Y3Al5O12∶Eu nanophosphors were synthesized by a gel combustion method. The structure of phosphors was characterized by XRD and FTIR. YAG phase came to occur when YAG∶Eu precursors were sintered at 800 ℃, although t...Y3Al5O12∶Eu nanophosphors were synthesized by a gel combustion method. The structure of phosphors was characterized by XRD and FTIR. YAG phase came to occur when YAG∶Eu precursors were sintered at 800 ℃, although the phase was mainly amorphous. The organic groups pyrolyzed completely and pure YAG phase was obtained in the samples sintered at 900 ℃. In the formation of YAG phase, no intermediate phases such as YAP and YAM were detected. Both 5D0 → 7F1 orange and 5D0 → 7F2 red emission could be observed for all the sintered samples. However, the emission of amorphous samples was greatly different from that of crystalline ones. The former was mainly 5D0 → 7F2 red emission, but the latter was 5D0 → 7F1 orange emission. As sintering temperature rises, the ratio of orange to red for phosphors increases. Eu could be doped up to 8% in YAG host lattice, and fluorescence quenching was absent. It indicated that the gel combustion synthesis method can increase emission intensity and quenching concentration due to a good distribution of Eu3+ activators in Y3Al5O12 matrix.展开更多
Cerium and europium codoped yttrium aluminum garnet（YAG：Ce,Eu） nanophosphors were prepared by sol-gel method.We systematically explored the structure,composition,morphology and photoluminescence（PL） properties by...Cerium and europium codoped yttrium aluminum garnet（YAG：Ce,Eu） nanophosphors were prepared by sol-gel method.We systematically explored the structure,composition,morphology and photoluminescence（PL） properties by using X-ray diffraction,scanning electron microscope,high resolution transmission electron microscope,energy dispersive spectrometer,photoluminescence emission and excitation spectra techniques,and focused on clarifying the change of local structure surrounding Ce^3＋ ions by utilizing advanced quantitative ^27Al magic angle spinning nuclear magnetic resonance spectroscopy.The results show that the lattice constant slightly increases as the Ce^3＋ and Eu^3＋ ions incorporate,and the geometric distortion of local structure surrounding Ce^（3＋） activator introduced by the incorporated Eu^（3＋） coactivator causes the variation of crystal field,which results in red shift of Ce^3＋ PL emitting in YAG：Ce,Eu nanophosphor.Furthermore,the YAG：Ce,Eu nanophosphors could exhibit several sharp and narrow ^5D0 → ^7FJ（J = 1-4） emissions of Eu^3＋ ion besides the classic broad ^5d1 → ^4f（^2F（5/2）,^2F（7/2）） emissions of Ce^3＋ ion under near ultraviolet（UV） excitation.展开更多
Eu-doped Ce:YAG single crystal(SC) was fabricated by the Czochralski method. The crystal structure,optical and photoelectric property of the constructed w-LED was investigated. The XRD and HRTEM results show that YAG ...Eu-doped Ce:YAG single crystal(SC) was fabricated by the Czochralski method. The crystal structure,optical and photoelectric property of the constructed w-LED was investigated. The XRD and HRTEM results show that YAG crystal structure has little change when Eu^(3+), Ce^(3+) are doped. Absorption spectra and photoluminescence spectra show that the Ce,Eu:YAG single crystal can effectively absorb the 460 nm blue light to form a broadband emission center at 530 nm, decay curves of the crystal show that the energy transfer between Ce^(3+) and Eu^(3+) is highly suppressed. Compared with commercial Ce:YAG phosphor, Ce,Eu:YAG exhibits better thermal stability.展开更多
A novel technique for YAG:Ln(Ln=Eu,Ce) phosphor powder synthesis with a nanocrystalline structure was developed.Nanocrystalline YAG:Ln powder was prepared by an ultrasonic atomization and co-precipitation method using...A novel technique for YAG:Ln(Ln=Eu,Ce) phosphor powder synthesis with a nanocrystalline structure was developed.Nanocrystalline YAG:Ln powder was prepared by an ultrasonic atomization and co-precipitation method using a mixture solution of ammonium hydroxide(NH3·H2O) and ammonium hydrogen carbonate(NH4HCO3) as precipitant.The as-prepared nano-powders were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and fluorescence spectrometer.The obtained phosphor powders were homogenous and in size of 50-70 nm.The results demonstrated that by using ultrasonic atomization and co-precipitation process,we could synthesize a good quality YAG:Ln(Ln=Eu,Ce) phosphor powder that had many potential applications.展开更多
文摘Y3Al5O12∶Eu nanophosphors were synthesized by a gel combustion method. The structure of phosphors was characterized by XRD and FTIR. YAG phase came to occur when YAG∶Eu precursors were sintered at 800 ℃, although the phase was mainly amorphous. The organic groups pyrolyzed completely and pure YAG phase was obtained in the samples sintered at 900 ℃. In the formation of YAG phase, no intermediate phases such as YAP and YAM were detected. Both 5D0 → 7F1 orange and 5D0 → 7F2 red emission could be observed for all the sintered samples. However, the emission of amorphous samples was greatly different from that of crystalline ones. The former was mainly 5D0 → 7F2 red emission, but the latter was 5D0 → 7F1 orange emission. As sintering temperature rises, the ratio of orange to red for phosphors increases. Eu could be doped up to 8% in YAG host lattice, and fluorescence quenching was absent. It indicated that the gel combustion synthesis method can increase emission intensity and quenching concentration due to a good distribution of Eu3+ activators in Y3Al5O12 matrix.
基金Financial support from the NNSF of China(No.51171007 and 51271009)
文摘Cerium and europium codoped yttrium aluminum garnet（YAG：Ce,Eu） nanophosphors were prepared by sol-gel method.We systematically explored the structure,composition,morphology and photoluminescence（PL） properties by using X-ray diffraction,scanning electron microscope,high resolution transmission electron microscope,energy dispersive spectrometer,photoluminescence emission and excitation spectra techniques,and focused on clarifying the change of local structure surrounding Ce^3＋ ions by utilizing advanced quantitative ^27Al magic angle spinning nuclear magnetic resonance spectroscopy.The results show that the lattice constant slightly increases as the Ce^3＋ and Eu^3＋ ions incorporate,and the geometric distortion of local structure surrounding Ce^（3＋） activator introduced by the incorporated Eu^（3＋） coactivator causes the variation of crystal field,which results in red shift of Ce^3＋ PL emitting in YAG：Ce,Eu nanophosphor.Furthermore,the YAG：Ce,Eu nanophosphors could exhibit several sharp and narrow ^5D0 → ^7FJ（J = 1-4） emissions of Eu^3＋ ion besides the classic broad ^5d1 → ^4f（^2F（5/2）,^2F（7/2）） emissions of Ce^3＋ ion under near ultraviolet（UV） excitation.
基金Project supported by the National Natural Science Foundation of China(51372172,51672192)
文摘Eu-doped Ce:YAG single crystal(SC) was fabricated by the Czochralski method. The crystal structure,optical and photoelectric property of the constructed w-LED was investigated. The XRD and HRTEM results show that YAG crystal structure has little change when Eu^(3+), Ce^(3+) are doped. Absorption spectra and photoluminescence spectra show that the Ce,Eu:YAG single crystal can effectively absorb the 460 nm blue light to form a broadband emission center at 530 nm, decay curves of the crystal show that the energy transfer between Ce^(3+) and Eu^(3+) is highly suppressed. Compared with commercial Ce:YAG phosphor, Ce,Eu:YAG exhibits better thermal stability.
基金Project supported by the National Science Foundation of China (60777030, 50972061)the Natural Science Foundation for Distinguished Young Scientists of Zhejiang Province (R4100364)+1 种基金the Natural Science Foundation of Ningbo City (2009A610007,2010A610185)K.C. Wong Magna Fund in Ningbo University
文摘A novel technique for YAG:Ln(Ln=Eu,Ce) phosphor powder synthesis with a nanocrystalline structure was developed.Nanocrystalline YAG:Ln powder was prepared by an ultrasonic atomization and co-precipitation method using a mixture solution of ammonium hydroxide(NH3·H2O) and ammonium hydrogen carbonate(NH4HCO3) as precipitant.The as-prepared nano-powders were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),and fluorescence spectrometer.The obtained phosphor powders were homogenous and in size of 50-70 nm.The results demonstrated that by using ultrasonic atomization and co-precipitation process,we could synthesize a good quality YAG:Ln(Ln=Eu,Ce) phosphor powder that had many potential applications.
