Comparison of Electron Acceleration Ability of SiO2 and ZnS from ZnS： Er Transient Electroluminescence

The acceleration ability of electrons in SiO2 and ZnS was compared through the variation of emission intensity based on ZnS ： Er electroluminescence during the reverse of polarity of sinusoidal voltage. In order to avoid the influence of work function of electrode, cathodal and anodal materials were ITO （indium tin oxide）. The ratio of maximum emission intensity under positive and negative half period is 2.18. This result demonstrates that the electron acceleration ability of SiO2 is 2.18 times stronger than that of ZnS.     

Luminescent Properties of A Novel Terbium Complex Tb（o-BBA）3（phen）

A novel rare earth complex of terbium ion with 2-benzoylbenzoic acid and 1, 10-phenathroline （Tb（o-BBA）3 （phen）, o-BBA-2-benzoylbenzoic acid, phen = 1, 10-phenathroline） was used as an electroluminescent material for the first time. The Tb complex was blended with poly（N-vinylcarbazole） （PVK） in different weight ratios and spinn to coated into films （noted as PVK ：Tb films）. The photoluminescence （PL） properties of films were investigated and the optimum weight ratio between PVK and Tb（o-BBA）3（phen） was found to be 3：1. Monolayer devices with the structure ITO/PVK： Tb/AI were fabricated and emitted green light, which was characteristic of Tb^3＋ emission. The results show that mecha- nisms for PL and EL are different. The PL is considered to be caused because of energy transfer and direct excitation to the Tb（o-BBA）3（phen） molecule, while EL is mainly on charging trapping.     

Photoluminescence study of SiO₂ coated Eu³⁺:Y₂O₃ core-shells under high pressure

Uniform core-shell Eu3+:Y2O3/SiO2 spheres were synthesized via precipitation and the Stber method.The structural transition of core-shell Eu3+:Y2O3/SiO2 was studied by using high pressure photoluminescence spectra.With pressure increasing,the emission intensities of 5D0→7F0,1,2 transitions of Eu3+ ions decreased and the transition lines showed a red shift.The relative luminescence intensity ratio of 5D0→7F2 to 5D0→7F1 transitions decreased with increasing pressure,indicating lowering asymmetry around Eu3+ ions.During compression,structural transformation for cores in the present core-shell Eu3+:Y2O3/SiO2 sample from cubic to monoclinic took place at 7.5 GPa,and then the monoclinic structure turned into hexagonal above 15.2 GPa.After the pressure was released,the hexagonal structure transformed back to monoclinic and the monoclinic structure was kept stable to ambient pressure.     

Luminescent Properties of BaMgAl10O17： Eu2＋ Phosphors Coated with Y2SiO5

BaMgAl10O17： Eu^2＋ phosphors was prepared by the solid-reaction method. Y2SiO5 was coated uniformly on the surface of phosphor by the surface-coated method, and the luminescent and deterioration properties were discussed. The XRD and SEM results show that Y2SiO5 film is produced on the surface of BAM phosphor. The emission spectrum analysis shows that the peak of the phosphor does not change after coating. The two phosphors were applied to lamps and the deterioration was tested at different ignited time. The keep ratio of luminous flux of the phosphor coated with Y2SiO5 is higher than that of the uncoated phosphor.     

Upconversion luminescence of Y2O3：Er^3＋ ,Yb^3＋ nanoparticles prepared by a homogeneous precipitation method

Y2O3： Er^3＋, Yb^3＋ nanoparticles were synthesized by a homogeneous precipitation method without and with different concentrations of EDTA 2Na. Upconversion luminescence spectra of the samples were studied under 980 nm laser excitation. The results of XRD showed that the obtained Y2O3：Er^3＋,Yb^3＋ nanoparticles were of a cubic structure. The average crystallite sizes calculated were in the range of 28-40 nm. Green and red upconversion emission were observed, and attributed to ^2H11/2,^4S3/2→^4I15/2 and ^4F9/2→^4I15/2 transitions of the ion, respectively. The ratio of the intensity of green emission to that of red emission drastically changed with a change in the EDTA 2Na concentration. In the sample synthesized without EDTA, the relative intensity of the green emission was weaker than that of the red emission. The relative intensities of green emission increased with the increased amount of EDTA 2Na used. The possible upconversion luminescence mechanisms were discussed.     

Photoluminescent properties of Ca2Gd8（SiO4）6O2： Dy^3＋ phosphor films prepared by sol-gel process

There are growing interests on phosphor thin films owing to their potential application in high-resolution devices such as cathode ray tubes and flat panel display devices. The solution-based sol-gel method is one of the most important techniques for the synthesis of various functional coating films. Compounds with the apatite structure are very suitable host lattices for various luminescent ions. Ca2RE8（SiO4）6O2 （ RE=Y, Gd, La ） is a kind of ternary rare-earth-metal silicate with oxyapatite structure, which has been used as host material for the luminescence of various rare earth and mercury-like ions. In this article, Ca2Gd8（SiO4）6O2：Dy^3＋phosphor films were dip-coated on quartz glass substrates through the sol-gel process. X-ray diffraction （XRD）, atomic force microscopy （AFM）, photoluminescence （PL） spectra, as well as lifetimes were used to characterize the resulting films. AFM study revealed that the phosphor films consisted of homogeneous particles. The Dy^3＋ showed its characteristic emission in crystalline phosphor films, i.e., ^4F9/2-^6H15/2 and ^4F9/2-^6H13/2.     

A Study on La2O3－Y2O3－Mo Secondary Emission Material

The substrate molybdenum doped with La2O3, Y2O3 cathode material was made by the powder metallurgy method. The secondary emission coefficients of the materials were tested. The experimental results show that Mo cathodes doped with La2O3, Y2O3 have good secondary emission properties. When the cathodes are activated, the maximal secondary emission coefficients of these cathodes are higher than 2.0 and can meet the practical requirement. The distribution of the rare earth in the interior and at surface of this kind of cathode material before and after emission was studied using Scanning Electronic Microscopic (SEM) and X-Ray Photoelectron Spectrum(XPS). The analysis results show that the rare earth is easy to gather at grain boundaries and the relevant concentration of rare earth on the surface after emission is obviously greater than that before emission.     

Study of Electroplex Emission from Organic Electroluminescent Devices with Rare Earth Complex

A novel organic electroluminescent device was made with the structure of ITO/PVK：Tb0.5Eu0.5（TTA）3 Dipy/ BCP/Alq3/Al（a） which utilized the rare earth complex Tb0.5Eu0.5（TTA）3 Dipy as the emitting layer. When it was driven under a direct electric field, 612 nm emission from EU^3＋ and 410 nm emission from PVK were observed. In addition, in the EL spectrum a new peak at 490 nm appeared. From the analysis of different devices, the mechanism of the new emission was studied. It was concluded that the new emission was the electroplex originating from the interface between the ligand （TTA）3Dipy and BCP.     

Promotion Effect of Lantanum ions on Co／SiO2 Catalysts Prepared via Solvated Metal Atom Impregnation Method

In order to assess the promotional effects of La^3 on CO hydrogenation of Co/SiO2 catalyst, solvated metal atom impregnation (SMAI) method was used to prepare unpromoted 10% (mass fraction) Co/SiO2 and a series of La^3 -promoted 10% (mass fraction) Co/SiO2 catalyst with different La/Co atomic ratios (0.1, 0.3, 0.5). X-ray diffraction (XRD), and CO chemisorption measurements show that the cobalt particle size decreases as the La/Co ratios increase. X-ray photoelectron spectrescopy indicates that cobalt is in zero-valent state for all the samples. Catalytic test shows that the catalytic activity of La^3 -promoted Co/SiO2 in CO hydrogenation is higher than that of unpromoted Co/SiO2, and enhances with the La/Co ratios increase. La^3 promotion also causes the enhanced selectivity of Co/SiO2 catalyst for higher hydrocarbon products.     

Measuring and Modeling of Density for Selected CaO-MgO-Al2O3-SiO2 Slag With Low Silica

 The densities of the selected quaternary CaO-MgO-Al2O3-SiO2 slag with low silica were measured by the Archimedean method in a wide temperature range from 1773 to 1873 K. Nine different slag compositions were chosen based on three different levels of CaO content and three different levels of SiO2 content. wMgO was equal to 7.0%. wCaO were varied from 40.04% to 50.64%, for wSiO2=10.25%-20.70%. The effects of temperature, SiO2 content and optical basicity were studied. It is shown that density decreases approximately linearly with an increase in temperature. Under the same CaO content, the density decreases with increasing of SiO2 content, and increases with optical basicity increasing. Based on the experimental data as the boundary of the homogenous phase region predicated by FACTSAGE software, the mass triangle model is used to calculate the density of selected limited homogenous phase region. The results showed that the mass triangle model works well.     

Comparison of Electron Acceleration Ability of SiO2 and ZnS from ZnS: Er Transient Electroluminescence

The acceleration ability of electrons in SiO2 and ZnS was compared through the variation of emission intensity based on ZnS: Er electroluminescence during the reverse of polarity of sinusoidal voltage. In order to avoid the influence of work function of electrode, cathodal and anodal materials were ITO (indium tin oxide). The ratio of maximum emission intensity under positive and negative half period is 2.18. This result demonstrates that the electron acceleration ability of SiO2 is 2.18 times stronger than that of ZnS.     

Emission Characteristics of PVK Doped TbY（o-MBA）6（phen）2 Systems

Since the pioneering work of Tang and VanSlykeon organic light emitting diodes(OLEDs)in1987,OLEDs have been particularlyinterestedin because oftheir potential applications in next-generationflat-pan-el displays and large-area flexible displays[1~3].Rareearth complex materials have been widely used incathodoluminescent display phosphor screens,lasersand lamps because their photoluminescence PL ex-hibits high quantumefficiencies and very sharp spec-tral bands.Inthe1990s,Kido et al[4~6]first…     

Photoluminescence and Electroluminescence Studies on Tb-Doped Silicon Rich Oxide Materials and Devices

Light emitting diode (LED) compatible with sili-con-based integrated circuit (IC) has been a highlydesirable candidate for optical interconnections .It isalso economically desirable to replace expensive III-VLEDs with low-cost ,silicon-based devices . Unfortu-nately,it has long been believed that crystalline sili-conis a poor light emitting material because of its na-ture of indirect bandgap . With the discovery of strongPL from porous silicon[1],the understanding of thelight emitting pr…     

Fabrication of Green Electroluminescent Devices

Ｄｉｓｐｌａｙｓｂａｓｅｄｏｎｏｒｇａｎｉｃｌｉｇｈｔｅｍｉｔｔｉｎｇｄｅｖｉｃｅｓ (ＯＬＥＤｓ)ｈａｖｅｂｅｃｏｍｅｐｏｔｅｎｔｉａｌｒｅ ｐｌａｃｅｍｅｎｔｓｏｆｌｉｑｕｉｄ ｃｒｙｓｔａｌｄｉｓｐｌａｙｓ (ＬＣＤｓ)ｄｕｅｔｏｔｈｅｉｒｗｉｄｅｖｉｅｗｉｎｇａｎｇｌｅ ,ｈｉｇｈｅｒｂｒｉｇｈｔ ｎｅｓｓ,ｅａｓｅｏｆｃｏｌｏｒｔｕｎａｂｉｌｉｔｙ ,ｆａｓｔｒｅｓｐｏｎｓｅｔｉｍｅａｎｄｌｏｗｄｒｉｖｉｎｇｖｏｌｔａｇｅ[1] .Ｔｈｅｇｒｅｅｎｏｒ ｇａｎｉｃＥＬｄｉｓｐｌａｙｕｓｉｎｇｔｒｉｓ(8 ｈ…     

Emission of Rare Earth Complex Tb0.5Eu0.5 （asprin）3phen

The coprecipitate Tho.sEuo.5(asprin)3phen was synthesized. By doping the rare earth complex into polymer PVK, the EL device was fabricated with the structure of ITO/PVK: RE/PBD/AI. Compared with the device using PVK/Eu (asprin)3phen blend as the light emitting layer, the emission of Eu^3 in the PVK/Th0.5Eu0.5(asprin)3 phen blend is great-ly enhanced along with the quenching of the emission of PVK.     

Photoluminescent properties of Ca2Gd8(SiO4)6O2: Dy3+ phosphor films prepared by sol-gel process

There are growing interests on phosphor thin films owing to their potential application in high-resolution devices such as cathode ray tubes and flat panel display devices. The solution-based sol-gel method is one of the most important techniques for the synthesis of vari-ous functional coating films. Compounds with the apatite structure are very suitable host lattices for various luminescent ions. Ca2RE8(SiO4)6O2 ( RE=Y, Gd, La ) is a kind of ternary rare-earth-metal silicate with oxyapatite structure, which has been used as host mate-rial for the luminescence of various rare earth and mercury-like ions. In this article, Ca2Gd8(SiO4)6O2:Dy3 phosphor films were dip-coated on quartz glass substrates through the sol-gel process. X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) spectra, as well as lifetimes were used to characterize the resulting films. AFM study revealed that the phosphor films consisted of homoge-neous particles. The Dy3 showed its characteristic emission in crystalline phosphor films, i.e., 4F9/2–6H15/2 and 4F9/2–6H13/2.     

Organic Light-Emitting Device Based on Terbium Complex

Organiclight emittingdevices(OLEDs)have beenattractingconsiderableinterestbecauseoftheir lowdrive voltage,potentialapplicationsinflatpanel displaysincethefirstdouble layerstructuredevice withhighefficiencyandluminancewasfabricatedby TangandVanSlykein1987[…     

Organic Light Emitting Devices Based on Terbium Complex

Rare earth complex Tb(BA)3phen was synthesized, which is first used as an emitting material in electroluminescence. The properties of monolayer device with the swing film rate of 1000 r·min-1(70 nm) and the weight ratio of 1:5(PVK:Tb(BA)3phen) are the best. And the highest brightness of this device reached 26.8 cd·cm-2 at a fixed bias of 21 V. Bright green emission could be obtained from the optimized double-layer device and the highest EL brightness of the device reached 322 cd·m-2 at the voltage of 22 V.