Single phase of Ba1-x MgAl10O17 ： x Eu^2＋ （0.02≤ x ≤ 0. 14） phosphors was first successfully prepared by coprecipitation in aqueous medium with a “reverse strike” method, using oxalic acid and ammonia together...Single phase of Ba1-x MgAl10O17 ： x Eu^2＋ （0.02≤ x ≤ 0. 14） phosphors was first successfully prepared by coprecipitation in aqueous medium with a “reverse strike” method, using oxalic acid and ammonia together as precipitants. Completely crystallized phosphors were obtained at 1300 ℃, which is 300 ℃ lower than the temperature of solid-state reaction. Their photoluminescence was investigated under UV and VUV region, respectively. The emission spectra of Ba1-x MgAl10O17：xEu^2＋ samples excited by 254 or 147 nm showed a characteristic wide band with the peak centred at about 450 454 nm. Optimum emission intensity reached at x = 0.1 and then concentration quenching occurred. The synthesized phosphor shows 10% higher emission intensity than that prepared by solid-state reaction.展开更多
Heterogeneous precipitation method was used to prepared surface coating on self-made BaMgAl10O17 : Eu phosphor. Results illustrate that the coating film can be silicon dioxide in amorphous state with 50 nm in thicknes...Heterogeneous precipitation method was used to prepared surface coating on self-made BaMgAl10O17 : Eu phosphor. Results illustrate that the coating film can be silicon dioxide in amorphous state with 50 nm in thickness. Photolumi-nescence results indicate that the coating layer presents an observable improved effect on the enhancement of thermal stability. When baked at 600℃for 1 h, the luminance of coated BAM keeps at 92% higher than that of uncoated BAM by 23% . This protective effect can be attributed to the high compact degree and uniformity of this amorphous SiO2 coating film which is served as a diffusion block layer to inbreak oxygen atom, thus releases the oxidation extent of Eu2 + effectively.展开更多
The mechanisms of thermal,ultraviolet and vacuum ultraviolet radiation degradation behaviors of the Eu2+,Mn2+ co-doped BaMgAl10O17 phosphors were investigated comparatively.The result indicated that the Mn2+ ions whic...The mechanisms of thermal,ultraviolet and vacuum ultraviolet radiation degradation behaviors of the Eu2+,Mn2+ co-doped BaMgAl10O17 phosphors were investigated comparatively.The result indicated that the Mn2+ ions which replaced the Mg2+ sites in the sample were stable and negligibly influenced by treatments.The oxidation and migration of Eu2+ ions primarily caused the thermal degradation of the sample.The vacuum ultraviolet radiation degradation was primarily because of the migration of Eu2+.The ultraviolet radiation increased traps which trended the Eu2+r to be in a metastable state,leading to the ultraviolet radiation degradation of the sample.The vacuum ultraviolet excited luminous loss of samples after ultraviolet radiation partly originated from the interruption of energy transfer from the host to activators by traps.展开更多
Ca-doped Ba Mg Al10O17：Eu2＋,Mn2＋（BAM） blue phosphors were synthesized by flux assisted solid-state reaction method using Ca F2 and Ba F2 as co-flux.Good dispersity and particle size homogenization of hexagonal pu...Ca-doped Ba Mg Al10O17：Eu2＋,Mn2＋（BAM） blue phosphors were synthesized by flux assisted solid-state reaction method using Ca F2 and Ba F2 as co-flux.Good dispersity and particle size homogenization of hexagonal pure phase BAM were obtained by sintering at 1400 ℃.The effects of the Ca2＋ ions content on the structure, morphology and photoluminescence properties of the phosphors were studied.The results indicated that the incorporation of Ca could decrease the lattice constant, improve the homogeneity and dispersity and enhance the photoluminescence（PL） intensity of the phosphor effectively.The optimum Ba0.86Ca0.04Mg0.97Al10O17：0.1Eu2＋,0.03Mn2＋ PL intensity was enhanced for about 30% and relative brightness was improved about 4%.Furthermore, the synthesized BAM and commercial BAM phosphors were annealed for 30 min at 600 oC in air.The Ca-doped phosphors had stronger emission intensity, higher brightness and better chromaticity stability than that of the commercial phosphor.These results indicated that Ca-doped blue phosphors had good potential applications in the commercial tricolor fluorescent lamps as well as in other display and lamps.展开更多
基金Project supported bythe National Natural Science Foundation of China (50272026) ,the Excellent Young Teachers ProgramofMOE,China (EYTP) and the Natural Science Foundation of Gansu Province (ZS031-A25-033-C)
文摘Single phase of Ba1-x MgAl10O17 ： x Eu^2＋ （0.02≤ x ≤ 0. 14） phosphors was first successfully prepared by coprecipitation in aqueous medium with a “reverse strike” method, using oxalic acid and ammonia together as precipitants. Completely crystallized phosphors were obtained at 1300 ℃, which is 300 ℃ lower than the temperature of solid-state reaction. Their photoluminescence was investigated under UV and VUV region, respectively. The emission spectra of Ba1-x MgAl10O17：xEu^2＋ samples excited by 254 or 147 nm showed a characteristic wide band with the peak centred at about 450 454 nm. Optimum emission intensity reached at x = 0.1 and then concentration quenching occurred. The synthesized phosphor shows 10% higher emission intensity than that prepared by solid-state reaction.
基金Project supported by Jiangsu Province High Tech Foundation (BG2002024)
文摘Heterogeneous precipitation method was used to prepared surface coating on self-made BaMgAl10O17 : Eu phosphor. Results illustrate that the coating film can be silicon dioxide in amorphous state with 50 nm in thickness. Photolumi-nescence results indicate that the coating layer presents an observable improved effect on the enhancement of thermal stability. When baked at 600℃for 1 h, the luminance of coated BAM keeps at 92% higher than that of uncoated BAM by 23% . This protective effect can be attributed to the high compact degree and uniformity of this amorphous SiO2 coating film which is served as a diffusion block layer to inbreak oxygen atom, thus releases the oxidation extent of Eu2 + effectively.
基金supported by the National Natural Science Young Foundation of China(Grant No.10904057)the Fundamental Research Funds for the Central Universities(Grant No.Lzjbky-2011-125)+1 种基金the National Science Foundation for Distinguished Young Scholars(Grant No.50925206)the National Natural Science Foundation of China(Grant No. 10874061)
文摘The mechanisms of thermal,ultraviolet and vacuum ultraviolet radiation degradation behaviors of the Eu2+,Mn2+ co-doped BaMgAl10O17 phosphors were investigated comparatively.The result indicated that the Mn2+ ions which replaced the Mg2+ sites in the sample were stable and negligibly influenced by treatments.The oxidation and migration of Eu2+ ions primarily caused the thermal degradation of the sample.The vacuum ultraviolet radiation degradation was primarily because of the migration of Eu2+.The ultraviolet radiation increased traps which trended the Eu2+r to be in a metastable state,leading to the ultraviolet radiation degradation of the sample.The vacuum ultraviolet excited luminous loss of samples after ultraviolet radiation partly originated from the interruption of energy transfer from the host to activators by traps.
基金Project supported by National Science Foundation for Distinguished Young Scholars(50925206)Gansu Provincial Science and Technology Department(041214)
文摘Ca-doped Ba Mg Al10O17：Eu2＋,Mn2＋（BAM） blue phosphors were synthesized by flux assisted solid-state reaction method using Ca F2 and Ba F2 as co-flux.Good dispersity and particle size homogenization of hexagonal pure phase BAM were obtained by sintering at 1400 ℃.The effects of the Ca2＋ ions content on the structure, morphology and photoluminescence properties of the phosphors were studied.The results indicated that the incorporation of Ca could decrease the lattice constant, improve the homogeneity and dispersity and enhance the photoluminescence（PL） intensity of the phosphor effectively.The optimum Ba0.86Ca0.04Mg0.97Al10O17：0.1Eu2＋,0.03Mn2＋ PL intensity was enhanced for about 30% and relative brightness was improved about 4%.Furthermore, the synthesized BAM and commercial BAM phosphors were annealed for 30 min at 600 oC in air.The Ca-doped phosphors had stronger emission intensity, higher brightness and better chromaticity stability than that of the commercial phosphor.These results indicated that Ca-doped blue phosphors had good potential applications in the commercial tricolor fluorescent lamps as well as in other display and lamps.
