Investigation on the amounts of Na2CO3 and sulphur to obtain pure Y2O2S and up-conversion luminescence of Y2O2S:Er

The process to prepare pure phase of hexagonal Y2O2S was investigated. Effect of mixed flux of Na2CO3 and S amounts was studied. The phase composition and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the single phase of Y2O2S with smooth morphology could not be obtained as the molar ratio of Y2O3, Na2CO3 and S was in the range of 1:(0.5-1):(2-3) until the molar ratio was increased to 1:1.5:4. Different Er3+ concentration doped Y2O2S...     

La2O2S∶Yb,Er的制备及其上转换发光性能

采用共沉淀法制备了氧化物La2O3∶Yb,Er,高温硫熔法煅烧后得到硫氧化物La2O2S∶Yb,Er颗粒,采用XRD和SEM对其晶体结构和微观形貌进行表征,利用荧光光谱仪测试其上转换发光性能.结果表明,共沉淀温度40℃、草酸过量5%、草酸浓度2.34%、pH值5.53～6.45、热处理温度800℃时可得理想La2O3∶...     

Y2O2S:Yb,Ho上转换发光材料的制备及性能

利用硫熔法制备了不同浓度的Yb和Ho掺杂的Y2O2S:Yb,Ho上转换发光材料。采用X线衍射仪、扫描电镜和荧光光谱仪对粉体的相组成、形貌和上转换发光性能进行表征。结果表明:不同浓度的Yb和Ho掺杂后没有改变Y2O2S的晶体结构;颗粒形貌较为规则,多呈现多面体状,分散性较好,颗粒表面很光滑;在980nm激光激发下,Y2O2S:Yb,Ho呈现出以绿光发射为主的上转换荧光,Yb的最佳掺杂量为8%(摩尔分数),Ho的最佳掺杂量为2%(摩尔分数),Ho3+和Yb3+掺杂浓度可显著影响不同颜色发射峰的强度;对激活离子Ho3+来说,同类离子之间发生能量传递和交叉弛豫行为,导致上转换荧光强度发生猝灭;对敏化离子Yb3+来说,Yb3+吸收能量,以热的形式释放出来,产生杂质猝灭。     

Bi2O3/ATO混烧填料的制备及其红外发射率研究

采用固相法制得了Bi2O3/ATO混烧填料.借助XRD、紫外-可见分光光度计、SEM、EDS、FT-IR以及红外辐射率仪对Bi2O3/ATO混烧填料的相组成、可见光区的反射率、形貌、元素组成、红外透过率和红外辐射率进行了表征.结果表明,实验制得的Bi2O3/ATO混烧填料具有较好的红外透明性;随着Bi2O3含量的增加,...     

白光LED用钛酸盐红色荧光粉的研究进展

钛酸盐因具有优异的化学稳定性和光学性能而成为优异的发光基质材料,综述了钛酸盐作为白光LED用红色荧光粉的国内外研究进展。分别介绍了偏钛酸盐(MTiO3)型、正钛酸盐(M2TiO4)型和其他类型的钛酸盐红色荧光粉及其制备方法,并重点介绍了其光谱调控机理。对性能较好的荧光粉进行了重点推介,对钛酸盐红色荧光粉的发展趋势做了简要展望。     

SmBO3粉体的颗粒度对其反射性能的影响

分析了SmBO3颗粒度对粉体散射作用和吸收作用的影响.激光防护功能填料对激光的散射作用主要考虑米氏散射;在激光防护功能填料质量一定的条件下,粒径越小,粒子数就越多,粒子对光的吸收截面越大,吸收系数也就越大.对于SmBO3激光防护功能填料,折射率n=1.95时,激光波长为1.06μm,散射面积比Q(γ)随粒径参数γ的函数变化关系图可以得到当X=1.771时,SmBO3的散射面积比最大,此时27πλ=1.771.即r≈298nm.所以当颗粒尺寸大约在600nm左右时,SmBO3微粒的散射消光作用最强.在1.05～1.15μm波长范围内,随着SmBO3颗粒的长大,粉体对1.06μm波长处的光的反射率有所降低,并在颗粒大小为587nm左右时达到最低值,约为0.5%.而当颗粒尺寸进一步长大时,SmBO3粉体对1.06μm波长处的光的反射率值又有所提高.当颗粒大小达到1μm左右时,SmBO3粉体对1.06μm波长处的光的反射率约0.6%.这与理论计算得出的具有最佳散射消光的SmBO3粉末的颗粒尺寸为600nm左右相一致,符合理论计算结果.激光测试也显示600nm左右的SmBO3颗粒对1.06μm激光的反射率最低,符合理论计算结果.     

钡铁氧体吸波涂层的制备及其影响因素研究

用固相法制备了W-型钡铁氧体BaZn0.6Co1.4Fe16O27粉末并用其制备了吸波涂层。通过正交实验讨论了涂层厚度、搅拌时间和铁氧体含量对涂层吸波性能的影响,并用Statistica8.0软件对涂层的最佳制备条件进行了预测。根据正交试验结果,厚度为1.81mm、铁氧体质量分数为75%、搅拌时间为0.5h的吸波涂层具有最优的吸波性能,其微波吸收值在8.2～18.0GHz频段内均高于10dB,吸收峰值在15.3GHz左右更是达到了33dB。由软件预测得到的最佳制备条件与正交实验结果相符。     

Citrate sol-gel combustion preparation and photoluminescence properties of YAG:Ce phosphors

Yellow-emitting YAG:Ce3+ nanocrystalline phosphors were prepared by citrate sol-gel combustion method using citric acid as the fuel and chelating agent. The influence of mole ratio of citric acid to metallic ions (MRCM), pH value of the solution, calcination temperature and Ce-doped concentration on the structures and properties of as-prepared powders were investigated in detail. Higher crystallinity and better luminescence performance powders were obtained at MRCM=2, pH=3 and the calcination temperature of 1200 °C. The phosphors exhibited the characteristic broadband visible luminescence of YAG:Ce. The optimum concentration of Ce3+ was 1.0 mol.%, and the concentration quenching was derived from the reciprocity between electric dipole and electric quadrupole (d-q). Especially, the pH value of the solution was a key factor to obtain a stable sol-gel system and then obtain pure and homogeneous rare earth ions doped YAG phosphors at a lower tem-perature. The Y3Al5O12:Ce0.03 phosphor with optimized synthesis-condition and composition had a similar luminescence intensity with the commercial phosphor YAG:Ce.     

白光LED用钛酸盐红色荧光粉的研究进展

钛酸盐因具有优异的化学稳定性和光学性能而成为优异的发光基质材料,综述了钛酸盐作为白光LED用红色荧光粉的国内外研究进展。分别介绍了偏钛酸盐(MTiO3)型、正钛酸盐(M2TiO4)型和其他类型的钛酸盐红色荧光粉及其制备方法,并重点介绍了其光谱调控机理。对性能较好的荧光粉进行了重点推介,对钛酸盐红色荧光粉的发展趋势做了简要展望。     

Effects of rare earth oxides on dielectric properties of Y2Ti2O7 series ceramics

A series of Y2Ti2O7 microwave dielectric ceramics were synthesized by conventional solid-state method. The effects of rare earth oxide (La2O3, CeO2, Nd2O3, Sm2O3, Eu2O3, Gd2O3 and Dy2O3) and Nd2O3 doping content on the microstructure and dielectric properties of Y2Ti2O7 ceramics were investigated. The experimental results showed that the rare earth ions were considered to dissolve in Y-sites of the pyrochlore structure, different rare earth oxides and concentration had different influences on Y2Ti2O7 cerami...