Luminescence Intensity Of Tb3 Research Articles

Luminescence properties and energy transfer of Ce3+, Tb3+ codoped Ba2GaB4O9Cl Phosphor

In this paper, a series of Ba2GaB4O9Cl:Ce3+,Tb3+ phosphors were synthesized by the conventional high-temperature solid-state reaction. The incorporation of Ce3+ ions as sensitizers significantly enhances the absorption and luminescence intensity of Tb3+ ions in the Ba2GaB4O9Cl phosphor. The energy transfer from Ce3+ to Tb3+ occurs through the electric quadrupole-quadrupole interaction, with an energy transfer efficiency of 48 %. The internal quantum efficiency of Ba2GaB4O9Cl:Ce3+,Tb3+ phosphor is 39.95 % upon 316 nm excitation. At 423 K, the emission intensity of Ba2GaB4O9Cl:Ce3+,Tb3+ can keep 53.28 % of its initial value at room temperature. All these results indicate that the Ba2GaB4O9Cl:Ce3+,Tb3+ phosphor has potential application for white LED.

Constructing Tb3+→Mn2+ energy transfer to realize tunable luminescence and optical temperature measurement in glass-ceramics containing Y2Sn2O7

By using the melt crystallization method, Tb4O7−MnO2 co-doped glass-ceramics containing Y2Sn2O7 were synthesized. The heat treatment for glass-ceramics was determined to be 700 °C/1.5 h using differential scanning calorimetry analysis, X-ray diffraction, scanning electron microscopy, and light transmittance curves. FTIR spectroscopy further confirmed the precipitation of the Y2Sn2O7. Although MnO2 was used as the Mn source in this experiment, the glass-ceramic showed the luminescent properties of Mn2+. The emission spectra and fluorescence decay curves of Tb4O7−MnO2 co-doped glass-ceramics demonstrate the energy transfer phenomenon of Tb3+→Mn2+. When the doping concentration of MnO2 increases, the glass-ceramics can realize tunable luminescence from green light to yellow light to orange light. At 473 K, the luminescence intensity of Tb3+ and Mn2+ were 84.3% and 33.0% of those at room temperature. In terms of absolute and relative sensitivity, the maximum values for glass-ceramics were 1.18 × 10−2 K−1 and 1.52% K−1. The minimum temperature resolution is 0.05 K at 298 K. It is demonstrated that the prepared Tb4O7−MnO2 co-doped glass-ceramics containing Y2Sn2O7 have a promising application in the field of optical temperature measurement.

Tb3+ ion luminescence monitors β-dicalcium silicate mineralization conversion

Tb3+ doped β-dicalcium silicate (β-Ca2SiO4: Tb3+) phosphors with different concentrations of Tb3+ were successfully manufactured by the high-temperature solid-state method. The crystal structures, morphological, chemical composition, and optical performances of these before and after mineralization phosphors were investigated via X-ray diffraction, scanning electron microscopy, energy dispersives X-ray spectroscopy, as well as photoluminescence. The crystal structure of β-Ca2SiO4 can be stabilized by adding Tb3+ ions. Under 375 nm excitation wavelength, Tb3+ occurs on 5D4→7F5 transition, β-Ca2SiO4: Tb3+ phosphors exhibit intense green emission which is located at 543 nm. During the mineralization experiment, β-Ca2SiO4: Tb3+ phosphors showed good biological activity and were rapidly transformed into hydroxyapatite (HA), and its luminescence intensity attenuated synchronously. All results suggest that the mineralization process of β-Ca2SiO4: Tb3+ can be monitored by observing the change in luminescence intensity of Tb3+ ions.

PH assists for selective determination of Acyclovir by the Emission Enhancement of Tb3+Chemosensor in tablet and serum samples

A new selective method for the determination of acyclovir in tablets and serum samples was developed. The method depends on the luminescence enhancement of Tb3+ chemo sensor with different concentrations of acyclovir at pH 10. Acyclovir can form a complex with Tb3+ ion of 1:3 molar ratio in DMSO. The luminescence intensity of Tb3+-acyclovir complex increases as the concentration of the drug increases at λex=320 nm, pH 10 in DMSO. The linear range for determination of the selected drug in DMSO 1.0 x 10-9 –1 x 10-5 mol L-1 the detection limits were 0.24 x 10-9 mol L-1.

A lanthanide doped metal-organic framework demonstrated as naked eye detector of a trace of water in organic solvents including alcohols by monitoring the turn-on of luminescence

It is very crucial to have a very simple, instant and low-cost detection and estimation of a trace of water in common organic solvents including alcohols. To obtain the sensor material we have synthesized a metal-organic framework (MOF) {[Y1.0Mn1.5(PDA)3(H2O)3]·3.5H2O}, 1, (PDA = 2,6-pyridinedicarboxylic acid) through hydrothermal process. A doping of compound 1 by 10 % terbium {[Y0.9Tb0.1Mn1.5(PDA)3(H2O)3]·3.5H2O}, 1:Tb, was done through an isomorphous substitution technique. The most advantageous point about 1:Tb was the metal centre luminescence, which was largely stokes shifted from the excitation light making possible the naked eye observation. The weak metal centre luminescence intensity of dehydrated 1:Tb (excluding lattice and coordinated water molecules) in organic solvents EtOH, CH3OH, CH3CN, THF and n-heptane showed huge turn-on in presence of trace amounts of H2O in the said solvents. The luminescence intensity of Tb3+ centre was enhanced by several folds with a limit of detection 1.12 %(v/v), 0.47 %(v/v), 0.04 %(v/v), 0.13 %(v/v) and 0.53 %(v/v) respectively. The coordinated water molecules as well as the lattice water molecules in 1:Tb play a vital role during sensitization of the Tb3+ centre by enhancing the rigidity of the structure and facilitating the formation of LMCT state which ultimately results in a huge turn-on of metal centre luminescence.

Luminescent Properties of Europium(III), Gadolinium(III), and Terbium(III) Complexes with Alkyloxybenzoic Acids

Luminescent properties of europium(III), gadolinium(III), and terbium(III) complexes with 4-dodecyl- and 4-octadecyloxybenzoic acids were studied. Energies of excited triplet states of the acid anions (T1) were determined from phosphorescence spectra of the Gd(III) complexes measured at 77 K. The luminescence mechanism found that intramolecular energy transfer from the organic ligand to the lanthanide ion was effective for the Eu(III) complexes. Complexes of composition LnL3Phen, where Phen is 1,10-phenanthroline, were prepared to increase the luminescence intensity of the Tb(III) complexes. Experimental spectra showed that the integrated luminescence intensity of Tb3+ in TbL3Phen increased as compared with TbL3.

Перенос энергии от Ce-=SUP=-3+-=/SUP=- к Tb-=SUP=-3+-=/SUP=- в ортоборатах иттрия и гадолиния, полученных гидротермальным синтезом

AbstractWe studied the structure, IR absorption spectra, the spectral characteristics of photoluminescence and morphology of cerium- and terbium-doped orthoborates of gadolinium and yttrium obtained by hydrothermal synthesis at 200°C, as well as solid solutions of orthoborates on the basis of yttrium, gadolinium, and lutetium with composition RECe_0.01Tb_0.1BO_3 (RE = Lu_0.5Gd_0.39, Lu_0.5Y_0.39, and Y_0.5Gd_0.39). The X-ray diffraction spectrum of yttrium orthoborate Y_1 – _ x _– _ y Ce_ x Tb_ y BO_3 is described by a hexagonal lattice with space group P 6_3/ m , which, after annealing at 970°C, transforms into a monoclinic lattice with space group C 2/ c . High-temperature annealing of the studied orthoborates leads to a multiple, more than two orders of magnitude, increase in the luminescence intensity of Tb^3+ ions when the samples are excited in the absorption band of cerium ions. This effect is the result of a significant increase in the concentration of Ce^3+ ions in the orthoborates at high temperatures. It is shown that the luminescence of terbium ions is due to energy transfer from Ce^3+ to Tb^3+, which proceeds with high efficiency (∼85%) by the mechanism of dipole-dipole interaction between cerium and terbium.

Spectral and structural characteristics of Lu1 – x – y Ce x Tb y BO3 orthoborates prepared by the hydrothermal synthesis method

The structure, IR absorption spectra, morphology, and photoluminescence spectral characteristics of Lu1–x–y Ce x Tb y BO3 solid solutions prepared by the hydrothermal synthesis method have been investigated. According to the X-ray powder diffraction data, the Lu1–x–y Ce x Tb y BO3 samples hydrothermally synthesized at a temperature T = 200°C have the vaterite structure, and all the observed diffraction peaks correspond to the hexagonal phase with the space group P63/mmc, which is isostructural to pure lutetium borate LuBO3. Annealing of these samples at T = 970°C leads to a change in the structural modification and to the transition of the samples to the monoclinic phase with the space group C2/c. It has been found that, after annealing of these samples at temperatures T = 800–970°C, the luminescence intensity of Tb3+ ions upon excitation in the absorption band of Ce3+ ions increases by more than two orders of magnitude and becomes much higher than that in compounds of the same composition, but prepared by high-temperature synthesis. At the same time, annealing of lutetium borate doped only with terbium does not lead to a significant change in the luminescence intensity of Tb3+ ions. The possible reasons for a multiple increase in the luminescence intensity of terbium ions due to the annealing of the hydrothermally synthesized lutetium orthoborate samples doped with cerium and terbium ions have been discussed.

Cerium and terbium ions doped strontium aluminosilicate polycrystalline phosphors

Cerium and terbium ions doped strontium aluminosilicate polycrystalline phosphors with monoclinic structure identified to I2/c space group were synthesized by the high temperature solid-state reaction. Differential NUV-blue fluorescence behaviors of Ce3+ were exhibited under UVB radiation, which were originated from the luminescence centers with different crystal field environment. Bright green fluorescence of Tb3+ was released under UVA radiation, and with the intervention of Ce3+ ions, the effective excitation spectral range of Tb3+ ions was extended from UVA to UVB due to the energy transfer from Ce3+ to Tb3+. Upon the excitation in extended region, the luminescence intensity of Tb3+ was remarkably strengthened by a maximum fluorescence sensitization factor of ~152. These results demonstrate that Ce3+ and Tb3+ doped SrAl2Si2O8 polycrystals are valuable NUV-blue and green phosphors, which have potential applications for phototherapy and color display.

Luminescent properties of lithium-phosphate-borate glasses doped with Tb3+/ Eu3+ ions

The luminescence of Li2O-B2O3-P2O5-CaF2 scintillation glass doped Tb3+, Eu3+ under different types of excitation sources are investigated. Changing the europium concentration of 0.5 to 1 wt% leads changes in luminescence intensity of Tb3+ ions. The luminescence spectrum of the Tb3+ ions are depend on the concentration of Eu3+. It was found, that the luminescence decay kinetics of terbium ion in the band 543 nm depending on the concentration of europium and from type of excitation. The difference in the nature of the luminescence decay kinetics of glasses under pulsed photo- and electronic excitation discussed.

New polymerizable luminescence probe for detection of Chlorfenvinphos and Dichlorvos pesticides

Luminescence quenching probe ratio Tb(III):(L) in 1:3 stoichiometric has been studied in methanol in the bearing of the pesticides Chlorfenvinphos and Dichlorvos. The luminescence intensity of Tb(III)–(L)3 probe decreases as the concentrations of the pesticide increases. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence quenching of Tb(III)–(L)3 probe in the solution. The detection limits were 1.9 and 1.96µM for Chlorfenvinphos and Dichlorvos, respectively. Stern–Volmer studies at different temperatures, indicating that collisional quenching dominates for the pesticides. The binding constants (K) and thermodynamic parameters (∆S°, ∆H° and ∆G°) of the interaction of pesticides with the complex were evaluated. A polymer containing Tb(III)–(L)3 complex and the polymerizable ligand (L; as monomer) was prepared. The polymer was characterized using EDAX, FT-IR and thermal analysis (TGA and DTA). The interaction of the polymer with Chlorfenvinphos and Dichlorvos was investigated, which gave different behavior from Tb(III)–(L)3 complex with limit of detection of 0.43 and 0.32µM for pesticides Chlorfenvinphos and Dichlorvos, respectively.

Luminescence intensity and dopant concentration in AlN:Tb

The luminescence intensity of Tb3+ embedded in sputter deposited and subsequently annealed AlN shows strong concentration dependence. The intensity of the characteristic green luminescence of Tb3+ rises at low concentrations with rising concentration. At higher concentrations, strong concentration quenching occurs. The optimum concentration range of Tb3+ in AlN was observed to range between 2.5at% Tb and 3.6at% Tb. The experimentally evaluated concentration dependence results can be described by a rate equation approach based on available models of luminescence quenching.

Synthesis, structural, thermal and optical studies of rare earth coordinated complex: Tb(Sal) 3Phen

Complexes of salicylic acid (Sal) and 1,10-phenanthroline (Phen) were synthesized coordinated with terbium ion (Tb 3+) in crystalline phases. The structural characterizations of the lanthanide complex were made using FT-IR, NMR ( 1H and 13C) and XRD techniques. These measurements confirm the formation of Tb(Sal) 3Phen complex structure. The thermal aspects of the complex were examined using DTA and TGA techniques. An enhancement in luminescence intensity of Tb 3+ ion bands were observed in Tb(Sal) 3Phen complex as compared to TbCl 3 crystals on 355 nm laser excitation. Enhancement is reported due to the efficient energy transfer process from Sal to Tb 3+ ions. This is also confirmed by the time resolved photoluminescence spectroscopy with increase in lifetime of Tb 3+ ions due to encapsulation in Sal/Phen network. Our system in itself can be a deserving candidate for luminescent solar collector material when coupled with solar cells.

Luminescent properties of Tb 3+ and Gd 3+ ions doped aluminosilicate oxyfluoride glasses

Tb 3+ and Gd 3+ ions doped lithium–barium–aluminosilicate oxyfluoride glasses have been prepared. The transmission, emission and excitation spectra were measured. It has been found that those Tb 3+-doped lithium–barium–aluminosilicate oxyfluoride glasses exhibit good UV-excited luminescence. The luminescence intensity of Tb 3+ ion increases for those (Tb 3+, Gd 3+)-codoped glasses. Energy transfer process from Gd 3+ ion to Tb 3+ ion is indicated.

Preparation and characterization of Tb 3+ and Tb(sal) 3· nH 2O doped PC:PMMA blend

Tb doped polycarbonate:poly(methyl methacrylate) (Tb–PC:PMMA) blend was prepared with varying proportions of PC and PMMA. Thermal and spectroscopic properties of the doped polymer have been investigated employing Fourier Transform Infrared (FTIR) absorption and differential scanning calorimetric (DSC) techniques. PC:PMMA blend (with 10 wt% PC and 90 wt% PMMA) shows better miscibility. Optical properties of the dopant Tb 3+ ions have been investigated using UV–vis absorption and fluorescence excited by 355 nm radiation. It is seen that luminescence intensity of Tb 3+ ion depends on PC:PMMA ratio and on Tb 3+ ion concentration. Concentration quenching is seen for TbCl 3·6H 2O concentration larger than 4 wt%. Addition of salicylic acid to the polymer blend increases the luminescence from Tb 3+ ions. Luminescence decay curve analysis affirms the non-radiative energy transfer from salicylic acid to Tb 3+ ions, which is identified as the reason behind this enhancement.

Synthesis, Photoluminescence and Energy Transfer of Two Novel Tb(III) Ternary Complexes

Two novel Tb(III) ternary complexes with 2-aniline carbonyl benzoic acid (HAB) as the first ligand, imidazo [5,6-f] phenanthroline(IP) and 1,10-phenanthroline(phen)as the secondary ligands were synthesized. The structures of the ligands and Tb(III) complexes were confirmed by elemental analysis, IR spectra and UV spectra. The fluorescence spectra suggested that the luminescence intensity of Tb(HAB)3IP was obviously higher. Further investigation showed that HAB was the donor of energy, IP and phen which functioned as “energy ladder” could transfer the energy in the system of ternary complexes. If this “energy ladder” was located suitable, it could bridge the energy level difference between the triplet state of first ligand and excited states of rare earth ion .So, the intramolecular energy could transfer efficiently to central Tb3+ ion and competitive luminescence of HAB was also reduced.

Luminescence switching behavior through redox reaction in Ce3+ co-doped LaPO4:Tb3+ nanorods: Re-dispersible and polymer film

Re-dispersible Tb(3+) doped LaPO(4) nanorods have been prepared using ethylene glycol (EG) as a capping agent as well as reaction medium at a relatively low temperature of 150 °C. The X-ray diffraction study reveals that all the doped samples are well crystalline with a monoclinic structure of the LaPO(4) phase. The luminescence intensity of (5)D(4)→(7)F(5) transition at 543 nm (green) is more prominent than that of (5)D(4)→(7)F(6) transition at 487 nm (blue) for all the samples. This is related to the polarizing effect from [PO(4)](3-) to the Tb(3+) site. Concentration dependent luminescence study shows that the luminescence intensity of Tb(3+) increases up to 10 at.% and decreases above this. This is due to the concentration quenching effect arising from cross relaxation among Tb(3+)-Tb(3+) ions. The results show that nanoparticles prepared in EG medium gives an enhanced luminescence compared to that prepared in water. This is attributed to the multiphonon relaxation effect from O-H groups surrounding over nanoparticles as well as the extent of increase of agglomeration among particles for samples prepared in water. Significant enhancement in the emission of Tb(3+) is also observed when Ce(3+) is used as the sensitizer in LaPO(4):Tb(3+)nanorods. The optimum concentration of Ce(3+) for maximum luminescence is found to be 7 at.% in Ce(3+) sensitized LaPO(4):Tb(3+) (5 at.%). Based on the energy transfer process from Ce(3+) to Tb(3+), the luminescence of Tb(3+) can be switched OFF and ON by performing oxidation and reduction of Ce(3+)↔Ce(4+) using KMnO(4) and ascorbic acid, respectively. The samples are re-dispersible in water, methanol and can be incorporated into polyvinyl alcohol (PVA) films. They show a dark green emission under ultraviolet radiation.

Sensitization effects of supramolecular assemblies on the luminescence of terbium-ion prulifloxacin complexes

Luminescence enhancement of terbium-ion prulifloxacin complexes (Tb(III)–PUFX) in supramolecular hydrogels formed by assembly of 1,3:2,4-di-O-benzylidene-D-sorbitol (DBS) was investigated by steady-state fluorescence, varying temperature fluorescence and time-resolved fluorescence. The luminescence images show that Tb(III)–PUFX were dispersed in the DBS gels. The luminescence intensity of Tb(III)–PUFX in the DBS gels was significantly increased in comparison with that in corresponding aqueous solutions. The varying temperature fluorescent spectra show that the luminescence intensity of Tb(III)–PUFX decreased with an increase in the temperature. This implies that the luminescence enhancement of Tb(III)–PUFX is related to the dissociation and the formation of the DBS assemblies. Time-resolved fluorescence measurements show slower rotational motion in DBS gels in comparison with that in the corresponding aqueous solutions. This may be ascribed to a unique microstructure of three-dimensional network formed by DBC aggregates, resulting in deactivation of the nonradiative relaxation. The images of field emission scanning electron microscopy and polarized optical microscopy indicate that the morphology of the DBS assemblies was not influenced upon addition of Tb(III)–PUFX to the DBS gels.

Elucidation of a Novel Extracellular Calcium-binding Site on Metabotropic Glutamate Receptor 1α (mGluR1α) That Controls Receptor Activation*

Metabotropic glutamate receptor 1α (mGluR1α) exerts important effects on numerous neurological processes. Although mGluR1α is known to respond to extracellular Ca(2+) ([Ca(2+)](o)) and the crystal structures of the extracellular domains (ECDs) of several mGluRs have been determined, the calcium-binding site(s) and structural determinants of Ca(2+)-modulated signaling in the Glu receptor family remain elusive. Here, we identify a novel Ca(2+)-binding site in the mGluR1α ECD using a recently developed computational algorithm. This predicted site (comprising Asp-318, Glu-325, and Asp-322 and the carboxylate side chain of the receptor agonist, Glu) is situated in the hinge region in the ECD of mGluR1α adjacent to the reported Glu-binding site, with Asp-318 involved in both Glu and calcium binding. Mutagenesis studies indicated that binding of Glu and Ca(2+) to their distinct but partially overlapping binding sites synergistically modulated mGluR1α activation of intracellular Ca(2+) ([Ca(2+)](i)) signaling. Mutating the Glu-binding site completely abolished Glu signaling while leaving its Ca(2+)-sensing capability largely intact. Mutating the predicted Ca(2+)-binding residues abolished or significantly reduced the sensitivity of mGluR1α not only to [Ca(2+)](o) and [Gd(3+)](o) but also, in some cases, to Glu. The dual activation of mGluR1α by [Ca(2+)](o) and Glu has important implications for the activation of other mGluR subtypes and related receptors. It also opens up new avenues for developing allosteric modulators of mGluR function that target specific human diseases.

On the relationship between the luminescence of heterometallic terbium-copper-podand complexes and the ligand structure

The formation conditions and luminescence of heterometallic Tb-Cu complexes with structurally similar podands containing different numbers of oxymethylene fragments were studied (n = 2−7). The component ratio in mono- and different-metal complexes were 1: 1 and 1: 1: 1, respectively. The possibility of complex formation for the carbonyl and enol forms was estimated by molecular mechanics. The results were in good agreement with experimental data. The most pronounced enhancement of luminescence intensity of Tb(III) ions in heterometallic Tb-Cu complexes was observed for podands containing two and three oxymethylene fragments (L1 and L2, respectively) and the probability of complex formation with these podands is higher than with the podands containing four to seven oxymethylene fragments (L3–L5).