共查询到20条相似文献,搜索用时 15 毫秒
1.
Bingjie Liu Mu Gu Xiaolin Liu Chen Ni Di Wang Lihong Xiao Riu Zhang 《Journal of Alloys and Compounds》2007,440(1-2):341-345
Nanosized Gd1.92−x−yZnxLiyEu0.08O3−δ phosphor was fabricated by combustion synthesis. The effect of Zn2+ and Li+ ions on the crystallization behavior, morphology, and luminescence property of Gd2O3:Eu3+ was investigated. The results indicated that incorporation of Zn2+ and Li+ ions into Gd2O3:Eu3+ nanoparticles (NPs) could lead to a remarkable increase of photoluminescence or X-ray excited luminescence, and the intensity at 612 nm was increased by a factor of 7.1 or 21.5 in comparison with that of undoped sample. The enhanced luminescence was regarded as the results of the creation of oxygen vacancies due to the Gd3+ sites occupied by Li+ ions, the alteration of the crystal field surrounding the activator Eu3+ ions owing to the incorporation Zn2+ ions into interstitial sites, and the flux effect of Zn2+ and Li+ ions. The Zn- and Li-codoped Gd2O3:Eu3+ phosphor with highly enhanced luminescence is very encouraging for applications in high-resolution display devices. 相似文献
2.
Orange-reddish-emitting phosphor AlPO4:Eu3+ were fabricated by solid-state reactions at high temperature. X-ray diffraction analysis revealed that AlPO4 doped with 3 mol% of Eu3+ (AlPO4:0.03Eu3+) was pure orthorhombic phase. The photoluminescence study shows that the intensity of magnetic dipole transition (5D0 → 7F1) at 594 nm dominates over that of electric dipole transition (5D0 → 7F2) at 613 nm. The optimum concentration of Eu3+ for the highest luminescence is found to be 3 mol%. The PL excitation spectrum is composed of CTB of Eu-O and excitation lines of Eu3+ ions. The strongest excitation lines appeared at 392 nm. The color coordinates, quantum yield and lifetime for AlPO4:0.03Eu3+ were measured. All the spectrum features indicate that AlPO4:Eu3+ might be a promising phosphor for display devices or w-LEDs. 相似文献
3.
Yoshinori Yonesaki Qiang DongNur Suhaiza Binti Mohamad Akira MiuraTakahiro Takei Junji YamanakaNobuhiro Kumada Nobukazu Kinomura 《Journal of Alloys and Compounds》2011,509(35):8738-8741
A simple solid-state reaction was used to apply a vitreous-phase coating onto Eu2+-doped BaCa2MgSi2O8 blue-phosphor particles. The vitreous phase was generated by liquid phase sintering at 1200 °C. The coated phosphor exhibited resistant to an acid dispersant. When a small amount of Al and La was added in raw materials, they were incorporated in the vitreous coating phase. 相似文献
4.
This paper reports the photoluminescence (PL) properties of Tb3+ in NaBa4(BO3)3, as well as the time-resolved luminescence properties. The PL excitation spectrum exhibits intense f → f transition absorption; the PL emission spectrum shows the strongest 5D4 → 7F5 emission at 540 nm. The relative intensity of 5D3 emission is much weaker than that of 5D4 emission even in the samples with lower Tb3+ concentration. The 5D3 → 5D4 cross-relaxation produces a marked increase in the 5D3 decay rate with increasing Tb3+ concentrations and introduces a non-exponential component into the initial part of the decay. The dipole-dipole interaction is found to be responsible for the cross-relaxation. The decay curves of 5D4 → 7F5 transition exhibit an initial rise phenomenon. The two exponential fitting indicates that the initial slow rise is attributed to the 5D3 → 5D4 cross-relaxation process. 相似文献
5.
Polycrystalline powder sample of KSr4(BO3)3 was synthesized by high-temperature solid-state reaction. The influence of different rare earth dopants, i.e. Tb3+, Tm3+ and Ce3+, on thermoluminescence (TL) of KSr4(BO3)3 phosphor was discussed. The TL, photoluminescence (PL) and some dosimetric properties of Ce3+-activated KSr4(BO3)3 phosphor were studied. The effect of the concentration of Ce3+ on TL intensity was investigated and the result showed that the optimum Ce3+ concentration was 0.2 mol%. The TL kinetic parameters of KSr4(BO3)3:0.002 Ce3+ phosphor were calculated by computer glow curve deconvolution (CGCD) method. Characteristic emission peaking at about 407 and 383 nm due to the 4f05d1 → 2F(5/2, 7/2) transitions of Ce3+ ion were observed both in PL and three-dimensional (3D) TL spectra. The dose–response of KSr4(BO3)3:0.002 Ce3+ to γ-ray was linear in the range from 1 to 1000 mGy. In addition, the decay of the TL intensity of KSr4(BO3)3:0.002 Ce3+ was also investigated. 相似文献
6.
BaMgAl10O17:Eu2+ nanorods were synthesized by sol-gel technique, and their luminescent properties were investigated upon the irradiation of vacuum ultraviolet (VUV) light. By introducing surfactant cetyl-tri-methyl-ammonium bromide (CTAB) in sol-gel process and additional Mg2+ in the raw materials, the emission intensity and thermal stability of the nanophosphor were both enhanced. The above improvements made it possible that the nanosized BAM phosphor could be a good alternative for PDP application. 相似文献
7.
Ying XiaoDapeng Wu Yi JiangNing Liu Junli LiuKai Jiang 《Journal of Alloys and Compounds》2011,509(19):5755-5760
Nano-sized Y2O3:Eu3+ hollow spheres were fabricated via a facile strategy including preparation of the hollow precursor and a later calcination. Moreover, the growth process of these hollow spheres was monitored by time-dependent experiments and their luminescence properties were also intensively studied. The products exhibit strong red emitting at 613 nm under ultraviolet excitation and control experiments were carried out to optimize the synthetic conditions. It was found 850 °C calcination with 9 mol% doping level could give out the best photoluminescence performance. Moreover, a possible mechanism for the enhanced PL performance was also proposed based on the FT-IR investigation. 相似文献
8.
9.
Mingzhu YangYu Sui Shipeng WangXianjie Wang Yang WangShuchen Lü Tianquan LüWanfa Liu 《Journal of Alloys and Compounds》2011,509(2):266-270
Eu3+ doped Y2O3 nanocrystals are synthesized via precipitation and hydrothermal methods. With the increase of hydrothermal temperature, the number of surface states decreases when nanorods are formed. The decrease of surface states induces the increase in the ratio of S6 site to C2 site, and meanwhile results in the spectral red-shift of charge transfer band as well as the enhancement of red emission. The results indicate that the surface states and optical properties have close correlations. 相似文献
10.
Effects of sucrose concentration on morphology and luminescence performance of Gd2O3:Eu nanocrystals
Lingling Xu Bo Wei Weiwei An Zhe Lü Hong Gao Yungang Zhang Zhiguo Zhang 《Journal of Alloys and Compounds》2008,460(1-2):524-528
Red Gd2O3:Eu nanophosphors were prepared by novel sucrose-assisted combustion method. The sucrose hydrolysis and complexing procedures were discussed by the Fourier transform infrared spectroscopy (FTIR) analysis. The effect of sucrose-to-metal ratio (S:M) on morphology and luminescence intensity of Gd2O3:Eu nanocrystals were investigated. And the optimum ratio was found to be S:M = 7:1, as confirmed by the results of scanning electron microscope (SEM), transmission electron microscope (TEM) and photoluminescence (PL) measurements. The highest photoluminescence emission from the particles obtained at S:M = 7:1 was about 85% of the commercial red phosphors. 相似文献
11.
Jianhui ShiDeming Liu Lizhu TongXuwei Yang Hua Yang 《Journal of Alloys and Compounds》2011,509(42):10211-10216
In this paper, we report on the bifunctional Fe3O4@SiO2@YP0.1V0.9O4:Dy3+ nanocomposites were prepared by the solvothermal method and sol-gel method. The structure, photoluminescence (PL) and magnetic properties of the nanocomposites were characterized by means of X-ray diffraction, scanning electron microscope, transmission electron microscope, PL excitation and emission spectra and vibration sample magnetometry. It is shown that Fe3O4@SiO2@YP0.1V0.9O4:Dy3+ nanocomposites with a core-shell structure present excellent fluorescent and magnetic properties. Additionally, the effects of the magnetic field on the luminescence properties of nanocomposites were discussed. 相似文献
12.
Radenka Krsmanovi
eljka Anti Ivana Zekovi Miroslav D. Dramianin 《Journal of Alloys and Compounds》2009,480(2):494-498
The synthesis of nanophosphors for various applications and the improvement of their working parameters constitute one of the most topical problems of nowadays technology. Zinc-silicate has been extensively used as host material for phosphors in cathode ray tubes, and nowadays for phosphors in electroluminescent devices. In this work we present novel synthesis procedure for obtaining Zn2SiO4:Eu3+ powder, based on the combination of standard sol–gel and modified combustion method. Influence of preparation conditions on the structure and morphology are analyzed using X-ray diffraction and scanning electron microscopy. Luminescence properties of Eu3+ are investigated with fluorescence emission and lifetime measurements. 相似文献
13.
Xianghong He Mingyun GuanChunyong Zhang Tongming ShangNing Lian Yan Yao 《Journal of Alloys and Compounds》2011,509(38):L341
Eu3+-activated Li2Zn2(MoO4)3 multiwavelength excited red-emitting phosphors were synthesized via a solid state reaction. The structure and photoluminescence characteristics were investigated by X-ray powder diffraction and fluorescent spectrophotometry, respectively. The excitation spectrum included a strong broadband ranging from 250 to 350 nm and some sharp peaks at 363, 384, 395, 465, and 533 nm, which matchs the radiations of near-UV or blue light-emitting diodes chip well. Upon excitation either of near-UV or blue even green light, the intense red emission with 615 nm peak can be observed, which is ascribed to the 5D0-7F2 transition of Eu3+ ions. The chromaticity coordinates (x = 0.65, y = 0.34) of the as-obtained phosphor is very close to the National Television Standard Committee standard values (x = 0.67, y = 0.33). All these characteristics suggest that Eu3+-doped Li2Zn2(MoO4)3 wavelength-conversion material to be suitable candidate red component for phosphor-converted white light-emitting diodes. 相似文献
14.
The novel red-emitting phosphors K2Ba(MoO4)2: Eu3+, Sm3+ were prepared by solid-state reaction and their crystal structures, photo luminescent characteristics were investigated. The results show that all samples can be excited efficiently by UV (397 nm) and blue (466 nm) light, which are coupled well with the characteristic emission from UVLED and blue LED, respectively. A small amount of Sm3+, acting as a sensitizer, increased the energy absorption around 400 nm. In the Eu3+-Sm3+ co-doped system, both Eu3+ and Sm3+ f-f transition absorptions are observed in the excitation spectra, the intensities of the main emission line (5D0 → 7F2 transition of Eu3+ at 616 nm) are strengthened because of the energy transition from Sm3+ to Eu3+. The doping concentration of Eu3+-Sm3+ was optimized. The approach to charge compensation was used: Ba2+ → Eu3+/Sm3+ + X− (X = F, Cl, and Br), and the influence of charge compensation on the luminescent intensity of phosphors is investigated. 相似文献
15.
Mingzhu YangYu Sui Shipeng WangXianjie Wang Yang WangShuchen Lü Zhiguo ZhangZhiguo Liu Tianquan LüWanfa Liu 《Journal of Alloys and Compounds》2011,509(3):827-830
The influences of Bi3+ doping on the optical properties of Er3+:Y2O3 are investigated under UV and IR excitations. The emission intensity of Er3+ is remarkably enhanced by the introduction of Bi3+ under both two excitations. The emission enhancement under UV excitation originates from the energy transfer from Bi3+ to Er3+, while under IR excitation it can be attributed to the modification of the local crystal field around the Er3+. 相似文献
16.
Mingzhu Yang Yu Sui Shuchen LüMingji Wang Xianjie WangMuhong Wu Yang WangTianquan Lü Wanfa Liu 《Journal of Alloys and Compounds》2011,509(34):8590-8594
Bi3+ and Er3+ codoped Y2O3 was prepared by sol-gel method. The upconversion emission was investigated under 980 nm excitation. For samples without Bi3+, the quenching concentration of 2H11/2/4S3/2 level of Er3+ is 3.0 mol%. However, by 1.5 mol% Bi3+ doping the quenching concentration increases to 5.0 mol%; meanwhile, the green emission is enhanced 1.9 times. The results indicate that both the quenching concentration and the emission intensity of 2H11/2/4S3/2 level can be increased by Bi3+ doping. 相似文献
17.
Ruijin YuWeijia Ding Gongguo ZhangJianhui Zhang Jing Wang 《Journal of Alloys and Compounds》2011,509(28):L273
A new series of blue-emitting Ce3+-doped CaLaGa3S7 thiogallate chalcogenide phosphors were synthesized by a solid-state reaction method. Their luminescence properties were investigated by photoluminescence excitation, emission spectra and lifetime. The critical dopant concentration was found to be 0.15 mol of Ce3+ (Rc = 15 Å) and the fluorescence lifetime of Ce3+ in CaLaGa3S7:0.15 Ce3+ was 12.9 ns. The blue-emitting LED was fabricated by combining an InGaN chip (395 nm) with a CaLaGa3S7:Ce3+ phosphor. The CIE chromaticity coordinates of the blue LED were calculated to be (0.14, 0.23). 相似文献
18.
Chenning Zhang Tetsuo UchikoshiJi-Guang Li Takayuki WatanabeTakamasa Ishigaki 《Journal of Alloys and Compounds》2011,509(36):8944-8951
Nb5+:Eu3+-codoped TiO2 nanopowders for chemical composition adjustment have been synthesized via Ar/O2 radio-frequency thermal plasma. X-ray diffraction (XRD) results reveal that all the resultant powders exhibited mixture polymorphs of anatase (mean size: ∼45 nm) as the major phase and rutile (mean size: ∼71 nm). Rutile formation was promoted by the Eu3+ doping but suppressed by the Nb5+ addition. Combined observation using FE-SEM and TEM indicates that all the plasma-synthesized powders had a majority of facet-shaped particles (several nanometers) and a small proportion of nearly spherical crystals (∼150 nm). For the defect-mediated photoluminescence (PL) emission through the energy transfer from the TiO2 host to the Eu3+ activator, the PL intensity originating from the 5D0 → 7F2 electronic transition weakened but that from the 5D0 → 7F1 electronic transition strengthened with increasing Nb5+ content. This may be a result of the decrease in the oxygen vacancy defects in the TiO2 host lattice, as revealed by the joint means of UV-vis absorption spectra and excitation and emission spectra. 相似文献
19.
Guifang JuYihua Hu Li ChenXiaojuan Wang Zhongfei MuHaoyi Wu Fengwen Kang 《Journal of Alloys and Compounds》2011,509(18):5655-5659
A series of Eu3+ activated Na3Gd1−xEux(PO4)2 (0 ≤ x ≤ 1) phosphors were synthesized by solid-state reaction method. The structures and photo-luminescent properties of these phosphors were investigated at room temperature. The results of XRD patterns indicate that these phosphors are isotypic to the orthorhombic Na3Gd(PO4)2. The excitation spectra indicate that these phosphors can be effectively excited by near UV (370-410 nm) light. The intensities of magnetic dipole transition 5D0 → 7F1 and forced electric dipole transition 5D0 → 7F2 are comparable, and the energy ratio (5D0 → 7F1/5D0 → 7F2) is 1.1. The emission spectra exhibit strong reddish orange performance (CIE chromaticity coordinates: x = 0.62, y = 0.38), which is due to the 5D0 → 7FJ transitions of Eu3+ ions. The correlation between the structure and the photo-luminescent properties of the phosphors was studied. The energy transfer and concentration quenching of the phosphors were discussed. Na3Gd1−xEux(PO4)2 has a potential application for white light-emitting diodes. 相似文献
20.
D. ThangarajuA. Durairajan S. Moorthy Babu Y. Hayakawa 《Journal of Alloys and Compounds》2011,509(41):9890-9896
Nanocrystalline KHo(WO4)2 (KHW) particles were successfully synthesized via conventional Pechini sol-gel method. Prepared precursor gel was calcined at 250, 550, 600, 650 and 700 °C, and the resulting samples were analyzed with TG-DTA, powder X-ray diffraction, FT-IR, Raman, FESEM, TEM, UV-Vis-NIR (diffuse reflectance spectrum (DRS)), fluorescence and vibrating sample magnetometer (VSM). Thermal degradation of derived gel was observed up to 400 °C and phase formation starts from 550 °C. The product phase formation at higher annealing temperature was investigated by means of powder XRD. Organic liberation in the samples with respect to temperature was analyzed using FT-IR spectrum. Raman spectrum reveals the formation of tungsten ribbons as well as the quality of the samples while increasing the calcination temperature. The nano size of the synthesized particles was confirmed with FESEM and TEM micrographs. Reflectance and emission studies reveal the corresponding absorption and emission properties of trivalent state holmium ion. Paramagnetic behavior of the derived KHW was confirmed with VSM results. 相似文献