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1.
Rhabdophane-type Eu3+,Tb3+-codoped LaPO4·nH2O single-crystal nanorods with the compositions La0.99999-xEuxTb0.00001PO4·nH2O (x?=?0–0.03), La0.99999-yTbyEu0.00001PO4·n′H2O (y?=?0–0.010), and La0.99999-zTbzEu0.000007PO4·n′′H2O (z?=?0–0.012) were hydrothermally synthesized with microwaves. It is shown that the Eu3+,Tb3+ codoping does not affect the thermal stability of these nanorods, which is due to the formation of substitutional solid solutions with both Eu3+ and Tb3+ replacing La3+ in the crystal lattice. Moreover, it is also shown that monazite-type Eu3+,Tb3+-codoped LaPO4 single-crystal nanorods can be obtained by calcining their rhabdophane-type Eu3+,Tb3+-codoped LaPO4·(n,n′ or n′′)H2O counterparts at moderate temperature in air, and that they are thermally stable. It is also observed that, for the same Eu3+,Tb3+-codoping content, the monazite-type Eu3+,Tb3+-codoped LaPO4 nanorods exhibit higher photoluminescent efficiency than the rhabdophane-type Eu3+,Tb3+-codoped LaPO4· (n,n′ or n′′)H2O nanorods. Moreover, it is found that the highest photoluminescence emission corresponds to the monazite-type La0.96999Eu0.02Tb0.00001PO4 nanorods for the La0.99999-xEuxTb0.00001PO4 system. However, for those compositions energy transfer from Tb3+ to Eu3+ does not occur. In addition, for an efficient energy transfer to occur, a content of at least 1?mol% Tb3+ is needed in all the studied materials.  相似文献   

2.
KSr1−xPO4:xTb3+ phosphors with various concentrations (x = 0.05, 0.06, 0.07, 0.08) of Tb3+ ions were synthesized in succession by using microwave assisted sintering. The sintering condition was set at 1200 °C for 1 h in air. The microstructural and luminescent characteristics of KSrPO4:Tb3+ phosphors were investigated and are discussed here. The XRD result shows that the prepared KSr1−xPO4:xTb3+ phosphors would have an impure phase as the Tb3+ ion increases to more than x = 0.06. The photoluminescence measurement shows that the series of the emission-state 5D4 → 7F6, 5D4 → 7F4, and 5D4 → 7F3, corresponding to the typical 4f → 4f intra-configuration forbidden transitions of Tb3+, are appeared and the major emission peak is around at 542 nm. Moreover, the maximum photoluminescence intensity is appeared when the molar concentration of Tb3+ is 0.06. The decay time value of the KSr1−xPO4:xTb3+ phosphors with x = 0.06 is about 0.27 ms.  相似文献   

3.
Rare-earth ions (Eu3+, Tb3+) activated magnesium calcium bismuth titanate [(MgCa)2Bi4Ti5O20] ceramics were prepared by conventional solid state reaction method for their structural and luminescence properties. By using XRD patterns, the structural properties of ceramic powders have been analyzed. Emission spectrum of Eu3+:(MgCa)2Bi4Ti5O20 ceramic powder has shown strong red emission at 615 nm (5D0 → 7F2) with an excitation wavelength λexci = 393 nm and Tb3+:(MgCa)2Bi4Ti5O20 ceramic powder has shown green emission at 542 nm (5D4 → 7F5) with an excitation wavelength λexci = 376 nm. In addition, from the measurements of scanning electron microscopy (SEM), Fourier transform-infrared (FTIR) and energy dispersive X-ray analysis (EDAX) results the morphology, structure and elemental analysis of these powder ceramics have been studied.  相似文献   

4.
High-efficient Ce3+/Tb3+ co-doped Ba3Y2B6O15 phosphors with multi color-emitting were firstly prepared, and their structural and luminescent properties were studied by XRD Rietveld refinement, emission/excitation spectra, fluorescence lifetimes as well as temperature-variable emission spectra. Upon 365?nm excitation, the characteristic blue Ce3+ band along with green Tb3+ peaks were simultaneously found in the emission spectra. Moreover, by increasing concentration of Tb3+, a blue-to-green tunable emitting color could be realized by effective Ce3+→Tb3+ energy transfer. Furthermore, all Ba3Y2B6O15: Ce3+, Tb3+ phosphors exhibit high internal quantum efficiency of ~?90%, while the temperature-variable emission spectra reveal that the phosphors possess impressive color stability as well as good thermal stability (T50 =?~?120?°C). The results indicate that these efficient color-tuning Ba3Y2B6O15: Ce3+, Tb3+ might be candidate as converted phosphor for UV-excited light-emitting diodes.  相似文献   

5.
Color tunable Tb3+ doped SrGd2Al2O7 nanophosphor is synthesized employing a facile and economic urea assisted solution combustion approach. XRD studies confirm the crystallization of single phased SrGd2(1-x)Tb2xAl2O7 nanophosphor in tetragonal lattice with I4/mmm (139) space group. Rietveld refinement is performed over SrGd1.9Tb0.1Al2O7 sample to execute qualitative as well as quantitative phase analysis. TEM analysis confirms the more or less spherical shaped phosphors in nano domain with average particle size ranging 45–80?nm. Photoluminescent investigation reveals that this nanophosphor can be successfully excited by ultraviolet light yielding significant luminescent properties arising due to radiative transitions from 5D3,4 levels to 7Fj levels. Dipole-dipole interactions are solely responsible for the energy transfer causing concentration quenching. Concentration controlled luminescent tendency can be employed to induce chromaticity from blue to green region. Findings of the study proclaim the application of this nanophosphor as one of the green component of tricolor based ultraviolet excited white LEDs.  相似文献   

6.
Tb3+-doped La1−xAlO3 phosphor powders are successfully synthesized by the solution combustion method, using citric acid as the combustion fuel. The crystal structure and photoluminescence properties of La1−xAlO3:xTb3+ phosphors are studied, depending on Tb3+ content. The strongest emission peak is found at 543 nm, which originates from the 5D47F5 transition of Tb3+ ions, indicating green emission. Among the fabricated phosphors, the La0.9AlO3:0.1Tb3+ phosphor emits the strongest green light. The excellent luminescent properties make it a possible candidate for white light-emitting diodes and various photonic applications.  相似文献   

7.
Series of UV excited Ba3Lu(PO4)3:Tb3+,Mn2+ phosphors with tunable green to red emissions had been prepared using solid state reactions. Powder X-ray diffraction and Rietveld structure refinement were used to investigate the phase purity and crystal structure of the prepared samples. Under UV excitation, the Ba3Lu(PO4)3:Tb3+,Mn2+ samples exhibited not only the typical Tb3+ emission peaks but also the broad emission band of Mn2+ ions due to the efficient Tb3+→Mn2+ energy transfer which had been verified by luminescence spectra and decay curves. Utilizing the Inokuti-Hirayama model, the Tb3+→Mn2+ energy transfer mechanism was determined to be the electronic dipole–quadrupole interaction. Moreover, the emission spectra of Ba3Lu(PO4)3:0.80Tb3+,0.015Mn2+ sample at different temperatures manifested that our prepared phosphors possessed good thermal stability. The luminescence properties investigation results revealed the potential value of Ba3Lu(PO4)3F:Tb3+,Mn2+ in application for UV excited phosphor converted white light emitting diodes.  相似文献   

8.
Bi(Sc1/3Mo2/3)O4 ceramics were prepared via solid state reaction method. It crystallized with an ordered scheelite-related structure (a?=?16.9821(9)?Å, b?=?11.6097(3)?Å, c?=?5.3099(3)?Å and β?=?104.649(2)°) with a space group C12/C1, in which Bi3+, Sc3+ and Mo6+ are ?8, ?6 and ?4 coordinated, respectively. Bi(Sc1/3Mo2/3)O4 ceramics were densifiedat 915?°C, giving a permittivity (εr) ~24.4, quality factor (Qf, Q?=?1/dielectric loss, f?=?resonant frequency) ~48, 100?GHz and temperature coefficient of resonant frequency (TCF)?~??68?ppm/°C. Impedance spectroscopy revealed that there was only a bulk response for conductivity with activation energy (Ea) ~0.97?eV, suggesting the compound is electrically and chemically homogeneous. Wide band dielectric spectra were employed to study the dielectric response of Bi(Sc1/3Mo2/3)O4 from 20?Hz to 30?THz. εr was stable from 20?Hz to the GHz region, in which only ionic and electron displacive polarization contributed to the?εr.  相似文献   

9.
With solid‐state reaction method, series of Y4Si2O7N2:Tb3+ phosphors were prepared under the high‐temperature and high‐pressure conditions. The photoluminescence properties at room and high temperature were investigated. Two groups of emission lines have been observed, which are corresponding to Tb3+ 5D37FJ (J = 6, 5, 4, 3, 2) and 5D47FJ (J = 6, 5, 4, 3) transitions. The physical mechanisms for excitation, emission, concentration quenching, and thermal quenching were investigated. The cross‐relaxation mechanism between the 5D3 and 5D4 emission was investigated and discussed. The Tb–Tb critical distance for cross‐relaxation was calculated to be ~13 Å. The optimum Tb3+ concentration in this phosphor is 15 mol%. The quadrupole–quadrupole interaction dominates the non‐radiative energy transfer between the Tb3+ luminescence centers and causes the concentration quenching. This phosphor shows high thermal stabilities that at 150°C the intensity remains 92% compared with that measured at room temperature. The present work suggests that this Tb3+‐doped Y4Si2O7N2 material is a kind of potential green‐emitting phosphor.  相似文献   

10.
R2.9Eu0.1Sb5O12 (R=Y, Gd, La) polycrystalline powders were prepared by solid-state reaction and characterized by X-ray powder diffraction (XRD), photoluminescence, decay lifetimes, and CIE color coordinates. The phosphors can be efficiently excited by UV-light and presents the emission covering the entire visible spectrum. Except for the commonly reported 5D07F0,1,2,3,4 transitions of Eu3+ ions in R2.9Eu0.1Sb5O12 (R=Y, La), higher 5D1,2,3 states present stronger emission lines. This produces white emission in the single-phased phosphor, whereas R2.9Eu0.1Sb5O12 (R=Gd) shows orange emission due to the absence of 5D3,2 transitions. The emission mechanism from the high-energy levels of 5D1,2,3 Eu3+ ion in R2.9Eu0.1Sb5O12 (R=Y, Gd, La) phosphors is also discussed.  相似文献   

11.
Tb3+‐doped and Eu2+, Tb3+ co‐doped Ca9Y(PO4)7 phosphors were synthesized by conventional solid‐state method. Additionally, the luminescence properties, decay behavior and energy transfer mechanism have already been investigated in detail. The green emission intensity of Tb3+ ions under NUV excitation is weak due to its spin‐forbidden f‐f transition. While Eu2+ can efficiently absorb NUV light and yield broad blue emission, most of which can be absorbed by Tb3+ ions. Thus, the emission color can be easily tuned from cyan to green through the energy transfer of Eu2+→Tb3+ in Ca9Y(PO4)7:Eu2+,Tb3+ phosphor. In this work, the phenomenon of cross‐relaxation between 5D3 and 5D4 are also mentioned. The energy transfer is confirmed to be resulted from a quadrupole‐quadrupole mechanism.  相似文献   

12.
A new vanadate Ca3LiMgV3O12 and its Eu3+-doped counterparts were synthesized. Rietveld confinement result of Ca3LiMgV3O12 host indicates that it belongs to cubic space group Ia-3d with parameters of a =?12.4300?Å, V =?1920.49?Å3, Z?=?8. Under UV excitation, pure Ca3LiMgV3O12 exhibits a bluish-green broadband emission at 490?nm, while Eu3+ doped Ca3LiMgV3O12 shows one bluish-green broad band with a series of red sharp peaks, which originate from the V5+-O2- charge transfer and the Eu3+ intra-4f transitions, respectively. The occurrence of VO4→Eu3+ energy transfer is confirmed by decay lifetime analysis and time-resolved emission spectra. It is found that emitting color varies from bluish-green to orange-red with increasing Eu3+ concentration. VO4 bluish-green and Eu3+ red emission shows different thermal quenching response with increasing temperature, due to their different activation energy.  相似文献   

13.
《Ceramics International》2017,43(11):8163-8170
(Tb1-xCex)3Al5O12 yellow phosphors (0≤x≤0.05) were calcined from their coprecipitated carbonate precursors, and the effects of the temperature and atmosphere (air and H2) of calcination on the sequence of phase evolution and the characteristics of the powders were investigated in detail. The activation energy for the crystallite growth during calcination was estimated to be ~39 kJ/mol. The powder calcined at 1000 °C showed good reactivity and was sintered into a ceramic plate of ~97% dense (average grain size: ~1.3 µm) in a H2/Ar gas mixture at the relatively low temperature of 1500 °C. The phosphors simultaneously exhibit the 4f8→4f75d1, 7F65D3 and 7F65D4 excitations of Tb3+ and the 4f1→5d1 excitation of Ce3+ when monitoring the yellow emission of Ce3+ at 560 nm, suggesting the presence of efficient Tb3+→Ce3+ energy migration. The optimal Ce3+ content for luminescence was found to be x=0.015 and 0.01 under the direct excitation of Ce3+ and through Tb3+→Ce3+ energy transfer, respectively, and concentration quenching of luminescence was analyzed to be resulted from exchange interaction. Luminescence features of the phosphors, including excitation, emission, quantum yield, fluorescence lifetime, color coordinates and color temperature, were thoroughly investigated against the processing temperature and Ce3+ content, with an in-depth discussion on the process of energy transfer among the optically active Tb3+ and Ce3+ ions. The materials may find application in blue-light excited white LEDs.  相似文献   

14.
Terbium (Tb3+) doped oxyfluoro-titania-phosphate glasses of chemical composition (in mol%), (60 - x) P2O5 – 15 BaF2 – 20 CaF2 – 5 TiO2 – x Tb4O7, x?=?0.05, 0.1 and 0.1 were fabricated by usual melt-quenching technique. Photoluminescence (PL) properties of the samples have been investigated by excitation, emission and decay profiles. Upon excitation at 377?nm, the PL spectra exhibit an intense band at 541?nm which corresponds to the 5D47F5 transition. The intensity ratio of green-to-blue (IG/IB) was found to be 9.2 for 0.1?mol% of Tb3+-doped glass. High-energy absorption bands were not resolved in the absorption spectrum but disclosed in the photoluminescence excitation spectrum. Decay curves were unveiled non-exponential and mono-exponential behaviours for the 5D3 and 5D4 levels, respectively. Lifetime of the 5D3 and 5D4 levels was decreased up to 0.1?mol%, and thereafter it was increased with the increase of Tb3+ ion concentration upon 377?nm excitation. The CIE chromaticity coordinates were supported that the green emission was predominant in Tb3+-doped oxyfluoro-titania-phosphate glasses.  相似文献   

15.
A series of orange-red emitting Sm3+ activated Ba0.85Ca0.15Ti0.90Zr0.10O3 (BCZT: xSm3+, x?=?0.001–0.007) are synthesized by a conventional solid-state reaction method. The Sm3+ ions composition dependent photoluminescence properties are systematically investigated. Under the excitation of a 407?nm near-ultraviolet light, the ceramics exhibit strong characteristic emission of Sm3+ ions with dominant orange-red emission peak at around 595?nm, which is ascribed to the transition of 4G5/26H7/2. The BCZT: 0.004Sm3+ ceramic displays the optimal emission among these Sm3+-doped BCZT solid solutions. Moreover, the photoluminescence intensity exhibits extremely sensitive to temperature, suggesting that BCZT: 0.004Sm3+ could be applicable for temperature sensing. A maximum relative sensitivity of 1.89%?K?1 at 453?K is obtained. Furthermore, the existence of ferroelectricity in the BCZT host combined with Sm3+ activated photoluminescence properties could be useful for developing optical-electro multifunctional materials and devices.  相似文献   

16.
《应用陶瓷进展》2013,112(8):455-459
Abstract

Tb3+ doped Y2O2SO4 (Y2O2SO4:Tb3+) microflakes were prepared by a combination method of electrospinning and calcination. The two-dimensional microflakes had smooth surface and high radial/axial ratio. Crystal structures of the Y2O2SO4:Tb3+ microflakes resulted in layer by layer growth in axial direction. A possible formation mechanism was proposed on the basis of experimental results, which indicated that poly(vinyl pyrrolidone) played the role of the nanostructure directing template and revealed the growth priority in radial direction. The microflakes showed a favourable fluorescent property symbolised by the characteristic green emission (541 nm) resulting from the 5D47F5 transition of Tb3+ ions under 229 nm ultraviolet excitation. The maximum intensity of Tb3+ emission of the Y2O2SO4:Tb3+ microflakes was 2·3 times stronger than that of the Y2O2SO4:Tb3+ bulk powders with the same doping concentration.  相似文献   

17.
This study aimed to improve the purity and performance of alumina ceramics used as ball milling media. High-alumina ceramics (>?96?wt% Al2O3), with high densification and excellent abrasion resistance, were fabricated by the cold isostatic pressing method. The effects of adding the rare earth Tb4O7 on the densification, abrasion resistance, crystalline phase, micro-morphology and grain size of the ceramics were studied. The experiment results showed that the densification and abrasion resistance of the samples increased with Tb4O7 addition. The sample with 0.8?wt% Tb4O7 sintered at 1625?°C exhibited the best performance, with a linear shrinkage, relative density and abrasion rate of 22.28%, 95.70% and 0.103‰, respectively. The abrasion resistance improved by 27.5% compared with the sample without Tb4O7. X-ray diffraction analysis indicated that the primary phases of the samples were corundum, spinel, CaAl12O19 and α-quartz, and a small quantity of Tb3Al5O12 was generated when more than 0.4?wt% Tb4O7 was added. Furthermore, some Mg2+ and Ca2+ ions in the liquid phases dissolved into Tb3Al5O12 crystalline grains during the sintering process, which enhanced the grain boundary cohesion of the materials. Scanning electron microscopy indicated that the existence of Tb3Al5O12 at grain boundaries reduced the average size of the corundum grains. This helped transform inter-granular fractures into trans-granular fractures, thereby improving the abrasion resistance of the ceramic materials.  相似文献   

18.
New tris(3-phenyl-4-aroyl-5-isoxazolonate)terbium(III) complexes have been synthesized and characterized by various spectroscopic techniques. Due to an efficient energy transfer from the heterocyclic β-diketonate ligand to the central Tb3+, these complexes show a strong emission corresponding to Tb3+5D47FJ (J = 6, 5, 4, 3) transitions, with 5D47F5 (545 nm) green emission as the most prominent one. The overall quantum yields and luminescent lifetimes of these complexes were found to be promising as compared to previously reported terbium-1-phenyl-3-methyl-4-acyl-5-pyrazolonate complexes.  相似文献   

19.
A series of Eu3+-doped C12H18Ca3O18 phosphors were synthesized through a facile hydrothermal method and the properties of as-prepared phosphors were explored by X-ray diffractometer (XRD), scanning electron microscope (SEM), and photoluminescence (PL) spectrometer. The exploration results indicated that the C12H18Ca3O18:Eu3+ had been successfully synthesized. The morphology of C12H18Ca3O18:Eu3+ was a strip with the size of 100–4000 nm × 50–400 nm × 50–200 nm and the ratio of length to width of 2–80. The strongest emission peak of C12H18Ca3O18:Eu3+ around 620 nm was ascribed to 5Do7F2 transition of Eu3+, and the peaks centered at 590, 653 and 694 nm respectively corresponded to 5Do7F1, 7F3, and 7F4 transitions. C12H18Ca3O18: Eu3+ gave the red light emission, as indicated by color coordinate analysis. The photoluminescence intensity of the phosphors prepared under the Eu3+ concentration of 6% was the highest. The crystal structure of C12H18Ca3O18:Eu3+ was changed after europium ions occupied the lattice position of calcium ions. Europium ion could displace calcium arbitrarily. As a new kind of matrix, calcium citrate possesses the properties of both organic and inorganic compounds and the luminescent C12H18Ca3O18: x Eu3+ particles may be applied in biological fluorescent tags and luminescent materials.  相似文献   

20.
In present work, a series of Eu doped zinc borate, ZnB2O4, phosphors prepared via wet chemical synthesis and their structural, surface morphology, cathodoluminescence (CL) and thermoluminescence (TL) properties have been studied. Phase purity and crystal structure of as-prepared samples are confirmed by X-ray diffraction measurements (XRD) and they were well consistent with PDF card No. 39-1126, indicating the formation of pure phase. The thermoluminescence (TL) behaviors of Eu activated ZnB2O4 host lattice are studied for various beta doses ranging from 0.1 to 10?Gy. The high-temperature peak of Eu activated sample located at 192?°C exhibited a linear dose response in the range of 0.1–10?Gy. Initial rise (IR) and peak shape (PS) methods were used to determine the activation energies of the trapping centres. The effects of the variable heating rate on TL behaviour of Eu activated ZnB2O4 were also studied. When excited using an electron beam induced light emission (i.e cathodoluminescence, CL) at room temperature (RT), the as-prepared phosphors generate reddish-orange color due to predominant emission peaks of Eu3+ ions located at 576–710?nm assigned to the 5D07FJ (J=1,2,3, and 4) transitions. The maximum CL intensity for Eu3+ ions at 614?nm with transition 5D07F2 was reached Eu3+ concentration of 5?mol%; quenching occurred at higher concentrations. Strong emission peak for Eu3+ ions at 614?nm with transition 5D07F2 is observed. The CL experimental data indicate that ZnB2O4:Eu3+ phosphor as an orange-red emitting phosphor may be promising luminescence materials for the optoelectronic applications.  相似文献   

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