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1.
Aluminium oxide (Al2O3) has widely been used for catalysts, insulators, and composite materials for diverse applications. Herein, we demonstrated if γ‐Al2O3 was useful as a luminescence support material for europium (Eu) (III) activator ion. The hydrothermal method and post‐thermal treatment at 800°C were employed to synthesize Eu(III)‐doped γ‐Al2O3 nanofibre structures. Luminescence characteristics of Eu(III) ions in Al2O3 matrix were fully understood by taking 2D and 3D‐photoluminescence imaging profiles. Various sharp emissions between 580 to 720 nm were assigned to the 5D07FJ (J = 0, 1, 2, 3, 4) transitions of Eu(III) activators. On the basis of X‐ray diffraction crystallography, Auger elemental mapping and the asymmetry ratio, Eu(III) ions were found to be well doped into the γ‐Al2O3 matrix at a low (1 mol%) doping level. A broad emission at 460 nm was substantially increased upon higher (2 mol%) Eu(III) doping due to defect creation. The first 3D photoluminescence imaging profiles highlight detailed understanding of emission characteristics of Eu(III) ions in Al oxide‐based phosphor materials and their potential applications.  相似文献   

2.
A series of heteroleptic terbium(III) complexes with fluorinated 2-thenoyltrifluoroacetone (TTFA) and other heteroaromatic units have been synthesized. The developed heteroleptic complexes were inspected via elemental study, cyclic voltammetry, thermal analysis and spectroscopic investigations. Optical band-gap data proposed the conducting property of prepared complexes. The photoluminescence emission profiles illustrated peaks based on terbium(III) cation (Tb3+) positioned at ~617, 586, 546 and 491 nm, imputed to 5D4 to 7FJ (J = 3,4,5,6) transitions separately. Most intense peak at 546 nm corresponding to 5D47F5 transition is accountable for the green emissive character of developed complexes. The luminous character of complexes reveals the sensitization of Tb3+ by ligands. Color parameters further corroborates the green emanation of Tb3+ complexes. The photometric characteristics of complexes recommended their usages in designing display devices.  相似文献   

3.
A series of Eu3+‐activated NaLi2PO4 novel phosphors was synthesized by the solid‐state reaction method. The X‐ray diffraction (XRD) and photoluminescence (PL) properties of these phosphors were investigated at room temperature. The excitation spectra indicate that these phosphors can be effectively excited by near‐UV (370–410 nm) light. The emission spectra exhibit strong reddish‐orange performance, which is due to the 5D07FJ transitions of Eu3+ ions. The orange emission from transition 5D07F1 is dominant over that of 5D07F2. The concentration quenching of Eu3+ was observed in NaLi2PO4:Eu3+ when the Eu concentration was at 1 mol%. The impact of doping Eu3+ and photoluminescence properties were investigated and we propose a feasible interpretation. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

4.
A novel ligand containing multiple coordinating groups (sulfinyl, carboxyl and carbonyl groups), acetophenonylcarboxymethyl sulphoxide, was synthesized. Its corresponding two lanthanide (III) binary complexes were synthesized and characterized by element analysis, molar conductivity, FT‐IR, TG‐DTA and UV spectroscopy. Results showed that the composition of these complexes was REL3L (ClO4)2·3H2O (RE = Eu (III), Tb (III); L = C6H5COCH2SOCH2COOH; L = C6H5COCH2SOCH2COO). FT‐IR results indicated that acetophenonylcarboxymethyl sulphoxide was bonded with an RE (III) ion by an oxygen atom of the sulfinyl and carboxyl groups and not by an oxygen atom of the carbonyl group due to high steric hinderance. Fluorescent spectra showed that the Tb (III) complex had excellent luminescence as a result of a transfer of energy from the ligand to the excitation state energy level (5D4) of Tb (III). The Eu (III) complex displayed weak luminescence, attributed to low energy transfer efficiency between the triplet state energy level of its ligand and the excited state (5D0) of Eu (III). As a result, the Tb (III) complex displayed a good antenna effect for luminescence. The fluorescence decay curves of Eu (III) and Tb (III) complexes were also measured. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

5.
Y2‐xGeMoO8:REx (RE = Eu, Tb) phosphors were synthesized using a facile sol–gel method. The morphology and structure of the phosphors were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD); while their luminescent properties were investigated by photoluminescence (PL) spectrometry. Our results reveal that all of these Y2‐xGeMoO8:REx (RE = Eu, Tb) phosphors adopted the tetragonal phase, belonging to Scheelite (CaWO4) structure. The obtained YGeMoO8:Eu phosphors exhibit a strong emission in the red light range which can be assigned to the 5D07F2 transition of Eu3+ when it is excited at 459 nm. Under 392 and 489 nm excitation, the YGeMoO8:Tb phosphors present predominant green emission (5D47F5) at 540 nm. The highest emission of the phosphors can be achieved by adjusting the doping concentration to be 0.25 for Eu3+ and 0.15 for Tb3+, respectively. The promising luminescence properties of these materials indicate that they can be potentially applied to white‐light‐emitting diodes. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

6.
In this work, aluminum-gadolinium oxides with different phases were prepared by the non-hydrolytic sol-gel route, using lower temperatures than those employed in methods such as solid-state reaction and Pechini method. The influence of heating treatment on sample structure was investigated. The formation process and the local structure of the samples are discussed on the basis of thermal, X-ray diffraction, photoluminescence (PL) spectroscopy, and infrared spectroscopy analyses. The quantum efficiency of Eu3+ in the different phases obtained in this studied was evaluated. Initial crystallization and the GdAlO3 phase were observed at temperatures around 400 °C. PL data of all the samples revealed the characteristic transition bands arising from the 5D0 → 5FJ (J = 0, 1, 2, 3, and 4) manifolds under maximum excitation at 275, 393, and 467 nm in all cases. The 5D0 → 7F2 transition often dominates the emission spectra, indicating that the Eu3+ ion occupies a site without inversion center.  相似文献   

7.
KLaSiO4:Tb3+ phosphors were synthesized using the sol–gel method. The structure and luminescence properties of the materials were characterized using X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, thermogravimetry–differential thermal analysis, fluorescence spectra and calculated Commission Internationale de l'éclairage coordinates. The results showed that the material had a hexagonal structure, and that doping of Tb3+ did not change the crystal structure of KLaSiO4. FTIR spectroscopy confirmed the existence of stretching vibrations of Si–O, bending vibrations of Si–O–Si, and asymmetric tensile vibrations of Si–O in KLaSiO4. The excitation spectrum of the sample consisted of 4f7→5d1 broadband absorption and the characteristic excitation peak of Tb3+, the excitation peak at 232 nm belongs to the spin allowed 7FJ7DJ transition of Tb3+, the excitation peak at 268 nm belongs to the spin forbidden 7FJ9DJ transition of Tb3+, and the absorption band of 7FJ7DJ transition is split. Under excitation at 232 nm, the emission peak of the sample was composed of the 5D47FJ (J = 6, 5, 4, 3) energy level transition of Tb3+. The highest emission peak is located at 543 nm, which belongs to the 5D47F5 transition and emits green light. Concentration quenching occurred when the Tb3+ doping concentration was greater than 1% mol, the quenching mechanism was an electric dipole–electric dipole action. When the ratio of citric acid to total metal ions was 1:1 and the annealing temperature was 800°C, the surface defects of the phosphors were greatly reduced, the quenching effect was reduced, and the luminous intensity reached the maximum.  相似文献   

8.
This work reports Eu(III) and Tb(III) luminescence titrations in which the lanthanide ions were used as spectroscopic probes for Ca(II) ions to determine the metal binding ability of Ac-NESVKEEGGW-NH(2) and Ac-NESVKEDGGW-NH(2). These decapeptides correspond to the putative calcium binding region of the plant antifungal proteins SI-alpha1 from Sorghum bicolor and of Zeathionin from Zea mays, respectively. The luminescence spectra for the Eu(III)-decapeptide system (red emission) with the excitation at the Trp band at 280 nm showed an enhancement of the intensities of the 5D(0)-->7F(J) transitions (where J=0-4) with increments of Eu(III) ion concentration. The photoluminescence titration data of the terbium ion (green emission) in the decapeptide solutions showed intensification of the 5D(4)-->7F(J) transitions (J=0-6), similar to that observed for the Eu(III) ion. Thus, energy transfer from Ac-NESVKEEGGW-NH(2) and Ac-NESVKEDGGW-NH(2) to the trivalent lanthanide ions revealed that these peptides are capable of binding to these metal ions with association constants of the order of 10(5) M(-1). The amino acid derivative Ac-Trp-OEt also transferred energy to Tb(III) and Eu(III) ions as judged from the quenching of tryptophan luminescence. However, the energy transfers were significantly lower. Taken together the luminescence titration data indicated that Ac-NESVKEEGGW-NH(2) and Ac-NESVKEDGGW-NH(2) bind efficiently to both trivalent lanthanide ions and that these ions may be used as probes to distinguish an anionic peptide from a neutral amino acid derivative.  相似文献   

9.
Mikhail Tsvirko 《Luminescence》2022,37(8):1387-1394
The luminescence and absorption spectra of the lanthanide ions in solids and coordination compounds are characterized by sharp pure electronic lines, which are accompanied by much weaker lines of vibronic transitions. The vibronic spectroscopy is a good probing tool for investigations of the properties of surrounding ion ligands. The lanthanides formates are efficient luminescent crystals and can be viewed as the elementary type in the whole class of the oxygen-containing lanthanide coordination compounds. The intensity of vibronic transitions in spectra of luminescence and excitation europium (5D07F2, 7F05D2), terbium (7F65D4), gadolinium (6P7/28S7/2) in anhydrous formates of the type Ln(HCOO)3 (Ln = Eu, Tb, Gd) and Y(HCOO)3.2H2O doped with Eu3+ and Tb3+ (C ~1 mol%) are reported. Also, the infrared and Raman spectra were obtained for the same compounds. Related integral intensity vibronic sidebands depend on the type of electronic transition of the same ion and varies for the same electronic transitions in different crystals. The obtained experimental data referring to the rate constants of vibronic transitions and intensity distribution in vibronic spectra on normal vibrations of the formate groups are in agreement with the predictions based on the Stavola–Dexter theory of cooperative vibronic transitions.  相似文献   

10.
A novel phosphor LiBaPO4 doped with rare earths Eu and Dy prepared by high temperature solid‐state reaction method is reported. The phosphors were characterized by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL). The emission and excitation spectra of these materials were measured at room temperature with a spectrofluorophotometer. The excitation spectra of LiBaPO4:Eu3+ phosphor can be efficiently excited by 394 nm, which is matched well with the emission wavelength of near‐UV light‐emitting diode (LED) chip. PL properties of Eu3+‐doped LiBaPO4 exhibited the characteristic red emission coming from 5D07 F1 (593 nm) and 5D07 F2 (617 nm) electronic transitions with color co‐ordinations of (0.680, 0.315). The results demonstrated that LiBaPO4:Eu3+ is a potential red‐emitting phosphor for near‐UV LEDs. Emission spectra of LiBaPO4:Dy3+ phosphors showed efficient blue (481 nm) and yellow (574 nm) bands, which originated from 4 F9/26H15/2 and 4 F9/26H13/2 transitions of the Dy3+ ion, respectively. The 574 nm line is more intense than the 481 nm lines, which indicates that the site Dy3+ is located with low symmetry. This article summarizes fundamentals and possible applications of optically useful inorganic phosphates with visible photoluminescence of Eu3+ and Dy3+ ions. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

11.
Six novel 8‐hydroxyquinoline derivatives were synthesized using 2‐methyl‐8‐hydroxyquinoline and para‐substituted phenol as the main starting materials, and were characterized by 1H nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV) light analysis and infra‐red (IR) light analysis. Their complexes with Eu(III) were also prepared and characterized by elemental analysis, molar conductivity, UV light analysis, IR light analysis, and thermogravimetric–differential thermal analysis (TG–DTA). The results showed that the ligand coordinated well with Eu(III) ions and had excellent thermal stability. The structure of the target complex was EuY1–6(NO3)3.2H2O. The luminescence properties of the target complexes were investigated, the results indicated that all target complexes had favorable luminescence properties and that the introduction of an electron‐donating group could enhance the luminescence intensity of the corresponding complexes, but the addition of an electron‐withdrawing group had the opposite effect. Among all the target complexes, the methoxy‐substituted complex (–OCH3) had the highest fluorescence intensity and the nitro‐substituted complex (–NO2) had the weakest fluorescence intensity. The results showed that 8‐hydroxyquinoline derivatives had good energy transfer efficiency for the Eu(III) ion. All the target complexes had a relatively high fluorescence quantum yield. The fluorescence quantum yield of the complex EuY3(NO3)3.2H2O was highest among all target complexes and was up to 0.628. Because of excellent luminescence properties and thermal stabilities of the Eu(III) complexes, they could be used as promising candidate luminescent materials.  相似文献   

12.
The O-alkylation of glycolate with maleate yielding carboxymethoxysuccinate (cmos) is a lanthanide(III) promoted reaction. It is demonstrated that the reaction can be studied on-line with the help of an optical fiber setup, monitoring the luminescence of the Eu(III) optical probe. During the reaction the 5D0→F0 transition shifts to lower wavenumbers and the average lifetime of the excited 5D0 level of the Eu(III) ion increases, when substantial amounts of Eu(cmos)2 are formed. The average number of OH oscillators in the first coordination sphere of the Eu(III) ion is decreased by two if one cmos per Eu(III) is formed. The concentration of cmos can be obtained by on-line measurements of the lifetime of the 5D0 excited stare.  相似文献   

13.
In this study, a series of LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) down‐converting phosphors were synthesized using a modified sol–gel combustion method, and their photoluminescence (PL) properties were investigated as a function of activator concentration and annealing temperature. The resultant particles were characterized using X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, UV/Vis diffuse reflectance spectroscopy and PL spectra. The highly crystalline LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) phosphors with an average size of 200–300 nm obtained at 1100°C have an orthorhombic aeschynite‐type structure and exhibit the highest luminescent intensity in our study range. The emission spectra of LaNbTiO6:RE3+ (RE = Tb, Dy, Ho) phosphors under excitations at UV/blue sources are mainly composed of characteristic peaks arising from the f–f transitions of RE3+, including 489 nm (5D47F6) and 545 nm (5D47F5) for Tb3+, 476 and 482 nm (4F9/26H15/2) and 571 nm (4F9/26H13/2) for Dy3+, and 545 nm (5F4 + 5S25I8) for Ho3+, respectively. The luminescent mechanisms were further investigated. It can be expected that these phosphors are of intense interest and potential importance for many optical applications. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

14.
The wet chemical synthesis, X‐ray diffraction and photoluminescence characteristics in alkaline halosulfate phosphors such as LiMgSO4Cl:Eu and LiZnSO4Cl:Eu are reported in this paper. The effect of Li ion on Eu3+ luminescence (5D07F2 electronic transition) and incorporation of Eu3+ ion in lithium base alkaline halosulfate phosphor has been studied. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

15.
16.
A new halophosphor K3Ca2(SO4)3 F activated by Eu or Ce and K3Ca2(SO4)3 F:Ce,Eu co‐doped halosulfate phosphor has been synthesized by the co‐precipitation method and characterized for its photoluminescence (PL). The PL emission spectra of the K3Ca2(SO4)3 F :Ce phosphor show emission at 334 nm when excited at 278 nm due to 5d → 4f transition of Ce3+ ions. In the K3Ca2(SO4)3 F:Eu lattice, Eu2+ (440 nm) as well as Eu3+ (596 nm and 615 nm) emissions have been observed showing 5D07 F1 and 5D07 F2 transition of the Eu3+ ion, which is in the blue and red region of the visible spectrum respectively. The trivalent europium ion is very useful for studying the nature of metal coordination in various systems owing to its non‐degenerate emitting 5D0 state. K3Ca2(SO4)3 F:Ce,Eu is suitable for Ce3+ → Eu2+ → Eu3+ energy transfer in which Ce3+and Eu2+ play the role of sensitizers and Eu2+ and Eu3+ act as the activators. The observations presented in this paper are relevant for lamp phosphors. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

17.
A new phosphor CaAl(SO4)2Br doped with Dy, Ce and Eu is reported. Rare earth (Dy, Eu and Ce)‐doped polycrystalline CaAl(SO4)2Br phosphors were prepared using a wet chemical reaction method and studied for X‐ray diffraction and photoluminescence (PL) characteristics. Dy3+ emission in the CaAl(SO4)2Br lattice was observed at 484 and 574 nm in the blue and yellow regions of the spectrum, which are assigned to 4 F9/26H15/2 and 4 F9/26H13/2 transitions of the Dy3+ ion, respectively. While the PL emission spectra of CaAl(SO4)2Br:Ce phosphor showed Ce3+ emission at 347 nm due to 5d → 4f transition of the Ce3+ ion. In a CaAl(SO4)2Br:Eu lattice, Eu3+ emissions were observed at 593 and 617 nm, coming from the 5D07 F1 and 5D07 F2 electron transitions, respectively. The PL study showed that the intensity of electric dipole transition at 617 nm dominates over that of magnetic dipole transition at 590 nm. The maximum PL intensity was obtained for a 1 mol% concentration of Eu3+ in CaAl(SO4)2Br host lattice. The results showed that the material may be a promising candidate as a blue‐, yellow‐ and red‐emitting phosphor. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

18.
Solid ternary europium complexes consisting of fluorinated β-diketone (thenoyltrifluoroacetone, TTFA) and heteroaromatic bidentate auxiliary ligands were synthesized. The luminescence features of the complexes were estimated using various spectral measurements and clearly proved that the Eu3+ ion is efficiently sensitized by ligands by an antenna effect. Photoluminescence excitation spectra have shown that Eu(III) complexes are excited effectively in the ultraviolet (UV) region and the corresponding emission spectra consist of characteristic peaks attributed to the 5D07FJ transitions of the europium ion with the strongest emission peak at 611 nm (5D07F2). From photoluminescence (PL) data, decay time, Judd–Ofelt parameters, transition rates, and quantum efficiency of the complexes were also determined. The Commission Internationale de l'éclairage (CIE) colour coordinates indicated the bright red emission of ternary europium complexes. Correlated colour temperature values indicated the utilization of these complexes in display devices. Judd–Ofelt and photophysical parameters were also estimated theoretically using LUMPAC software. Various frontier molecular orbitals and their respective energy were determined. These red emissive europium complexes could be utilized for fabricating solid-state lighting systems.  相似文献   

19.
KNaSO4 microphosphor doped with Ce,Gd and Ce,Tb and prepared by a wet chemical method was studied using X‐ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) characterization. KNaSO4 has a 5‐µm particle size detected by SEM. KNaSO4:Ce3+,Tb3+ showed blue and green emission (at 494 nm, 557 nm, 590 nm) of Tb3+ due to 5D47FJ (J = 4, 5, 6) transitions. KNaSO4:Ce3+,Gd3+ showed luminescence in the ultraviolet (UV) light region at 314 nm for an excitation at 271 nm wavelength. It was observed that efficient energy transfer took place from Ce3+ → Gd3+ and Ce3+ → Tb3+ sublattices indicating that Ce3+ could effectively sensitize Gd3+ or Tb3+ (green emission). Ce3+ emission weakened and Gd3+ or Tb3+ enhanced the emission significantly in KNaSO4. This paper discusses the development and understanding of photoluminescence and the effect of Tb3+ and Gd3+ on KNaSO4:Ce3+. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

20.
The synthesis of thallium(III) chloride and bromide was performed in solution by chlorination and bromination, respectively, of the suspensions of the corresponding thallium(I) halides in acetonitrile. Crystalline compounds TlX3(CH3CN)2 (X = Cl, Br) were prepared from the acetonitrile solutions. Thallium(III) chloride and bromide in dimethylsulfoxide solution were obtained by dissolving the corresponding solid compounds TlX3(CH3CN)2 (Cl, Br) in DMSO. Both acetonitrile and dimethylsulfoxide solutions of thallium(III) chloride were studied by UV-Vis and 205Tl NMR spectroscopy. The UV-Vis study of the TlCl3-CH3CN system showed presence of at least two thallium(III) chloride species. Only one signal arising from the thallium(III) species was, however, detected by the 205Tl NMR in the solution because of the fast chemical exchange. The 205Tl NMR study of thallium(III) chloride in dimethylsulfoxide showed three separate signals assigned to the solvated , TlCl3 and species. The crystalline compounds of trichlorobis(dimethylsulfoxide)thallium(III) and tribromobis(dimethylsulfoxide)thallium(III) were prepared and their crystal structures were solved by single-crystal X-ray analysis. The thallium atom in the complexes has a trigonal bipyramidal environment built by three halide ions occupying equatorial positions of the polyhedron and two oxygen atoms of the DMSO molecules in the apical positions.  相似文献   

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