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Single-Molecule Based Electroluminescent Device as Future White Light Source
摘要: During last two decades spectacular development of light emitting diodes (LEDs) has been achieved owing to their widespread application possibilities. However, traditional LEDs suffer from unavoidable energy loss due to the down conversion of photons, toxicity due to the involvement of rare-earth materials in their production, higher manufacturing cost, and reduced thermal stability that prevent them from all-inclusive applications. To address the existing challenges associated with current commercially available white LEDs, herein, we report on a broadband emission originating from an intrinsic lanthanide-free single-molecule based LED. Self-assembly of a butterfly-shaped strontium-based compound {[Sr(H2btc)2(MeOH)(H2O)2]·2H2O} (1) was achieved through the reaction of Sr(NO3)2 with a benzene-1,2,3-tricarboxylic acid hydrate (1,2,3-H3btc) under hydrothermal conditions. White LED based on this single molecule exhibited a remarkable broadband luminescent spectrum with Commission Internationale de l’Eclairage (CIE) coordinates at (0.33, 0.32) under 30 mA current injection. Such a broad luminescent spectrum can be attributed to the simultaneous existence of several emission lines originating from the intramolecular interactions within the structure. To further examine the nature of the observed transitions, density functional theory (DFT) calculations were carried out to explore the geometric and electronic properties of the complex. Our study thus paves the way toward a key step for developing a basic understanding and the development of high performance broadband light emitting devices with environment-friendly characteristics based on organic?inorganic supramolecular materials.
关键词: Electroluminescence,Photoluminescence,Single Molecule,WLEDs,Strontium
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Method for Calculating Electronic Polarizability of Water Molecules and Refractive Index
摘要: A method for calculating the electronic polarizability of water molecules is proposed. In the approximation of this method, the electronic components of the hyperpolarizability of the first and second order for the water molecule are determined.
关键词: water molecule,electron polarizability,refractive index,hyperpolarizability,electronic polarizability,molar refraction
更新于2025-09-23 15:22:29
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Sharp phase-separated interface of 6,13-bis(triisopropylsilylethynyl) pentacene/polystyrene blend films prepared by electrostatic spray deposition
摘要: In this study, organic field-effect transistors (OFETs) based on blend films comprising 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) and polystyrene (PS) were fabricated. The blend films were prepared by electrostatic spray deposition (ESD). A vertically phase-separated structure (TIPS pentacene (top)/PS (bottom)) can be spontaneously formed without additional treatments such as solvent-vapor annealing, which is significantly different from the blend with poly(methyl methacrylate) (PMMA). Due to the sharp phase-separated interface, OFETs based on the TIPS pentacene/PS blend films exhibited superior characteristics and operational stability.
关键词: Organic field-effect transistor,Small molecule/polymer blend,Electrostatic spray deposition,Vertical phase separation
更新于2025-09-23 15:22:29
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Accelerated FRET-PAINT microscopy
摘要: Recent development of FRET-PAINT microscopy significantly improved the imaging speed of DNA-PAINT, the previously reported super-resolution fluorescence microscopy with no photobleaching problem. Here we try to achieve the ultimate speed limit of FRET-PAINT by optimizing the camera speed, dissociation rate of DNA probes, and bleed-through of the donor signal to the acceptor channel, and further increase the imaging speed of FRET-PAINT by 8-fold. Super-resolution imaging of COS-7 microtubules shows that high-quality 40-nm resolution images can be obtained in just tens of seconds.
关键词: FRET-PAINT,Super-resolution fluorescence microscopy,FRET,Single-molecule localization microscopy
更新于2025-09-23 15:22:29
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Single-Molecule Imaging of mRNA Localization and Regulation during the Integrated Stress Response
摘要: Biological phase transitions form membrane-less organelles that generate distinct cellular environments. How molecules are partitioned between these compartments and the surrounding cellular space and the functional consequence of this localization is not well understood. Here, we report the localization of mRNA to stress granules (SGs) and processing bodies (PBs) and its effect on translation and degradation during the integrated stress response. Using single mRNA imaging in living human cells, we find that the interactions of mRNAs with SGs and PBs have different dynamics, very few mRNAs directly move between SGs and PBs, and that specific RNA-binding proteins can anchor mRNAs within these compartments. During recovery from stress, we show that mRNAs that were within SGs and PBs are translated and degraded at similar rates as their cytosolic counterparts. Our work provides a framework for using single-molecule measurements to directly investigate the molecular mechanisms of phase-separated compartments within their cellular environment.
关键词: P-bodies,integrated stress response,degradation,stress granules,LARP1,mRNA localization,single-molecule imaging,translation
更新于2025-09-23 15:22:29
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Detection of metal-molecule-metal junction formation by surface enhanced Raman spectroscopy
摘要: Vibrational modes play a key role in characterizing metal-molecule-metal junctions, but their detection currently either requires single-molecule sensitivity or the generation of defect-free large-scale junctions. Here we demonstrate that surface-enhanced Raman scattering (SERS) on non-ideal surfaces can provide a significant amount of information despite many defects in the layer. We determine the vibrational signature of the molecular electronic junction for palladium ions complexed and reduced on 4-mercaptopyridine adsorbed on rough gold and gold nanoparticles using SERS and density functional theory (DFT). We show that these non-ideal surfaces can be used to probe kinetics of metal ion complexation and establish the success of electrochemical metallization. SERS on non-ideal surfaces is thus revealed as a useful tool to rapidly establish the key process parameters in making molecular electronic junctions before embarking on more detailed studies on single molecules or single crystal surfaces.
关键词: gold,4-mercaptopyridine,Metal-molecule-metal junctions,surface-enhanced Raman spectroscopy
更新于2025-09-23 15:22:29
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Single-molecule imaging of the transcription factor SRF reveals prolonged chromatin-binding kinetics upon cell stimulation
摘要: Serum response factor (SRF) mediates immediate early gene (IEG) and cytoskeletal gene expression programs in almost any cell type. So far, SRF transcriptional dynamics have not been investigated at single-molecule resolution. We provide a study of single Halo-tagged SRF molecules in fibroblasts and primary neurons. In both cell types, individual binding events of SRF molecules segregated into three chromatin residence time regimes, short, intermediate, and long binding, indicating a cell type-independent SRF property. The chromatin residence time of the long bound fraction was up to 1 min in quiescent cells and significantly increased upon stimulation. Stimulation also enhanced the long bound SRF fraction at specific timepoints (20 and 60 min) in both cell types. These peaks correlated with activation of the SRF cofactors MRTF-A and MRTF-B (myocardin-related transcription factors). Interference with signaling pathways and cofactors demonstrated modulation of SRF chromatin occupancy by actin signaling, MAP kinases, and MRTFs.
关键词: SRF,single molecule,neuron,transcription,HaloTag
更新于2025-09-23 15:22:29
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SMoLR: visualization and analysis of single-molecule localization microscopy data in R
摘要: Background: Single-molecule localization microscopy is a super-resolution microscopy technique that allows for nanoscale determination of the localization and organization of proteins in biological samples. For biological interpretation of the data it is essential to extract quantitative information from the super-resolution data sets. Due to the complexity and size of these data sets flexible and user-friendly software is required. Results: We developed SMoLR (Single Molecule Localization in R): a flexible framework that enables exploration and analysis of single-molecule localization data within the R programming environment. SMoLR is a package aimed at extracting, visualizing and analyzing quantitative information from localization data obtained by single-molecule microscopy. SMoLR is a platform not only to visualize nanoscale subcellular structures but additionally provides means to obtain statistical information about the distribution and localization of molecules within them. This can be done for individual images or SMoLR can be used to analyze a large set of super-resolution images at once. Additionally, we describe a method using SMoLR for image feature-based particle averaging, resulting in identification of common features among nanoscale structures. Conclusions: Embedded in the extensive R programming environment, SMoLR allows scientists to study the nanoscale organization of biomolecules in cells by extracting and visualizing quantitative information and hence provides insight in a wide-variety of different biological processes at the single-molecule level.
关键词: Image analysis,Image quantification,Super-resolution,Microscopy,R,Single-molecule localization
更新于2025-09-23 15:22:29
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Bio-Molecular Applications of Recent Developments in Optical Tweezers
摘要: In the past three decades, the ability to optically manipulate biomolecules has spurred a new era of medical and biophysical research. Optical tweezers (OT) have enabled experimenters to trap, sort, and probe cells, as well as discern the structural dynamics of proteins and nucleic acids at single molecule level. The steady improvement in OT’s resolving power has progressively pushed the envelope of their applications; there are, however, some inherent limitations that are prompting researchers to look for alternatives to the conventional techniques. To begin with, OT are restricted by their one-dimensional approach, which makes it difficult to conjure an exhaustive three-dimensional picture of biological systems. The high-intensity trapping laser can damage biological samples, a fact that restricts the feasibility of in vivo applications. Finally, direct manipulation of biological matter at nanometer scale remains a significant challenge for conventional OT. A significant amount of literature has been dedicated in the last 10 years to address the aforementioned shortcomings. Innovations in laser technology and advances in various other spheres of applied physics have been capitalized upon to evolve the next generation OT systems. In this review, we elucidate a few of these developments, with particular focus on their biological applications. The manipulation of nanoscopic objects has been achieved by means of plasmonic optical tweezers (POT), which utilize localized surface plasmons to generate optical traps with enhanced trapping potential, and photonic crystal optical tweezers (PhC OT), which attain the same goal by employing different photonic crystal geometries. Femtosecond optical tweezers (fs OT), constructed by replacing the continuous wave (cw) laser source with a femtosecond laser, promise to greatly reduce the damage to living samples. Finally, one way to transcend the one-dimensional nature of the data gained by OT is to couple them to the other large family of single molecule tools, i.e., fluorescence-based imaging techniques. We discuss the distinct advantages of the aforementioned techniques as well as the alternative experimental perspective they provide in comparison to conventional OT.
关键词: plasmonic optical tweezers,femtosecond optical tweezers,photonic crystal optical tweezers,fluorescence,single molecule and cell studies
更新于2025-09-23 15:22:29
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Carbazole based ionic small molecule emitter for non-doped light-emitting electrochemical cells
摘要: Great efforts have been made to develop blue emitting organic small molecules for light-emitting electrochemical cells. Herein, blue emitting CPC (CarPhenCar) was synthesized and its emissive properties were studied. CPC exhibits blue fluorescence in toluene solution as well as in solid thin-films. CPC exhibits good thermal and electrochemical stabilities. Application of CPC molecule in solution processed light-emitting electrochemical cells resulted blue emission centered at 485 nm with brightness of 454 cd/m2, current efficiencies of 1.33 cd/A and external quantum efficiencies of 1.76%. These results adequately demonstrate the practicability of tuning the emission color of phenothiazine derivative into blue region.
关键词: Small molecule,ionic,light-emitting electrochemical cells,blue fluorescence
更新于2025-09-23 15:22:29