A series of alkaline earth sulfides based phosphors Ca_ 0.8 Sr_ 0.2 S∶Eu 2+ ,Tm 3+ were covered with a layer of protective coating with alkaline earth fluorides by heating the mixture of phosphor and NH_4HF_2...A series of alkaline earth sulfides based phosphors Ca_ 0.8 Sr_ 0.2 S∶Eu 2+ ,Tm 3+ were covered with a layer of protective coating with alkaline earth fluorides by heating the mixture of phosphor and NH_4HF_2 at elevated temperatures. The coatings were characterized by means of XRD and SEM. The optical properties of the coated phosphors and the influences of the coating on their properties have been discussed extensively. The stabilities of the coated and uncoated phosphors have been compared.展开更多
Carbonate coprecipitate precursors were prepared by mixed nitrate solutions containing M2+(M2+=Sr2+,Ba2+),Y3+ and Er3+ as the cation sources and(NH4)2CO3 as the precipitator.MY2S4:Er3+ phosphors were synthesized by ca...Carbonate coprecipitate precursors were prepared by mixed nitrate solutions containing M2+(M2+=Sr2+,Ba2+),Y3+ and Er3+ as the cation sources and(NH4)2CO3 as the precipitator.MY2S4:Er3+ phosphors were synthesized by calcining the carbonate precursors with CS2 as the sulfurization reagent at 1050 ℃ for 4 h.XRD patterns show that the synthesized SrY2S4 and BaY2S4 crystalline powders possess the orthorhombic [CaFe2O4]-type structure.Photoluminescent measurements indicate that there were mainly red emitting(4F9/2→4I15/2) and green emitting(2H11/2→4I15/2 and 4S3/2→4I15/2) of Er3+ in the SrY2S4 while there was only red emitting(4F9/2→4I15/2) in BaY2S4:Er3+.BaY2S4:Er3+ is considered as a novel red phosphor candidate with a high monochromaticity.展开更多
文摘A series of alkaline earth sulfides based phosphors Ca_ 0.8 Sr_ 0.2 S∶Eu 2+ ,Tm 3+ were covered with a layer of protective coating with alkaline earth fluorides by heating the mixture of phosphor and NH_4HF_2 at elevated temperatures. The coatings were characterized by means of XRD and SEM. The optical properties of the coated phosphors and the influences of the coating on their properties have been discussed extensively. The stabilities of the coated and uncoated phosphors have been compared.
文摘Carbonate coprecipitate precursors were prepared by mixed nitrate solutions containing M2+(M2+=Sr2+,Ba2+),Y3+ and Er3+ as the cation sources and(NH4)2CO3 as the precipitator.MY2S4:Er3+ phosphors were synthesized by calcining the carbonate precursors with CS2 as the sulfurization reagent at 1050 ℃ for 4 h.XRD patterns show that the synthesized SrY2S4 and BaY2S4 crystalline powders possess the orthorhombic [CaFe2O4]-type structure.Photoluminescent measurements indicate that there were mainly red emitting(4F9/2→4I15/2) and green emitting(2H11/2→4I15/2 and 4S3/2→4I15/2) of Er3+ in the SrY2S4 while there was only red emitting(4F9/2→4I15/2) in BaY2S4:Er3+.BaY2S4:Er3+ is considered as a novel red phosphor candidate with a high monochromaticity.
