The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence propert...The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence properties and the drift of chromaticity coordinates(CIE) of the(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors and the color conversion glass ceramics were studied in the sintering temperature range from 600℃ to 800℃. The luminous intensity and internal quantum yield(QY) of the blue-green phosphors and glass ceramics decreased with the sintering temperature increasing. When the sintering temperature increased beyond 750℃, the phosphors and the color conversion glass ceramics almost had no peak in photoluminescence(PL) and excitation(PLE) spectra. The results showed that the blue-green phosphors had poor thermal stability at higher temperature. The lattice structure of the phosphors was destroyed by the glass matrix and the Ce^3+ in the phosphors was oxidized to Ce^4+, which further caused a decrease in luminescent properties of the color conversion glass ceramics.展开更多
Synthesis of oxynitride solid solutions CaAl4-xSixO7-xNx:Eu2+ (x = 0 - 4) was attempted by the solid state reaction (SSR) methods using Si3N4 and AlN as nitrogen sources. The Ca3Al8Si4O17N4 (x = 4/3) sample with the h...Synthesis of oxynitride solid solutions CaAl4-xSixO7-xNx:Eu2+ (x = 0 - 4) was attempted by the solid state reaction (SSR) methods using Si3N4 and AlN as nitrogen sources. The Ca3Al8Si4O17N4 (x = 4/3) sample with the high phase purity was obtained when AlN was used as a nitrogen source whereas the sample synthesized using Si3N4 as another nitrogen source contained a Ca2Al2SiO7 impurity. Thus, it was revealed that AlN was a preferable nitrogen source for the synthesis of Ca3Al8Si4O17N4 by the SSR method. The solid solutions around x = 4/3 activated with Eu2+ exhibited bluish-green luminescence with emission maxima at 480 nm by the excitation at 250 - 450 nm. Thus, the CaAl4-xSixO7-xNx: Eu2+ solid solutions especially for Ca3Al8Si4O17N4:Eu2+ (x = 4/3) were developed as novel展开更多
A series of Eu3＋ and Dy3＋ doped/co-doped as well as un-doped BaB2Si2Os phosphors were synthesized via solid state reaction method. The PL result showed typical blue and green emission from Dy3＋ and red emission fro...A series of Eu3＋ and Dy3＋ doped/co-doped as well as un-doped BaB2Si2Os phosphors were synthesized via solid state reaction method. The PL result showed typical blue and green emission from Dy3＋ and red emission from Eu3＋. The f-f transitions in- volving the lanthanide ions along with dopant site occupancy were discussed thoroughly. Phonon assisted energy transfer process was observed from Eu3＋ to Dy3＋, which enhanced the emissions of Dy3＋. Combinations of the emissions from Eu3＋ and Dy3＋ showed a possible white to red tuneable emission on the CIE diagram. The white warmth emissions of the phosphor were revealed to be ad- justable through designing the dopant concentration and excitation wavelengths. An unusual energy transfer that originated from Eu3＋ to Dy3＋ was also discovered and the energy transfer mechanism was discussed. Proposed energy transfer mechanism was investigated using luminescence decay lifetime. All the phosphor exhibited efficient excitation in the UV range which matched well with the emissions from GaN-based LED chips. This presented the BaB2Si208 phosphor as a promising candidate for white LED applications. The effects of doping on the structural properties and the optical band gap of BaB2Si208 phosphor were also discussed in this study.展开更多
基金Project supported by the Science and Technology Planning Project of Zhejiang Province,China(Grant No.2018C01046)Enterprise-funded Latitudinal Research Projects,China(Grant Nos.J2016-141,J2017-171,J2017-293,and J2017-243)
文摘The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence properties and the drift of chromaticity coordinates(CIE) of the(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors and the color conversion glass ceramics were studied in the sintering temperature range from 600℃ to 800℃. The luminous intensity and internal quantum yield(QY) of the blue-green phosphors and glass ceramics decreased with the sintering temperature increasing. When the sintering temperature increased beyond 750℃, the phosphors and the color conversion glass ceramics almost had no peak in photoluminescence(PL) and excitation(PLE) spectra. The results showed that the blue-green phosphors had poor thermal stability at higher temperature. The lattice structure of the phosphors was destroyed by the glass matrix and the Ce^3+ in the phosphors was oxidized to Ce^4+, which further caused a decrease in luminescent properties of the color conversion glass ceramics.
文摘Synthesis of oxynitride solid solutions CaAl4-xSixO7-xNx:Eu2+ (x = 0 - 4) was attempted by the solid state reaction (SSR) methods using Si3N4 and AlN as nitrogen sources. The Ca3Al8Si4O17N4 (x = 4/3) sample with the high phase purity was obtained when AlN was used as a nitrogen source whereas the sample synthesized using Si3N4 as another nitrogen source contained a Ca2Al2SiO7 impurity. Thus, it was revealed that AlN was a preferable nitrogen source for the synthesis of Ca3Al8Si4O17N4 by the SSR method. The solid solutions around x = 4/3 activated with Eu2+ exhibited bluish-green luminescence with emission maxima at 480 nm by the excitation at 250 - 450 nm. Thus, the CaAl4-xSixO7-xNx: Eu2+ solid solutions especially for Ca3Al8Si4O17N4:Eu2+ (x = 4/3) were developed as novel
基金supported by Fundamental Research Grant Scheme of Malaysia(J130000.2526.03H97)the National Natural Science Foundation of China(51372142)
文摘A series of Eu3＋ and Dy3＋ doped/co-doped as well as un-doped BaB2Si2Os phosphors were synthesized via solid state reaction method. The PL result showed typical blue and green emission from Dy3＋ and red emission from Eu3＋. The f-f transitions in- volving the lanthanide ions along with dopant site occupancy were discussed thoroughly. Phonon assisted energy transfer process was observed from Eu3＋ to Dy3＋, which enhanced the emissions of Dy3＋. Combinations of the emissions from Eu3＋ and Dy3＋ showed a possible white to red tuneable emission on the CIE diagram. The white warmth emissions of the phosphor were revealed to be ad- justable through designing the dopant concentration and excitation wavelengths. An unusual energy transfer that originated from Eu3＋ to Dy3＋ was also discovered and the energy transfer mechanism was discussed. Proposed energy transfer mechanism was investigated using luminescence decay lifetime. All the phosphor exhibited efficient excitation in the UV range which matched well with the emissions from GaN-based LED chips. This presented the BaB2Si208 phosphor as a promising candidate for white LED applications. The effects of doping on the structural properties and the optical band gap of BaB2Si208 phosphor were also discussed in this study.
