Tb-doped Samples Research Articles

Evaluation of scintillation and dosimetric properties of undoped and Tb-doped Ba3Y(PO4)3 single crystals

Undoped and Tb-doped Ba3Y(PO4)3 single crystals were synthesized by the floating zone method. Photoluminescence (PL), scintillation, and dosimetric properties of the obtained single crystals were measured. The highest PL quantum yield value was obtained from the 15% Tb-doped crystal. In X-ray-induced scintillation spectra, the undoped crystal showed an emission peak due to self-trapped exciton at 400 nm. Tb-doped crystals showed emission peaks in the range of 375–620 nm, originated from 4f-4f transitions of Tb3+. In addition, the undoped and Tb-doped crystals showed luminescence peaks in similar locations to the scintillation spectra in thermally and optically stimulated luminescence (TSL and OSL). In TSL dose response functions, the 1% Tb-doped sample exhibited the highest TSL intensity, and the TSL signal was detectable from 0.01 mGy. In OSL dose response functions, the 5% Tb-doped sample exhibited the highest OSL intensity, and the OSL signal was observed from 0.1 mGy.

Photoluminescence, scintillation, and dosimetric properties of undoped and Tb-doped Ba3Gd(PO4)3 single crystals

Undoped and Tb-doped Ba3Gd(PO4)3 single crystals were synthesized by the floating zone method. Photoluminescence (PL), scintillation, and thermally stimulated luminescence (TSL) properties of the obtained single crystals were evaluated. The highest PL quantum yield value was obtained from the 5% Tb-doped single crystal. In X-ray-induced scintillation and TSL spectra, the undoped sample represented an emission peak originating from the 4f–4f transition of Gd3+ at 310 nm. The Tb-doped samples represented emission peaks originating from the 4f–4f transitions of Tb3+ and Gd3+ in the range of 310–620 nm. In TSL dose response functions, the 1% Tb-doped sample showed the highest TSL intensity, and the lower detection limit was 0.01 mGy.

Photoluminescence and scintillation properties of Tb-doped CaHfO3 single crystals

CaHfO3 was investigated as a promising candidate for a scintillator because of high density and large effective atomic number. Tb-doped CaHfO3 single crystals with various Tb concentrations were synthesized by the floating zone method, and the photoluminescence (PL) and scintillation properties were investigated. All the samples showed the highest PL emission intensity at 550 nm, and the origin of this emission was identified as 4f-4f transitions of Tb3+ by the obtained PL decay time constants. The X-ray-induced scintillation spectra showed several emission peaks in the range of 350–650 nm, which were attributed to the 4f-4f transitions of Tb3+. Based on the results of the pulse height spectra, the light yield of the 1.0% Tb-doped sample was calculated to be 12,000 photons/MeV, respectively.

The Saturation of the Response to an Electron Beam of Ce- and Tb-Doped GYAGG Phosphors for Indirect β-Voltaics

GYAGG:Tb (Ce) scintillators have been confirmed to be promising sources of light emission when excited by an intense 150 keV electron beam. The saturation of the scintillation yield under such excitation conditions has been studied. To explain the results obtained, a model that considers the Auger quenching mechanism was used. The Ce-doped material did not show saturation, whereas a moderate 30% drop of the yield was measured in the Tb-doped sample at the highest excitation beam intensity ~1 A/cm2. This put forward a way to exploit the Tb-doped scintillator for indirect β-voltaic batteries.

Optical, scintillation, and dosimetric properties of undoped and Tb-doped CaYAlO4 single crystals

Optical, scintillation, and dosimetric properties of the undoped and Tb-doped CaYAlO4 single crystals grown by the floating zone method were evaluated. Several photoluminescence (PL) emission peaks due to the 4f–4f transitions of Tb3+ ion were observed at 385–620 nm under excitation at 250 nm in Tb-doped CaYAlO4 samples. Under X-ray irradiation, scintillation peaks of the Tb-doped CaYAlO4 crystals were consistent with the PL emission peaks. In terms of a dosimetric property, the 0.1% Tb-doped crystal exhibited the highest thermally stimulated luminescence intensity and the widest linear responses in the range of 0.01–1000 mGy among the samples.

Synthesis of Tb-doped SiO2 glasses by spark plasma sintering method and evaluation of photoluminsecence and thermally stimulated luminescence properties

Tb-doped SiO2 glasses were synthesized by the spark plasma sintering (SPS) method, and optical and thermally stimulated luminescence (TSL) properties were investigated. The diffuse transmittance spectra of the 0.01, 0.05, and 0.1% Tb-doped SiO2 samples included the absorption due to the 4f-5d transitions of Tb3+ ions. In photoluminescence properties, all the Tb-doped SiO2 samples showed several emission peaks due to the 4f-4f transitions of Tb3+ ions and oxygen deficiency vacancy (ODC). The TSL glow curves indicated the glow peak at 140 °C, and only the emission peaks attributed to the 4f-4f transition of Tb3+ ions were observed in TSL spectra of the 0.01, 0.05, and 0.1% Tb-doped SiO2 samples. The integrated TSL intensity of the 0.1% Tb-doped samples had a proportional relationship in the range of 0.01–1000 mGy. The TSL intensity of the 0.05% Tb-doped glass after 72 h from X-ray irradiation was about 69% with respect to the one immediately after X-ray irradiation. In addition, the 0.05% Tb-doped SiO2 glass could use the multiple time for TSL dosimetry.

Examination of pairing mechanism, orbital hybridization, stabilization and magnetization behavior of Tb/Y and Zn/Cu partially substituted Y-123 Superconductors

The effect of homovalent Tb/Y and Zn/Cu substitution on electrical, superconducting, structural, and magnetic features of Y-123 ceramic materials is extensively examined by powder X-ray diffraction, electrical resistivity, scanning electron microscopy, energy dispersive X-ray spectrometry, DC magnetization VSM measurements and related calculations. Y1−xTbxBa2Cu3O7-ɤ and YBa2(Cu1−xZnx)3O7-ɤ samples are prepared with four different molar percentages (0.0 ≤x ≤ 0.15) using the sol-gel technique. DC magnetization data and the Bean model are used to evaluate change in critical current densities with an applied magnetic field. Energy-dispersive X-ray spectrometry measurements indicate that materials are exactly produced in the desired stoichiometric ratios. Moreover, all the experimental findings show that the fundamental characteristic properties are observed to decrease with replacement mechanism. The degradation mechanism with partial substitution is thoroughly explained scientifically in the basic contents for the first time. The role of Tb/Y and Zn/Cu partial substitution on the oxygen concentration level in unit cell, ordering degree in the Cu-O ribbons, lattice cell parameters, grain size, and the number of holes in the σ antibonding in-plane Cu-O bonds are also discussed in detail. Additionally, beginning of weak-interaction problems between adjacent superconductive layers, formation of microscopic structural faults and decoupling of superconducting grains are noted to be the negative effect of substitution mechanism. Regardless, it is observed that Tb-doped samples possessing more uniform surface morphologies with better surface texture and connection quality between particles show much higher magnetization behavior and superconducting properties. All in all, this study developing a scientific methodology about why fundamental characteristic features change with the partial replacements of Tb/Y and Zn/Cu in crystal systems seems a pioneering investigation to construct novel and feasible application fields for the Y-123 ceramic compounds.

Evaluation of radiation-induced luminescence properties of Tb-doped LiCaPO4

We have investigated photoluminescence (PL), scintillation, and dosimetric properties of the undoped and Tb-doped LiCaPO4 samples. The luminescence origin of the undoped and Tb-doped samples were ascribed to the self-trapped exciton (STE) and 4f-4f transitions of the Tb3+, respectively. In Thermally stimulated luminescence (TSL) glow curves, undoped samples showed main peak at 220 °C, and Tb-doped samples showed main peak at 130 °C. The Tb-doped samples demonstrated the more than 50 times higher TSL intensity than that of undoped one. In addition, the lowest measurable dose (LMD) of the Tb-doped samples were estimated to exceed 1 μGy.

Characterization and thermoluminescence study of gamma irradiated Tb-doped ZnO and undoped ZnO synthesized by spray pyrolysis method

High gamma dose-resistant undoped ZnO and Tb-doped ZnO thermoluminescent (TL) micro-phosphors were prepared by the spray pyrolysis method. Scanning electron microscopy shows crystalline rods with hexagonal morphology, (0.1-0.4 µm diameter, and about 1 µm length). Raman spectra dispersion reveals a würtzite form. Photoluminescence (PL) study of irradiated zinc oxide films indicates the generation of defects produced by gamma irradiation resulting in an increased probability of electron-hole exciton recombination. PL spectrum shows emission bands from 5D4-7Fj=6,5,4,3 transitions ascribed to Tb3+ dopant in zinc oxide phosphor. X-ray diffraction patterns for both types of films growth (undoped ZnO and Tb-doped ZnO) are typical of zinc oxide crystalline structure, with no noticeable effect of Tb ions. Dosimetric properties, for both samples, show a low TL fading signal and TL reproducibility signal for undoped ZnO and Tb-doped ZnO samples was 29 and 57 %, respectively. The kinetic parameters such as activation energy E, frequency factor s, and Rm values, were obtained by Computerized Glow Curve Deconvolution (CGCD) assuming Mixed Order Kinetic model (MOK). The results show that the MOK well described the glow curves of zinc oxide films. The heating rate effects produced a broadening of glow peak located at 420 K. For purposes like radiation detector, atomic effective number (Zeff) was obtained: 27.74 and 56.47 for undoped ZnO and Tb-doped ZnO samples, respectively. The samples were exposed to gamma radiation in a wide range of 0.25–20 kGy dose. TL properties of undoped ZnO and Tb-doped ZnO samples show that these materials could be used to detect high doses in a gamma radiation field.

The scintillation mechanisms in Ce and Tb doped (GdxY1-x)Al2Ga3O12 quaternary garnet structure crystalline ceramics

Scintillation mechanisms and performance parameters of quaternary (Gd,Y)3Al2Ga3O12 compositionally disordered polycrystalline garnet type ceramics doped with Ce or Tb have been investigated for the first time. Similar light yield dependence on a Gd content in the composition was evidenced for both dopants. The highest light yield achieved in Tb doped samples was found to be four times higher than in Ce doped samples, which was achieved by tuning of the resonance conditions for energy transfer from Gd subsystem to Tb3+ activators due to the variation of Gd content in the matrix. The exceptional role of the Gd3+ subsystem is forming the high light yield of Tb doped quaternary garnets under different kinds of ionizing radiation is pointed out.

Effective dopants for CuI single nanocrystals as a promising room temperature thermoelectric material

Room temperature (RT) thermoelectric (TE) materials are of great importance for harvesting energy from solar heat or other hot environments. The nontoxic, earth-abundant copper iodide (CuI) has a high Seebeck coefficient at RT; however, its electrical conductivity needs to be further enhanced for better TE performance. In this work, pure and doped CuI single nanocrystals were synthesized by the precipitation method in ethanol medium. The formed CuI nanoparticles (NPs) have high crystallinity in the gamma phase. Among several metallic dopants, Tb and Fe were found to be effective for enhancing the TE performance of CuI NPs. The Tb-doped sample was found to have the highest TE power factor. The concentration of this dopant was optimized for maximum TE performance. The TE power factor and Figure of merit values at RT were enhanced from approximately 30 μW/m K2 and 0.01 for the pure CuI NPs to approximately 210 μW/m K2 and 0.08 for the 0.05 mol% Tb-doped sample, respectively. This enhancement is correlated with the incorporation of this dopant in mixed chemical states. The pure and Tb-doped CuI NPs were characterized by several techniques, including XDR, XPS, TEM, SEM, and UV–visible spectroscopy. The Tb-doped sample might be suitable for RT TE devices and generators.

Dosimetric properties of undoped and Tb-doped MgAl2O4 transparent ceramics

Undoped and Tb-doped MgAl2O4 transparent ceramics were synthesized by the Spark Plasma Sintering (SPS) method, and dosimetric properties were investigated. The Tb-doped sample showed thermally stimulated luminescence (TSL) and optically stimulated luminescence (OSL), in which the emission center was Tb3+ ions. The TSL glow peaks of the Tb-doped sample are detected at 64, 151, 235, 299, and 385 °C. The Tb-doped sample had a linear TSL response in a dose range from 0.01 to 1000 mGy.

Scintillation and dosimetric properties of Tb-doped CaF2 translucent ceramics synthesized by the spark plasma sintering method

ABSTRACT CaF2 translucent ceramics with different concentrations of Tb were synthesized by the spark plasma sintering (SPS) method, and their photoluminescence, scintillation and dosimetric properties were characterized. The Tb-doped samples exhibited scintillation with several sharp peaks across the range from 365–630 nm due to 4 f-4 f transitions of Tb3+ and with a broad peak at approximately 300 nm due to self-trapped excitons. Among the sample investigated, the scintillation intensity in the 365–630 nm range was highest for the 0.5% Tb-doped sample. As a dosimetric property, the Tb-doped samples exhibited thermally-stimulated luminescence (TSL) with a glow peak at approximately 90°C, and with a TSL response in a linear relationship to the X-ray dose over the dose range from 0.001 to 1 mGy. Optically stimulated luminescence (OSL) due to the 4 f-4 f transitions of Tb3+ was detected in the Tb-doped samples, moreover and the lowest detectable limit of OSL was at most 100 mGy.

Synthesis and characterization of PbS nanowires doped with Tb3+ ions by using chemical bath deposition method

Crystalline lead sulfide (PbS) nanowires doped with terbium (Tb3+) ions were synthesized by the chemical bath deposition method at room temperature. The powder was obtained from an aqueous solutions using lead acetate dehydrate, terbium nitrate, thiourea, potassium hydroxide and ammonia. The terbium molar concentrations were varied in the deposition process to investigate the effect on the structural, optical, morphological and luminescent properties of PbS nanowires. The crystalline size was found to be dependent on the concentration of the Tb3+ ions used. The estimated average crystalline sizes were calculated from the X-ray diffraction and found to be 34, 33 and 37 nm for PbS: 0% Tb3+, PbS: 0.2% Tb3+ and PbS: 0.5% Tb3+, respectively. The scanning electron microscopy micrographs depict nanowire shape for the undoped as well as Tb-doped samples. The energy-dispersive X-ray and Auger electron spectroscopy analyses confirmed the presence of all the expected elements. The solid powder nanowires exhibited high absorptions in the UV–Vis regions. The band gap energies were estimated in the range of 1.99–2.46 eV. The absorption edge and the band gap energies of these PbS nanowires have shifted depending on the concentration of the dopant. The maximum luminescence intensity was obtained for PbS: 0.2% Tb3+ ions and luminescent quenching was observed for higher terbium concentrations.Graphic abstract

Evaluation of dosimetric properties of Tb-doped MgF2 transparent ceramics

We prepared Tb-doped MgF2 transparent ceramics by the spark plasma sintering method and then measured optical, scintillation and dosimetric properties. We observed sharp peaks due to 4f-4f transition of Tb3+ ion in all of photoluminescence (PL), scintillation, optically-stimulated luminescence (OSL) and thermally-stimulated luminescence (TSL). Especially, the 1 and 3 % Tb-doped MgF2 exhibited 120 times laeger TSL intensity as compared to the 0.01 % Tb-doped MgF2. In addition, we confirmed the TSL response of the 1 and 3 % Tb-doped samples was very sensitive to irradiation dose and showed a good linearity from 0.01–1000 mGy.

Luminescent properties of Tb and Eu activated AxB1-xAlO3 (A = Y, Lu, Gd; B = Lu; x = 0, 0.5, 1) mixed oxides crystals prepared by micro-pulling-down method

Within this work the single crystals of terbium- and europium-activated AxB1-xAlO3 (A = Y, Lu, Gd; B = Lu; x = 0, 0.5, 1) mixed perovskites were grown from the melt by micro-pulling-down method. The Eu3+ and Tb3+ doping ions were chosen intentionally, as they can create in the perovskite host the trapping centers for electrons and holes, respectively. Luminescent properties of the obtained crystals have been analyzed by cathodo- (CL) and thermo- (TL) luminescence measurements. The temperature and wavelength resolved TL spectra have been measured after the samples irradiation with beta particles of 90Sr/90Y source. We have found that the shape of CL and TL spectra of the studied perovskite crystals is strongly affected by the local surrounding of dopant, depending on the size of cations and cations-ligands distances in the perovskite hosts. It was confirmed that Eu-activated mixed perovskite crystals practically do not show a measureable TL in the UV-VIS range. In turn, the measured CL spectra showed a quite strong luminescence of Eu3+ ions in the red range. The measurements performed for Tb-doped samples showed a significant TL in the UV-VIS spectral range with the most prominent emission peak below 200 °C. The measured TL spectra showed a typical luminescence of Tb3+ ions in the green range. For Y–Lu substituted crystals the maximum of TL emission was shifted towards higher temperatures what is probably correlated with the band gap energy which is greater for LuAlO3 than for YAlO3.

Luminescent properties of Y(OH)3: Tb nanopowders synthesized by microwave-assisted hydrothermal method

In the present work, terbium-doped yttrium hydroxide was successfully synthesized by the microwave-assisted hydrothermal method using yttrium nitrate, terbium chloride, and lithium hydroxide as precursors; the study is based on samples with different terbium concentrations. X-ray diffraction indicates a pure hexagonal structure corresponding with the Y(OH)3 structure, as well as a preferential growth along (110) planes for the Tb-doped samples. FTIR confirms the presence of Y–OH bonds and no adsorbed nitrogen or N–O bonds. SEM images indicate the formation of rods smaller than 1 μm in length and diameters ranging from 80 to 55 nm while TEM images confirm the presence of large areas corresponding to (110) planes. The sample doped at 4 at.% presented the maximum photoluminescent intensity, though the sample doped at 2 at.% presented the highest values of quantum yield (23.5%). Quantum yield values decay with terbium concentration to a value of 7.89% for the 10 at.% concentration, such changes are attributed to a quenching effect and to differences in the photon-extraction efficiency. Photoluminescence decay time values decrease monotonically from 1.133 for the 2 at.% sample to 0.453 ms for the sample doped at 10 at.%, such behavior is attributed to a self-stimulated emission.

Luminescence properties of Yb3+-Tb3+ co-doped amorphous silicon oxycarbide thin films

This work analyzes the photoluminescence emission of Yb3+ and Tb3+ ions in co-doped silicon oxycarbide thin films, their activation by thermal treatment, and reveals their luminescent properties regarding the energy transfer between them. Three samples of silicon oxycarbide were prepared by rf magnetron sputtering from SiC, Yb and Tb targets in an oxygen/argon atmosphere. The first one is the undoped silicon oxycarbide sample, the second one is Tb single doped, and the last one is the Yb-Tb co-doped sample. All three samples are identified as silicon oxycarbides with a low carbon content using energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The latter shows the presence of the vibrational modes of Si–C and Si–O bonds. Subsequent annealing treatments up to temperatures of 750 °C led to the rare earths optical activation in the samples. For each annealing step, we present the photoluminescence spectra using an above-bandgap excitation of 325 nm. The Tb3+ and Yb3+ -related luminescence lines were identified. The Yb3+ ions luminescence for the co-doped sample shows concentration quenching above annealing temperatures of 500 °C whereas the Tb3+ ions luminescence intensity remains almost constant. The analysis of the photoluminescence excitation spectra shows the direct excitation of the Tb3+ ions in the Tb-doped samples. A high suppression of the direct excitation of the Tb3+ ions in the Yb-Tb co-doped samples was observed. The energy transfer from Tb3+ to Yb3+ ions in co-doped samples is evidenced, first, by the decrease of the Tb3+ photoluminescence intensity in the co-doped compared to the Tb doped sample. Second, a change from nearly single exponential to nonexponential decay in the Tb3+ photoluminescence decay curves and third, by the reduction of the Tb3+ decay time from 1.2 ms in the Tb-doped sample to 0.5 ms in the Yb-Tb co-doped sample.

Photoluminescence, scintillation and TSL properties of Tb-doped strontium aluminoborate glasses

We synthesized strontium aluminoborate glasses doped with different concentrations of Tb (0.1, 0.5, 1.0 and 5.0 mol.%) by the conventional melt-quenching technique, and investigated their photoluminescence (PL), scintillation and thermally-stimulated luminescence (TSL) properties to develop phosphor materials for radiation dosimetric methods. The Tb-doped samples showed PL and scintillation with sharp peaks approximately at 485, 540, 545, 580 and 620 nm due to the 4f-4f transitions of Tb3+. The 1.0% Tb-doped sample exhibited the highest intensity in PL and scintillation among the samples investigated. In addition, the Tb-doped samples showed TSL with a main glow peak approximately at 75 °C measured after X-ray irradiation of 1000 mGy. The TSL intensity of the 0.1% Tb-doped sample was the highest, and the 0.1–1.0% Tb-doped samples showed TSL with a linear response feature over the dose range of 0.1–1000 mGy.

Luminescence and scintillation properties of rare-earth-doped LaAlO3 single crystals

LaAlO3 perovskite single crystals doped with Ce, Eu or Tb have been grown by micro-pulling-down method. X-ray diffraction analysis confirmed low-temperature rhombohedric phase. Energy-dispersive Laue mapping revealed sub-grains in the grown crystals. For the Ce-doped crystals, very low radioluminescence efficiency was found and the observed emission was ascribed to defects. Photoluminescence spectra were significantly different from the radioluminescence ones. They were significantly quenched at room temperature and the related luminescence showed also unusually high Stokes shift. High radioluminescence efficiency was found for the Tb-doped samples and especially for the Eu-doped ones, which would point to the fact that in LaAlO3 the scintillation process is more favorable for the luminescence ions which tend to capture an electron first.