Advanced Materials Research Vols. 557-559

Abstract: Study on phosphor materials is the key for the development of solid-state lighting, especially finding alternative red phosphor for white light emitting diodes (LEDs). In this paper, a novel Eu³⁺-doped (Sr_0.68Ba_0.3)₄Al₂O₇ red phosphor was synthesized by solid-state reaction, and its photoluminescent property was measured by fluorescence spectrophotometer. The effect of Eu³⁺ doping concentration on photoluminescent property of (Sr_0.68Ba_0.3)₄Al₂O₇ was investigated, and the optimum concentration of Eu³⁺ was found to be 4mol%. XRD patterns indicated that all the peaks of (Sr_0.68Ba_0.3)₄Al₂O₇:Eu³⁺ could be attributed to the Sr₄Al₂O₇ phase and the luminescence intensity increased with the increase of temperature.

Abstract: Labeling cardiovascular drugs probes with a fluorescent tag is an alternative method of measuring drugs activities and distributions in vivo, and further using of advanced tools to diagnose or detect cardiovascular diseases. Using this approach, a fluorescent probe (betahistine-Flu, 1) of Betahistine-based was synthesized and characterized by 1H NMR, 13C NMR and LC-MS, and its UV-Vis absorption spectral and fluorescence spectral, and fluorescence imaging in cell model were investigated. It was found that the fluorescent probe display strong green fluorescence, and have good optical effect in cell. This study reveals a good and interesting results of betahistine-directed fluorescent probe, and its may be a possible candidate for cardiovascular disease diagnosis and analysis in vivo.

Abstract: We present an approach of synthesizing magnetic polyglycidyl methacrylate (PGMA) microspheres by a simple method of dispersion polymerization. Water-based Magnetic fluids which have different surface properties disperse in reaction system. The magnetic microspheres are appropriate to construct liquid chip carriers. In this work, citric acid-modified and citric acid sodium-modified magnetic nanoparticles for the preparation of magnetic microspheres are investigated. SEM results indicated that the magnetic microspheres have an average diameter of 3.78 μm with excellent monodispersity (PDI 1.09). Magnetization curve of Fe3O4 nanoparticles using superconducting quantum magnetometer showed their good performance in magnetic response characteristics. Chemical structures and crystal form of magnetic Fe3O4 were characterized and analyzed using FT-IR and XRD methods.

Abstract: A new small molecule N,N-dimethylpyren-1-amine (DMPA) was synthesized and its vinyl polymer poly(N,N-dimethylpyren-1-amine) was polymerized by free radical polymerization. The chemical structure and properties of DMPA and P(DMPA) were characterized by NMR, GPC, TGA, DSC, UV-Vis, PL, CV and quantum yield measurements.

Abstract: The uniform Au nanoclusters ( NCs) were prepared with a simple method, and we used the uniform Au NCs and annioic tetrakis (4-sulfonatophenyl) (TPPS) porphyrin to prepare a pH sensor, of which fluorescence can be reversely modulated depending on the pH change. The fluorescence modulation of the pH sensor is related to fluorescence resonant energy transfer（FRET）from the Au NCs to TPPS.

Abstract: Phase transitions and critical phenomena are investigated within a two-sublattice model. In the framework of the random fields with the exchange interaction method the system of equations is obtained. It allows us to establish conditions under which magnetic phase transitions are possible. Critical concentration of ferromagnetic atoms which is necessary for the existence of ferromagnetic, ferrimagnetic and antiferromagnetic phases is determined.

Abstract: In this paper we investigate the dependence of the magnetic states of heterophase particles on mechanical multiaxial stresses. It is shown that for such particles, there are four possible states, and the conditions of stability of these states are determined.

Abstract: In this work, high quantum yield nanodots were produced by using an organosilane as a coordinating solvent and fabricated the product into solid films. In order to assess the practicality as a material for optoelectronic device, solid state properties were analyzed extensively including UV stability and thermal stability.

Abstract: 1-(2,5-Dimethyl-thien-3-yl)-2-(4-bromo-3,5-dimethyl-thien-2-yl)perfluorocyclopentene has been synthesized. The open-ring isomer of the compound in hexane is colorless and the absorption maximum was observed at 316 nm (ε = 8700M^-1cm^-1). The close-ring isomer of the compound in hexane is yellow and the absorption maximum was observed at 468 nm (ε = 6280M^-1cm^-1). Upon irradiation with 313 nm light, the conversion from the open- to the closed-ring isomer of the compound εwas 72% in the photostationary state. Bromo at 4-position of the thiophene moieties does not affect the absorption maximum and changes slightly absorption coefficient.

Abstract: A bright blue emission material, bis {(benzimidazol-2-yl) Pyridenato} magnesium (MgBIP) used for organic light emitting devices, has been synthesized. The decomposition temperature was observed at 517 °C and no melting transition (Tm) of MgBIP was observed up to 400 °C. For three-layer LED devices with the configuration of ITO/NPB/MgBIP/ Alq₃/MgAg, the white light emission covering the whole visible region from 400 to 750 nm with the maximum brightness of 2770 cd/m² and current density of 304 mA/cm² was observed.