Terbium Concentration Research Articles

Synthesis, characterization, and temperature-dependent luminescence of Tb3+-activated and self-activated Sr10(PO4)6Cl2 phosphors

In this work, a series of new nanosized phosphors based on strontium chlorapatite (Sr10(PO4)6Cl2, abbreviated as SrClAp) with varying terbium concentration were synthesized using a modified microwave-hydrothermal method. This study meticulously investigated the impact of Tb3+ concentration and annealing temperature on factors such as crystal purity, particle morphology, photoluminescence, chromatic properties, and the mechanism of thermal quenching.The synthesized phosphors underwent characterization using X-Ray Diffraction (XRD) and scanning electron microscopy (SEM) to verify their crystal structure purity and examine their morphology. Upon near-ultraviolet (NUV) excitation at the 378 nm line, the obtained nanosized powders emitted green light arising from the characteristic 5D4→7FJ (J = 6, 5, 4, 3) transitions of Tb3+ ions. Notably, a broad host-related emission was discernible at 80 K, with its intensity diminishing as the temperature increased. The mechanism governing this host-related emission and the process of its thermal quenching have been proposed. Moreover, a comprehensive exploration of the influence of ambient temperature on the emission of Tb3+-doped SrClAp was undertaken.

Concentration-dependent luminescence characterization of terbium-doped strontium aluminate nanophosphors.

The present investigation describes the synthesis of luminescent terbium-doped strontium aluminate nanoparticles emitting bright green light, which were synthesized through a solid-state reaction method assisted by microwave radiation. Various samples containing different concentrations of Tb were synthesized, and an analysis of their structural and morphological features was conducted using powder x-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The band gaps of the samples were determined utilizing the Kubelka-Munk method. The quenching mechanism observed was identified to be due to dipole-dipole interaction using the Dexter theory. The optimized sample with a terbium concentration of 4at.% has a luminescence lifetime of 1.05 ms with 20.62% quantum efficiency. The results of this study indicate that the terbium-doped strontium aluminate fluorescent nanoparticles exhibit promising potential for a wide range of applications, including bioimaging, sensing and solid-state lighting.

Tb3+ doped CaWO4 nanomaterials for double level multicolor mode anticounterfeiting

Numerous new demands and obstacles have been posed to contemporary luminescent materials and anti-counterfeiting systems by the ever-increasing importance of data security and identification. The legibility, repeatability, multicolorism, and stimuli-responsiveness of luminescent materials have recently garnered a lot of interest in this area. A multicolor luminescent material, CaWO4:Tb3+, was effectively synthesized using an ethylene glycol-aided solvothermal technique in our present study. Under the 254 nm UV light, the sample may change its emission color from blue to green by increasing the concentration of Tb3+ dopant from 0 to 5 at%. However, its color changes from bluish-white to greenish-white when excited at 365 nm UV light. Energy transfer from host to Tb3+ ions increases with increasing the terbium concentration with an efficiency of 62 % for 5 at% doped samples. Anti-counterfeiting ink for screen-printed alphabets is made from samples with adjustable luminescence. Luminescent security goods can benefit from the material's outstanding multicolor anti-counterfeiting qualities, as demonstrated by the results under diverse light sources.

Occurrence of rare earth elements in umbilical cord serum and association with thyroid hormones and birth outcomes in newborns

Rare earth elements (REEs) are emerging contaminants that are increasingly used in high technology products. However, limited information is available regarding exposure to REEs and associated health effects in neonates. This study aimed to investigate the association between REE concentrations and thyroid hormone levels, as well as birth outcomes in 109 newborns in Beijing, China. We measured the concentrations of 16 REEs and thyroid hormones in umbilical cord serum. To assess the impact of exposure to individual REEs and REE mixtures on thyroid hormone levels and birth outcomes, we employed univariate linear regression, least absolute shrinkage and selection operator (LASSO), and weighted quantile sum (WQS) models. We detected 14 REEs at high rates (92.6%–100%), with yttrium exhibiting the highest median (interquartile range) concentration [43.94 (0.33–172.55) ng/mL], followed by scandium [3.64 (0.46–11.15) ng/mL]. Univariate analyses showed that per logarithmic (ln)-unit change of neodymium (Nd) and samarium (Sm) was associated with 0.039 [95% confidence interval (CI): 0.001, 0.007] and 0.031 (95% CI: 0.003, 0.060) increases in free thyroxine (FT4) levels, respectively. Moreover, 14 REEs exhibited significant associations with triiodothyronine (T3) levels, resulting in increases ranging from 0.066 to 0.307. Elevated concentrations of terbium (Tb) [per ln-unit change: −0.021 (95% CI: −0.041, −0.01)] and lutetium (Lu) [-0.023 (95% CI: −0.043, −0.002)] were inversely correlated with birth length in newborns. A further multiple exposure analysis employing the LASSO model identified Sm, Nd, Y, Sc, and Lu as critical factors influencing FT4 and T3 levels. Additionally, WQS analyses showed positive associations between exposure to a mixture of 14 REEs and FT4 (P = 0.046), T3 (P < 0.001), and birth length (P = 0.049). These findings suggest that in utero exposure to REEs might disrupt thyroid hormone homeostasis and impact intrauterine growth. Further studies are warranted to validate these findings and elucidate the underlying mechanisms.

Terbium(III) oxide as rare earth metal modifier in PbO/Bi2O3 sodium borate glasses for highly efficient optoelectronic devices: Synthesis, characterization, and applications

This paper explores the incorporation of Terbium(III) oxide as a rare earth metal modifier in sodium borate glasses containing PbO/Bi2O3, aiming to enhance the efficiency of optoelectronic devices. The synthesis and characterization of these glasses are detailed, highlighting the unique properties introduced by Terbium(III) oxide. The study investigates the regularities in the characteristics such as physical, XRD, UV, FTIR, and optical properties of 70B2O3–15Na2O – 15PbO – (5-x)Bi2O3 – xTb2O3, where x = 0; 1; 2; 3; 5 mol% prepared glassy samples, considering varying concentrations of bismuth and the modifier (e.g. Tb2O3), and examines their mutual impact on the borate glass matrix involved. It is found that there are sharp peaks on the diffraction pattern, which increase in width and intensity with increasing Terbium concentration from 3 to 5 mol% in the glass matrices, e.g. two-phase structures, amorphous and crystalline, are observed. Moreover, a wide excitation band in the glass matrix is also observed in the region of 200–320 nm. The study delves into the potential applications of these modified glasses in highly efficient optoelectronic devices, contributing valuable insights to the advancement of materials for technological applications.

TB3+ CONCENTRATION EFFECT ON THE PHOTO - AND RADIOLUMINESCENCE RESULT OF LANTHANUM BORATE GLASS FOR YELLOWISH GREEN LASER APPLICATION

The melt-quenching technique was used to prepare lanthanum borate glass doping with Tb3+ (LBTb) to investigate physical and luminescent characteristics. The result more a concentration of doped terbium increases the glass density, molar volume, and refractive index. The higher Tb2O3 concentrations in glasses led to an increase of absorbance in the VIS and NIR range. The emission spectra of glasses were recorded at excitation wavelengths of 228 and 377 nm, and it was found that these glasses emit yellowish-green light. Tb3+ doped glass exhibited the highest intensity at 544 nm. The optimal concentration of terbium with the most significant emission in LBTb glass is 7 mol%, whereas decay time decreases as Tb2O3 content increases. The PL measurement showed a similar pattern with the spectrum of RL emissions. Moreover, this glass performs an integral scintillation efficiency of 36.32% compared with BGO crystal. According to the CIE 1931 chromaticity, the LBTb emitted a yellowish-green color. Terbium-doped glasses have attractive potential to be used in yellowish-green lasers.

Sodium zinc phosphate glasses doped with Tb3+ and Tb3+/Eu3+ as multicolor phosphor for green laser stimulated emission and WLED applications

Sodium zinc phosphate glasses doped with Tb3+ and Tb3+/Eu3+ were synthesized by the melt quenching method. Spectroscopic properties of the these glasses were analyzed to investigate their suitability as multicolor phosphor for green laser stimulated emission and WLED applications. In the 1.0 mol% Tb2O3 doped sodium zinc phosphate glass, the 5D4→7F5 green transition exhibits gain linewidth and optical gain values larger than those reported in other phosphate glasses doped with the same terbium content. The tonality of emitting light from the glass singly doped with terbium shifts from green to bluish-white and greenish-white as Tb2O3 content decreases from 2.0–2.5 mol% to 0.5–1.0 mol% under excitation at 350 nm. A 574 nm yellow tonality, close to warm-white one of 3564 K, is attained in the co-doped glass, wherein the europium emission is sensitized through the terbium excitation at 340 nm. The co-doped glass can also emit 591 nm orange light and 609 nm reddish-orange light, with color purities above 93 %, under Tb3+/Eu3+ (377 nm) and Eu3+ (393 nm) excitations, respectively.

Nonlinear refraction in high terbium content borogermanate glass bulk and fiber

High terbium content glasses have stood out in technological areas due to their simultaneous ability of magnetization and transparency in the visible spectrum. Such magneto-optical glasses are relevant for several optical devices, including optical modulators, sensors, and isolators. While terbium ions are responsible for magnetic response, glass formers, and modifiers provide a branch of desirable mechanical, chemical, and optical properties, which can further be tailored by compositional manipulation. Determination of Verdet constant is usual in magneto-optical glass, however, little attention has been devoted to the determination of the optical properties, moreover the nonlinear ones. Herein, we investigate the nonlinear index of refraction (n2) of a novel magneto-optical glass shaped in bulk and optical fibers. Although the fabrication of fibers with high terbium content is challenging, the usage of optical fibers is important to improve signal that arises from magneto-optical and Kerr effects, since both depend on light propagation path. Bulk and optical fiber of 96(60GeO2-25B2O3–4Al2O3–10Na2O–1PbO) – 4Tb4O7 (mol%) glass were characterized by Z-scan and D-scan techniques, respectively, using femtosecond laser pulses. It was obtained the n2 spectrum in the range of 550–1200 nm for the former, which was modeled based on BGO model, revealing the role of oxygen ions for the optical nonlinearity. The optical fiber fabrication process does not compromise the n2 value, remaining n2=(5±2)×10−20m2/W at 790 nm according to D-scan measurements, which is equivalent to values determined by Z-scan, i.e. (6±2)×10−20m2/W. Additionally, the chemical states of the various elemental components of GBANP-4Tb glasses were investigated by X-ray photoelectron spectroscopy (XPS). The analysis of the Ge 3d and Tb 4f photoelectron spectra of the GBANP-4Tb glasses revealed the presence of Ge4+, Tb3+ and Tb4+ oxidation states. These results are relevant to expand the knowledge on magneto-optical materials, moreover regarding their optical response in the femtosecond regime, broadening its application in ultrafast magneto-optical devices.

Terbium Removal from Aqueous Solutions Using a In2O3 Nanoadsorbent and Arthrospira platensis Biomass.

Terbium is a rare-earth element with critical importance for industry. Two adsorbents of different origin, In2O3 nanoparticles and the biological sorbent Arthrospira platensis, were applied for terbium removal from aqueous solutions. Several analytical techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy, were employed to characterize the adsorbents. The effect of time, pH, and terbium concentration on the adsorption efficiency was evaluated. For both adsorbents, adsorption efficiency was shown to be dependent on the time of interaction and the pH of the solution. Maximum removal of terbium by Arthrospira platensis was attained at pH 3.0 and by In2O3 at pH 4.0-7.0, both after 3 min of interaction. Several equilibrium (Langmuir, Freundlich, and Temkin) and kinetics (pseudo-first order, pseudo-second order, and Elovich) models were applied to describe the adsorption. The maximum adsorption capacity was calculated from the Langmuir model as 212 mg/g for Arthrospira platensis and 94.7 mg/g for the In2O3 nanoadsorbent. The studied adsorbents can be regarded as potential candidates for terbium recovery from wastewater.

Bright Green Emission of Tb3+ Doped Lithium Sodium Potassium Borate Glasses for Photonic Application

The melt-quenching approach was implemented to create terbium-doped lithium sodium potassium borate glasses (LNKBTb). Archimedes’ principle, absorption and luminescence spectra, including CIE chromaticity were used to characterize the properties of glasses. Terbium in glasses absorbs photon in the visible and near infrared ranges. The intense green emission at 544 nm was generated by the terbium 5D4 to 7F5 transition when excited with ultraviolet–visible (UV–Vis) light. The emission intensities of LNKBTb glasses increased with increasing terbium concentrations up to 4 mol%, after which they decreased, resulting in the concentration quenching effect, whereas decay time decreases as Tb2O3 content increases. In CIE 1931, the overall color of emission is green. May bring can continue to develop to use as a photonic material in green light sources and lasers.

Phase stabilization and optical response in the ultraviolet range, due to terbium concentration in hafnium oxide nanoparticles

This work reports the influence of terbium trivalent ions on growing kinetics and the phase in hafnium oxide nanoparticles, as well as response to radiation in the range from 256 to 286. The nanoparticles were obtained by the hydrothermal route maintaining the temperature constant and varying the reaction time and the terbium concentration. The results show a gradual change in the phase with the concentration of terbium trivalent ions, going from the monoclinic phase, present at low concentrations, to the tetragonal phase, which appears from dopant concentrations greater than 5% at., increasing in amount with concentration of dopant. These phases appear as two perfectly defined morphologies. Furthermore, there is a significant change in radiative lifetimes when the tetragonal phase appears.

Biochemical indicators of the lipid metabolism in workers involved in the processing of raw materials and production of rare metal products

Introduction. In recent years, the use of rare earth elements has been expanding in various innovative research and high-tech industries, which leads to an increase in the volume of their extraction and processing and makes it possible to develop a negative impact on the health of workers under conditions of long-term industrial exposure to rare earth elements with the air of the working area.&#x0D; The purpose of the work is to study and evaluate the deviations of the biochemical parameters of the lipid spectrum in workers, due to the chemical factors of the technological process of processing raw materials and production of rare metal products.&#x0D; Materials and methods. The study and evaluation of the content of rare earth elements in the blood of workers, the study of biochemical parameters, statistical analysis, modelling of cause-and-effect relationships were carried out.&#x0D; Results. Workers exposed to rare-earth elements with the air of the working area (100% of workplaces) showed increased concentrations of holmium, dysprosium, yttrium, neodymium, niobium and terbium in the blood from 1.5 to 2.5 times compared to similar indicators in workers who were not associated with technological process. Elevated levels of total cholesterol, VLDL and triglycerides in blood serum, a decrease in the total antioxidant activity of blood plasma in workers relative to the physiological norm and similar indicators in the comparison group were established. A significant relationship of the identified deviations with an increased blood concentration of niobium, dysprosium and holmium has been proven.&#x0D; Limitations. The study took into account the aerogenic inhalation effect of rare earth elements on the health of workers involved in the processing of raw materials and production of rare metal products. &#x0D; Conclusion. Long-term inhalation exposure to rare earth elements contained in the air of the working area caused changes in biochemical parameters, reflecting the depletion of antioxidant defense resources, inducing disorders of lipid metabolism. The identified negative effects in workers can lead to pro-atherogenic vascular inflammation under conditions of continuing industrial exposure. The obtained results should be taken into account for the development of recommendations aimed at minimizing the negative consequences of the impact of the studied chemical factors of the labour process on the health of workers.

Исследование свойств монокристаллов ниобата лития одинарного и двойного легирования — функциональных материалов оптоэлектроники

A series of six LiNbO3:Tb ([Tb] = 0.1 — 2.89 wt%) crystals and seven LiNbO3:Er ([Er] = 0.08÷2.71 wt%) crystals were grown according to a single methodology. Optical uniformity and optical resistance were compared in LiNbO3:Tb and LiNbO3:Er of various chemical composition. The periods of the crystal lattice were determined by the methods of a full -profile analysis of the XRD patterns of polycrystals; models of the atomic structure of LiNbO3:Tb and LiNbO3:Er crystals were analyzed with a change in the dopant concentration. In a series of LiNbO3:Tb crystals, a concentration threshold near the concentration of terbium ~ 2.2 — 2.3 wt% was discovered for the first time. A concentration threshold near the concentration of erbium ~ 2.4 — 2.5 wt% was discovered in LiNbO3:Er. In the area of the concentration threshold, pronounced anomalies of physicochemical, optical and structural characteristics are observed. Growth irregular and regular domain microstructures were revealed in as-grown LiNbO3:Tb and LiNbO3:Er crystals by optical and atomic force microscopy. Structural characteristics and threshold effects are studied in LiNbO3:Gd and LiNbO3:Gd,Cu crystals by Raman spectroscopy, PILS, laser conoscopy and optical microscopy. In LiNbO3:Gd crystals the photorefractive effect is suppressed at as low concentration as [Gd] = 0.05 wt%. For LiNbO3:Gd,Cu crystals a distinct photorefractive response is observed, it increases with increasing Cu concentration. The effect of the association of defects (carriers) is experimentally confirmed and thermodynamically justified by the example of oxygen-octahedron structures such as perovskite and pseudoi:lmental during ion conduction in a certain temperature interval. The discovered phenomenon is extremely important for creating and evaluating the temperature range of operability of ion current sources.

Substitutions in Nd5−xTbxMo3O16+δ Series: Phase Formation, Atomistic Modeling, and Crystal Structure of Nd5Mo3O16+δ-Based Solid Solutions

Samples of the Nd5−xTbxMo3O16+δ series were obtained by solid-state synthesis from metal oxides at 1050°C. The formation of solid solutions based on cubic and monoclinic phases and a two-phase region between them was observed in the Nd5−xTbxMo3O16+δ compositions. Increasing the terbium content in the system leads to a decrease in the unit cell parameters of the cubic and monoclinic phases within their homogeneity regions, which confirms the formation of solid solutions. It has been established that the terbium oxidation state in the Nd5Mo3O16+δ crystal structure is +3. The predominant placement of terbium atoms in the 8c position is observed by crystal structure refinement and confirmed by the results of the atomistic simulation. The introduction of terbium into the crystal structure of neodymium molybdate leads to a decrease in the Ln1–O1 and Ln2–O2 interatomic distances. The atomistic simulation was performed by the GULP program using the fit potential of the terbium ion. Terbium molybdate with Tb5Mo3O16+δ composition is a subtraction solid solution based on Tb2MoO6. Increasing the unit cell parameters of Tb5Mo3O16+δ monoclinic phase compared to Tb2MoO6 was confirmed by structure refinement and atomistic simulation.

Synthesis Optimization of BaGdF5:x%Tb3+ Nanophosphors for Tunable Particle Size

X-ray photodynamic therapy (XPDT) is aimed at the treatment of deep-located malignant tumors thanks to the high penetration depth of X-rays. In XPDT therapy, it is necessary to use materials that effectively absorb X-rays and convert them into visible radiation-nanophosphors. Rare-earth elements, fluorides, in particular, doped BaGdF5, are known to serve as efficient nanophosphor. On the other hand, the particle size of nanophosphors has a crucial impact on biodistribution, cell uptake, and cytotoxicity. In this work, we investigated various Tb:Gd ratios in the range from 0.1 to 0.5 and optimized the terbium content to achieve the maximum luminescence under X-ray excitation. The effect of temperature, composition of the ethylene glycol/water solvent, and the synthesis technique (solvothermal and microwave) on the size of the nanophosphors was explored. It was found that the synthesis techniques and the solvent composition had the greatest influence on the averaged particle size. By varying these two parameters, it is possible to tune the size of the nanophosphor particles, which make them suitable for biomedical applications.

Hormetic activation of nano-sized rare earth element terbium on growth, PSII photochemistry, antioxidant status and phytohormone regulation in Lemnaminor

Soils contaminated with rare earth elements (REEs) can damage agriculture by causing physiological disorders in plants which are evaluated as the main connection of the human food chain. A biphasic dose response with excitatory responses to low concentrations and inhibitory/harmful responses to high concentrations has been defined as hormesis. However, not much is clear about the ecological effects and potential risks of REEs to plants. For this purpose, here we showed the impacts of different concentrations of nano terbium (Tb) applications (5-10-25-50-100-250-500 mg L−1) on the accumulation of endogeneous certain ions and hormones, chlorophyll fluoresence, photochemical reaction capacity and antioxidant activity in duckweed (Lemna minor). Tb concentrations less than 100 mg L−1 increased the contents of nitrogen (N), phosphate (P), potassium (K+), calcium (Ca2+), magnesium (Mg2+), manganese (Mn2+) and iron (Fe2+). Chlorophyll fluorescence (Fv/Fm and Fv/Fo) was suppressed under 250–500 mg L−1 Tb. In addition, Tb toxicity affected the trapped energy adversely by the active reaction center of photosystem II (PSII) and led to accumulation of inactive reaction centers, thus lowering the detected level of electron transport from photosystem II (PSII) to photosystem I (PSI). On the other hand, 5–100 mg L−1 Tb enhanced the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), NADPH oxidase (NOX), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione S-transferase (GST). Tb (5–50 mg L−1) supported the maintenance of cellular redox status by promoting antioxidant pathways involved in the ascorbate-glutathione (AsA-GSH) cycle. In addition to the antioxidant system, the contents of some hormones such as indole-3-acetic acid (IAA), gibberellic acid (GA), cytokinin (CK) and salicylic acid (SA) were also induced in the presence of 5–100 mg L−1 Tb. In addition, the levels of hydrogen peroxide (H2O2) and lipid peroxidation (TBARS) were controlled through ascorbate (AsA) regeneration and effective hormonal modulation in L. minor. However, this induction in the antioxidant system and phytohormone contents could not be resumed after applications higher than 250 mg L−1 Tb. TBARS and H2O2, which indicate the level of lipid peroxidation, increased. The results in this study showed that Tb at appropriate concentrations has great potential to confer tolerance of duckweed by supporting the antioxidant system, protecting the biochemical reactions of photosystems and improving hormonal regulation.

Separation of Gadolinium(III) from Terbium(III) by the Liquid-Liquid Extraction Method with Dibutyldithiophosphate as the Extractant

The purpose of this research is to separate gadolinium(III) from terbium(III), by the liquid-liquid extraction method, with the extractant dibutyl dithiophosphate. Gadolinium(III) and terbium(III) have been selected in this study to see if the two metallic ions still could be separated although they have only one difference in atomic number, and in fact, terbium (65Tb) is the next to gadolinium(64Gd), in the lanthanide series. Also besides, the two metals have been found together in the same mineral such as gadolinite, and in some other minerals in Indonesia. Extraction parameters have been firstly selected and extraction conditions have been optimized as well, using the experimental design of Plackett Burman. Thus, experiments have been done to select which of the nine parameters (i.e. Gd(III) and Tb(III) concentrations, the concentration of the extractant (dibutyl dithiophosphate), pH, volume ratio of aqueous phase to the organic phase, extraction temperature, shaking rate, shaking time, resting time (after shaking), have their significant effect on the extraction efficiency and separation. The data resulted from this study show that there were five of the nine factors studied that determine the extraction efficiency and separation. They were (with its respective optimum value in the bracket): Gadolinium concentration [Gd(III)](5 ppm), terbium concentration [Tb(III)](5 ppm), pH(3.0), shaking time (10 minutes), and rest time after shaking (10 minutes).

Determination of Fe and Tb concentrations in geological and environmental samples using the instrumental neutron activation analysis method combined with the γ − γ coincidence technique

The instrumental neutron activation analysis (INAA) method was combined with the γ − γ coincidence technique to measure Iron (Fe) and Terbium (Tb) concentrations in geological (Montana II Soil) and environmental (Coal Fly Ash) standard materials. The measured concentrations, which agree well with the corresponding certified values, are compared with those obtained from the traditional INAA method. It is demonstrated that employing the γ − γ coincidence technique slightly improves the accuracy of the analysis. Furthermore, the coincidence technique enhances the detection limits of Tb by ∼4.5 and ∼5.5 times in environmental and geological samples, respectively, but has almost no enhancement in those of Fe. The γ − γ coincidence technique therefore does not always promote the analysis quality of the INAA method, but it is effective for analyzing elements whose characteristic γ rays sustain a high Compton background and/or are overlapped with other γ rays.

Electrochemical oxidation of terbium(III) in aqueous media: influence of supporting electrolyte on oxidation potential and stability

Apart from the generally dominant trivalent oxidation state, several lanthanides can occur in divalent or tetravalent states as well. Changing the valence state alters the chemical properties and, therefore, gives the opportunity to ease intragroup lanthanide separations. The hydrated terbium(III) ion has a highly positive reduction potential (E0 = + 3.1 V vs. SHE), but it can be oxidized to its tetravalent state via ozonolysis or electrolysis, and stabilized in highly concentrated carbonate solutions. In this study, terbium(III) is electrochemically oxidized to terbium(IV) in aqueous carbonate, nitrate, and periodate media. Spectroscopic and elemental analysis were done to characterize terbium(IV) and to gain insight in the stability of these complexes in the aqueous electrolytes of carbonate, nitrate, and periodate. In all these electrolytes, oxidation and stabilization were achieved at different pH, terbium concentration, salt concentration and applied potentials. The most promising electrolyte was found to be carbonate, since it allowed to attain more concentrated and more stable terbium(IV) solutions.Graphical abstract

Influence of Tb3+ ions concentration and temperature on lithium bismuth alumino borosilicate glasses for green photonic device applications

Lithium bismuth alumino borosilicate (LiBiAlBSi) glasses doped with various concentrations of trivalent terbium (Tb3+) ions were prepared to explore their physical, optical, and photoluminescence (PL) characteristics features. Diffraction pattern recorded for an undoped as well as doped (1.5 mol% of Tb3+) LiBiAlBSi glass ascertained the amorphous nature. Absorption spectra reveal several peaks in n-UV and blue regions. The indirect optical band gap for Tb3+ doped LiBiAlBSi glasses was found in the 3.16-3.46 eV range. PL measurements such as emission (under 378 nm excitation) and excitation (under 542 nm emission) were recorded to study the usage of the as-prepared glasses for green photonic device applications. PL emission spectra reveal four emission bands of Tb3+ ions originating from the excited level of 5D4 to 7FJ (=3,4,5,6) levels. The intensity of the emission peak observed in the green region at 542 nm (5D4→7F5) escalates up to 1.5 mol% of Tb3+ ion concentration and declines beyond due to concentration quenching. Dexter theory applied to the PL emission spectral features reveals dipole-dipole interaction among Tb3+ ions responsible for the transfer of energy and thereby concentration quenching. The CIE coordinates and CCT values calculated for the as-prepared glasses are closure to the values of intense green emission given by the European Broadcasting Union illuminant. The experimental lifetime values (τexp) measured for the intense green emission (5D4→7F5) are reducing with the upsurge in the content of Tb3+ ions in the titled glasses. Correlation of τexp values with the PL emission spectral data facilitate the estimation of radiative properties. Relatively high activation energy value estimated from the temperature-dependent PL show the thermal stability of the optimized glass. The PL (excitation, emission, decay, temperature-dependent) studies along with colorimetric studies confirm the aptness of the LBiAlBSiTb15 glass for photonic applications such as laser and tricolour w-LEDs as a green emitting component.