Synthesis and Fluorescence of Europium-Doped Barium Fluoride Cubic Nanocolumns

Europium-doped barium fluoride cubic nanocolumns were synthesized from the quaternary water in oil reverse microemulsions. In this process, the aqueous cores of water/cetyl trimethyl ammonium bromide (CTAB)/n-butanol/n-oe-tane reverse mieroemulsions were used as mieroreaetors for the precipitation of europium doped barium fluoride. XRD analysis shows that under the dopant concentration of 0.06% (molar fraction), the products are single phase. The result products are cubic column-like with about 30 - 50 nm edge length of cross section, and about 200 nm of length obtained from the transmission electron microscopy (TEM), and atomic force microscopy (AFM). Under the 0.06% (molar fraction) of dopant concentration, the fluorescence of Eu^2 and Eu^3 under the 589 of excitation wavelength is observed.     

Eu~2 在BaF_2—2RF_3(R=La、Gd、Lu和Y)与MF_2—LuF_3(M=Ca、Sr和Ba)体系中的光谱结构

本文考察了Eu~(2 )在BaF_2—2RF_3(R=La、Gd、Lu和Y)体系中的光谱结构。实验发现,室温下Eu~(2 )在BaF_2—2LaF_3与BaF_2—2GdF_3体系中只有宽带的f—d跃迁发射。而在BaF_2—2LuF_3和BaF_2—2YF_3体系中除了有宽带的f—d跃迁发射之外,在3600nm附近还有f—f跃迁的尖峰发射。认为这是由于晶场强度不同造成的。比较了Eu~(2 )在MF_2—LuF_3(M=Ca、Sr、Ba)体系中的光谱特性。指出,随着碱土金属离子半径增大,电负性变小,晶场强度则减弱。室温下只观察到Eu~(2 )在BaF_2—LuF_3体系中的尖峰结构。     

LaF3:Ce3+荧光特性的研究

LaF3：Ce多晶中Ce^3 的荧光发射谱由双峰带结构组成。Ce^3 与其他稀土粒子共掺杂，Ce^3 发射强度均降低，原因是一部分稀土离子(如Eu^3 等)与Ce^3 产生了电子转移；一部分稀土离子(如Er^3 等)与Ce^3 产生了能量传递。     

Long-Lasting Properties of Rare Earth-Doped Y2O2S Phosphors

The aim of this presentation is to report a new result of afterglow materials. The Y2O2S:Ln^3 (Ln = Sm, Tm)phosphors show bright reddish orange and orange-yellow colors when excited by UV or visible light. The main spectroscopic characterizations of Sm^3 and Tm^3 in yttrium oxysulfide and their long-lasting phosphorescence were measured and discussed in this presentation. Their long-lasting phosphorescence can be seen by the naked eyes clearly for about one hour in the dark room after the irradiation light sources were removed. XRD and photoluminescence (PL) spectra as well as the luminance decay were used to characterize these long-lasting phosphorescence phosphors. The results of XRD indicate that the products synthesized through the flux fusion method under 1050℃ for 6 h have a good crystallization without any detectable amount of impurity phase. Both the PL spectra and luminance decay results reveal that these phosphors have efficient luminescent and good long-lasting properties. We believe that the experimental data gathered in our present work will be useful in finding some new long-lasting phosphors with different colors.     

Luminescence Properties of Rare Earth Ions in Cadmium Metasilicate

The luminescence properties of CdSiO3:RE^3 phosphors doped with various rare earth ions are reported. The series of rare earth ions doped CdSiO3 phosphors are prepared by the conventional high-temperature solid-state method, and characterized by XRD and photoluminescence (PL) spectra. The results of XRD measurement indicate that the products fired under 1050 ~C for 3 h have a good crystallization without any detectable amount of impure phase. The PL spectra measurement results show that CdSiO3 is a novel self-activated luminescent matrix. When rare earth ions such as Y^3 ,La^3 , Gd^3 , Lu^3 , Ce^3 , Nd^3 , Ho^3 , Er^3 , Tm^3 and Yb^3 are introduced into the CdSiO3 host, one broadband centered at about 420 nm resulted from traps can be observed. In the case of other earth ions which show emissions at the visible spectrum region, such as Pr^3 , Sm^3 , Eu^3 , Tb^3 and Dy3 , the mixture of their characteristic line emissions with the ～420 nm strong broadband luminescence results in various emitting colors. As a consequence, different emitting colors can be attairied via introducing certain appropriate active ions into the CdSiO3 matrix. In additional, this kind of phosphors shows good long-lasting properties when excited by UV light. All the results show that CdSiO3 is a potential luminance matrix.