Undoped and Eu3+-doped Sr2CeO4 luminescent materials were prepared by sol-gel method. The structure and uncommon photoluminescence of Sr2CeO4∶Eu3+ phosphors were investigated in detail by powder X-ray diffraction (XR...Undoped and Eu3+-doped Sr2CeO4 luminescent materials were prepared by sol-gel method. The structure and uncommon photoluminescence of Sr2CeO4∶Eu3+ phosphors were investigated in detail by powder X-ray diffraction (XRD), Raman spectrum, and photoluminescence spectrum, respectively. The XRD results demonstrate that the as-prepared Sr2CeO4 phosphor is single phase and well crystallized. For Sr2CeO4∶Eu3+ phosphor, its excitation spectrum consists of a broad intense band from host and Eu3+-O2-charge transfer and a number of small peaks from Eu3+ ion. The broad emission band originated from Sr2CeO4 host and Eu3+ emission lines in the blue, green, and red regions coexist. Not only the characteristic transition lines from the lowest excited 5D0 level of Eu3+ but also those from higher energy levels 5DJ (J=1, 2) of Eu3+ ions are observed. These unusual luminescence properties result from the low vibration energy of Sr2CeO4 host-lattice and different energy transfer process from host to activator.展开更多
Superfine Sr2CeO4:RE3+ (RE=Eu, Sm) phosphors were synthesized at relatively low temperature by a modified sol-gel method using nitrates as raw materials, ethylenediaminetetraacetic acid (EDTA) as complexing agent. Sin...Superfine Sr2CeO4:RE3+ (RE=Eu, Sm) phosphors were synthesized at relatively low temperature by a modified sol-gel method using nitrates as raw materials, ethylenediaminetetraacetic acid (EDTA) as complexing agent. Single phase phosphors could be obtained at calcination temperature above 800 °C and pH value higher than 6.4 of initial solution. The as-prepared powders consisted of uniform crotch-like grains. The preparation process was monitored by thermogravimetric and differential thermal analysis (TG-DTA) ...展开更多
A novel, high-temperature, mechano-chemical（HTMC） method was developed to synthesise singlephase Sr_2CeO_4：Eu^（3＋）phosphor. Phosphors were characterised by X-ray diffraction（XRD）, scanning electron microscopy...A novel, high-temperature, mechano-chemical（HTMC） method was developed to synthesise singlephase Sr_2CeO_4：Eu^（3＋）phosphor. Phosphors were characterised by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and luminescence spectra. Compared with phosphors prepared by the traditional hightemperature solid state method and citric acid gel method, single-phase Sr_2CeO_4：Eu^（3＋）powders by using the HTMC method, with small average particle sizes of about 5 μm, a narrow size distribution range and uniform dispersion, were prepared at 800 ℃, and reached their maximum luminescent intensity at 900 ℃.Under ultraviolet excitation at 298 nm, the sample showed good luminescence with the strongest red light of 616 nm. However, Sr_2CeO_4：Eu^（3＋）was prepared at the higher temperature of 1100 ℃ by solid state method and citric acid gel method. The particle size was too large and uneven with phosphor agglomeration by high-temperature solid state method. The luminescent intensity reached a maximum for Sr_2CeO_4：Eu^（3＋）phosphor at a synthesis temperature of 1100 ℃ by using the high-temperature solid state method, and at 1200 ℃ by both citric acid gel and chemical precipitation methods. Furthermore, the advantages of the Sr_2CeO_4：Eu^（3＋）powder prepared by HTMC method were discussed compared with that prepared using traditional high-temperature solid state and citric acid gel methods.展开更多
基金Project supported bythe JSTUFoundation of Science Research (KYY05039)
文摘Undoped and Eu3+-doped Sr2CeO4 luminescent materials were prepared by sol-gel method. The structure and uncommon photoluminescence of Sr2CeO4∶Eu3+ phosphors were investigated in detail by powder X-ray diffraction (XRD), Raman spectrum, and photoluminescence spectrum, respectively. The XRD results demonstrate that the as-prepared Sr2CeO4 phosphor is single phase and well crystallized. For Sr2CeO4∶Eu3+ phosphor, its excitation spectrum consists of a broad intense band from host and Eu3+-O2-charge transfer and a number of small peaks from Eu3+ ion. The broad emission band originated from Sr2CeO4 host and Eu3+ emission lines in the blue, green, and red regions coexist. Not only the characteristic transition lines from the lowest excited 5D0 level of Eu3+ but also those from higher energy levels 5DJ (J=1, 2) of Eu3+ ions are observed. These unusual luminescence properties result from the low vibration energy of Sr2CeO4 host-lattice and different energy transfer process from host to activator.
基金Project supported by the National Natural Science Foundation of China (10776014)High-Tech Foundation of Jiangsu Province (BG2007047)
文摘Superfine Sr2CeO4:RE3+ (RE=Eu, Sm) phosphors were synthesized at relatively low temperature by a modified sol-gel method using nitrates as raw materials, ethylenediaminetetraacetic acid (EDTA) as complexing agent. Single phase phosphors could be obtained at calcination temperature above 800 °C and pH value higher than 6.4 of initial solution. The as-prepared powders consisted of uniform crotch-like grains. The preparation process was monitored by thermogravimetric and differential thermal analysis (TG-DTA) ...
文摘A novel, high-temperature, mechano-chemical（HTMC） method was developed to synthesise singlephase Sr_2CeO_4：Eu^（3＋）phosphor. Phosphors were characterised by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and luminescence spectra. Compared with phosphors prepared by the traditional hightemperature solid state method and citric acid gel method, single-phase Sr_2CeO_4：Eu^（3＋）powders by using the HTMC method, with small average particle sizes of about 5 μm, a narrow size distribution range and uniform dispersion, were prepared at 800 ℃, and reached their maximum luminescent intensity at 900 ℃.Under ultraviolet excitation at 298 nm, the sample showed good luminescence with the strongest red light of 616 nm. However, Sr_2CeO_4：Eu^（3＋）was prepared at the higher temperature of 1100 ℃ by solid state method and citric acid gel method. The particle size was too large and uneven with phosphor agglomeration by high-temperature solid state method. The luminescent intensity reached a maximum for Sr_2CeO_4：Eu^（3＋）phosphor at a synthesis temperature of 1100 ℃ by using the high-temperature solid state method, and at 1200 ℃ by both citric acid gel and chemical precipitation methods. Furthermore, the advantages of the Sr_2CeO_4：Eu^（3＋）powder prepared by HTMC method were discussed compared with that prepared using traditional high-temperature solid state and citric acid gel methods.
