3d Levels Research Articles

A statistical model of thermal ionization of excited Ce ions in YAG

A statistical model based on the condition of thermal and diffusive equilibrium between the conduction electrons and the electrons in the excited 5d1 level of Ce3+ is presented. Using this model, we find the probability for an excited Ce3+ ion to be thermally ionized leading to an electron in the conduction band. The density of conduction electrons is then calculated over a wide range of temperatures and excitation densities. The observed quenching of emission at high temperature in Ce-doped YAG with low Ce concentrations is also investigated within this model. It is shown that the experimentally-observed nonradiative losses in this phosphor can be reasonably simulated assuming losses occur via nonradiative decay from the conduction band to the Ce3+ ground state.

Effect of Nutritional Deprivation after Sleeve Gastrectomy on Bone Mass, Periostin, Sclerostin and Semaphorin 4D: A Two-Year Longitudinal Study.

Bariatric surgery induces bone loss, but the exact mechanisms by which this process occurs are not fully known. The aims of this 2-year longitudinal study were to (i) investigate the changes in areal bone mineral density (aBMD) and bone turnover markers following sleeve gastrectomy (SG) and (ii) determine the parameters associated with the aBMD variations. Bone turnover markers, sclerostin, periostin and semaphorin 4D were assessed before and 1, 12 and 24 months after SG, and aBMD was determined by DXA at baseline and after 12 and 24 months in 83 patients with obesity. Bone turnover increased from 1 month, peaked at 12 months and remained elevated at 24 months. Periostin and sclerostin presented only modest increases at 1 month, whereas semaphorin 4D showed increases only at 12 and 24 months. A significant aBMD decrease was observed only at total hip regions at 12 and 24 months. This demineralisation was mainly related to body weight loss. In summary, reduced aBMD was observed after SG in the hip region (mechanical-loading bone sites) due to an increase in bone turnover in favour of bone resorption. Periostin, sclerostin and semaphorin 4D levels varied after SG, showing different time lags, but contrary to weight loss, these biological parameters did not seem to be directly implicated in the skeletal deterioration.

Effects of Sc3+ admixture on luminescence and scintillation properties of Ce3+-doped Lu2Y(Al5-xScx)O12 (x = 1, 1.5, 2) garnet single-crystalline films

Effects of Sc3+ admixture on luminescence and scintillation properties were studied in Ce3+ - doped Lu2Y(Al5-xScx)O12 (x = 1, 1.5, 2) garnet single-crystalline films grown by the isothermal liquid phase epitaxy technique. The Ce3+ photoluminescence (PL) was slightly blue shifted with increasing Sc content due to a decrease in crystal field splitting of the Ce3+ 5d levels. In addition, the thermal activation energy of PL quenching, estimated from the temperature dependence of PL decay times, decreased with increasing Sc content. Lu2YAl4ScO12:Ce exhibited the highest light yield (LY) value of 420 photons/MeV at 5.5 MeV α particles along with a fast scintillation decay time constant (τe) of 17.4 ns. At room temperature, the decrease of LY value with increasing Sc content could be attributed to the thermal ionization process.

Structural, microstructural characterization and luminescence spectroscopy of europium-doped strontium titanate prepared by the sol-gel method

In this work, we report on the polycrystalline Sr1-3x/2EuxTiO3, x = 0.01–0.07 materials prepared by the sol-gel route and their optical properties. The Sr1-3x/2EuxTiO3 powders calcined at 1000 °C showed a microstructure consisting of nanograins with average particle size decreasing from 86.32 nm to 51.87 nm with the increase of Eu amount from 1 at% to 7 at% Eu, as revealed SEM and TEM investigations. Optimized sintering conditions of Eu-doped SrTiO3 ceramics (1400 °C, 4h in air) led to materials with a single phase of cubic SrTiO3. The high purity and uniform distribution of the chemical elements of as-fabricated SrTiO3 doped with Eu guaranteed good optical properties. The emission of the Eu3+ ion mainly occurs for the transitions from the 5D0 level to the levels of the 7Fj (j = 1, 2) term, more precisely, the 5D0 → 7F2 electric dipole transition (∼615 nm) or the 5D0 → 7F1 magnetic dipole transition (∼595 nm). The CIE coordinates of all samples calculated from the emission spectra obtained under the 395 nm and 465 nm excitation wavelength are located in the orange-red region. Therefore, this europium-doped SrTiO3 phosphor is a promising candidate for application as a red-emitting component in solid-state light sources.

Deep insight on two luminous mechanism and optical properties of Pr doped MgGeO3 red/NIR luminescent materials

In this work, MgGeO3:Pr3+ system is prepared by high-temperature solid phase method under the condition of different temperature and Pr content. MgGeO3:Pr3+ could emit 622 nm (red), 716 nm (red), 903 nm (NIR) and 1081 nm (NIR) lights under the external excitation of 251 nm and 425–500 nm. Due to the different excitation wavelengths, MgGeO3:Pr3+ has completely different electronic transition paths, resulting in a much larger emission intensity under 251 nm excitation than that excited by 425∼500 nm. When the incident light wavelength is 251 nm, the excitation process is VB→1D2 level of Pr3+, and the emission is due to transition of 1D2→3H4, 1D2→3H5, 1D2→3H6(3F2) and 1D2→3F3,4. When the wavelength of incident light is 425∼500 nm, the excitation process is 3H4→CB, the emission is CB→1D2, and then 1D2→3H4, 1D2→3H5, 1D2→3H6(3F2) and 1D2→3F3,4. At the same time, the emission spectrum and X-ray diffraction measurements show that the most fundamental factor determining the emission intensity of the sample is the concentration of the luminescent center (Pr3+ that can emit light) in the MgGeO3 grain. Increasing the sintering temperature and Pr element content in raw materials can increase the of Pr3+ concentration in the grain (increase the concentration of the luminescent center). However, if the concentration of Pr3+ in the grain is too high, Pr3+ would lose the function of the luminescence center, resulting in a decrease in the concentration of the luminescence center, thereby reducing the luminescence intensity.

First-Principles Analysis of the Effects of Covalency and Ionicity on the 4f-5d Transition Energy of Ce3+ in Garnet-Type Oxides

Abstract A blue light-emitting diode (LED) and a yellow phosphor are frequently combined to create white LEDs, with (Ce3+)-doped YAG as a common phosphor utilized in this process. Yellow light is produced when Ce3+ ions, excited by blue LEDs, are combined with direct blue light to form white light. This study investigated the effects of electronic characteristics, such as covalency and ionicity, on the 5d and 4f level energies of Ce3+ in garnet-type crystals using relativistic discrete variational-Xα (DV-Xα) molecular orbital (MO) calculations. The purpose of this study is to elucidate a detailed mechanism for the centroid shift of the 5d level energies of Ce3+ in crystals based on the MO theory. The theoretical 4f-5d transition energies agreed well with experimental ones, and electronic structure analysis revealed a high correlation between the centroid shift and the net charge of Ce3+. The primary cause of the centroid shift of the 5d level energies relative to the lowest 4f level of Ce3+ in crystals is an increase of the 4f level energies caused by a reduction of the net charge of Ce3+. These results provide a theoretical foundation for the creation of novel Ce3+-doped garnet phosphors for use in displays and solid-state lighting.

Spectroscopy and absolute photoluminescence quantum yield of Eu3-doped zinc-tellurite glasses for solid state lightning applications

Spectroscopic properties of Eu3+-doped tellurite glass composed of 74 TeO2 + 15 ZnO +5 Nb2O5 + 5 TiO2 + 1.0 Eu2O3(mol %) have been investigated. Phonon energy of the host glass constituents that are linked up with the Eu3+ ions have been evaluated from the photoluminescence excitation spectrum which is found to be 760 cm−1. By utilizing the emission spectrum, the Judd-Ofelt (JO) intensity parameters (Ωλ, λ = 2 and 4) are calculated. The obtained JO parameters are utilized for evaluating the emission cross-sections (σ(λp)) of 5D0 → 7FJ (J = 1, 2 and 4) transitions. An intense emission at 613 nm due to the transition5D0 → 7F2is observed upon 465 nm excitation. Among these, the 5D0 → 7F2 (613 nm) transition has been exhibited the highest (σ(λp)) value and it found to be 2.11 × 10−22 cm2. For the 5D0 level, quantum efficiency (η) is corroborated theoretically as 58.4% and it is in line with absolute quantum yield of 56.7% obtained by Integrating sphere method. The results of Eu3+-doped TZNTEu1.0 glass are significant for the development of solid-state lighting devices at around 613 nm under the excitation of 465 nm.

Thermally-assisted photosensitized emission in a trivalent terbium complex

Luminescent lanthanide complexes containing effective photosensitizers are promising materials for use in displays and sensors. The photosensitizer design strategy has been studied for developing the lanthanide-based luminophores. Herein, we demonstrate a photosensitizer design using dinuclear luminescent lanthanide complex, which exhibits thermally-assisted photosensitized emission. The lanthanide complex comprised Tb(III) ions, six tetramethylheptanedionates, and phosphine oxide bridge containing a phenanthrene frameworks. The phenanthrene ligand and Tb(III) ions are the energy donor (photosensitizer) and acceptor (emission center) parts, respectively. The energy-donating level of the ligand (lowest excited triplet (T1) level = 19,850 cm−1) is lower than the emitting level of the Tb(III) ion (5D4 level = 20,500 cm−1). The long-lived T1 state of the energy-donating ligands promoted an efficient thermally-assisted photosensitized emission of the Tb(III) acceptor (5D4 level), resulting in a pure-green colored emission with a high photosensitized emission quantum yield (73%).

Excited State Dynamics of Undoped and Eu3+-doped TbAl3(BO3)4 Crystals

The room temperature luminescence spectra and emission decay curves of undoped and Eu3+-doped TbAl3(BO3)4 crystals, grown using the flux growth technique, are presented and discussed. The experimental results show that excitation of the Tb3+ levels gives rise to 5D0 emission from the Eu3+ ion, and therefore non-radiative energy transfer is operative involving the two ions. Analysis of the experimental data indicates that the excitation of the Tb3+ donor ion gives rise to diffusion limited migration of the energy in the 5D4 level of the Tb3+ subset of cations, followed by the energy transfer process populating the 5D0 level of Eu3+. Upon increasing the concentration of the Eu3+ acceptor, the mainly green emission intensity and the decay time of the 5D4 level decrease, whilst the red emission of 5D0 becomes dominant. The experimental data are interpreted on the basis of the trigonal huntite-type structure of the double borate crystals under investigation.

Gadolinium oxide single crystals: Optical properties and radiation resistance

Large-size high optical quality Gd2O3 single crystals were grown from solution at T = 1145 °C by Czochralski method. XRD analysis showed that the crystal structure is characterized by a single cubic phase (С-phase). Absorption spectra and luminescence properties of Gd2O3 doped with impurity Tb3+ ion were studied. The absorption spectrum is determined by electronic transitions in Gd3+ ion (spectral region of 245–315 nm) and interband electron transitions below 240 nm. Intraconfigurational radiative f-f transitions from 5D4 level in Tb3+ ion are clearly manifested upon both UV- and X-ray excitation. At the same time, 6PJ → 8S7/2 radiative transitions in Gd3+ ions are completely absent. This fact indicates high efficiency of nonradiative energy transfer from Gd3+ to Tb3+ ions. Thermo-luminescent spectroscopy shows the absence of charge carrier trapping centers, which proves the perfection of its crystal structure. The crystal under study shows high radiation resistance to high-energy (E = 10 MeV, D = 105 kGy) electron beam. However, the effects of irradiation appear only in the photoluminescence excitation spectra and thermally stimulated luminescence.

The value of serum Sema4D level in predicting the prognosis of patients with acute ST-segment elevation myocardial infarction and with high thrombus burden

BackgroundAcute ST-segment elevation myocardial infarction (STEMI) is a serious cardiovascular disease. High thrombus burden is an independent risk factor for poor prognosis of acute myocardial infarction. However, there is no study on the correlation between soluble semaphorin 4D (sSema4D) level and high thrombus burden in patients with STEMI.PurposeThis study aimed to investigate the relationship between sSema4D level and the thrombus burden of STEMI and further explore its effect on the main predictive value of the occurrence of major adverse cardiovascular events (MACE).MethodsFrom October 2020 to June 2021, 100 patients with STEMI diagnosed in our hospital’s cardiology department were selected. According to the thrombolysis in myocardial infarction(TIMI)score, STEMI patients were divided into high thrombus burden groups (55 cases) and non-high thrombus burden groups (45 cases) 0.74 patients with stable coronary heart disease (CHD) were selected as stable CHD group, and 75 patients with negative coronary angiography (CAG) were selected as control group. Serum sSema4D levels were measured in 4 groups. The correlation between serum sSema4D and high-sensitivity C-reactive protein (hs-CRP) in patients with STEMI was analyzed. The relationship of serum sSema4D levels between the high and non-high thrombus burden group was evaluated. The effect of sSema4D levels on the occurrence of MACE was explored in one year after percutaneous coronary intervention.ResultsSerum sSema4D level was positively correlated with hs-CRP level in STEMI patients (P < 0.05) with a correlation coefficient of 0.493. The sSema4D level was significantly higher in the high versus non-high thrombus burden group (22.54(20.82,24.17), P < 0.05). Moreover, MACE occurred in 19 cases in high thrombus burden group and 3 cases in non-high thrombus burden group. The results of Cox regression analysis showed that sSema4D was an independent predictor of MACE (OR = 1.497,95% CI: 1.213–1.847, P < 0.001).ConclusionThe sSema4D level is associated with coronary thrombus burden and is an independent risk factor for MACE.

A New Look at the Explanation of Differences in Properties between La3+ and Lu3+ Titanate Hosts Occupied by Eu3+

In order to improve the quality of WLEDs, considerable efforts have been devoted to investigate red phosphor. In this study, two double perovskites La2MgTiO6 and La2ZnTiO6 and two novel pyrochlores Lu2MgTiO6 and Lu2ZnTiO6 doped with 1%Eu3+ were synthesized by the co-precipitation method. The crystal structure, absorption, excitation, and emission spectra of all samples were investigated in detail. Dissimilar luminescent behaviors of the studied samples were observed. Due to the different site symmetry of Eu3+, each compound exhibits a different emission spectrum. The emission of the magnetic dipole transition is dominant in all the spectra of the Lu-based hosts, while the forced electric dipole transition is the strongest one in the spectra of the others. Besides, the ones crystallized in double perovskite structures possess larger bandgaps and show a more intense emission from the 5D1 level of Eu3+ as compared to the pyrochlore compounds. Furthermore, the distinct mechanism of the cross-relaxation of four titanate compounds was investigated. The above findings contribute to the understanding of the two novel pyrochlore hosts.

The Ultraviolet-Visible Luminescence of Ce3+ in Ca2Mg(BO3)2 Phosphors with Potential Applications

New phosphors Ca2Mg(BO3)2: Ce3+ were synthesized by the solid-state reaction method at a high temperature. The phase purity was characterized by powder X-ray diffraction (XRD). The ultraviolet-visible (UV-Vis) optical properties of Ce3+ have been investigated, and the lowest 5d levels, the emission, and the Stokes shifts of Ce3+ in the host lattice were identified. In addition, its concentration quenching process was also studied. The results show that Ce3+ ions enter Ca2+ sites with only one emission in a UV-Vis range and that the optimum doping concentration is x = 0.05. The excitation and emission spectra were evaluated to clearly reveal luminescence features.

Salivary Semaphorin 4D Level in Patients with Different Severities of Periodontitis (Observational Case–Control Study)

Background: Periodontal diseases are progressive, destructive, and inflammatory conditions of the tissues that support the teeth. An immune response is triggered by microbial dysbiosis in the sub-gingival biofilm. Semaphorin 4D (Sema4D) is a glycoprotein expressed by osteoclasts, T-cells, and activated B-cells involved in both immune response and bone remolding. Objectives: This study attempted to assess the salivary levels of Sema4D in patients with different severities (stages I–IV) of periodontitis in comparison to healthy control. Materials and Methods: A total of 171 participants of both genders were included into this case–control study. From the dental centers in Al-Najaf city and the Department of Periodontics in the College of Dentistry, University of Kufa, five groups were established for them: clinically healthy periodontium control group (19 subjects), Stage I periodontitis group (38 subjects), Stage II periodontitis group (38 subjects), Stage III periodontitis group (38 subjects), and Stage IV periodontitis group (38 subjects). The clinical periodontal parameters were examined after collecting whole unstimulated salivary samples from all individuals. The levels of Sema4D in saliva samples were estimated utilizing the ELISA technique. Statistical analysis used: ANOVA test, Games-Howell test, and Pearson correlation (r) test. Results: The findings revealed that the mean level of salivary Sema4D was the highest in the stage IV periodontitis group (758.11 ± 139.119), followed by stage III periodontitis group (725.815 ± 127.055), stage II periodontitis group (679.169 ± 121.993), stage I periodontitis group (601.742 ± 145.459), and control group (366.515 ± 47.635) respectively with a significant difference (P ≤ 0.01). Conclusions: The periodontitis patients showed higher Sema4D levels in unstimulated saliva as compared to the control. Hence, this molecule may play an essential role in the pathogenesis of periodontitis.

Clinical values of serum Semaphorin 4D (Sema4D) in medication‑related osteonecrosis of the jaw

BackgroundBisphosphonates (BPs) are widely used in clinical practice to prevent and treat bone metabolism-related diseases. Medication-related osteonecrosis of the jaw (MRONJ) is one of the major sequelae of BPs use. Early prediction and intervention of MRONJ are of great significance.MethodsNinety-seven patients currently on treatment with BPs or with a history of BPs usage and 45 healthy volunteers undergoing dentoalveolar surgery were included in this study. Participants' serum Semaphorin 4D (Sema4D) levels were measured and analyzed before participants underwent surgery (T0) and after a 12-month follow-up (T1). Kruskal–Wallis test and ROC analysis were used to examine the predictive effect of Sema4D on MRONJ.ResultsSema4D levels in serum of patients corresponding to confirmed MRONJ were significantly lower at both T0 and T1 time points compared to non-MRONJ and healthy controls. Sema4D has a statistically predictive effect on the occurrence and diagnosis of MRONJ. Serum Sema4D levels were significantly reduced in MRONJ class 3 patients. MRONJ patients who received intravenous BPs had significantly lower Sema4D levels than those who received oral BPs.ConclusionSerum Sema4D level has predictive value for the onset of MRONJ in BPs users within 12 weeks after dentoalveolar surgery.

The influence of Eu3+ doping on the optical and structural properties of the Ge2Y2O7 crystalline phase through a soft chemical process

The present work reports on the synthesis, structural and optical properties of Ge2Y2-xEuxO7 composition powders, with x ranging from 0.0 to 0.16 (from 0.0 to 4.0 mol% Eu3+). We synthesized stable and transparent sols, homogeneous gels, and powders treated at 1100 °C by a soft chemical route, and the effect of Eu3+ concentrations was evaluated. X-ray diffraction (XRD), infrared vibrational spectroscopy (FTIR), Raman spectroscopy, diffuse reflectance spectroscopy (DRS), emission and excitation photoluminescence spectroscopy (PL, PLE), decay curves of emission intensity as a function of time and quantum yield were obtained. An annealing temperature of 1100 °C was enough to obtain a single Ge2Y2O7 crystalline phase and the decrease of Χ2 value (from 2.32 to 1.74) with the increase of Eu3+ doping in the matrix, observed with the Rietveld refinement of the XRD patterns of the samples, is due to the crystallization process. Diffuse reflectance spectra and optical bandgap of 4.7 eV for Ge2Y0.88Eu0.12O7 (3.0 mol% Eu3+) – determined by Kubelka- Munk model – showed the good optical quality of the samples, which were considered non-conducting. All doped samples possessed visible photoluminescence emission from Eu3+ ions under excitation at 394 nm, with higher emissions occurring in the red region from 5D0 → 7F2 transition, with R/O relation equal to 2.6 and purity of red color higher than 85 % for the sample with x = 0.012. Analyzing photoluminescence emission spectra, the lifetime values and Judd-Ofelt parameters, we determined that Eu3+ occupied two different sites of the Ge2Y2O7 host matrix, replacing Y3+ ions, with the quenching concentration occurring between x = 0.12 and x = 0.16. The average decay lifetime of 5D0 level from Eu3+ was around 1.66 ms, with average quantum efficiency around of 48 % and an internal quantum yield equal to 7.17 %. Moreover, we evaluated their emission luminescence properties upon 394 nm excitation to explore for the first time the possibility of using this material in thermal sensing applications.

Excitation wavelength dependent color tunability, white light generation and enhanced optical emission in mixed phase ZnO–CAZO:xEu3+ over single phase ZnO:xEu3+ phosphors: a comparative study

Mixed phase ZnO-CAZO:xEu3+ phosphors have been synthesized by solid state reaction method to get tunable light including white light under excitation with different wavelengths. The XRD, SEM, FTIR, UV–vis absorption, photoluminescence excitation and emission spectra of the samples and the lifetime of 5D0 level of Eu3+ ions have been studied. The ZnO phosphor has well known hexagonal structure, whereas Ca3Al4ZnO10 (CAZO) has orthorhombic structure. The UV–vis spectral studies show that the materials have wide band gap. The excitation spectra of ZnO-CAZO:xEu3+ phosphors with λ em = 613 nm show broad bands at 270 and 370 nm alongwith discrete peaks due to Eu3+ ion. An excitation with 370 nm of ZnO-CAZO:xEu3+ phosphors results a broad continuum from 400–700 nm with maxima at 520 nm. The excitation with 270/394 nm on the other hand gives intense discrete peaks due to Eu3+ ion alongwith broad host emission. However, on excitation with 467 nm, it gives intense red emission with CIE coordinates (0.64, 0.36) and color purity 90%. The emission intensity is maximum for ZnO-CAZO:1.5Eu3+ phosphor. The excitation with 394 nm, results white light for ZnO-CAZO:0.5Eu3+ phosphor with CIE coordinates (0.34, 0.35), which is almost equal to the ideal white light coordinates (0.33, 0.33). The emission intensity in the mixed condition (ZnO-CAZO:1.5Eu3+) is 4.94 times greater than its single (ZnO:1.5Eu3+) phase under 370 nm excitation.

A Comparative Study of Eu3+-Doped Sillenites: Bi12SiO20 (BSO) and Bi12GeO20 (BGO)

The spectroscopic properties of Eu3+-doped Bi12SiO20 (BSO) were investigated and compared with that of Eu3+-doped Bi12GeO20 (BGO). The emission properties and the absorption spectra have been measured at 10 K as well as at 300 K (room temperature). Luminescence was detected due to the direct excitation of the 5D0 level of Eu3+, as well as through the excitation of the 5D1 level. The Judd-Ofelt theoretical framework was used to compute the radiative lifetimes (τ) and the omega parameters (Ωλ). The electric dipole transition probabilities, asymmetry ratios (R), along with the branching ratios (β) were also determined based on the obtained experimental data. The strongest detected luminescence belongs to the 5D0 → 7F0 transition observed at 578 nm, similar to the BGO sillenite. Reasons for the major presence of the 5D0 → 7F0 emission, theoretically forbidden by the Judd-Ofelt Theory, were investigated and compared with that of the BGO sillenite. Obtained results showed that the strong 5D0 → 7F0 line is also present in Eu:BSO, indicating that this is a feature of the entire sillenite family and not just Eu:BGO.

Visible DC approach by controlling the UV light in (Eu3+/Tb3+) co-activated TBZN glasses for w-LEDs and a-Si solar cells

Borotellurite (TBZN: TeO2–B2O3–ZnO–Na2O) glasses co-activated with Eu3+ and Tb3+ ions were fabricated by a melt quenching method to know their ability for white light sources and solar converters. Amorphous nature, morphology, elemental mapping of the chemical composition, and functional groups of glasses were investigated. The down conversion (DC) process was studied on the luminescence characteristics of Eu3+/Tb3+ co-activated TBZN glasses by ultraviolet light (UV:351 & 378 nm) conversion and these glasses exhibit the characteristic red (5D0→7F1,2,3,4) luminescence of Eu3+ along with green (5D4→7F5) and blue (5D4→7F6) luminescence of Tb3+ ions in the visible region. Upon 378 nm of UV radiation, the co-activating of Tb3+ with Eu3+ ions improves the green and red DC emissions by 2 and 4 orders of magnitude due to energy transfer (ET) from Eu3+ to Tb3+, respectively. The evidence of ET: Eu3+ → Tb3+ is stated by the declining of red emission (%) and decay times from the 5D0 level of Eu3+ ions, and the reduction in decay times was confirmed to be dipole-dipole interaction in the means of Reisfeld and Dexter's ET process. The solar spectral performance of the excitation and de-excitation spectra of (Eu3+/Tb3+):TBZN glass system is imparted with the standard solar spectrum. Results are also discussed in terms of integrated intensity of red to green emission in (%), critical transfer distance (Rc), (x, y) color coordinates, correlated color temperatures (CCT), color purity (CP), and quantum efficiency (ηQE) values to discriminate the potentiality of (Eu3+/Tb3+):TBZN glass system in white light emitting diodes and solar cells.

The Effect of Alkali-Fluoride on the Photoluminescence Properties of Tb3+ Doped on Phosphate Glass Medium

The effect of alkali fluoride on the photoluminescence properties of Tb3+ doped on the phosphate glass was discovered. However, the composition of the glass samples were 20Li2O–10AlF3–69P2O5–1Tb2O3 (LAPTb) and 20Li2O–10AlF3–10NaF–59P2O5–1Tb2O3 (LANPTb). To study optical properties were examined through their absorption and luminescence spectra. Luminescence spectra were investigated by photoluminescence. Characteristic luminescence bands corresponding to electronic transitions of terbium ions (Tb3+) were detected under two direct excitations of Tb3+ ions. Upon 377 nm excitation, the glass samples were obtained transition terbium 5D4 → 7F5 at 544 nm showed a green laser. The decay time Tb3+ for the 5D4 level has been confirmed and the result was 2.865 ms and 2.982 ms corresponding to LAPTb was LANPTb, respectively. The green laser application has been investigated by a CIE-color-coordinates diagram with a color purity is ~73%.