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采用静电纺丝法合成了纤维状的Bi2Fe4O9前驱体,再对前驱体进行热处理得到了棒状的Bi2Fe4O9.通过X射线衍射、扫描电子显微镜及透射电子显微镜表征了合成样品的物相及形貌特征.结果表明合成的样品为Bi2Fe4O9单相,属于正交晶系;退火处理导致纤维状的前驱体转变为棒状的Bi2Fe4O9.紫外-可见吸收光谱表明制备的Bi2Fe4O9对光的吸收范围广,不仅对紫外光具有较强吸收,而且对可见光也有一定的吸收.通过振动样品磁强计测定Bi2Fe4O9磁滞回线研究其磁学特性,相应的矫顽力HC≈82 Oe(1 Oe=79.5775 A/m),剥离顺磁信号后的剩磁Mr≈0.25 emu/g,研究发现Bi2Fe4O9样品具有弱铁磁性,并且软磁性能有所提高. 相似文献
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在还原气氛下利用高温固相法制备了Ba3.982-x(Si3O8)2∶0.008Eu2+,xCe3+,0.01Dy3+系列样品。光谱分析表明,Ce3+进入到晶格中将取代不同Ba2+格位从而形成不同的发光中心。通过Ce3+→Eu2+的能量传递,得到了一系列发光颜色可调、余辉颜色为绿色的长余辉发光材料。Ce3+的掺入可以增大样品的余辉强度但是同时缩短了样品的余辉时间。热释光谱的分析表明,Ce3+的掺入可以同时增加浅陷阱T1和深陷阱T3的数量,深陷阱对载流子的再捕获效应导致了样品余辉强度的增大和余辉时间的缩短。 相似文献
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Photoluminescence degradation mechanism of BaMgAl10O17:Eu2+ phosphor by vacuum ultraviolet irradiation 下载免费PDF全文
<正>A real high power vacuum ultraviolet light source is applied to the investigation on the vacuum ultraviolet irradiation degradation of BaMgA10O17:Eu2+ phosphor.The degradations of emission intensity and color quality of the sample are clearly observed after irradiation.It reveals that the oxidation of Eu2+ during irradiation is partly responsible for the degradations.The excitation and absorption spectra show that some traps generated during irradiation have negative influence on the luminescence of sample and these traps have been identified as positively charged oxygen vacancies by positron annihilation.The investigations on host emission and decay curve further confirm that these oxygen vacancies are involved in the perturbation of energy transfer from the host to Eu2+ and finally result in the degradation. 相似文献
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釆用高温固相法制备了NaCaPO4∶Dy3+系列样品, 并在紫外(UV)及真空紫外(VUV)区域研究了系列样品的发光性能. 紫外激发光谱显示在350 nm处有最强的激发峰, 可以有效地吸收紫外光并将其转化为可见光. 真空紫外激发光谱表明, NaCaPO4∶Dy3+能有效地吸收无汞荧光灯的激发源并将其转化为可见光. 系列样品发光均呈现为白色, 这种材料有潜力作为全色显示材料应用于发光二极管(LED)和无汞荧光灯中. 相似文献
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用燃烧法成功合成了Zn2 -xSiO4∶xMn(0≤x≤ 0 .10 )粉末样品并表征了其发光特性。XRD测量结果表明 ,在 6 0 0℃下燃烧数分钟、90 0℃以上进行热处理 4h后 ,所得样品为单相Zn2 -xSiO4∶xMn(0≤x≤ 0 .10 ,Willemite)。监控 5 2 5nm发射 ,测得Zn2 -xSiO4∶xMn(0 相似文献
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Zn2SiO4:Mn2+荧光粉的燃烧法合成及其发光特性 总被引:4,自引:2,他引:2
用燃烧法成功合成了Zn2-xsiO4:xMn(0≤x≤0.10)粉末样品并表征了其发光特性.XRD测量结果表明,在600℃下燃烧数分钟、900℃以上进行热处理4 h后,所得样品为单相Zn2-xSiO4:xMn(0≤χ≤0.10,Willemite).监控525 nm发射,测得Zn2-xSiO4:xMn(0<χ≤0.10)的最强激发峰为Mn2+的6A1→4T1跃迁(约254 nm).254 nm激发下,Zn2-xSiO4:xMn(0<χ≤0.10)的最强发射峰为Mn2+的3d电子组态内自旋禁戒的4Ti→6AJ跃迁(约525 nm).结果表明,发光强度、最强峰位、最佳激活剂浓度等与初始原料、燃烧温度、燃烧剂的用量、粉末粒度等有关. 相似文献
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Photoluminescence properties of Y0.75-xGdxAl0.10BO3:Eu3+0.10, 0.05R3+ (R= Sc, Bi) (0.00≤x≤0.45) 下载免费PDF全文
Y$_{0.75 -
x}$GdxAl0.10BO$3:Eu$^{3+}0.10, 0.05R3+
($R$=Sc, Bi) ($0.00 ≤ x ≤ 0.45$) powder samples are prepared
by solid-state reaction and their luminescence properties are
investigated. With the replacement of Y3+$ ions by Sc3+$
(or Bi3+)$ and Gd3+$ ions in (Y,Al)BO$3:Eu, the
intensities of emission at 254 and 147~nm are remarkably improved,
because Sc3+$ ions can absorb UV light and transfer the energy
to Eu3+$ ions efficiently. Moreover, Gd3+$ and Bi$^{3 +
}$ ions act as an intermediate ``bridge' between the sensitizer and
the activator (Eu3+)$ in energy transfer to produce light in
the (Y, Gd)BO$3:Bi3+$, Eu3+$ system more effectively.
After doping an appropriate concentration of Gd3+$ into
Y$_{0.50}$Gd$_{0.25}$Al0.10BO$3:Eu3+_{0.01}$,
Bi$^{3+}_{0.05}$, the emission intensity reaches its maximum, which
is nearly 110{\%} compared with the red commercial phosphor
(Y,Gd)BO$3:Eu and better chromaticity coordinates (0.650, 0.350)
are obtained. 相似文献