Two triphenylamine-based derivatives that can be used as two-photon absorption chromophore,tris{4-[4-(3-trifluoromethyl-3-oxopanoyl)]phenyl}amine (1) and tris{4-[4-(3-phenyl-3-oxopanoyl)] phenyl} amine (2) were successfully synthesized and fully characterized by elemental analysis,IR,1H NMR and MS. The single crystal X-ray diffraction analysis showed that the molecules possess D-(π-A)3 structures. One-and two-photon absorption and fluorescence in various solvents were experimentally investigated. A data recording experiment proved the potential application of these chromophores.
Nano-structured cubic SnO2 crystalines were successfully synthesized through solvothermal route.The obtained products were characterized by X-ray diffraction (XRD),transmission electron microscopy (TEM) and high resolution TEM (HRTEM).The study showed that,the SnO2 particles were rutile structured and almost uniformly cube shaped crystals in quantum size (3-8 nm).Self-assembly behavior of the cubic SnO2 quantum dots was also observed.The synthesis process can be defined as an nonhydrolysis (NH) hydroxylation reaction provided by the amide elimination of carboxylated precursors.The formation of cubic morphology of SnO2 can be ascribed to the mild reaction featured by high nucleation rate and low growth rate,surface energy difference of the crystallographic facets of SnO2 and the passivation effect of the starting material-dodecylamine which drastically reduced the dipole interation.The selfassembly of the cubic SnO2 quantum dots was driven by van der Waals force and capillary force.
A tricyanofuran (TCF) acceptor-based nonlinear optical (NLO) chromophore (2-(3-cyano-4-(4-((2-hydroxyethyl)(methyl)amino)styryl)-5,5-dimethylfuran-2(5H)-ylidene)malononitrile,abbr. FS) was synthesized and then reacted with 3-isocyarmatopropyl triethoxysilane (ICTES) to form a functionalized silicon alkoxide precursor (named ICTES-FS).Sol solutions were obtained after co-hydrolysis/condensation of ICTES-FS,tetraethoxysilane (TEOS) and 3-(Trimethoxysilyl)propyl methacrylate (TSPM).Transparent films were only fabricated with the sol containing high concentration of TSPM.Higher concentration of TSPM was found useful to abate dipolar chromophore interactions and consequent aggregation problems.Second- order NLO properties and temporal stability of sol-gel films were also investigated by virtue of in situ second harmonic generation (SHG).
Four photopolymerization initiators with D-π-D (D,donor; π,conjugation system) structure have been synthesized by solvent-free reaction and characterized by 1H NMR spectroscopy,IR and elemental analysis. The one-photon and two-photon excited fluorescence have been investigated in different solvents. Experimental results of the one-photon and two-photon absorption cross sections show different trends in OPA and TPA ability with different substitution groups in donor units.
A simple sonochemical route for the surface coating of titanium dioxide on cadmium sulfide nanocrystal was reported. After 2 h ultrasonic irradiation treatment, the mixture of CdS nanocrystals and tetrabutyl titanate in an aqueous medium yielded CdS/TiO2 nanocrystals composites with core/shell structure. The thickness of TiO2 layer with smooth interface could be easily controlled via changing the concentration of the precursors and the time of irradiation. The core/shell nanocrysrals were characterized by X-ray diffraction, transmission electron microscope and UV-vis spectrometry techniques. The prepared semiconductor composites with particular band structure present appealing properties especially in photochemical activity.
Two carbazole-based polymerization initiators possessing blue fluorescence emission have been synthesized via Wittig reaction in the solid phase at room temperature.Two-photon excited fluorescence(TPEF) spectra for them were investigated under 800 nm fs laser pulse and two-photon absorption cross sections were determined by the Z-scan technique.Then two-photon initiating polymerization(TPIP) microfabrication experiments were successfully carried out.Three-dimensional lattice and artificial defects were gained,indicating that they were viable candidates for the two-photon polymerization initiator in practical application of microfabrication.
HU RenTaoLüLiangFeiRUAN BanFengWANG PengZHANG MingLiangZHOU HongPingLI ShengLiWU JieYingTIAN YuPeng
Highly crystalline orthorhombic Bi2WO6 powders were hydrothermally synthesized from aqueous solutions of Na2WO4·2H2O and Bi (NO3)3·5H2O over a wide range of pH. The effect of pH on morphologies, sizes and properties of the Bi2WO6 crystals was investigated. The band gaps of the as-prepared Bi2WO6 were determined from the onset of the absorption edge of UV-vis diffuse reflectance spectra. The methyl orange photodegradation was employed as a probe reaction to test the photocatalytic activity of the as-prepared samples under visible light irradiation. The photocatalytic activities of methyl orange degradation under visible light irradiation are strongly dependent on the pH used in the synthesis. The highest efficiency is observed at pH=7.
