The (Y,Gd)BO3:Tb3+ and Li+-doped (Y,Gd)BO3:Tb3+ phosphors were prepared by high temperature solid-state method. The inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), scanning ...The (Y,Gd)BO3:Tb3+ and Li+-doped (Y,Gd)BO3:Tb3+ phosphors were prepared by high temperature solid-state method. The inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), scanning electron microscopy (SEM), and the excitation and emission spectra were used to characterize the samples. The results of ICP-AES and XRD indicated that Li+ ions could enter the (Y,Gd)BO3:Tb3+ lattice and induce the lattice expansion. It could be seen from SEM that the particles were spherical a...展开更多
To further understand the energy loss mechanism of the ＂charge transfer process＂ that was proposed in our previous work on Eu^2＋-Mn^2＋ co-doped phosphors, the influence of synthetic temperature and heating time on...To further understand the energy loss mechanism of the ＂charge transfer process＂ that was proposed in our previous work on Eu^2＋-Mn^2＋ co-doped phosphors, the influence of synthetic temperature and heating time on the photoluminescence（PL） behavior of M5（PO4）3Cl：Eu^2＋,Mn^2＋（M=Ca, Sr） phosphors was investigated by analyzing their PL spectra and decay curves. For the Ca phase, an increase in the synthetic temperature resulted in an increase in the loss from the ＂charge transfer process＂ since more Eu^2＋ ions were involved in the Eu^2＋-Mn^2＋ clusters. This was contrary to the thermodynamic expectation. To solve this contradiction, we proposed that the formation of Eu^2＋-Mn^2＋ clusters was kinetically blocked at lower synthetic temperatures. With an increase in heating time for the phosphors synthesized at lower temperature（such as 1100 ℃） the PL intensity decreased, which supported the above assertion.展开更多
Green emitting Eu^2＋ doped（CaxSr（1–x））6Si（25.6）Al（6.4）N（41.6）O（4.4） phosphors with x value ranging from 0 to 0.1 were synthesized by the solid state reaction method under nitrogen atmosphere.The X-ray di...Green emitting Eu^2＋ doped（CaxSr（1–x））6Si（25.6）Al（6.4）N（41.6）O（4.4） phosphors with x value ranging from 0 to 0.1 were synthesized by the solid state reaction method under nitrogen atmosphere.The X-ray diffraction（XRD）patterns of the phosphors with different Ca^2＋ concentrations indicated that pure sialon phases were obtained.Crystal structure of these sialon phases was estimated to be a commensurate composite network stacking by two different types of layers.Intense and tunable green emissions with a slight red shift from 515 to 520 nm were observed with varying Ca/Sr ratios.The emission intensity decreased gradually because of the increase of the crystal splitting effect.Thermal quenching properties of the phosphors with different Ca^2＋ saturation were also discussed.The thermal stability became worse as more Ca^2＋ ions substituted for Sr^2＋ ions according to a larger Stokes shift.The solid solution phosphors could be a promising candidate for white LEDs for their interesting photoluminescence properties when the thermal stability would be improved.展开更多
基金Project supported by the Ministry of Science and Technology of China (2006CB601104, 2008AA03A324)
文摘The (Y,Gd)BO3:Tb3+ and Li+-doped (Y,Gd)BO3:Tb3+ phosphors were prepared by high temperature solid-state method. The inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), scanning electron microscopy (SEM), and the excitation and emission spectra were used to characterize the samples. The results of ICP-AES and XRD indicated that Li+ ions could enter the (Y,Gd)BO3:Tb3+ lattice and induce the lattice expansion. It could be seen from SEM that the particles were spherical a...
基金supported by the National Natural Science Foundation of China(21371015,51304086)the National Basic Research Program of China(2014CB643801)the National High Technology Research and Development Program of China(2011AA03A101)
文摘To further understand the energy loss mechanism of the ＂charge transfer process＂ that was proposed in our previous work on Eu^2＋-Mn^2＋ co-doped phosphors, the influence of synthetic temperature and heating time on the photoluminescence（PL） behavior of M5（PO4）3Cl：Eu^2＋,Mn^2＋（M=Ca, Sr） phosphors was investigated by analyzing their PL spectra and decay curves. For the Ca phase, an increase in the synthetic temperature resulted in an increase in the loss from the ＂charge transfer process＂ since more Eu^2＋ ions were involved in the Eu^2＋-Mn^2＋ clusters. This was contrary to the thermodynamic expectation. To solve this contradiction, we proposed that the formation of Eu^2＋-Mn^2＋ clusters was kinetically blocked at lower synthetic temperatures. With an increase in heating time for the phosphors synthesized at lower temperature（such as 1100 ℃） the PL intensity decreased, which supported the above assertion.
基金Project supported by the National Key Basic Research Program of China(2014CB643801)the National Natural Science Foundation of China(51102021,51302016)
文摘Green emitting Eu^2＋ doped（CaxSr（1–x））6Si（25.6）Al（6.4）N（41.6）O（4.4） phosphors with x value ranging from 0 to 0.1 were synthesized by the solid state reaction method under nitrogen atmosphere.The X-ray diffraction（XRD）patterns of the phosphors with different Ca^2＋ concentrations indicated that pure sialon phases were obtained.Crystal structure of these sialon phases was estimated to be a commensurate composite network stacking by two different types of layers.Intense and tunable green emissions with a slight red shift from 515 to 520 nm were observed with varying Ca/Sr ratios.The emission intensity decreased gradually because of the increase of the crystal splitting effect.Thermal quenching properties of the phosphors with different Ca^2＋ saturation were also discussed.The thermal stability became worse as more Ca^2＋ ions substituted for Sr^2＋ ions according to a larger Stokes shift.The solid solution phosphors could be a promising candidate for white LEDs for their interesting photoluminescence properties when the thermal stability would be improved.
