首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 468 毫秒
1.
Tb3+-doped ZnMoO4 green phosphor was synthesized by a co-precipitation method. The morphology and structure of the phosphor were characterized by Scanning electron microscopy (SEM) and X-ray diffraction (XRD). Photoluminescence (PL) spectra were also used to characterize the ZnMoO4:Tb3+ samples. The results show that ZnMoO4:Tb3+ phosphor has triclinic structure with diameters ranging from 1.0 to 2.0 μm. The obtained ZnMoO4:Tb3+ phosphor emits green light emission centered at 541 nm corresponding to the 5D4  7F5 transition of Tb3+ when excited by 378 nm or 488 nm. The optimized concentration of Tb3+ is 15 mol.% for the highest emission intensity at 541 nm, and the concentration quenching occurs when the Tb3+ concentration is beyond 15 mol.%. The concentration quenching mechanism can be interpreted by the quadrupole–quadrupole interaction of Tb3+ ions. The present work suggests a convenient, cost-effective method for green phosphor, which may lead to potential applications in white light-emitting diodes (WLED).  相似文献   

2.
A novel green phosphor Mg2GeO4:Tb3+ with pure phase was prepared by the solid state reaction. The luminescence properties were investigated in detail. The diffusion reflection spectra of the undoped and Tb3+ doped Mg2GeO4 phosphors were recorded, the result reveals that there is an absorption band superposition of the host material and Tb3+ ion. The study on the excitation and diffusion spectra shows that there is an effective energy transfer from the host material to Tb3+ ion. Under 277 and 172 nm excitation, the phosphor presents predominant green emission at 543 and 547 nm respectively. The excitation intensity at 172 nm is about 1.8 times of that at 272 nm. The promising luminescence properties make it a candidate for application in Plasma Display Panel.  相似文献   

3.
Eu3+, Er3+ and Yb3+ co-doped BaGd2(MoO4)4 two-color emission phosphor was synthesized by the high temperature solid-state method. The structure of the sample was characterized by XRD, and its luminescence properties were investigated in detail. Under the excitation of 395 nm ultraviolet light, the BaGd2(MoO4)4:Eu3+,Er3+,Yb3+ phosphor emitted an intense red light at 595 and 614 nm, which can be attributed to 5D0  7F1 and 5D0  7F2 transitions of Eu3+, respectively. The phosphor will also show bright green light under 980 nm infrared light excitation. The green emission peaks centred at 529 and 552 nm, were attributed to 4H11/2  4I15/2 and 4S3/2  4I15/2 transitions of Er3+, respectively. It indicated that the two-color emission can be achieved from the same BaGd2(MoO4)4:Eu3+,Er3+,Yb3+ host system based on the different pumping source, 395 nm UV light and 980 nm infrared light, respectively. The obtained results showed that this kind of phosphor may be potential in the field of multi-color fluorescence imaging and anti-counterfeiting.  相似文献   

4.
A green-emitting phosphor of Eu2+-activated Sr5(PO4)2(SiO4) was synthesized by the conventional solid-state reaction. It was characterized by photoluminescence excitation and emission spectra, and lifetimes. In Sr5(PO4)2(SiO4):Eu2+, there are at least two distinguishable Eu2+ sites, which result in one broad emission situating at about 495 nm and 560 nm. The phosphor can be efficiently excited in the wavelength range of 250–440 nm where the near UV (~ 395 nm) Ga(In)N LED is well matched. The dependence of luminescence intensities on temperature was investigated. With the increasing of temperature, the luminescence of the phosphor shows good thermal stability and stable color chromaticity. The luminescence characteristics indicate that this phosphor has a potential application as a white light emitting diode phosphor.  相似文献   

5.
Single crystalline Eu3+/Tb3+-codoped ZnO nanocrystals have been synthesized by using a simple co-precipitation method. Successful doping is realized so that strong green and red luminescence can be efficiently excited by ultraviolet and near ultraviolet radiation, demonstrating an efficient energy transfer from ZnO host to rare earth ions. The energy transfer from the ZnO host to Tb3+ in ZnO: Tb3+ samples and ZnO host to Eu3+ in the ZnO: Eu3+ samples under UV excitation are investigated. It is found that the red 5D0  7F2 emission of Eu3+ ions decreases with increasing temperature but the green 5D4  7F5 emission of Tb3+ ions increases with increasing temperature, implying a different energy transfer processes in the two samples. Moreover, energy transfer from Tb3+ ions to Eu3+ ions in ZnO nanocrystals is also observed by analyzing luminescence spectra and the decay curves. By adjusting the doping concentration, the Eu3+/Tb3+-codoped ZnO phosphors emit green and red luminescence with chromaticity coordinates near white light region, high color purity and high intensity, indicating that they are promising light-conversion materials and have potential in field emission display devices and liquid crystal display backlights.  相似文献   

6.
《Optical Materials》2014,36(12):2183-2187
This paper reports the microstructure, luminescence and thermal stability properties of the NaSr1−xPO4:xTb3+ powders (x = 0.008, 0.01, 0.02, 0.04 and 0.06) via the conventional solid-state sintering at 1200 °C for 5 h. The X-ray diffraction result verifies all diffraction peaks are pure phase of NaSrPO4. The luminescence results show that the NaSrPO4:xTb3+ powders mainly excited at 370 nm have a series of the emission-states, related to the typical 4f  4f intra-configuration forbidden transitions of Tb3+, and a major emission peak of around 546 nm. The concentration quenching of the NaSr1−xPO4:xTb3+ phosphors is appeared at x = 0.02. The decay time values of the NaSr1−xPO4:xTb3+ phosphors for the 5D4 state of the Tb3+ are around 3.30 ms to 3.60 ms. It is also found the chromaticity coordinate of NaSrPO4:Tb3+ phosphor varies with the increase of the concentration of Tb3+ ions from blue to green. Moreover, the thermal stability of the NaSrPO4:xTb3+ phosphors is slightly better than that of conventional YAG phosphors.  相似文献   

7.
A novel green phosphor Tb3+ doped AlPO4 was synthesized by conventional solid-state reaction method. The phosphor showed prominent luminescence in green due to the 5D4-7F5 transition of Tb3+. Structural characterization of the luminescent material was carried out with X-ray powder diffraction (XRD) analysis. The XRD measurements indicated that there are no crystalline phases other than AlPO4. Luminescence properties were analyzed by measuring the excitation and photoluminescence spectra. Photoluminescence measurements indicated that the phosphor exhibited bright green emission at about 542 nm under UV excitation. It is shown that the 3 mol% of doping concentration of Tb3+ ions in AlPO4:Tb3+ phosphor is optimum. The measured chromaticity for the phosphors AlPO4:Tb3+ under UV excitation is (0.32, 0.53).  相似文献   

8.
A novel green emitting phosphor, Eu2+-activated Ca6Sr4(Si2O7)3Cl2, was synthesized using the solid-state reaction and its temperature-dependent luminescence characteristic was reported for the first time. Crystallographic site-occupations of Eu2+ ions in this host were assigned and two distinguishable Sr2+ sites were confirmed. As the temperature increases, the emission lines of Ca6Sr3.99(Si2O7)3Cl2:0.01Eu2+ show an anomalous blue-shift along with the broadening bandwidth and decreasing emission intensity, which is ascribed in terms of the phonon-assisted back tunneling from the excited state of low-energy emission band to the high-energy emission band in the configuration coordinate diagram. Further, the luminescence quenching temperature, the activation energy for thermal quenching (ΔE), and the chromaticity coordinates were also investigated. In view of its preferable excitation spectrum profile, intense green emission peaking at 511 nm, and high thermal luminescence stability, the as-prepared phosphor is expected to find applications as a new green emitting phosphor for near-UV light emitting diodes.  相似文献   

9.
《Optical Materials》2009,31(12):1848-1853
The VUV excited luminescent properties of Ce3+, Tb3+, Eu3+ and Tm3+ in the matrices of KMGd(PO4)2 (M = Ca, Sr) were investigated. The bands at about 165 nm and 155 nm in the VUV excitation spectra are attributed to host lattice absorptions of the two matrices. For Ce3+-doped samples, the Ce3+ 5d levels can be identified. As for Tb3+-doped samples, typical 4f–5d absorption bands in the region of 175–250 nm were observed. For Eu3+ and Tm3+-doped samples, the O2−–Eu3+ and O2–Tm3+ CTBs are observed to be at about 229 nm and 177 nm, respectively. From the standpoints of color purity and luminescent efficiency, KCaGd(PO4)2:Tb3+ is an attractive candidate of green light PDP phosphor.  相似文献   

10.
《Optical Materials》2014,36(12):2062-2067
The UV–Vis luminescence of NaLnF4:Pr3+ (Ln = Y, Lu) materials can be efficiently excited by vacuum UV radiation (VUV) such as the 172 nm emission of mercury-free Xe-discharge lamps. In this work, the optical properties of the cubic α-phase and the hexagonal β-phase of NaLnF4:Pr3+ (Ln = Y, Lu) powders are compared regarding particle sizes in the nano- and micrometer regime. Upon VUV excitation, the emission spectra of both crystal phases are found to be dominated by intraconfigurational [Xe]4f2–[Xe]4f2 transitions, which is explained by the chemical properties of the ternary fluorides. Furthermore it is observed that the emission and excitation spectra of nano- and micro-scale powders are very similar, but that the luminescence intensity is affected by the average particle size.  相似文献   

11.
Present study deals with Eu3+ activated novel alkaline earth metal (Sr and Ca) gallium oxide phosphors, Sr(2.92?x)Ca(x)Ga2O6:Eu3+0.08 (x = 0 to 2.92). Crystal structure, morphology and luminescence (excitation, emission and CIE coordinate) properties of these phosphors have been studied as a function of Ca concentration. Doping of Ca ions into Sr2.92Ga2O6:Eu3+ phosphor gives rise to a significant enhancement in overall fluorescence and the optimum emission is attained for pure Ca2.92Ga2O6:Eu3+ phosphor for x = 2.92. The intensity ratio of 5D0  7F2 to 5D0  7F1 transitions (monochromaticity) of Eu3+ for different doping concentration of Ca suggests that asymmetry around the Eu3+ ion increases with increase in Ca ion concentration, which is responsible for enhanced emission. The excellent optical features, such as broad excitation band (230–480 nm) and excellent emission in red region (at 614 nm), conclude that calcium gallet phosphor could be a potential candidate for light emitting diodes and display applications.  相似文献   

12.
Well-crystallized flower-like SrCO3:Tb3+ phosphors have been synthesized by an inexpensive and friendly solvothermal process using polyvinylpyrrolidone (PVP, K30) as an additive without further annealing treatment. X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FESEM) as well as photoluminescence spectroscopy (PL) were used to characterize the resulting samples. The amount of PVP and the reaction time have strong effect on the morphology of the SrCO3:Tb3+ particles. The results of XRD confirm the formation of a well-crystallized SrCO3 phase with an orthorhombic structure. The possible formation mechanism for flower-like SrCO3:Tb3+ phosphor is proposed. The SrCO3:Tb3+ phosphors show the characteristic 5D47FJ (J = 6, 5, 4, 3) emission lines with green emission 5D47F5 (544 nm) as the most prominent group under ultraviolet excitation.  相似文献   

13.
《Optical Materials》2014,36(12):2128-2131
Green-emitting (Gd1−xyLaxTby)2O(WO4)2 (0  x  0.05, 0.05  y  0.15) phosphors were synthesized in a single phase form by the conventional solid-state reaction method, and their photoluminescent properties were characterized. The (Gd1−xyLaxTby)2O(WO4)2 phosphors showed strong and broad excitation bands from 230 to 350 nm, corresponding to the energy transition from the 4f8 to 4f75d configuration of Tb3+ and the charge-transfer (CT) transition of O2−−W6+. The oxytungstate phosphors exhibited typical emission peaks assigned to the transition from 5D4 to 7FJ (J = 6, 5, 4, and 3) of Tb3+, and the luminescence emission intensity was effectively enhanced by the La3+ doping into the host Gd2O(WO4)2 lattice. The highest green emission intensity was obtained for (Gd0.87La0.03Tb0.10)2O(WO4)2, where the relative emission intensity was 63% that of a commercial green-emitting (La0.52Ce0.31Tb0.17)PO4 phosphor.  相似文献   

14.
Lanthanide complexes with N-(diphenylphosphoryl)-4-methylbenzenesulfonamide (HPMSP) as new sensitizers of visible luminescence were obtained. The series of stable lanthanide complexes Na[Ln(PMSP)4], where Ln = Eu3+, Gd3+, Tb3+ were characterized by X-ray diffraction, IR, absorption, emission, and excitation spectra at 295 and 77 K as well as luminescence decay times and intrinsic emission quantum yields. The Tb complex, exhibiting relatively efficient ligand-to-metal energy transfer and strong metal-centred emission, is a promising candidate for effective UV-to-visible energy converters. Temperature dependent quenching of sensitized 5D0 europium emission and presence of 5D1 emission are discussed.  相似文献   

15.
《Materials Research Bulletin》2013,48(11):4749-4753
A series of single-phased emission tunable NaBa4(BO3)3:Ce3+, Tb3+ phosphors were synthesized by solid-state reaction. The crystal structure, photoluminescence properties, concentration quenching and energy transfer of NaBa4(BO3)3:Ce3+, Tb3+ were systematically investigated. The wavelength-tunable bluish-green light can be realized by coupling the emission bands centered at 425 and 543 nm ascribed to the contribution from Ce3+ and Tb3+, respectively. The energy transfer from Ce3+ to Tb3+ in NaBa4(BO3)3 host was studied and demonstrated to be a resonant type via a dipole–dipole interaction mechanism. The energy transfer efficiency (Ce3+  Tb3+) obtained by decay curves was consistent with the result calculated by the emission intensity, which gradually increased from 0% to 84.5% by increasing the Tb3+ doping content from 0 to 0.45. The results indicate that the NaBa4(BO3)3:Ce3+, Tb3+ phosphors have potential applications as an ultraviolet-convertible phosphor due to its effective excitation in the ultraviolet rang.  相似文献   

16.
We synthesized Mn4+-activated BaGeF6 red phosphor by the chemical reaction method from HF, H2SiF6, BaF2, KMnO4, and GeO2 powder. The structural and optical properties of BaGeF6:Mn4+ were investigated using X-ray diffraction analysis, secondary electron microscopy observation, electron spin resonance measurement, photoluminescence (PL), PL excitation (PLE) and Raman scattering spectroscopies, and luminescence decay time measurement. Temperature dependence of the PL intensity was measured from T = 20 to 500 K and analyzed by taking into consideration the Bose–Einstein phonon occupation number. The PLE spectra measured at T = 20 and 300 K and luminescence decay time at T = 20–460 K were also analyzed based on the Franck–Condon and conventional thermal quenching models, respectively. Comprehensive discussion was given on the Mn4+-related PL properties and Raman scattering behaviors in a family of the barium hexafluorometallate phosphors.  相似文献   

17.
Vacuum ultraviolet (VUV) excitation and emission properties of Tb3+ ion doped silico-aluminate phosphor Ca1.5Y1.5Al3.5Si1.5O12:Tb3+ was studied. Upon excitation with vacuum ultraviolet (VUV) and near UV light excitation, the phosphor showed strong green-emission peaked at 545 nm corresponding to the 5D4 → 7F5 transition of Tb3+, and the highest PL intensity at 545 nm was found at a content of about 14 mol% Tb3+. The 4f–5d transition absorption of Tb3+ is in the range from 150 nm to 260 nm, and there is an energy transfer from the host to the rare earth ions. Field emission scanning electron microscopy (FE-SEM) images showed the particle size of the phosphor was less than 3 μm.  相似文献   

18.
An orange reddish emitting phosphor, LaMgAl11O19:Sm3+, was synthesized by a high temperature solid-state reaction, and the phase formation, crystal structure and luminescence properties were investigated respectively. The LaMgAl11O19:Sm3+ phosphor presents a highly intense orange reddish emission peak under the near ultraviolet excitation at 403 nm, which is corresponds to the 4G5/2  6HJ (J = 5/2, 7/2, 9/2 and 11/2) transitions of Sm3+ ions. It was found that the dipole–dipole interactions mainly results in the concentration quenching in the LaMgAl11O19:Sm3+ phosphor with a critical quenching concentration at about 5 mol%. The temperature dependence of luminescence properties was studied from 25 to 200 °C and indicated that LaMgAl11O19:0.05Sm3+ phosphors had a relatively higher quenching temperature. The chromatic properties of LaMgAl11O19:0.05Sm3+ phosphor have been found to have chromaticity coordinate of (0.578, 0.420). All these properties indicate that the orange reddish emitting LaMgAl11O19:Sm3+ phosphor has a potential application in w-LEDs.  相似文献   

19.
A novel red emitting phosphor, Eu3+-doped Na2Ca4Mg2Si4O15, was prepared by the solid-state reaction. X-ray powder diffraction (XRD) analysis confirmed the formation of Na2Ca4Mg2Si4O15:Eu3+. Field-emission scanning electron-microscopy (FE-SEM) observation indicated a narrow size-distribution of about 300 nm for the particles with spherical shape. Upon excitation with vacuum ultraviolet (VUV) and near UV light, the phosphor showed strong red-emission lines at around 611 and 617 nm, respectively, corresponding to the forced electric dipole 5D0  7F2 transition of Eu3+, and the highest PL intensity at 617 nm was found at a content of about 8 mol% Eu3+. The optical properties study suggests that it is a potential candidate for plasma display panels (PDPs) application.  相似文献   

20.
The apatite related compound Sr10[(PO4)5.5(BO4)0.5]BO2 (SrBPO) doped with Ce3+ was synthesized via solid state reaction method. Undoped SrBPO shows blue-green emission under ultraviolet (UV) and X-ray excitation due to the defects in the host. When excited by vacuum ultraviolet–ultraviolet (VUV–UV) light or X-ray, Ce3+ doped SrBPO shows a broad emission band peaking at 450 nm originating from 5d–4f transition of Ce3+ and defects in the host. The phosphor exhibits strong excitation bands in UV range and a weak broad excitation band in VUV region. The site occupation of Ce3+ was proposed based on fluorescence decay curves. Electronic structure shows the compound is an indirect semiconductor with a band gap of 3.04 eV. The extremely small density of states of [PO4]3− or [BO4]5− group near Fermi level or in the conduction band is a possible origin of the weak excitation band in the VUV range. A possible mechanism was proposed to explain the luminescence properties observed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号