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1.
Prof. Jen-Shyang Ni Tianliang Min Yaxi Li Menglei Zha Dr. Pengfei Zhang Prof. Chun Loong Ho Prof. Kai Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10265-10271
Planar luminogens have encountered difficulties in overcoming intrinsic aggregation-caused emission quenching by intermolecular π-π stacking interactions. Although excited-state double-bond reorganization (ESDBR) can guide us on designing planar aggregation-induced emission (AIE) luminogens (AIEgens), its mechanism has yet been elucidated. Major challenges in the field include methods to efficiently restrict ESDBR and enhance AIE performance without using bulky substituents (e.g., tetraphenylethylene and triphenylamine). In this study, we rationally developed fluoro-substituent AIEgens with stronger intermolecular H-bonding interaction for restricted molecular motions and increased crystal density, leading to decreased nonradiative decay rate by one order of magnitude. The adjusted ESDBR properties also show a corresponding response to variation in viscosity. Furthermore, their aggregation-induced reactive oxygen species (ROS) generations have been discovered. The application of such planar AIEgen in treating multidrug-resistant bacteria has been demonstrated in a mouse model. The relationship between ROS generation and distinct E/Z-configurational stacking behaviors have been further understood, providing a design principle for synthesizing planar AIEgen-based photosensitizers. 相似文献
2.
Chirped fiber grating was used in dispersion compensator. We tried to use the same phase mask to write fiber grating of different wavelength with two methods to reduce the price of the fiber grating. 相似文献
3.
Yong Zhao Xianliang Sheng Jin Zhai Lei Jiang Chunhe Yang Zhongwei Sun Yongfang Li Daoben Zhu 《Chemphyschem》2007,8(6):856-861
Titanium dioxide (TiO(2)) photoelectrodes with micro/nano hierarchical branched inner channels have been prepared by an electrohydrodynamic (EHD) technique and assembled to form dye-sensitized solar cells (DSSCs). Excellent penetration of ionic-liquid electrolytes and enhanced light harvesting in the longer wavelength region are realized within the composite-structure electrode, thus a better fill factor (ff) of 75.3 % and higher conversion efficiency (eta) of 7.1 % are obtained for viscous ionic-liquid electrolytes compared to pure nanostructured films. Hierarchical branched channels in the photoanodes can efficiently improve the transport properties of redox-active species in viscous electrolytes, which is demonstrated by electrical impedance spectroscopy (EIS). The incident monochromatic photon-to-electron conversion efficiency (IPCE) shows that enhanced light scattering in the composite film is of benefit for light harvesting and thus for solar energy conversion efficiency. 相似文献
4.
TEM investigation of formation mechanism of monocrystal-thick b-oriented pure silica zeolite MFI film 总被引:3,自引:0,他引:3
Li S Li Z Bozhilov KN Chen Z Yan Y 《Journal of the American Chemical Society》2004,126(34):10732-10737
The first direct transmission electron microscopic (TEM) observation has been carried out on the continuous monocrystal-thick b-oriented pure silica zeolite MFI films produced by in situ crystallization. The self-supporting film samples for TEM study were fabricated by dissolving the steel substrate with acid. This TEM study is free of those artifacts that are typically associated with TEM sample preparations, and allows us to investigate the "true" structure and texture of a very large area of the film and at the same time to focus at will on each individual zeolite crystal in the film. Abundant TEM information including crystallographic orientation relationships among crystals in the film (both out-of-plane and in-plane), grain boundaries, and each crystal grain was obtained. This TEM investigation provides direct unambiguous new evidence to support the homogeneous nucleation mechanism, by which the films form through homogeneous nucleation and crystal growth in the bulk to form equal-sized disk-shape crystals, followed by self-assembly of these crystals onto the substrate to produce a two-dimensional close-packed structure. The last stage of the film formation involves simultaneous space-limited growth and rotation of the individual crystals to realize the in-plane crystallographic control within the film. 相似文献
5.
液晶电视由于其优异的显示性能将会越来越受到青睐。本文简要综述了近年来电视用液晶材料的研究进展,归纳总结了这些液晶材料的合成方法及其热性能、介电各向异性、双折射率、粘度等特性。 相似文献
6.
A novel hyperbranched polyester acrylate (HPEA) was synthesized based upon ethylenediamine tetraacetic acid as a “core” molecule, 5‐hydroxyisophthalic acid as an AB2 monomer, and 2‐hydroxyethyl acrylate as an endcapping reagent. The obtained oligomer has an unsaturation concentration of 4.10 mmolC?C g?1 measured by nuclear magnetic resonance and a wide molecular weight distribution of 1.64 measured by gel permeation chromatography. The two‐photon absorption (TPA) photopolymerization of HPEA under the exposure of a Ti : sapphire femtosecond laser with a wavelength of 800 nm was investigated through laser exposure dose‐dependant spatial resolutions of its resins. The TPA photopolymerization thresholds at the range 1.6–4.3 × 107 mJ cm?2, and exposure dose windows at the range 3.4–4.3 for three formulations were determined. A spatial resolution of 0.85 μm was obtained through the TPA photopolymerization of the formulation containing 1 wt% photoinitiator and 0.3 wt% photoinhibitor. A diffraction grating and real three‐dimensional coupled gear wheel created by TPA photopolymerization were described to demonstrate the unique capability of HPEA in microfabrications. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
7.
Chen H Aleksandrov A Chen Y Zha S Liu M Orlando TM 《The journal of physical chemistry. B》2005,109(22):11257-11262
Polycrystalline gadolinia-doped ceria (GDC) surfaces were studied using low-energy (5-400 eV) electron stimulated desorption (ESD). H(+), O(+), and H(3)O(+) were the primary cationic desorption products with H(+) as the dominant channel. H(+), H(3)O(+), and O(+) have a 22 eV threshold followed by a yield change around 40 eV. H(+) also has an additional yield change approximately 75 eV and O(+) has an additional change approximately 150 eV. The O(+) ESD yield change approximately 150 eV may indicate bond breaking of Gd-O and the involvement of oxygen vacancies. The H(+) and H(3)O(+) threshold data collectively indicate the presence of hydroxyl groups and chemisorbed water molecules on the GDC surfaces. ESD temperature dependence measurements show that the interaction of water with GDC surface defect sites, mainly oxygen vacancies, influences the desorption of H(+), O(+), and H(3)O(+). The temperature dependence of the O(+) ESD at 400 eV incident electron energy yields a 0.21 eV activation energy. This is close to the energy needed for oxygen vacancy production next to a pair of Ce(3+) on a CeO(2) surface. These results may indicate a correlation between the O(+) ESD yield and oxygen vacancy density on GDC surfaces and a potential correlation of O(+) ESD and GDC ionic conductivity. 相似文献
8.
IntroductionConsiderableattelltionisno\vbeillgpaidtotheCO7refonningof.etha..llto]forseveralreasonst(l)withthedevelopmentofindustrics.moreandnlorcCOZIsabettedintotheatmosphere,leadingto"greenhouseeffect",whichhasbroughtaboutgreatilltcreslallovertheworld.Th… 相似文献
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