The designed Ce^3＋-doped alkaline-earth silicate phosphors CamSr2 m-nBanSiO4：Ce^3＋,Li^＋ （CSBS：Ce^3＋） were synthesized by a high temperature solid-state reaction. The crystal field splitting and the centroid sh...The designed Ce^3＋-doped alkaline-earth silicate phosphors CamSr2 m-nBanSiO4：Ce^3＋,Li^＋ （CSBS：Ce^3＋） were synthesized by a high temperature solid-state reaction. The crystal field splitting and the centroid shift from the flee ion energy of 5d configuration were approximated from the spectrum for Ca2SiO4, Sr2SiO4 and Ba2SiO4 phosphors. The single-phase purity was checked by means of X-ray diffraction. Here, when the doped concentration of Ca2. is less than 80% （m 〈 1.6）, we report the structural phase transformation from monoclinic system [3-Ca2Si04 to orthorhombic system α′-Ca2SiO4. The phosphors excited by near-ultraviolet （NUV） light at wavelengths ranging from 200 to 400 nm demonstrate a broad asymmetric blue emission band. The emission peak wavelength redshifts firstly from 417 nm of Ca2SiO4 to 438 nm of Sro.3Cal.6SiO4, and then blueshifts to 411 nm of Sr2SiO4, and the end of 401 nm of Ba2SiOa. These results indicate that the tunable blue-emission of the phosphors can he realized through changing the solid solution components, which has a potential use as a blue component for fabricated precision modulation LEDs light sources and auxiliaries of SSC plastics films for different plant growths. We discuss in detail the possible mechanism and energy diagram of the tunable blue luminescence in CamSr2-M-nBaNSiO4：Ce^3＋.Li^＋ phosphors.展开更多
为了研究随着三元碱土离子配比变化其正硅酸盐物相组成、发光性能的变化规律,优选高效荧光粉,同时探讨单相区和混合相区发光性能的变化内在机制,建立组分-结构-发光性能关联,本文采用高温固相法制备(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.0...为了研究随着三元碱土离子配比变化其正硅酸盐物相组成、发光性能的变化规律,优选高效荧光粉,同时探讨单相区和混合相区发光性能的变化内在机制,建立组分-结构-发光性能关联,本文采用高温固相法制备(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu系列荧光粉,共计44个样,分析其二元、三元物相组成和光谱,得出其物相组成和紫外激发发光CIE值。实验表明,(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu体系中物相组成随着组元含量存在渐变性;富Ba端形成了Ba 2SiO 4相单相区(Sr最大量含量为35%、Mg为30%),单相区随着Sr 2+、Mg 2+固溶,晶格常数减小,结晶度提高。(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu荧光粉在紫外激发下其颜色和亮度随着组元含量也呈现渐变性,Ba 2SiO 4相单相区荧光粉均为绿色荧光粉且随着Sr 2+、Mg 2+固溶荧光亮度逐渐增大(精细光谱表明单相区内Mg 2+、Sr 2+离子有促进Eu 2+离子进入高发光效率的格位的效果);Mg 2SiO 4-Sr 2SiO 4二元系列为红色荧光粉;单相区外的样品点随着Ba 2+的减少,荧光粉紫外激发荧光颜色逐渐由绿变红(混合物相中Eu离子配位空间逐渐减小,Eu离子逐渐以Eu 3+离子形式存在)。(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu系列荧光粉的相组成、结构及发光性能随组元呈现渐变性关系,借鉴相图建立方法,可建立三元色像图(由样品发射光谱得出的CIE色像点,基于散点分布建立色像图);利用三元色像图可系统性优选高效荧光粉(优选出最佳绿色和红色荧光粉样品点为:(Mg 0.3 Ba 0.65 Sr 0.05)1.95 SiO 4∶0.05Eu和(Mg 0.65 Sr 0.35)1.95 SiO 4∶0.05Eu)。展开更多
Using natural mineral wollastonite, talc and quartz sands as raw materials, rare earth oxides (La2O3, Nd2O3 and Y2O3) as additives, the bio-soluble alkaline earth silicate fibers were prepared by melting and blowing p...Using natural mineral wollastonite, talc and quartz sands as raw materials, rare earth oxides (La2O3, Nd2O3 and Y2O3) as additives, the bio-soluble alkaline earth silicate fibers were prepared by melting and blowing process. The viscosity of the molten ma-terials, bio-solubility and crystallization behavior of the fiber were investigated. The results indicated that the fiber drawing tempera-ture range could be broadened since the slope of the temperature-viscosity curve decreased with adding rare earth oxide. The addition of rare earth oxide was beneficial to the increase of crystallization temperature by strengthening the network structure of the fiber. The existence of rare earth oxide in the fibers would reduce the solubility of the fibers, which still belonged to bio-soluble fibers.展开更多
基金Project supported by National Key Research and Development Program(2016YFB0302403)the National Natural Science Foundation of China(21571059)+1 种基金Natural Science Foundation of Hunan Province(2015JJ2100)Hunan Provincial Innovation Foundation for Postgraduate(CX2017B180)
文摘The designed Ce^3＋-doped alkaline-earth silicate phosphors CamSr2 m-nBanSiO4：Ce^3＋,Li^＋ （CSBS：Ce^3＋） were synthesized by a high temperature solid-state reaction. The crystal field splitting and the centroid shift from the flee ion energy of 5d configuration were approximated from the spectrum for Ca2SiO4, Sr2SiO4 and Ba2SiO4 phosphors. The single-phase purity was checked by means of X-ray diffraction. Here, when the doped concentration of Ca2. is less than 80% （m 〈 1.6）, we report the structural phase transformation from monoclinic system [3-Ca2Si04 to orthorhombic system α′-Ca2SiO4. The phosphors excited by near-ultraviolet （NUV） light at wavelengths ranging from 200 to 400 nm demonstrate a broad asymmetric blue emission band. The emission peak wavelength redshifts firstly from 417 nm of Ca2SiO4 to 438 nm of Sro.3Cal.6SiO4, and then blueshifts to 411 nm of Sr2SiO4, and the end of 401 nm of Ba2SiOa. These results indicate that the tunable blue-emission of the phosphors can he realized through changing the solid solution components, which has a potential use as a blue component for fabricated precision modulation LEDs light sources and auxiliaries of SSC plastics films for different plant growths. We discuss in detail the possible mechanism and energy diagram of the tunable blue luminescence in CamSr2-M-nBaNSiO4：Ce^3＋.Li^＋ phosphors.
文摘为了研究随着三元碱土离子配比变化其正硅酸盐物相组成、发光性能的变化规律,优选高效荧光粉,同时探讨单相区和混合相区发光性能的变化内在机制,建立组分-结构-发光性能关联,本文采用高温固相法制备(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu系列荧光粉,共计44个样,分析其二元、三元物相组成和光谱,得出其物相组成和紫外激发发光CIE值。实验表明,(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu体系中物相组成随着组元含量存在渐变性;富Ba端形成了Ba 2SiO 4相单相区(Sr最大量含量为35%、Mg为30%),单相区随着Sr 2+、Mg 2+固溶,晶格常数减小,结晶度提高。(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu荧光粉在紫外激发下其颜色和亮度随着组元含量也呈现渐变性,Ba 2SiO 4相单相区荧光粉均为绿色荧光粉且随着Sr 2+、Mg 2+固溶荧光亮度逐渐增大(精细光谱表明单相区内Mg 2+、Sr 2+离子有促进Eu 2+离子进入高发光效率的格位的效果);Mg 2SiO 4-Sr 2SiO 4二元系列为红色荧光粉;单相区外的样品点随着Ba 2+的减少,荧光粉紫外激发荧光颜色逐渐由绿变红(混合物相中Eu离子配位空间逐渐减小,Eu离子逐渐以Eu 3+离子形式存在)。(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu系列荧光粉的相组成、结构及发光性能随组元呈现渐变性关系,借鉴相图建立方法,可建立三元色像图(由样品发射光谱得出的CIE色像点,基于散点分布建立色像图);利用三元色像图可系统性优选高效荧光粉(优选出最佳绿色和红色荧光粉样品点为:(Mg 0.3 Ba 0.65 Sr 0.05)1.95 SiO 4∶0.05Eu和(Mg 0.65 Sr 0.35)1.95 SiO 4∶0.05Eu)。
基金supported by the National Basic Research Program of China(973 Program)(2014CB660802)the National Natural Science Foundation of China(51474166)Natural Science Foundation of Hubei Province(2012FFA102)
文摘Using natural mineral wollastonite, talc and quartz sands as raw materials, rare earth oxides (La2O3, Nd2O3 and Y2O3) as additives, the bio-soluble alkaline earth silicate fibers were prepared by melting and blowing process. The viscosity of the molten ma-terials, bio-solubility and crystallization behavior of the fiber were investigated. The results indicated that the fiber drawing tempera-ture range could be broadened since the slope of the temperature-viscosity curve decreased with adding rare earth oxide. The addition of rare earth oxide was beneficial to the increase of crystallization temperature by strengthening the network structure of the fiber. The existence of rare earth oxide in the fibers would reduce the solubility of the fibers, which still belonged to bio-soluble fibers.
