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研究了2.45 GHz微波灼烧(Ba,Sr)3MgSi2O8:Eu2+,Mn2+荧光粉的非热效应对Mn2+离子660 nm红光发射强度的影响。在相同的加热温度条件下,增加微波场的输出功率,微波非热效应导致Eu2+离子蓝光的跃迁概率增加,Eu2+通过(Ba,Sr)3MgSi2O8基质晶格把能量传递给Mn2+,进而使Mn2+的跃迁概率增加,导致红光发射增强。提出了一种微波场非热效应对能量传递影响的新观点,认为在微波加热过程中强微波磁场可能会对像Mn2+这样具有顺磁性的激活剂离子的能级结构和能量传递性质产生干扰作用。 相似文献
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Microwave-promoted pure host phase for red emission CaS:Eu2+ phosphor from single CaSO4 precursor and the photoluminescence property 下载免费PDF全文
We report a novel approach to obtaining a classical blue-green excitable CaS:Eu2+ phosphor with desired red emission by microwave (MW) firing procedure in the absence of adding elemental sulphur. The disturbing effect of MW electro- magnetic field on decomposition of CaSO4 into CaS activated by europium is distinctly observed to give pure host phase without adding any elemental sulphur and carbon. The host phase evolution is observed to be highly dependent on the variation of applied MW power from X-ray diffraction (XRD) patterns and the corresponding photoluminescence (PL), and a maximum PL intensity at 1100 W of MW power is acquired for the obtained purer host phase. The non-thermal and non-equilibrium effects by MW are revealed to correlate with the interaction between polar structure of the host and applied electromagnetic field. The results demonstrate an optional procedure to prepare this red-emitting phosphor in an effective, environment-friendly and scalable approach for phosphor production in the application of bio-illumination for plant cultivation and artificial photosynthesis. 相似文献
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采用AlOOH/Sr(NO3)2/SiO2/Eu复合胶体喷雾工艺制备了D50=3.83μm球形Sr2Al2SiO7:Eu2 梯次结构荧光粉.复合胶体喷雾过程形成雾滴,雾滴中纳米粒子组分在表面张力及毛细管力作用下自组装形成梯次结构干凝胶粉.干凝胶粉经1300 ℃灼烧得到梯次结构Sr2Al2SiO7:Eu2 荧光粉.X射线衍射(XRD)分析及晶格常量计算结果表明,Eu2 离子部分取代Sr2 格位进入Sr2Al2SiO7晶格.Sr2Al2SiO7:Eu2 荧光体激发谱由峰值位于326 nm附近的宽带构成,属于Eu2 的4f→5d跃迁吸收带;发射光谱峰值波长位于约500 nm处,属于Eu2 离子4f65d到4f7跃迁导致的宽带发射. 相似文献
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采用工业频率为2.45 GHz的高温微波法制备了纯基质相的CaS∶Eu2+红色发光材料,激发波段为410~580 nm,发射峰值波长为654 nm。在微波输入功率为1.0~1.1 k W的条件下,可以获得纯基质相CaS∶Eu2+发光材料;在1.2~1.3 k W功率范围,获得的样品中含有Ca O杂质相,且颗粒团聚严重。其中,1.1 k W制备的CaS∶Eu2+样品相纯度最高,发光性能最优。微波功率的变化本质上揭示了固体颗粒的介电损耗因子及其加热特性的变化,体系涉及的非平衡反应机制促使了纯基质相的形成,并影响材料晶相结构、粒径、形貌和发光性能。结果显示,高温微波制备技术通过控制输入功率及其物料的介电损耗性质,能够获得纯基质相并且颗粒小、团聚少的荧光粉。 相似文献
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We report a newly found strong disturbing effect orAl addition to the intensity ratios of blue and green emissions from single host full-colour phosphor of Ba3MgSi2-xAlxO8:0.02Eu^2+, 0.1Mn^2+ for near-UV excited white light. The phase-pure silicate phosphor in the size of around 4μm is prepared by salt-assisted spray pyrolysis route, having three-colour emissions at the wavelength peak values of 437nm, 500 nm and 608 nm simultaneously under the excitation of 375 nm. The amount variation orAl ion added to the phosphor host results in a drastic change of the intensity ratio between green and blue emissions, while the intensity of red light keeps unchanged. As a consequence, the combination of three colours lies in the white light region and can be tuned by precisely controlled addition oral content. The Raman spectroscopy verifies the modifying effect oral ion to the tetrahedral network in silicate hosts. We assume that by addition of Al ion, the amount of those two kinds of Eu^2+ substituting for those two kinds of Ba^2+ lattice sites with distinct energy levels of blue and green featured emissions can be adjusted to contribute to diversification of the ratios of blue and green emissions. 相似文献
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研究了Eu3+离子对拟薄水铝石高温相变及微结构的影响。XRD及热分析结果表明,拟薄水铝石在560,882及1224℃分别经历-γAlOOH→-γAl2O3,γ-Al2O3→-θAl2O3和-θAl2O3→-αAl2O3相变。Eu3+掺杂后-γAlOOH→-γAl2O3相变温度不变,-γAl2O3→-θAl2O3和-θAl2O3→-αAl2O3相变温度分别提高到1054和1237℃。晶胞体积增大及衍射峰2θ值减小说明Eu3+离子以部分离子取代的形式进入-γAl2O3及-θAl2O3晶格。Eu3+离子进入晶格抑制了γ-Al2O3及-θAl2O3晶粒生长速率。-θAl2O3→-αAl2O3相变过程中Eu3+离子随Al3+一起迁移,并与Al3+离子及O2-离子形成了一个新生化合物相EuAl12O19。分析认为,该化合物在-αAl2O3晶界间存在,阻碍了-θAl2O3→-αAl2O3相转变过程中离子扩散速率,使-θAl2O3→-αAl2O3相变活化能由822.0提高到1063.15 kJ.mol-1。Eu3+离子掺杂使-θAl2O3→-αAl2O3相变过程由形核控制转变为表面扩散控制。 相似文献
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Color-converted remote phosphor prototype of multiwavelength excitable borosilicate glass for white light-emitting diodes 下载免费PDF全文
We report a unique red light-emitting Eu-doped borosilicate glass to convert color for warm white light-emitting diodes. This glass can be excited by from 394 nm-peaked near ultraviolet light, 466 nm-peaked blue light, to 534 nm-peaked green light to emit desired red light with an excellent transmission in the wavelength range of 400-700 nm which makes this glass suitable for the color conversion without great cost of luminous power loss. In particular, assembling this glass to commercial white light-emitting diodes, the tested results show that the color rendering index is improved to 84 with a loss of luminous power by 12 percent at average, making this variety of glass promising for inorganic "remote-phosphor" color conversion. 相似文献
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锶铝比对稀土掺杂铝酸锶物相及发光性能的影响 总被引:8,自引:2,他引:8
用拟薄水铝石溶胶凝胶法成功制备了SrAl2O4:Eu^2 ,Dy^3 长余辉发光材料,样品无需球磨。XRD结果表明:当锶铝摩尔比Sr/Al>0.3时,发光基质主相为SrAl2O4,杂质相为Sr4Al2O7,Sr/Al比值继续降低至0.25,发光相则以Sr4Al14O25为主,此时杂质相中含有Sr4Al2O7和Dy4Al2O9。Sr4Al2O7相对SrAl2O4:Eu^3 ,Dy^3 的发光性能影响很大,而对Sr4Al14O25:Eu^2 ,Dy^3 的发光性能影响不大。Dy4Al2O9对SrAl2O4和Sr4Al14O25发光主相的发光性能影响都不大。光谱检测结果表明SrAl2O4:Eu^2 ,Dy^3 发光光谱是中心位于520nm的带状谱。余辉检测结果表明发光主相为SrAl2O4和Sr4Al14O25时,光衰曲线符合I=ct^-n规律,n值分别为n=1.081和n=1.079。 相似文献