SrCeO3:Sm3+红色发光粉的制备及发光性能

采用溶胶-凝胶法合成了SrCeO3∶Sm3+红色荧光粉,用XRD、SEM、FL分析表征了样品的结构、形貌及发光性能。研究了助熔剂H3BO3对其发光性能的影响。结果表明:样品为具有正交晶系结构的SrCeO3晶型,呈椭球型结构。荧光光谱测试结果表明:Sm3+掺杂的SrCeO3在紫外波段有两个吸收带,一是峰值位于320 nm左右的宽吸收带,归属于Ce4+→O2-的电荷迁移带,另一个为峰值位于408 nm的锐线吸收带,对应于Sm3+的6H5/2→4L13/2跃迁吸收;在波长408 nm的激发下,样品发红光,发射主峰位于601 nm,对应于Sm3+的4G5/2→6H7/2跃迁。样品的发光强度随着Sm3+和助熔剂H3BO3加入量的增加先增强,后减弱。当Sm3+的掺杂量为3mol%,H3BO3加入量为0.5 mol%时,发光强度最大。     

Eu3+掺杂双钙钛矿Sr2CaMoO6橙红色荧光粉的结构特征及其发光性能

采用EDTA-柠檬酸联合配位法制备一系列组成的(Sr1-xEux)2CaMoO6橙红色荧光粉。通过X射线衍射、拉曼光谱、扫描电镜及荧光光谱研究不同Eu3+离子掺杂浓度下Sr2CaMoO6∶Eu3+荧光粉的晶体结构、掺杂位置、形貌及其光致发光性能。Rietveld全谱拟合结果表明:掺杂后样品为(Ca/Mo)O6八面体少量倾斜的空间群为P21/n的正交双钙钛矿结构,随着Eu3+离子共掺杂浓度的增加,样品的晶胞体积减小;Eu3+离子取代八面体间隙的Sr2+位置致使双钙钛矿的T2g(1)拉曼振动模发生蓝移;在近紫外区宽而强电荷迁移带和蓝光激发下,该荧光粉分别发射以Eu3+离子5D0-7F1磁偶极跃迁为主的橙光和以5D0-7F2电偶极跃迁为主的红光,组成为(Sr0.98Eu0.02)2CaMoO6的荧光粉具有最强的橙红光发射强度,是一种潜在的适用于近紫外LED芯片的光转换红光材料。     

Nanocrystalline RE2O3:Tm3+ (RE: Gd3+, Y3+) Blue Phosphors Synthesized via the Combustion Method

This work reports on the preparation of a luminescent blue-emitting rare earth (RE) Tm-doped oxide phosphor. Nanocrystalline RE2O3:Tm3+ particles were prepared via the combustion method using citric acid, glycine, or urea as fuels. Samples were doped with different percentages of the activator Tm3+. The post-annealing treatment was performed in air for all the samples, at temperatures ranging from 800 to 1100 degrees C, for 4 h. The samples were characterized by X-ray diffraction (XRD), photoluminescence spectroscopy (PL) and scanning electron and transmission microscopies (SEM and TEM) in order to determine the best synthetic procedure. The post-annealed powders showed blue emission with maximum at 452 nm characteristics for Tm3+ transition 1D2 --> 3H4 (under UV excitation at 360 nm). Samples, presented a tri-dimensional porous structure (50-200 nm) formed of spheroid particles with a diameter between 20 and 60 nm. The best luminescent material was obtained when urea was used to prepare nanoparticles of Gd2O3 doped with 0.5% Tm3+, and 1100 degrees C was used as the post-annealing temperature.     

四[4,4'-双(4",4",4"-三氟代-1",3"-二氧代丁基)邻三联苯]双核铕配合物的发光及其在发光二极管中的应用

合成了一个双核铕的配合物,[HN(CH3CH2)3]2[Eu2(bdb)4]·CH3CH2OH,{H2bdb=4,4'-双(4",4",4"-三氟代-1",3"-二氧代丁基)邻三联苯}.该配合物在紫外和近紫外光激发下发出铕离子特征红光.配合物中三价铕离子的5D0激发态寿命为704μs,寿命曲线很好地和单指数衰减拟合曲线相吻合.监控614nm的红光发射,激发光谱位于250～420nm范围.在395nm处具有很强的激发强度,该配合物能够被395nm发射的InGaN芯片发出的近紫外光激发而发红光.变温光致发光测定表明,该配合物的温度淬灭效应很小.当温度升高到200℃,依然发射出很强的红光.配合物热稳定性达到260℃.发光性质和热稳定性满足制备LED器件的要求.将该配合物与395nm发射的InGaN芯片组合制备了红色发光二极管,当配合物和硅树脂的质量比为1:20,工作电流为20mA时,红色发光二极管的色坐标为x=0.61,y=0.31,发光效率为3.64lm/W.将该配合物与发蓝绿光的二-2-(2'-羟基苯基)苯并噻唑锌混合涂布在395nm发射的InGaN芯片上制备成了白光发光二极管,合适的质量比为铕配合物:锌配合物:硅树脂=1:1:25.工作电流为20mA时,色坐标x=0.32,y=0.32;色温Tc=6026K;显色指数Ra=81;发光效率为1.26lm/W.结果表明,该配合物是制备半导体高显色指数白光LED的一种红光材料.     

双四甲基铵四[4,4'-双(4",4",4"-三氟代-1",3"-二氧代丁基)联苯]双核铕(Ⅲ)配合物的合成及发光

合成了新配合物[N(CH_3)_4]_2[Eu_2(btb)_4](H_2btb=4,4'-双(4",4",4",-三氟代-1",3"-二氧代丁基)联苯).通过元素分析、红外光谱、紫外光谱对配合物的结构予以表征.在近紫外激发下,该配合物发射出强的铕离子特征红光.监控614nm的发射光,其激发光谱在391nm处具有很强的激发强度,能够被InGaN芯片发射光有效激发而发红光.将该配合物与395 nm发射的InGaN芯片组合制成了红色发光二极管,当配合物和硅树脂的质量比为1:30时,红色发光二极管的色坐标为x=0.6214,y=0.3159,器件的发光效率为0.59 lm·w~(-1).结果表明,配合物[N(CH_3)_4]_2[Eu_2(btb)_4]是制作白光二极管可供选用的红色发光材料.     

新型植物补光用远红光 (La,Gd,Y)2 MgTiO6:Cr3+荧光粉的光谱调控

Cr3+激活荧光粉因其具有远红光和近红外光发射的特性而受到广泛关注.本研究合成了一系列(La,Gd,Y)2MgTiO6:Cr3+荧光粉,在345 nm紫外光激发下,其发射波段为700～900 nm.采用离子取代策略对其光谱进行了调谐,通过Gd或Y取代La位点,发射主峰从766 nm分别蓝移至737 nm和757 nm;...     

Synthesis and luminescence properties of SrAl2O4:Eu,Dy nanosheets

We report an effective method to synthesize SrAl₂O₄:Eu²⁺,Dy³⁺ nanosheets. Sheet-like precursors were firstly synthesized by the solvothermal method, and acetate was used as the raw material. Then the final products were obtained by calcinating the precursor in a weak reductive atmosphere of H₂. The crystal structure and particle morphology were investigated by X-ray diffraction (XRD) patterns, field-emission scanning electron microscopy and transmission electron microscopy (FE-SEM and TEM) , respectively. A possible growth mechanism was proposed to reveal the formation process. Luminescence properties of the SrAl₂O₄:Eu²⁺,Dy³⁺ long-lasting phosphor were analyzed by measuring the excitation spectra, the emission spectra, the afterglow decay curve and the thermoluminescence curve. Both the photoluminescence (PL) spectra and luminance decay revealed that the phosphors had efficient luminescent and long lasting properties compared with the phosphors prepared by using nitrates as the raw material. Furthermore, the photoluminescence intensity was even a little higher than commercial phosphors.     

Na2CaSiO4∶RE3+(RE=Ce3+,Tb3+,Eu3+) 的制备及发光特性

采用高温固相法,合成了三价稀土离子(RE³⁺=Ce³⁺, Tb³⁺, Eu³⁺)掺杂的Na₂CaSiO₄(NCS)系列样品,并研究了其在紫外光激发下的发光特性。研究结果表明,Ce³⁺、Tb³⁺ 和Eu³⁺掺杂的NSC系列样品在紫外光源激发下,均呈现其特征发射,随着掺杂浓度的提高,发射强度逐渐增大。Ce³⁺、Tb³⁺和Eu³⁺的最佳摩尔分数分别为0.13、0.13和0.12,相应的色坐标分别计算为(0.17, 0.17)、(0.34, 0.58)和(0.66, 0.34),分别为很好的蓝光、绿光和红光。继续增加稀土离子的含量,发射强度降低。     

Ba3Ga(PO4)3:Dy3+荧光粉阴极射线发光研究

本文研究了采用高温固相法合成的Ba3Gd(PO4)3:Dy3 荧光粉的阴极射线发光特性.测试并比较了电子轰击前后荧光粉的CL谱、色坐标以及PL谱变化.Ba3Gd(PO4)3:0.06Dy3 荧光粉的色坐标为 x=0.454,y=0.424,Tc=2889.3 K.测试结果显示该荧光粉是一种低色温、暖白光荧光粉,并且具有高的饱和电流,有耐大电流密度电子束轰击的能力.     

碱金属和三价Eu离子共掺杂的碱土钼酸盐荧光粉发光性能

采用固相法制备了用于白光LED的Eu3+和碱土离子(Li+,Na+,K+)共激活的钼酸盐荧光粉AMoO4(A=Ca,Sr).通过X射线衍射图片看出,Eu3+和Na+的掺入降低了晶格参数,同时衍射峰强度明显增加.本文研究了荧光粉的激发光谱和发射光谱.它的激发谱覆盖了从240nm到500nm的范围,在470nm处有一个激发峰,这说明它能够被GaN LED发出的蓝光有效激发.发射谱表明它能够发射峰值位于616nm和624nm的红光.实验研究了碱土离子的量(摩尔分数)对AMoO4:Eu3+发光性能的影响,0.25是最合适的掺杂量.反应时间和反应温度对发光性能也有很大的影响.搅拌均匀的反应物在800℃灼烧3h得到的样品发光强度最强.