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《Materials Letters》2005,59(19-20):2433-2436
The lithium solubility limit, photoluminescence (PL) and photoluminescence excitation (PLE) properties of lithium ion co-activated ZnGa2O4:Bi3+,Li+ phosphor have been investigated. A LiGaO2 second phase began to appear from 3 mol% Li+ ion co-activated ZnGa2O4:Bi3+,Li+ phosphor. The enhanced brightness of blue (λex = 254 nm) and white (λex = 315 nm) colors of bismuth ions doped ZnGa2O4:Bi3+,Li+ phosphor was assigned to the formation of LiGaO2. Bi3+ activated lithium zinc gallate phosphor showed a more enhanced PLE peak around 315 nm than that of lithium zinc gallate phosphor when λem = 520 nm. Thus, we observed that the PL intensity of ZnGa2O4:Bi3+,Li+ phosphor with λem = 520 nm was much greater than that of ZnGa2O4:Li+ phosphor. Also, ZnGa2O4:Bi3+,Li+ phosphor exhibited a shorter decay time than that of ZnGa2O4:Li+ phosphor by about a factor of about 2. 相似文献
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采用水热法制备了ZnGa2O4纳米粉体,使用XRD、SEM、TEM及AFM对不同pH值条件下产物的结构及微观形貌进行了表征.结果表明pH值调节严重影响ZnGa2O4的晶相及粒度:当pH≥7.5时,可得到纯相的ZnGa2O4纳米粉体;随着pH的增加,晶胞参数增加,所得样品的平均粒径不断减小,其粒径范围为6~11nm,发射峰位置在450nm左右.所得样品的晶型很完整,GaO(OH)为细长棒状,ZnGa2O4晶粒为四方形和圆形. 相似文献
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R. Withnall A. L. Lipman G. R. Fern A. Rose J. Silver 《Journal of Materials Science: Materials in Electronics》2006,17(9):745-753
The emission properties of ZnGa2O4:Mn phosphors have been compared for samples prepared via an oxalate gel route and those prepared via a conventional solid
synthetic route. The firing conditions were found to be critical for obtaining good emission on account of possible redox
processes involving both the Mn2+ activator ion and the host ZnGa2O4 lattice itself. An interesting reversible shift was observed for the CIE coordinates of the cathodoluminescence when the
energy of the exciting electron beam was varied. This is explained by increased vibronic excitation of the ZnGa2O4:Mn phosphors at higher electron beam energies, resulting in a greater relative contribution of the vibronic side bands to
the green emission. 相似文献
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用硫熔法制备了系列红色蓄光材料Y2O2S :Eux^3+(0.01≤x≤0.10)的多晶粉末样品并系统研究了其发光特性。XRD结果表明,晶胞参数c随着Eu^3+含量的逐渐增大而增大,而晶胞参数α没有明显的线性变化关系,这与Y2O2S :Eu^3+的晶体结构有关。Y2O2S :Eux^3+(0.01≤x≤0.10)的激发光谱相似,在626nm发射光监控下最大激发波长约在330nm附近。在330nm激发下,随着Eu^3+含量逐渐增大,发射光谱最强发射峰位置从540nm右移至626nm,观察到红色特征发射峰626nm的强度逐渐增大,在Eu^3+含量为0.09时,其强度达到最大。在最佳合成条件及最佳Eu^3+含量下,正在进行掺杂Mg^2+和Ti^4+及其发光特性的研究。 相似文献
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A. R. Phani S. Santucci S. Di Nardo L. Lozzi M. Passacantando P. Picozzi C. Cantalini 《Journal of Materials Science》1998,33(15):3969-3973
High-quality bulk ZnGa2O4 has been synthesized from equimolar mixtures of ZnO and Ga2O3 by the conventional solid-state method. For the first time, the sample has been characterized in detail to confirm the formation of pure single phase of spinel ZnGa2O4. The formation of ZnGa2O4 has been confirmed by sintering the mixtures of ZnO and Ga2O3 at different temperatures, ranging from 900–1200 °C. It is observed that the single phase of ZnGa2O4 has been formed at and above 1000 °C sintering temperature for 24 h. The crystallinity and phase formation of this single phase has been confirmed by X-ray diffraction. X-ray photoelectron spectroscopic studies have been carried out for bulk ZnGa2O4 sintered at 1000 °C for 24 h which showed 14% Zn, 28% Ga and 58% O, indicating stoichiometric ZnGa2O4. A new parameter, the energetic separation between the Zn 2p3/2 and Ga 2p3/2 peaks, has been used as a sensitive tool to distinguish between a complete formation of ZnGa2O4 compound and a mixture of ZnO and Ga2O3 powders. Surface morphology studies by scanning electron microscopy reveal that the formation of ZnGa2O4 takes place in mosaic rod-like structure. The purity of the compound has also been checked by the energy dispersive X-ray method, indicating the absence of foreign ions and the ratio of zinc to gallium has been calculated and found to be 1 : 2, indicating stoichiometric ZnGa2O4. 相似文献
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《功能材料》2012,43(8)
用水热法在不同温度下制备结晶性较好、颗粒均一的CoFe2O4纳米颗粒,无需进一步煅烧。利用X射线衍射仪(XRD)、场发射扫描电镜(SEM)、穆斯堡尔谱仪和综合物性测量系统(PPMS)对不同温度下合成的样品进行表征。结果表明,随着合成温度的升高,CoFe2O4纳米颗粒的结晶性增强,粒径逐渐增大,样品的饱和磁化强度逐渐增强。当合成温度为500℃时,CoFe2O4纳米颗粒的饱和磁化强度达到64.1A.m2/kg,与块体的CoFe2O4(72A.m2/kg)接近。穆斯堡尔谱分析表明,当晶粒粒径超过了超顺磁性的临界尺寸,样品的超顺磁性消失,随着合成温度的升高,B位上Fe3+离子的比例增高,磁性能增强。 相似文献
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Stoichiometric and nonstoichiometric powders of cadmium indium oxide were derived from calcination of cadmium indium sulphide
prepared by flux method. The materials were confirmed by XRD. Thick films of above prepared powders were prepared on glass
substrates using screen printing technique. The thick films were characterized by SEM and EDAX. The electrical conductivity
of CdIn2O4 thick films was calculated. The gas sensing performance of stoichiometric thick films of CdIn2O4 was tested for various gases. The films showed good response to LPG. 相似文献
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以ZnCl2、Ga(NO3)3·xH2O、CoCl2·6H2O为原料,采用水热法制备了立方晶型的Zn1-xCoxGa2O4光催化剂,用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外漫反射(UV-Vis)、X射线光电子能谱(XPS)等测试手段对催化剂进行了表征,结果表明,Co成功地掺入到ZnGa2O4晶格内,Co的掺入能够影响催化剂的形貌,缩小催化剂的禁带宽度。光催化降解罗丹明B溶液实验结果表明,Co的掺入提高了催化剂的催化活性,掺入量为x=0.010的Zn1-xCoxGa2O4具有最佳的光催化性能,同时Zn1-xCoxGa2O4样品对罗丹明B溶液的光催化降解反应符合伪一级反应动力学规律。并对Co掺入后光催化活性提高的机理进行了讨论。 相似文献
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Wang Xiangyu Qiao Hengyang Wang Xuemei Xu Yue Liu Tong Song Fuzhou An Zhongfen Zhang Lingcui Shi Feng 《Journal of Materials Science: Materials in Electronics》2022,33(24):19129-19137
The phase pure ZnGa2O4 and ZnGa2O4 doped with Cr ions nanoparticles were successfully synthesized by the hydrothermal method, whose average particle sizes are about 10 nm, and the doping of Cr ions can slightly increase the particle sizes. The doping Cr ions can evenly distribute in the samples by the hydrothermal method. The infrared characteristic peaks of the products are in the range of 400–1000 cm?1. Blue emission is observed in phase pure ZnGa2O4, while NIR emissions are observed in the ZnGa2O4 products doped with Cr ions. ZnGa2O4:Cr nanoparticles have great application prospects in the field of biomedical imaging.
相似文献13.
B. G. Tagiev G. G. Guseinov R. B. Dzhabbarov O. B. Tagiev N. N. Musaeva A. N. Georgobiani 《Inorganic Materials》2000,36(12):1189-1191
ZnGa2S4:Eu,F and ZnGa2O4:Eu,F were synthesized and characterized by x-ray diffraction and photoluminescence (PL) measurements. ZnGa2S4:Eu,F has a tetragonal structure (sp. gr.
) with a= 5.272 Å and c= 10.451 Å, and ZnGa2O4:Eu,F has a cubic structure (sp. gr. Fd3m) with a= 8.32 Å. The PL spectrum of ZnGa2S4:Eu,F consists of a broad band (FWHM = 1.11 eV) at 565 nm due to the Eu2+ 5D
1 7F
2 transition, and the spectrum of ZnGa2O4:Eu,F shows four emissions due to the Eu3+
5
D
0 7
F
4 (max = 682 nm), 5
D
0 7
F
2 (max = 615 nm), 5
D
0 7
F
1 (max = 595 nm), and 5
D
0 7
F
0 (max = 584 nm) transitions. 相似文献
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Anthuvan John Peter I. B. Shameem Banu Jagannathan Thirumalai Samuel Paul David 《Journal of Materials Science: Materials in Electronics》2013,24(11):4503-4509
For the first time, CaMoO4: xEu3+ (x = 0.02, 0.04, 0.06, 0.08, 0.1) red phosphor nanoparticles were synthesized using the simple mechanochemically assisted solid state meta-thesis (SSM) reaction method and the luminescence properties as a function of Eu3+ ion concentration was investigated. The characteristics of the phosphor materials were analyzed using X-ray diffraction, fourier transform infrared spectroscopy, photoluminescence (PL) and diffuse reflectance spectroscopy. For 8 mol% of Eu3+ concentration, the phosphor shows an intensified excitation peak at 392 nm indicating a strong absorption. The PL emission spectra of CaMoO4: Eu3+ phosphors showed an intense peak at 615 nm (red) which corresponds to 5D0 → 7F2 transition of Eu3+. The optimal Eu3+ concentration in CaMoO4 phosphors for enhanced red emission occurs for 8 mol% and above this concentration, the emission intensity decreases due to quenching effect. The CIE colour coordinates of the CaMoO4: 0.08Eu3+ red phosphor coincide very well with the standard values of NTSC. The red emission intensity of the SSM prepared CaMoO4: 0.08Eu3+ red phosphor is 4.7 times greater than that of the commercial Y2O2S: Eu3+ red phosphor and 1.6 times more than the same phosphor prepared by the solid state reaction method. 相似文献
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A. R. Phani M. Passacantando L. Lozzi S. Santucci 《Journal of Materials Science》2000,35(19):4879-4883
Uniform crystals of ZnWO4 have been synthesised from the equimolar mixtures of ZnO and WO3 by conventional solid state method. For the first time the sample has been characterised detailedly to confirm the formation of pure single phase of perovskite ZnWO4. The formation of ZnWO4 has been confirmed by sintering the mixtures of ZnO and WO3 at two different temperatures one at 900 °C and other at 1000 °C. It is observed that the sample sintered at 1000 °C for 24 h shows complete formation of the single phase of ZnWO4. The crystallinity and the phase formation has been confirmed by X-ray diffraction technique. X-ray photoelectron spectroscopy measurements have been carried out for the bulk ZnWO4 sintered at 1000 °C for 24 h, showing 16% of Zn, 16% of W and 68% of O indicating stoichiometric ZnWO4. Surface morphology studies by scanning electron microscopy showed uniform crystals of ZnWO4. The purity of the compound has also been checked in depth by Energy Dispersive X-ray method indicating the absence of foreign ions apart from that, the ratio of Zn : W has been calculated and found to be 1 : 1 confirming the stoichiometric ZnWO4 inside the crystals. 相似文献
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The effects of the lithium substitution for copper on the properties of the superconducting YBa2Cu4O8 were studied. Single-phase YBa2Cu4–x
LixO8 was successfully prepared by the sol-gel method under ambient pressure over a composition range of 0x 0.08, while impurity phases appeared at x=0.10 and 0.20. The lattice constants of YBa2Cu4–x
Li
x
O8 were almost invariant with increasing lithium content x. The superconducting transition temperature decreased monotonically with increasing x in the range, 0x0.08. The suppression of superconductivity was discussed in terms of the impurity effect in the CuO2 planes. 相似文献
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The sol-gel procedure has been used to prepare vitreous materials whose compositions are situated in the liquid-liquid immiscibility area of the Na2O-B2O3 SiO2 phase equilibrium diagram. Gels were prepared from different precursors and under different experimental conditions. After determining optimum conditions for gelling and heat-treatment, the gels were characterized with the aid of thermal analysis, X-ray diffraction, density and specific surface area measurements, as well as infrared and near-infrared spectroscopy. The textures of the samples and their microstructures were studied by means of scanning electron microscopy and transmission electron microscopy, respectively. The phase separation in the gels was compared to the same phenomenon in one of the glasses of identical composition, but prepared by conventional melting. 相似文献