The green-emitting(Ce,Tb)MgAl11O19(CTMA) phosphor was prepared by the conventional high temperature solid-state reaction method.The effect of fluxes on the crystal structure,particle morphology,size distribution and p...The green-emitting(Ce,Tb)MgAl11O19(CTMA) phosphor was prepared by the conventional high temperature solid-state reaction method.The effect of fluxes on the crystal structure,particle morphology,size distribution and photoluminescence properties of CTMA phosphor was investigated by means of the X-ray powder diffraction,scanning electron microscopy and photoluminescence spectrum.The results showed that the addition of appropriate amount of MgF2-H3BO3 flux improved the phase purity of CTMA phosphor,and influen...展开更多
By a novel controlled combustion synthesis method, a large number of nanostructured ZnO whiskers with different morphologies, such as tetra-needles, long-leg tetra-needles and multi-needles, are prepared without any a...By a novel controlled combustion synthesis method, a large number of nanostructured ZnO whiskers with different morphologies, such as tetra-needles, long-leg tetra-needles and multi-needles, are prepared without any additive in open air at high temperature. The morphologies and crystalline structures of the as-prepared ZnO nanostructured whiskers are investigated by SEM and XRD. The possible growth mechanism on the nanostructured ZnO whiskers is proposed. The experimental results indicate that the dielectric constants and losses of the nanostructured ZnO whiskers are very low, demonstrating that the nanostructured ZnO whiskers are low-loss materials for microwave absorption in X-band. However, obvious microwave absorption in nanostructured ZnO whiskers is observed. The quasi-microantenna model may be attributed to the microwave absorption of the ZnO whiskers.展开更多
Y2O3:Eu3+ phosphors were synthesized by the surface diffusion method (SDM). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the struct...Y2O3:Eu3+ phosphors were synthesized by the surface diffusion method (SDM). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the structure, morphology and component of Y2O3:Eu3+ phosphors. The photoluminescent (PL) properties were also investigated. The results reveal that the PL intensity of Y2O3:Eu3+ phosphors prepared by the surface diffusion method (SDM) is much higher than that prepared by homogeneous co-precipitation. The luminescence efficiency of the sample (Y0.997, Eu0.003)2O3 prepared by the SDM is almost 1.9 times that by homogeneous co-precipitation. The concentration of Eu3+ in the phosphor Y2O3:Eu3+ prepared by the surface diffusion can be reduced greatly owing to the activator, Eu3+ ions, distributing mainly in the outer layer of the phosphors where the photon generation process occurs.展开更多
基金supported by the Independent Innovation Sci-Tech Foundation for Beijing Rapid-Growth Corporation
文摘The green-emitting(Ce,Tb)MgAl11O19(CTMA) phosphor was prepared by the conventional high temperature solid-state reaction method.The effect of fluxes on the crystal structure,particle morphology,size distribution and photoluminescence properties of CTMA phosphor was investigated by means of the X-ray powder diffraction,scanning electron microscopy and photoluminescence spectrum.The results showed that the addition of appropriate amount of MgF2-H3BO3 flux improved the phase purity of CTMA phosphor,and influen...
基金Supported by the National Natural Science Foundation of China under Grant Nos 50572010 and 10672020, the National Defense Founds under Grant Nos 51420205BQ0154, A2220061080）, and the National Key Basic Research Programme of China under Grant No 5131803.
文摘By a novel controlled combustion synthesis method, a large number of nanostructured ZnO whiskers with different morphologies, such as tetra-needles, long-leg tetra-needles and multi-needles, are prepared without any additive in open air at high temperature. The morphologies and crystalline structures of the as-prepared ZnO nanostructured whiskers are investigated by SEM and XRD. The possible growth mechanism on the nanostructured ZnO whiskers is proposed. The experimental results indicate that the dielectric constants and losses of the nanostructured ZnO whiskers are very low, demonstrating that the nanostructured ZnO whiskers are low-loss materials for microwave absorption in X-band. However, obvious microwave absorption in nanostructured ZnO whiskers is observed. The quasi-microantenna model may be attributed to the microwave absorption of the ZnO whiskers.
基金Project(2007CB613607) supported by the National Basic Research Program of China
文摘Y2O3:Eu3+ phosphors were synthesized by the surface diffusion method (SDM). X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the structure, morphology and component of Y2O3:Eu3+ phosphors. The photoluminescent (PL) properties were also investigated. The results reveal that the PL intensity of Y2O3:Eu3+ phosphors prepared by the surface diffusion method (SDM) is much higher than that prepared by homogeneous co-precipitation. The luminescence efficiency of the sample (Y0.997, Eu0.003)2O3 prepared by the SDM is almost 1.9 times that by homogeneous co-precipitation. The concentration of Eu3+ in the phosphor Y2O3:Eu3+ prepared by the surface diffusion can be reduced greatly owing to the activator, Eu3+ ions, distributing mainly in the outer layer of the phosphors where the photon generation process occurs.
