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排序方式: 共有619条查询结果,搜索用时 15 毫秒
1.
Shuzhen Li Bo Lu Xiaoyu Fang Prof. Dongpeng Yan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22812-22819
Smart molecular crystals with light-driven mechanical responses have received interest owing to their potential uses in molecular machines, artificial muscles, and biomimetics. However, challenges remain in control over both the dynamic photo-mechanical behaviors and static photonic properties of molecular crystals based on the same molecule. Herein, we show the construction of isostructural co-crystals allows their light-induced cracking and jumping behaviors (photosalient effect) to be controlled. Hydrogen-bonded co-crystals from 4-(1-naphthylvinyl)pyridine ( NVP ) with co-formers (tetrafluoro-4-hydroxybenzoic acid ( THA ) and tetrafluorobenzoic acid ( TA )) crystallize as isostructural crystals, but have different static and dynamic photo-mechanical behaviors. These differences are due to alternations in the orientation of NVP and hydrogen-bonding modes of the co-formers. After light activation, the 1D NVP-TA crystal splits and shears off within 1 s. For NVP-THA , its photostability and high quantum yield give novel photonic properties, including low optical waveguide loss, highly polarized anisotropy, and efficient up-conversion fluorescence. 相似文献
2.
Khalid Naim Manjeet Singh Sachin Sharma Dr. Rajesh V. Nair Prof. Paloth Venugopalan Dr. Subash Chandra Sahoo Dr. Prakash P. Neelakandan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(52):11979-11984
The design of molecular compounds that exhibit flexibility is an emerging area of research. Although a fair amount of success has been achieved in the design of plastic or elastic crystals, realizing multidimensional plastic and elastic bending remains challenging. We report herein a naphthalidenimine–boron complex that showed size-dependent dual mechanical bending behavior whereas its parent Schiff base was brittle. Detailed crystallographic and spectroscopic analysis revealed the importance of boron in imparting the interesting mechanical properties. Furthermore, the luminescence of the molecule was turned-on subsequent to boron complexation, thereby allowing it to be explored for multimode optical waveguide applications. Our in-depth study of the size-dependent plastic and elastic bending of the crystals thus provides important insights in molecular engineering and could act as a platform for the development of future smart flexible materials for optoelectronic applications. 相似文献
3.
Juan de Torres Petru Ghenuche Satish Babu Moparthi Victor Grigoriev Jérôme Wenger 《Chemphyschem》2015,16(4):782-788
Zero‐mode waveguides (ZMWs) can confine light into attoliter volumes, which enables single molecule fluorescence experiments at physiological micromolar concentrations. Of the fluorescence spectroscopy techniques that can be enhanced by ZMWs, Förster resonance energy transfer (FRET) is one of the most widely used in life sciences. Combining zero‐mode waveguides with FRET provides new opportunities to investigate biochemical structures or follow interaction dynamics at micromolar concentrations with single‐molecule resolution. However, prior to any quantitative FRET analysis on biological samples, it is crucial to establish first the influence of the ZMW on the FRET process. Here, we quantify the FRET rates and efficiencies between individual donor–acceptor fluorophore pairs that diffuse into aluminum zero‐mode waveguides. Aluminum ZMWs are important structures thanks to their commercial availability and the large amount of literature that describe their use for single‐molecule fluorescence spectroscopy. We also compared the results between ZMWs milled in gold and aluminum, and found that although gold has a stronger influence on the decay rates, the lower losses of aluminum in the green spectral region provide larger fluorescence brightness enhancement factors. For both aluminum and gold ZMWs, we observed that the FRET rate scales linearly with the isolated donor decay rate and the local density of optical states. Detailed information about FRET in ZMWs unlocks their application as new devices for enhanced single‐molecule FRET at physiological concentrations. 相似文献
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Carolin Kreisbeck 《Applicable analysis》2013,92(6):1153-1191
Mathematical settings in which heterogeneous structures affect electron transport through a tube-shaped quantum waveguide are studied, highlighting the interaction between material composition and geometric parameters like curvature and torsion. First, the macroscopic behaviour of a nanowire made of composite fibres with microscopic periodic texture is analysed, which amounts to determining the asymptotic behaviour of the spectrum of an elliptic Dirichlet eigenvalue problem with finely oscillating coefficients in a tube with shrinking cross-section. A suitable formal expansion suggests that the effective one-dimensional limit problem is of Sturm–Liouville type and yields the explicit formula for the underlying potential. In the torsion-free case, these findings are made rigorous by performing homogenization and 3d–1d dimension reduction for the two-scale problem in a variational framework by means of Γ-convergence. Second, waveguides with non-oscillating inhomogeneities in the cross-section are investigated. This leads to explicit criteria for propagation and localization of eigenmodes. 相似文献
7.
Matthew P. Ryder Joseph McGuire Karl F. Schilke 《Surface and interface analysis : SIA》2013,45(11-12):1805-1809
Optical waveguide lightmode spectroscopy (OWLS), based on the incoupling of laser light into a waveguide sensor by an optical grating, allows for the in situ measurement of protein adsorption. Few reports have described cleaning methods for the surfaces of such sensors, and in this investigation, we compare common methods for cleaning of silica surfaces in relation to their effectiveness for cleaning silica‐coated waveguide sensors used in OWLS. For this purpose, atomic force microscopy (AFM) analysis of surface morphology and OWLS detection of protein adsorption kinetics were used to evaluate waveguide sensors before and after cleaning. While AFM line scans showed a substantial increase in average waveguide peak‐to‐valley height after RCA cleaning relative to all other methods tested, chemical etching owing to the alkaline component of the rolling circle amplification method rendered the waveguide unusable for detection of protein adsorption with OWLS. A revised method, based on replacement of the alkaline step with immersion in sodium dodecyl sulfate, was not only effective at cleaning OWLS waveguides off‐the‐shelf but also showed excellent protein adsorption reproducibility after ex situ cleaning. Moreover, the revised method showed excellent reproducibility when applied in situ, between repeated adsorption‐elution cycles. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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We report on the structural and optical characterization of waveguides formed in YbVO4 crystals by Cu2+-ion implantation with an energy of 3.0 MeV and doses of 3.0×1014-1.0×1015 ions/cm2. The damage properties are determined by RBS/Channeling measurements with the help of simulation code RUMP. The m-line method is used to characterize the dark-mode spectroscopy in the planar waveguides. According to the reconstructed refractive index profile of the waveguide cross section, a numerical simulation is carried out to investigate the confinement of the light in the waveguides based on the beam propagation method. 相似文献
10.
设计了一种领结形中空表面等离子体波导.采用频域有限差分法,对这种波导所支持的基模的能流密度分布、有效折射率、传播长度和模式面积随几何结构参数和工作波长的依赖关系进行了分析.结果表明,沿纵向的能流主要分布在两个上下突起所形成的中间区域.通过调整几何参数及工作波长,可以调节模式的有效折射率、传播长度和模式面积.在工作波长确定的条件下,有效折射率随突起半径的增大呈减小趋势,而传播长度和模式面积则随着突起半径的增大呈增大趋势,四个角上的圆弧半径对波导的传输特性有微调作用,左右扇形区域的半径对波导的传输特性有较明显
关键词:
集成光学
光波导
表面等离子体波导 相似文献