La0.75NbO4:Eu3+0.25 and La0.65NbO4:Eu3+0.25,Bi3+0.10 phosphors were synthesized by solid-state reaction method,and their photoluminescence properties were discussed in detail.With the increased incorporation of the co...La0.75NbO4:Eu3+0.25 and La0.65NbO4:Eu3+0.25,Bi3+0.10 phosphors were synthesized by solid-state reaction method,and their photoluminescence properties were discussed in detail.With the increased incorporation of the co-activator Bi3+,the charge transfer(CT) bands of Nb5+→O2-and Eu3+→O2-(-280 nm) weakened and a new and significant broad band Bi3+-O2-(-330 nm) appeared,while the peaks at 395 and 466 nm assigned to f-f transitions of Eu3+ was slightly changed.Compared with the commercial phosphor Y2O2S:0.05Eu3+...展开更多
To date,most current reports on the development and optimization of artificial lighting sources have focused on the energy performance levels and limited color qualities of white light-emitting diodes(LEDs).However,th...To date,most current reports on the development and optimization of artificial lighting sources have focused on the energy performance levels and limited color qualities of white light-emitting diodes(LEDs).However,these properties are insufficient in terms of representing all performance levels required when adjusting white LEDs for healthy and smart lighting.Here,we introduce essential and advanced figures of merit pertaining to circadian performance as well as vision performance and color quality.We compare all possible properties of commercialized artificial lighting,daylight and four-package white LEDs which consist of long-wavelength pass dichroic filter(LPDF)-capped,phosphor-converted red,amber and green LEDs(pc-LEDs)and a blue LED.We show that these tunable four-package white LEDs produce a tunable circadian effect for melatonin suppression/secretion,a high color quality for color perception/reproduction,high efficiency for energy savings and tunable figures of merit for the smart LED lighting market.展开更多
A series of red phosphors Eu3＋-doped MMgP2O7（M=Ca,Sr,Ba） were synthesized by solid-state reaction method.X-ray powder diffraction（XRD） analysis confirmed the formation of pure CaMgP2O7,SrMgP2O7 and BaMgP2O7 phase...A series of red phosphors Eu3＋-doped MMgP2O7（M=Ca,Sr,Ba） were synthesized by solid-state reaction method.X-ray powder diffraction（XRD） analysis confirmed the formation of pure CaMgP2O7,SrMgP2O7 and BaMgP2O7 phase.Photoluminescence spectra of MMgP2O7（M=Ca,Sr,Ba）：Eu3＋ phosphors showed a strong excitation peak at around 400 nm,which was coupled with the characteristic emission（350-400 nm） from UV light-emitting diode.The CaMgP2O7：Eu3＋,SrMgP2O7：Eu3＋ and BaMgP2O7：Eu3＋ phosphors showed strong emission bands peaking at 612,593 and 587 nm,respectively.Due to the difference of the ion sizes between Ba2＋（0.142 nm）,Sr2＋（0.126 nm）,Ca2＋（0.112 nm）,Mg2＋（0.072 nm） and Eu3＋（0.107 nm）,Eu3＋ ions were expected to substitute for different sites in CaMgP2O7,SrMgP2O7 and BaMgP2O7 lattice.展开更多
基金supported by the Science Foundation of Guangxi Province (0731014)Innovation Project of Guangxi Graduate Education (105930903025)the Large-Scale Instrument of Guangxi Cooperates and Shares the Network (496-2007-075)
文摘La0.75NbO4:Eu3+0.25 and La0.65NbO4:Eu3+0.25,Bi3+0.10 phosphors were synthesized by solid-state reaction method,and their photoluminescence properties were discussed in detail.With the increased incorporation of the co-activator Bi3+,the charge transfer(CT) bands of Nb5+→O2-and Eu3+→O2-(-280 nm) weakened and a new and significant broad band Bi3+-O2-(-330 nm) appeared,while the peaks at 395 and 466 nm assigned to f-f transitions of Eu3+ was slightly changed.Compared with the commercial phosphor Y2O2S:0.05Eu3+...
基金This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)(No.2011-0017449).
文摘To date,most current reports on the development and optimization of artificial lighting sources have focused on the energy performance levels and limited color qualities of white light-emitting diodes(LEDs).However,these properties are insufficient in terms of representing all performance levels required when adjusting white LEDs for healthy and smart lighting.Here,we introduce essential and advanced figures of merit pertaining to circadian performance as well as vision performance and color quality.We compare all possible properties of commercialized artificial lighting,daylight and four-package white LEDs which consist of long-wavelength pass dichroic filter(LPDF)-capped,phosphor-converted red,amber and green LEDs(pc-LEDs)and a blue LED.We show that these tunable four-package white LEDs produce a tunable circadian effect for melatonin suppression/secretion,a high color quality for color perception/reproduction,high efficiency for energy savings and tunable figures of merit for the smart LED lighting market.
基金Project supported by National Natural Science Foundation of China (61066006)Natural Science Foundation of Guangxi Province (2011GXNSFA018054)
文摘A series of red phosphors Eu3＋-doped MMgP2O7（M=Ca,Sr,Ba） were synthesized by solid-state reaction method.X-ray powder diffraction（XRD） analysis confirmed the formation of pure CaMgP2O7,SrMgP2O7 and BaMgP2O7 phase.Photoluminescence spectra of MMgP2O7（M=Ca,Sr,Ba）：Eu3＋ phosphors showed a strong excitation peak at around 400 nm,which was coupled with the characteristic emission（350-400 nm） from UV light-emitting diode.The CaMgP2O7：Eu3＋,SrMgP2O7：Eu3＋ and BaMgP2O7：Eu3＋ phosphors showed strong emission bands peaking at 612,593 and 587 nm,respectively.Due to the difference of the ion sizes between Ba2＋（0.142 nm）,Sr2＋（0.126 nm）,Ca2＋（0.112 nm）,Mg2＋（0.072 nm） and Eu3＋（0.107 nm）,Eu3＋ ions were expected to substitute for different sites in CaMgP2O7,SrMgP2O7 and BaMgP2O7 lattice.
