As an Hg-free lamp using phosphor, the Bi^3＋ and EH^3＋ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum ultraviolet（VUV） excitation were investigated. The VUV photoluminescent ...As an Hg-free lamp using phosphor, the Bi^3＋ and EH^3＋ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum ultraviolet（VUV） excitation were investigated. The VUV photoluminescent intensity of Y2O2S：Eu^3＋ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S：Eu^3＋,Bi^3＋ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S：Eu^3＋,Bi^3＋ at 147 nm is mainly because the Bi^3＋ acts as a medium and effectively performs the energy transfer process： Y^3＋-O^2-→Bi^3＋→Eu^3＋, while the intense emission band at 172 nm is attributed to the absorption of the characteristic ^1So-^1P1 transition of Bi^3＋ and the direct energy transfer from Bi^3＋ to Eu^3＋. The Y2O2S：Eu^3＋,Bi^3＋ shows excellent VUV optical properties compared with the commercial （Y,Gd）BO3：Eu^3＋. Thus, the Y2O2S：Eu^3＋,Bi^3＋ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.展开更多
Y0.75-xGdxAl0.10BO3：Eu0.10^3＋,0.05R^3＋（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 Y^3＋ ions by Sc^3＋...Y0.75-xGdxAl0.10BO3：Eu0.10^3＋,0.05R^3＋（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 Y^3＋ ions by Sc^3＋ （or Bi^3＋）and Gd^3＋ ions in （Y,Al）BO3：Eu,the intensities of emission at 254 and 147 nm are remarkably improved, because Sc^3＋ inos can absorb UV light and transfer the energy to Eu^3＋ ions efficiently. Moreover, Gd^3＋ and Bi^3＋ ions act as an intermediate ＂bridge＂ between the sensitizer and the activator （Eu^3＋） in energy transfer to produce light in the （Y, Gd）BO3：Bi^3＋, Eu^3＋ system more effectively. After doping an appropriate concentration of Gd^3＋ into Y0.50Gd0.25Al0.10BO3：Eu0.01^3＋,Bi0.05^3＋,the emission intensity reaches its maximum, which is nearly 110% compared with the red commercial phosphor （Y,Gd）BO3：Eu and better chromaticity coordinates （0.650, 0.350） are obtained.展开更多
Mn^3＋ and Bi^3＋ co-doped Y6WO12 samples with hexagonal structure were synthesized via an improved salt pyrogenation method at a temperature region of 700-1100 ℃ for 3 h. In Y6WO12, Mn^3＋, substituting y^3＋, occup...Mn^3＋ and Bi^3＋ co-doped Y6WO12 samples with hexagonal structure were synthesized via an improved salt pyrogenation method at a temperature region of 700-1100 ℃ for 3 h. In Y6WO12, Mn^3＋, substituting y^3＋, occupies a seven-coordination site and its energy levels are treated in near Oh symmetry. The samples doped by Mn^3＋ alone emit the most intensive blue light at 420 nm under excitation at 247 nm due to charge transition （CT）. The mechanism of sensitization of Bi^3＋ for Y6WO12：Mn^3＋ was also analyzed by taking account of metal-to-metal chargetransfer （MMCT） from Bi^3＋ to Mn^3＋. As a consequence, the phosphor Y6WO12：Mn^3＋/Bi^3＋ can emit blue light under radiation of 370 nm, and the emission intensity is enhanced about five times by the sensitizer Bi^3＋. The optimal doping concentration of Bi^3＋ is determined as 1 at% for the emission at 420 nm in Y6WO12：0.5 at% Mn^3＋ phosphors.展开更多
基金Supported by the Project of the Combination of Industry and Research by the Ministry of Education of China and Guang-dong Province, China(No.0712226100023)
文摘As an Hg-free lamp using phosphor, the Bi^3＋ and EH^3＋ co-doped Y2O2S phosphors were prepared and their luminescence properties under vacuum ultraviolet（VUV） excitation were investigated. The VUV photoluminescent intensity of Y2O2S：Eu^3＋ was weak, however, considerably stronger red emission at 626 nm with good color purity was observed in Y2O2S：Eu^3＋,Bi^3＋ systems. Investigation on the photoluminescence reveals that the strong VUV luminescence of Y2O2S：Eu^3＋,Bi^3＋ at 147 nm is mainly because the Bi^3＋ acts as a medium and effectively performs the energy transfer process： Y^3＋-O^2-→Bi^3＋→Eu^3＋, while the intense emission band at 172 nm is attributed to the absorption of the characteristic ^1So-^1P1 transition of Bi^3＋ and the direct energy transfer from Bi^3＋ to Eu^3＋. The Y2O2S：Eu^3＋,Bi^3＋ shows excellent VUV optical properties compared with the commercial （Y,Gd）BO3：Eu^3＋. Thus, the Y2O2S：Eu^3＋,Bi^3＋ can be a potential red VUV-excited candidate applied in Hg-free lamps for backlight of liquid crystal display.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10874061)the Doctoral Program Foundation of Institutions of Higher Education of China (Grant No. 20040730019)the Project of the Combination of Industry and Research by the Ministry of Education and Guangdong Province of China (Grant No. 0712226100023)
文摘Y0.75-xGdxAl0.10BO3：Eu0.10^3＋,0.05R^3＋（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 Y^3＋ ions by Sc^3＋ （or Bi^3＋）and Gd^3＋ ions in （Y,Al）BO3：Eu,the intensities of emission at 254 and 147 nm are remarkably improved, because Sc^3＋ inos can absorb UV light and transfer the energy to Eu^3＋ ions efficiently. Moreover, Gd^3＋ and Bi^3＋ ions act as an intermediate ＂bridge＂ between the sensitizer and the activator （Eu^3＋） in energy transfer to produce light in the （Y, Gd）BO3：Bi^3＋, Eu^3＋ system more effectively. After doping an appropriate concentration of Gd^3＋ into Y0.50Gd0.25Al0.10BO3：Eu0.01^3＋,Bi0.05^3＋,the emission intensity reaches its maximum, which is nearly 110% compared with the red commercial phosphor （Y,Gd）BO3：Eu and better chromaticity coordinates （0.650, 0.350） are obtained.
基金financially supported by the National Natural Science Foundation of China (Nos. 51401130 and 51704064)Program for Liaoning Innovative Research Team in University (No. LT2015020)+2 种基金Hebei Province Higher Education Science and Technology Research Project (No. ZD2017309)Scientific and Technological Research and Development Plan of Qinhuangdao City (No. 201701B063)Northeastern University at Qinhuangdao Campus Research Fund (No. XNK201602)
文摘Mn^3＋ and Bi^3＋ co-doped Y6WO12 samples with hexagonal structure were synthesized via an improved salt pyrogenation method at a temperature region of 700-1100 ℃ for 3 h. In Y6WO12, Mn^3＋, substituting y^3＋, occupies a seven-coordination site and its energy levels are treated in near Oh symmetry. The samples doped by Mn^3＋ alone emit the most intensive blue light at 420 nm under excitation at 247 nm due to charge transition （CT）. The mechanism of sensitization of Bi^3＋ for Y6WO12：Mn^3＋ was also analyzed by taking account of metal-to-metal chargetransfer （MMCT） from Bi^3＋ to Mn^3＋. As a consequence, the phosphor Y6WO12：Mn^3＋/Bi^3＋ can emit blue light under radiation of 370 nm, and the emission intensity is enhanced about five times by the sensitizer Bi^3＋. The optimal doping concentration of Bi^3＋ is determined as 1 at% for the emission at 420 nm in Y6WO12：0.5 at% Mn^3＋ phosphors.
