The study of elastic organic single crystals (EOSCs) has emerged as a cutting‐edge research of crystal engineering. Although a few EOSCs have been reported recently, those suitable for ...optical/optoelectronic applications have not been realized. Here, we report an elastic crystal of a Schiff base, (E)‐1‐(4‐(dimethylamino)phenyl)iminomethyl‐2‐hydroxyl‐naphthalene. The crystal is highly bendable under external stress and able to regain immediately its original straight shape when the stress is released. It displays bright orange–red emission with a high fluorescence quantum yield of 0.43. Intriguingly, it can serve as a low‐loss optical waveguide even at the highly bent state. Our result highlights the feature and utility of “elasticity” of organic crystals.
Optical waveguide: Centimeter‐long elastic organic crystals of a Schiff base have been facilely prepared and display a bright orange–red emission at a fluorescence quantum yield of 0.43. These elastic crystals are waveguiding and have a low optical loss coefficient both in the straight and highly bended states.
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Organic crystals are generally brittle and tend to crack under applied stress. Doped organic crystals are even more brittle because of lattice defects. Herein, the first doped organic crystals 1d@2d, ...which display elastic bending ability under applied stress, are reported. Moreover, the potential applications of elastic‐doped crystals 1d@2d in flexible optoelectronics are impressively demonstrated. The elastic crystals 1d@2d with high quality and large size are crystalized by a simple and unique “self‐doping” process, which is a regular solution evaporation of crude product 1d (2,5‐dihydro‐3,6‐bis(octylamino)terephthalate) containing a minute amount of 2d (3,6‐bis(octylamino)terephthalate) as the oxidized byproduct. The host 1d is easily crystallized to form elastic crystals but is nonfluorescent, while the guest 2d has poor crystallinity and is highly emissive. The doping approach integrates the advantages of both 1d and 2d, and thus endows doped crystals 1d@2d with good elasticity as well as intense orange fluorescence. Taking these advantages, the application potentials of these doped crystals 1d@2d are evaluated by measuring optical waveguide and amplified spontaneous emission in both the straight and bent states.
Elastic‐doped organic crystals 1d@2d are crystalized by a simple and unique “self‐doping” process. Taking advantage of the good elasticity and intense fluorescence, a flexible optical waveguide and amplified spontaneous emission are realized in bent crystals 1d@2d, highlighting the feature of elasticity and the potential applications in flexible optoelectronics.
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Four-coordinate organoboron compounds with rigid π-conjugated structures are intensely luminescent and have high carrier mobility which enables them to be applied in optoelectronics including organic ...light-emitting diodes (OLEDs), organic field-effect transistors, as well as photoresponsive, sensory and imaging materials. Various chelate ligands and boron moieties have been explored to construct proper electronic structures and suitable molecular arrangements, which play important roles on the photophysical and electronic properties of the four coordinate boron compounds. These efforts have produced a number of fascinating molecules, some of which have exhibited high performance as light emitting materials. In this article, we provide an overview of the progress in the molecular construction of four-coordinate organoboron compounds with an emphasis on their applications in OLEDs.
A review of the progress made in the molecular construction of four coordinate organoboron compounds with an emphasis on their applications in OLEDs is presented.
Arc (activity‐regulated cytoskeleton‐associated protein) is posited as a critical regulator of long‐term synaptic plasticity at excitatory synapses, including long‐term potentiation, long‐term ...depression, inverse synaptic tagging and homoeostatic scaling, with pivotal roles in memory and postnatal cortical development. However, the mechanisms underlying the bidirectional regulation of synaptic strength are poorly understood. Here we review evidence from different plasticity paradigms, highlight outstanding issues and discuss stimulus‐specific mechanisms that dictate Arc function. We propose a model in which Arc bidirectionally controls synaptic strength by coordinate regulation of AMPA‐type glutamate receptor (AMPAR) trafficking and actin cytoskeletal dynamics in dendritic spines. Key to this model, Arc is proposed to function as an activity‐dependent regulator of AMPAR lateral membrane diffusion and trapping at synapses.
Arc is multifunctional in synaptic plasticity. We discuss stimulus‐specific mechanisms that dictate Arc function and propose a model in which Arc bidirectionally controls synaptic strength by coordinate regulation of AMPA‐type glutamate receptor (AMPAR) trafficking and actin cytoskeletal dynamics in dendritic spines. Key to this model, Arc is proposed to function as an activity‐dependent regulator of AMPAR lateral membrane diffusion and trapping at synapses.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Significant efforts have been made to develop high‐efficiency organic light‐emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) emitters with blue, green, yellow, and ...orange–red colors. However, efficient TADF materials with colors ranging from red, to deep‐red, to near‐infrared (NIR) have been rarely reported owing to the difficulty in molecular design. Herein, we report the first NIR TADF molecule TPA‐DCPP (TPA=triphenylamine; DCPP=2,3‐dicyanopyrazino phenanthrene) which has a small singlet–triplet splitting (ΔEST) of 0.13 eV. Its nondoped OLED device exhibits a maximum external quantum efficiency (EQE) of 2.1 % with a Commission International de L′Éclairage (CIE) coordinate of (0.70, 0.29). Moreover, an extremely high EQE of nearly 10 % with an emission band at λ=668 nm has been achieved in the doped device, which is comparable to the most‐efficient deep‐red/NIR phosphorescent OLEDs with similar electroluminescent spectra.
Seeing red: A V‐shaped molecule (TPA‐DCPP), which undergoes thermally activated delayed fluorescence (TADF) to emit in the near‐IR region, has been synthesized. The molecule incorporates triphenylamine (TPA) as the donor (D) and 2,3‐dicyanopyrazino phenanthrene (DCPP) as the acceptor (A). A nondoped OLED prepared using TPA‐DCPP exhibited a maximum external quantum efficiency (EQE) of 2.1 %, whereas the doped device had an EQE of almost 10 %.
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Graphene-based membranes have great potential to revolutionize nanofiltration technology, but achieving high solute rejections at high water flux remains extremely challenging. Herein, a family of ...ultrafine metal oxide/reduced graphene oxide (rGO) nanocomposites are synthesized through a heterogenous nucleation and diffusion-controlled growth process for dye nanofiltration. The synthesis is based on the utilization of oxygen functional groups on GO surface as preferential active sites for heterogeneous nucleation, leading to the formation of sub-3 nm size, monodispersing as well as high-density loading of metal oxide nanoparticles. The anchored ultrafine nanoparticles could inhibit the wrinkling of the rGO nanosheet, forming highly stable colloidal solutions for the solution processing fabrication of nanofiltration membranes. By functioning as pillars, the nanoparticles remarkably increase both vertical interlayer spacing and lateral tortuous paths of the rGO membranes, offering a water permeability of 225 L m
h
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and selectivity up to 98% in the size-exclusion separation of methyl blue.
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bstract
Phenomenological studies of cosmological collider physics in recent years have identified many 1-loop inflation correlators as leading channels for discovering heavy new particles around or ...above the inflation scale. However, complete analytical results for these massive 1-loop correlators are currently unavailable. In this work, we embark on a program of bootstrapping inflation correlators with massive exchanges at 1-loop order, with the input of tree-level inflation correlators and the techniques of spectral decomposition in dS. As a first step, we present for the first time the complete and analytical results for a class of 4-point and 3-point inflation correlators mediated by massive scalar fields at the 1-loop order. Using the full result, we provide simple and reliable analytical approximations for the signals and the background in the squeezed limit. We also identify configurations of the scalar trispectrum where the oscillatory signal from the loop is dominant over the background.
For a large and evolving software system, the project team could receive a large number of bug reports. Locating the source code files that need to be changed in order to fix the bugs is a ...challenging task. Once a bug report is received, it is desirable to automatically point out to the files that developers should change in order to fix the bug. In this paper, we propose BugLocator, an information retrieval based method for locating the relevant files for fixing a bug. BugLocator ranks all files based on the textual similarity between the initial bug report and the source code using a revised Vector Space Model (rVSM), taking into consideration information about similar bugs that have been fixed before. We perform large-scale experiments on four open source projects to localize more than 3,000 bugs. The results show that BugLocator can effectively locate the files where the bugs should be fixed. For example, relevant buggy files for 62.60% Eclipse 3.1 bugs are ranked in the top ten among 12,863 files. Our experiments also show that BugLocator outperforms existing state-of-the-art bug localization methods.
Recently, mechanically bendable organic single crystals have been widely studied as emerging flexible materials. However, only a very small percentage of organic crystals have been found to be ...elastic or plastic. In this study, crystal engineering is employed as a powerful strategy to improve the probability of constructing flexible organic crystals. Based on an organic compound, two polymorphs Cry‐R and Cry‐O with bright red and orange emissions, respectively, are obtained. Cry‐R, being brittle inherently, can form a naturally bent crystal with an optical waveguide as efficient as the straight crystal. The other polymorph Cry‐O can be elastically bent, almost into a loop, and displays an optical waveguide and amplified spontaneous emission in both the straight and bent state, demonstrating its multifunctional applications in flexible optical devices. In addition, the Y‐shaped crystals of Cry‐O obtained by natural growth are found to transduce single emitted light through the two branches and thus generate dual output signals simultaneously, which further highlights the utility of “crystal flexibility”. The results not only suggest a guideline to modify the mechanical compliance by crystal engineering but also provide a model of flexible organic crystals for multifunctional optical applications.
Naturally and elastically bent organic crystals with highly efficient orange and red emissions based on one compound are obtained by crystal engineering and they are found to display light transducing and amplifying capabilities in bent forms. This work provides a model of flexible organic crystals for multifunctional application in optical devices.
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