共查询到20条相似文献，搜索用时 15 毫秒
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Amy J. Thompson Joshua A. Powell Jamie N. Melville John C. McMurtrie Jack K. Clegg 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(25):2207431
Molecular crystals displaying elastic flexibility have important applications in the fields of optoelectronics and nanophotonic technologies. Understanding the mechanisms by which these materials bend is critical to the design of future materials incorporating these properties. Based on the known elastic properties of bis(acetylacetonato)copper(II), a series of 14 aliphatic derivatives are synthesized and crystallized. All those which grew in a needle morphology display noticeable elasticity, with 1D chains of π-stacked molecules parallel to the long metric length of the crystal a consistent crystallographic feature. Crystallographic mapping is used to measure the mechanism of elasticity at an atomic-scale. Symmetric derivatives with ethyl and propyl side chains are found to have different mechanisms of elasticity, which are further distinguished from the previously reported mechanism of bis(acetylacetonato)copper(II). While crystals of bis(acetylacetonato)copper(II) are known to bend elastically via a molecular rotation mechanism, the elasticity of the compounds presented is facilitated by expansion of their π-stacking interactions. 相似文献
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Lina Li Yubao Zhao Markus Antonietti Menny Shalom 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(44):6090-6097
The assembly of melamine and 2,5‐dihydroxy‐1,4‐benzoquinone results in new “sheet‐like” supramolecular crystals that by controlled thermal condensation can be converted to photoactive materials at relativity low temperatures. The condensation temperature alters the materials properties from polymer‐like to carbon materials alongside their morphology and elemental ratio. This new method opens the possibility for the synthesis of new organic, photoactive carbon–nitrogen based frameworks at low calcination temperatures with great simplicity. Photodegradation experiments of methylene blue reveal that the obtained materials can perform dye reduction photochemically with visible photons, while at the same time the photogenerated holes oxidize the dye toward small molecular fragments. 相似文献
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Asymmetric light transmission based on coupling between photonic crystal waveguides and L1/L3 cavity
A compact design of all-optical diode with mode conversion function based on a two-dimensional photonic crystal waveguide and an L1 or L3 cavity is theoretically investigated. The proposed photonic crystal structures comprise a triangular arrangement of air holes embedded in a silicon substrate. Asymmetric light propagation is achieved via the spatial mode match/mismatch in the coupling region. The simulations show that at each cavity’s resonance frequency, the transmission efficiency of the structure with the L1 and L3 cavities reach 79% and 73%, while the corresponding unidirectionalities are 46 and 37 dB, respectively. The functional frequency can be controlled by simply adjusting the radii of specific air holes in the L1 and L3 cavities. The proposed structure can be used as a frequency filter, a beam splitter and has potential applications in all-optical integrated circuits. 相似文献
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Wiktor Lewandowski Nataša Vaupotič Damian Pociecha Ewa Górecka Luis M. Liz-Marzán 《Advanced materials (Deerfield Beach, Fla.)》2020,32(41):1905591
Intensive research on chiral liquid crystals (LCs) has been fueled by their actively tunable physicochemical properties and structural complexity, comparable to those of sophisticated natural materials. Herein, recent progress in the discovery of new classes of chiral LCs, enabled by a combination of nano- and macroscale investigations is reviewed. First, an overview is provided of liquid crystalline phases, made of chiral and achiral low-weight molecules, that exhibit chiral structure and/or chiral morphology. Then, recent progress in the discovery of new classes of chiral LCs, particularly enabled by the application of resonant X-ray scattering is described. It is shown that the method is sensitive to modulations of molecular orientation and therefore provides information hardly accessible by means of other techniques, such as the sense of helical structures or chirality transfer across length scales. Finally, a perspective is presented on the future scope, opportunities, and challenges in the field of chiral LCs, in particular related to nanocomposites. 相似文献
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Yifan Yao Lei Zhang Emanuele Orgiu Paolo Samorì 《Advanced materials (Deerfield Beach, Fla.)》2019,31(23)
The scientific effort toward achieving a full control over the correlation between structure and function in organic and polymer electronics has prompted the use of supramolecular interactions to drive the formation of highly ordered functional assemblies, which have been integrated into real devices. In the resulting field of supramolecular electronics, self‐assembly of organic semiconducting materials constitutes a powerful tool to generate low‐dimensional and crystalline functional architectures. These include 1D nanostructures (nanoribbons, nanotubes, and nanowires) and 2D molecular crystals with tuneable and unique optical, electronic, and mechanical properties. Optimizing the (opto)electronic properties of organic semiconducting materials is imperative to harness such supramolecular structures as active components for supramolecular electronics. However, their integration in real devices currently represents a significant challenge to the advancement of (opto)electronics. Here, an overview of the unconventional nanofabrication techniques and device configurations to enable supramolecular electronics to become a real technology is provided. A particular focus is put on how single and multiple supramolecular fibers and gels as well as supramolecularly engineered 2D materials can be integrated into novel vertical or horizontal junctions to realize flexible and high‐density multifunctional transistors, photodetectors, and memristors, exhibiting a set of new properties and excelling in their performances. 相似文献
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Kastler M Pisula W Davies RJ Gorelik T Kolb U Müllen K 《Small (Weinheim an der Bergstrasse, Germany)》2007,3(8):1438-1444
A high-yielding synthesis afforded a hexa-peri-hexabenzocoronene carrying acrylate units at the end of six attached alkyl spacers. The polymerization of these acrylate moieties could be initiated with thermal energy and through direct photoactivation without the addition of a photoinitiator. This allowed the organization of the liquid-crystalline material to be fixed in either the crystalline state or the mesophase, which preserved the organization in the respective phase. The use of a focused synchrotron beam permitted selected regions of a thin film to be rendered insoluble. After "developing" the film in this lithographic process by dissolving the soluble, unpolymerized material, defined nano-objects remained on the substrate. In addition, the pronounced aromatic pi stacking of the novel material allows an organization in mesoporous membranes that could be fixed by thermal crosslinking. After the removal of the inorganic template, mechanically stable nanotubes were obtained, which were characterized by different microscopy techniques. 相似文献
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Interaction between liquid-crystalline elastic deformation and microphase separation in liquid-crystalline block copolymers enables them to supramolecularly assemble into ordered nanostructures with high regularity. With the help of liquid-crystalline alignment, parallel and perpendicular patterning of nanostructures is fabricated with excellent reproducibility and mass production, which provides nanotemplates and nanofabrication processes for preparing varieties of nanomaterials. Furthermore, nanoscale microphase separation improves the optical performance of block-copolymer fi lms by eliminating the scattering of visible light, leading to advanced applications in optical devices and actuators. Recent progress in liquid-crystalline block copolymers, including their phase diagram, structure-property relationship, nanostructure control and nanotemplate applications, is reviewed. 相似文献
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R. I. Gearba D. V. Anokhin A. I. Bondar W. Bras M. Jahr M. Lehmann D. A. Ivanov 《Advanced materials (Deerfield Beach, Fla.)》2007,19(6)
Columnar liquid crystals (LCs) are found to spontaneously form homeotropically‐aligned films when deposited on surfaces fabricated via friction transfer of polytetrafluoroethylene. The inside cover schematically shows the film structure of a phthalocyanine derivative together with the corresponding X‐ray diffraction pattern (inset). The results, reported on p. 815 by Dmitri Ivanov and co‐workers, indicate that not only are the columns homeotropically oriented but also that they form a single monodomain of macroscopic size. These findings can have an important impact for fabrication of LC‐based organic solar cells. 相似文献
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Dengfeng Lu Meng Qin Yonghang Zhao Hongxiang Li Longbo Luo Chunmei Ding Pei Cheng Meng Su Huiying Li Yanlin Song Jianshu Li 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(12):2206461
Structurally-colored photonic hydrogels which are fabricated by introducing hydrogels into thin films or photonic crystal structures are promising candidates for biosensing. Generally, the design of photonic hydrogel biosensors is based on the sensor-analyte interactions induced charge variation within the hydrogel matrix, or chemically grafting binding sites onto the polymer chains, to achieve significant volume change and color variation of the photonic hydrogel. However, relatively low anti-interference capability or complicated synthesis hinder the facile and low-cost fabrication of high-performance photonic hydrogel biosensors. Here, a facilely prepared supramolecular photonic hydrogel biosensor is developed for high-sensitivity detection of alkaline phosphatase (ALP), which is an extensively considered clinical biomarker for a variety of diseases. Responding to ALP results in the broken supramolecular crosslinking and thus increased lattice distancing of the photonic hydrogel driven by synergistic repulsive force between nanoparticles embedded in photonic crystal structure and osmotic swelling pressure. The biosensor shows sensitivity of 7.3 nm spectral shift per mU mL−1 ALP, with detection limit of 0.52 mU mL−1. High-accuracy colorimetric detection can be realized via a smartphone, promoting point-of-care sensing and timely diagnosis of related pathological conditions. 相似文献
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G. De&#x;Filpo F.&#x;P. Nicoletta G. Chidichimo 《Advanced materials (Deerfield Beach, Fla.)》2005,17(9):1150-1152
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压卡制冷材料是一类由压力驱动材料发生固态相变而释放/吸收相变潜热的固体材料。压卡制冷技术是以压卡材料为工质、以压力作为驱动力构建的新兴固态制冷技术。本文从压卡效应基本热力学、压卡材料体系和压卡制冷样机三个方面简要论述该领域的发展现状。近年来压卡材料体系蓬勃发展,涉及金属、无机非金属、有机物、有机-无机杂化材料等。庞压卡效应的发现使有机塑晶材料备受关注,因其大熵变、低驱动压力、成本低廉等优点成为最有希望获得应用的一类材料。相比于此,制冷样机的研制则略显滞后。样机设计中需要解决的核心问题是力-热的有效耦合,选择高导热系数流体作为传热及传压介质,通过调整流体的压力和流速,同时优化压卡制冷工质的几何构型有望获得最佳力-热有效耦合条件。在单级制冷的基础上,采用主动回热式压卡制冷方式可实现连续制冷。 相似文献