped YAP crystal.

Energy transfer and luminescent properties of Tb3+ and Tb3+, Yb3+ doped CNGG phosphors

In this work, calcium niobium gallium garnet (Ca3Nb1.6875Ga3.1875O12 - CNGG) ceramic samples single-doped with Tb3+ and co-doped with Tb3+ and Yb3+ ions were sintered by the solid-state reaction method. The structural characterization of the samples was carried out by X-ray diffraction measurements. The optimal concentration of Tb3+ ions corresponding to the maximum luminescence in the green spectral range in CNGG:x at% Tb (x = 0.1, 0.5, 1, 2, 3, 4, and 5) was determined to be 4 at%. The time-resolved luminescence of the 5D4 level (Tb3+) in the CNGG:x at% Tb samples was analysed to explore the quenching mechanisms involved in the Tb3+ green emission. Co-doped CNGG:4 at% Tb,y at% Yb (y = 0.5, 2, 4, 6, 8, and 10) ceramics were prepared and investigated. It is shown that CNGG:4 at% Tb,y at% Yb phosphors exhibit intense green luminescence under ultra-violet (UV), visible (VIS), and near-infrared (NIR) excitation, thus demonstrating the presence of simultaneous down-conversion (DC) and up-conversion (UC) processes. The dependence of the UC luminescence intensity on the diode laser pumping power was measured and the results indicate a two-photon process based on cooperative energy transfer (CET). Under UV excitation, the lifetime of the 5D4 (Tb3+) level slowly increases with increase of Yb3+ concentration, suggesting the energy transfer from Yb3+ to Tb3+ ions, while under NIR excitation, the lifetime of the 5D4 (Tb3+) level decreases with increase of Yb3+ ions concentration, indicating the presence of a strong energy transfer from Tb3+ to Yb3+ ions. The highest energy transfer efficiency of ηET ≈42% was determined for the CNGG:4 at% Tb,10 at% Yb sample. The obtained results indicate that CNGG:(Tb3+, Yb3+) could be efficient new yellowish-green-emitting phosphors.

A Highly Efficient Eu2+ Excited Phosphor with Luminescence Tunable in Visible Range and Its Applications for Plant Growth

AbstractA series of RbxK2−xCaPO4F:Eu2+ phosphors are synthesized using a high‐temperature solid‐phase method. An increase in the Rb+ concentration leads to the Eu2+‐excited phosphor emission spectra being shifted from red to cyan. Interestingly, the excitation spectrum does not exhibit any variations, which indicates the possibility of mixing the red (Rb0.2K1.8CaPO4F:Eu2+) and cyan (Rb2CaPO4F:Eu2+) phosphors for plant growth. This luminescence tuning is attributed to the substitution of K+ with Rb+, which produces an inferior crystal‐field splitting that increases the energy at the lowest 5d level, and enhances the rigidity of the crystal structure, which results in a gradual decrease in the Stokes shift and a consequent blue shift in the emission spectrum. Time‐resolved photoluminescence emission spectroscopy further confirms the occurrence of broadband emission owing to the occupation of multiple sites by Eu2+. Light‐emitting devices appropriate for plant growth are fabricated by mixing the two phosphors with a 380‐nm UV chip, and a light‐conversion film is prepared using the red phosphor and PDMS glue. The Chlorella‐based plant growth experiment reveals that the growth rate of Chlorella is 12.2% higher than that of the blank group, indicating the favorable effect of the light‐conversion film on plant growth.

Evaluating the link between blue-green luminescence and cross-relaxation processes in Tb3+-doped glasses

In this study, luminescence properties of Tb3+-doped low silica calcium aluminosilicate glasses are analyzed as a function of Tb3+ concentration (0.04–15.0 wt%). Decay curves for the 5D3 level are found to be non-exponential for all Tb3+ concentrations due to ion–ion energy transfer through cross-relaxation process. To identify the origin of the energy transfer mechanism, the decay curves were well fitted by Inokuti–Hirayama model (s = 6), which indicates that the energy transfer process is related to dipole–dipole interaction. Trivalent Tb-doped materials normally exhibit stronger green emission compared to blue emission, a feature that increases with Tb3+ concentration and is attributed to the cross-relaxation process. In this paper, we show a remarkable blue emission in comparison to other Tb3+-doped glasses. A theoretical model for the blue and green emissions, from 5D3 and 5D4 levels respectively, was proposed to establishing a link between the color emission and the 5D3 lifetime quenching due to a cross-relaxation process. This model was successfully applied to the experimental results of this paper as well as previous data in the literature.

Quantum cutting in Tm3+-activated Ca9Gd(PO4)7 phosphors and effect of Tm3+ concentration on emission spectra

In this work, to develop new quantum cutting (QC) luminescent materials and clarify the QC process, a series of Tm3+-activated Ca9Gd(PO4)7 (CGP) phosphors were prepared by conventional high-temperature solid state reaction method. The phase purity of the samples was checked by XRD patterns, and the structural features were analyzed on the basis of Rietveld refinement. The emission spectra of Tm3+ were measured by exciting at different wavelengths, in which the QC was identified. The main QC model was proposed when the Tm3+ is excited into 1D2 level. The occurrence of QC was further verified by comparing the decay lifetimes on 3H4 level under 357, 470 and 685 nm excitation. With increasing Tm3+ concentration, it was found that the 3H4→3H6 transition intensity around 806 nm exhibits faster increase rate than other ones by exciting at either 357 or 470 nm. This increase rate is more effective under 357 nm excitation thanks to the existence of QC process. The above investigation could show instructional significance for the development of other rare earth ions doped luminescent materials.

Electronic structure engineering of Gd2.97Tb0.03Ga5−xAlxO12 persistent luminescence phosphors

Gd2.97Tb0.03Ga5−xAlxO12 powders with different Ga:Al ratio were prepared using modified Pechini method. Changing Ga:Al ratio opens the way to modulate the energy gap, and so, to modify the spectroscopic properties of the phosphors. Al3+ ions stabilize the metastable Gd3Ga5O12 garnet structure widening the energy gap. With increasing Ga content in the garnet structure, the energy gap between an excited 5d level of Tb3+ ions and the conduction band (CB) decreases, which leads to an overlap of the conduction band with the 5d band suppressing the energy transfer between the 5d band and the 4f levels of Tb3+ ions. The band gap changes lead to the blue shift of charge transfer band due to an expansion of the unit cell and decreased interaction between oxygen ligands and luminescent ions. The collected spectroscopic data show significant effect of crystal field strength of the host matrix on both conventional and persistent luminescence. From the resultant data the influence of Ga:Al ratio on the luminescence properties and trapping/releasing of electrons is discussed. The mechanism of Tb3+ persistent luminescence in Gd2.97Tb0.03Ga5−xAlxO12 is proposed.

Color tunability imparted by multi-peak emissions of Eu3+ in fluoride-phosphate phosphors

Miscible-order NaGdF4 fluoride-phosphate phosphor has been synthesized based on tin-fluorophosphate glass with low-melting-point, retaining excellent luminescence property of fluoride nanoparticles. Multi-peak emissions from metastable 5DJ (J = 0, 1, 2 and 3) levels are released effectively in the Eu3+ doped fluoride nanoparticles, which lifetimes are at the order of millisecond and quantum efficiency at 5D0 level in high Eu3+ concentration still remains 88.9%. On the basis of multi-peak emissions from Eu3+ and wide-band blue framework from Sn2+, the color coordinates of the fluoride-phosphate phosphors are regulated to the white light region and the color rendering index reaches up to 88. Tunable color and high color rendering index make fluoride-phosphate phosphor become a potential candidate for high-quality white light source.

Multichannel emissions from 5DJ metastable levels of Eu3+ in miscible-phase phosphors

BaYF5: Eu3+-fluorophosphate (BYF: E-FP) miscible-phase phosphors with tunable white fluorescence and high color-rendering index (CRI) are synthesized by blending Ba(Y1−xEux)F5 (BYF: E) submicron crystals (SCs) into fluorophosphate glass. Adjusting the concentration of Eu3+ purposefully, the comparable intensity of blue, green and red components by multichannel emissions can be regulated to achieve the adjustable white light. The quantum efficiency of 5D0 level in Eu3+ reaches up to 90.8%, and the millisecond fluorescence lifetime of blue and green emissions from 5D1, 5D2 and 5D3 levels exhibit the effectiveness of metastable levels. In coordination with blue emission from Sn2+, the color coordinates of BYF: E-FP are concentrated in white region of chromaticity diagram and its CRI is able to reach as high as 86. Tunable white fluorescence and high CRI indicate that miscible-phase phosphors possess promising applications in optoelectronic lighting.

Thermal, structural and optical behaviour of Eu3+ ions in Zinc Alumino Boro-Silicate glasses for bright red emissions

In present work we report the thermal, structural and optical behaviour of 20SiO2-(20-x) B2O3–10Al2O3–10ZnO–30NaF–10ZnF2-xEu2O3 glass system where Eu2O3 ions is doped in different molar concentrations (x = 0.1, 0.5, 1.0, 1.5, 2.0 and 2.5 mol %). The Differential thermal analysis measurement was employed to study the thermal stability of the glasses through various thermal parameters such as Dietzel factor (ΔT), Hruby's parameter (KH), Weinberg Parameter (KW) and Lu and Liu Parameter (KLL). FTIR studies exhibit the presence of BO3, BO4, SiO2 vibrational units and the deconvoluted peak areas is used for the calculation of bridging and non-bridging oxygens. From the absorption spectra, the indirect bandgap energy (Eg) and Urbach's energy (EU) of the glasses have been calculated. Judd-Ofelt (JO) intensity parameters (Ω2 and Ω6) have been evaluated from the emission spectrum. The radiative parameters such as radiative transition probability (AR), branching ratio (βR), stimulated emission cross-section (σse) and radiative lifetimes (τR) were obtained using the JO parameters for the transitions 5D0→7F1,2,4 of Eu3+ ions. The decay life time of the 5D0 level is found to be single-exponential for all the Eu3+ doped glasses. An increase in lifetime values for the prepared glasses was found with increase in Eu3+ concentration from 0.1 mol% to 2.0 mol%. The colour chromaticity values and CCT values show the bright red emission from the prepared glasses.