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Self-assembly of clicked star-shaped triazines into functional nanostructures
摘要： Two non-amphiphilic star-shaped 2,4,6-tris(1,2,3-triazol-4-yl)-1,3,5-triazines showing different behavior in terms of self-assembly and luminescent properties are described. They aggregate in the liquid phase to form low-dimensional nanostructures with a variety of morphologies, such as spherical particles, one-hole hollow spheres, toroids, twisted fibers or helical nanotubes, just by varying the conditions of a straightforward reprecipitation method. Aggregation has an opposite effect concerning the fluorescent properties of the proposed compounds, either causing the enhancement or the quenching of the emission after the self-assembly. Quantum chemical calculations have been also performed to assist in the structural and electronic characterization of the two star-shaped compounds.
关键词： nanotube,triazine,nanoparticle,AIE,self-assembly
更新于2025-09-10 09:29:36
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Dynamics of gold nanoparticle clusters observed with liquid-phase electron microscopy
摘要： The dynamics of processes of nanoparticles such as diffusion, attraction and repulsion, and self-assembly of structures of nanoparticles at the solid-liquid interfaces differ significantly from those occurring for bulk conditions and their fundamental physical rules are still unknown. Here, we used liquid phase scanning transmission electron microscopy (LP-STEM) to study several aspects of nanoparticle dynamics of colloidal chitosan coated gold nanoparticle (TCHIT-AuNP) clusters in a liquid layer enclosed between two SiN membranes. We found that upon beam irradiation using an electron flux of 0.9 e?/s?2, the AuNPs assembled in clusters that shifted and rotated with time. The newly formed clusters could join and form larger clusters via a mechanism of oriented attachment. By increasing the electron flux to 6.2 e?/s?2, we observed the fragmentation of some of the clusters and TCHIT-AuNPs were exchanged between clusters. At the highest electron flux studied 25 e?/s?2, we observed AuNPs moving at a very slow speed compared to Brownian motion in liquid even though they were not permanently attached or pinned to the liquid-enclosing membrane. Experiments using branched polyethylenimine (BPEI) coated AuNPs were carried out for comparison.
关键词： nanoparticle clustering,nanoparticle dynamics,solid-liquid interface,gold nanoparticles,scanning transmission electron microscopy,liquid-phase electron microscopy
更新于2025-09-09 09:28:46
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Preparation and application of polystyrene-grafted alumina core-shell nanoparticles for dielectric surface passivation in solution-processed polymer thin film transistors
摘要： Polystyrene-grafted alumina nanoparticles were synthesized by silane coupling between dimethylchlorosilane-terminated polystyrene (PS) and gamma-type alumina nanoparticles and characterized. The surface grafting density of the polystyrene chains on the nanoparticles was estimated to be 0.13 molecules per square nanometer. The Al2O3-PS nanoparticles are solution processable in organic solvents, including ethyl acetate, butyl acetate, and toluene, which enabled preparation of blends with polystyrene or poly(methyl methacrylate). The dielectric constant of the Al2O3-PS nanoparticle/polymer blend films is composition tunable from 2.59 to 7.79. The alumina-PS nanoparticles and their blends with polymers were found to form efficient surface passivation films on the oxide dielectric layer in organic field-effect transistors (OFETs).
关键词： core-shell nanoparticle,alumina-polymer gate insulator,organic field-effect transistor,surface modification
更新于2025-09-09 09:28:46
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An Overview of the Synthesis of Gold Nanoparticles Using Radiation Technologies
摘要： At a nano-level, optical properties of gold are unique and gave birth to an emerging platform of nanogold-based systems for diverse applications, because gold nanoparticle properties are tunable as a function of size and shape. Within the available techniques for the synthesis of gold nanoparticles, the radiolytic synthesis allows proper control of the nucleation process without the need for reducing agents, in a single step, combined or not with simultaneous sterilization. This review details and summarizes the use of radiation technologies for the synthesis and preparation of gold nanoparticles concerning fundamental aspects, mechanism, current pathways for synthesis and radiation sources, as well as briefly outlines final applications and some toxicity aspects related to nanogold-based systems.
关键词： electron beam radiation,radiation technologies,X-ray,radiolytic synthesis,gamma radiation,gold nanoparticle
更新于2025-09-09 09:28:46
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Synthesis and Characterization of Pectin Functionalized Bimetallic Silver/ Gold Nanoparticles for Photodynamic Applications
摘要： Over the last decade, nanotechnology has become one of the most energetic evolving areas in research field. The astonishing properties of nanostructured materials are utilized in many field of research like energy, electronics and medicines. In this work, Functionalized silver, gold and Bimetallic Silver/Gold nanoparticles were prepared through chemical reduction in aqueous solution, following a method that was affable to the environment; this work will be stretching for photodynamic activities. AgNO3 and HAuCl4 were reduced using in-situ techniques in the presence of pectin and folic acid. Using the optical properties of metallic nanoparticles, surface plasmon resonance was determined from UV-Vis spectroscopy analysis, and the values obtained for silver and gold were approximately 350 nm and 543 nm in wavelength respectively. The absorption peaks of the surface plasmon band show a shift due to the size effect of the nanoparticles. The average hydrodynamic size and the size distribution of the synthesized nanoparticles were obtained through dynamic light scattering. To obtain a better understanding of the functionalization and conjugation conditions, High-resolution transmission electron microscopy has been used. The development of this process, which is compassionate for the environment, opens the possibility for many applications in the field of photodynamic applications.
关键词： Gold,Silver,Nanoparticle,Surface plasmon resonance
更新于2025-09-09 09:28:46
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Characterization of core–shell nanostructure consisting Si–Au–SiO2 based on manipulation of optical properties
摘要： In this article, we investigated some physical characteristics of core–shell nanostructure in optical regime and perturbation has been also introduced as an effective method in shaping of optical properties. The proposed nanostructures are composed of the selected materials as: Silicon, Silicon Dioxide and Gold. At first, the extinction cross section spectra are calculated for multilayer core–shell nanostructures in optical range and the configuration effect of the constructed materials in a multilayer nanostructure are investigated for determination of Plasmon range. Then, the new structures of core–shell nanoparticles (gold–silicon) are presented, which have an amount of impurity particle in their shells as perturbation and also their extinction cross section spectra are calculated. The obtained results in this article give a proper approach about perturbation effect in broadening, sharpening and shifting of optical response which are decisive factors especially nano-network systems. Indeed, it has been proposed that the impurity particles in the shells can be a mechanism for tuning of optical characteristics of the presented nanoparticles in practical fields and also creation of local oscillations as plasmonic resonances in a considered optical range. Besides, redshift in extinction cross section can be also created by particle perturbation. At the end, the effective permittivity of the perturbed core-shells are extracted. The optional frequency range is selected between 300 and 900 (THz).
关键词： Effective permittivity,Perturbation,Nanoparticle impurity,Extinction cross section,Core–shell nanostructure,Plasmonic resonance frequency
更新于2025-09-09 09:28:46
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Alkaline Phosphatase-Triggered Self-Assembly of Near-Infrared Nanoparticles for Enhanced Photoacoustic Imaging of Tumor
摘要： Photoacoustic (PA) imaging is advantageous for the diagnosis of superficial cancer with high spatial resolution. However, to the best of our knowledge, using an alkaline phosphatase (ALP)-activatable probe for enhanced PA imaging of tumor has not been reported. In this work, we rationally designed a NIR probe IR775-Phe-Phe-Tyr(H2PO3)-OH (1P) for PA imaging ALP activity in vitro and in tumor. Under the catalysis of ALP, 1P was efficiently converted to IR775-Phe-Phe-Tyr-OH (1) which self-assembled into the nanoparticles 1-NPs. Formation of 1-NPs induced a 6.4-fold enhancement of the 795 nm PA signal of 1P. In vivo tumor PA imaging results indicated that, compared with that in the ALP inhibitor-treated control group, PA contrast in the experimental group enhanced 2.3 folds at 4 h post 1P injection. By replacing the Phe-Phe-Tyr(H2PO3)-OH motif in 1P with other enzyme-cleavable ones, we hope more PA probes could be developed for the precise diagnoses of their corresponding cancers in the near future.
关键词： photoacoustic imaging,near-infrared nanoparticle,alkaline phosphatase,self-assembly
更新于2025-09-09 09:28:46
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Linear Optical Properties of Gold Colloid
摘要： Gold colloid was prepared by reducing HAuCl4·4H2O with Na3C6H5O7·2H2O. The morphology, size of gold nanoparticles and the optical property of colloid were characterized by transmission electron microscope and UV-Vis spectrophotometer, respectively. It shows that the gold nanoparticles are in the shape of spheres with diameters less than 8 nm, and the surface plasmon resonance absorption peak is located at about 438 nm. As the volume fraction of gold particles increases, the intensity of absorption peak strengthens. The optical property of gold colloid was analyzed by Maxwell-Garnett (MG) effective medium theory in the company of Drude dispersion model. The results show that the matrix dielectric constant is a main factor, which influences the optical property of gold colloid.
关键词： gold nanoparticle,aqueous-phase reduction,Maxwell-Garnett effective medium theory,Drude dispersion model
更新于2025-09-09 09:28:46
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Pyrite-Type CoS2 Nanoparticles Supported on Nitrogen-Doped Graphene for Enhanced Water Splitting
摘要： It is extremely meaningful to develop cheap, highly efficient, and stable bifunctional electrocatalysts for both hydrogen and oxygen evolution reactions (HER and OER) to promote large-scale application of water splitting technology. Herein, we reported the preparation of CoS2 nanoparticles supported on nitrogen-doped graphene (CoS2@N-GN) by one-step hydrothermal method and the enhanced electrochemical efficacy for catalyzing hydrogen and oxygen in water electrolysis. The CoS2@N-GN composites are composed of nitrogen-doped graphene and CoS2 nanocrystals with the average size of 73.5 nm. Benefitting from the improved electronic transfer and synergistic effect, the as-prepared CoS2@N-GN exhibits remarkable OER and HER performance in 1.0 M KOH, with overpotentials of 243 mV for OER and 204 mV for HER at 10 mA cm?2, and the corresponding Tafel slopes of 51.8 and 108 mV dec?1, respectively. Otherwise, the CoS2@N-GN hybrid also presents superior long-term catalytic durability. Moreover, an alkaline water splitting device assembled by CoS2@N-GN as both anode and cathode can achieve a low cell voltage of 1.53 V at 60 ?C with a high faraday efficiency of 100% for overall water splitting. The tremendously enhanced electrochemical behaviors arise from favorable factors including small sized, homogenously dispersed novel CoS2 nanocrystals and coupling interaction with the underlying conductive nitrogen-doped graphene, which would provide insight into the rational design of transition metal chalcogenides for highly efficient and durable hydrogen and oxygen-involved electrocatalysis.
关键词： water splitting,HER/OER,graphene,nanoparticle,composite,cobalt sulfide
更新于2025-09-09 09:28:46
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Structuring of Magnetic Nanoparticle Fluids for Decorative and Functional Printing and Coating
摘要： Printing and coating of magnetic inks is widely used in the field of magnetic barcode labels. Nanoparticle inks have gained increasing interest in the field of printed electronics. Controlling the transport of magnetic nanoparticle fluids by external magnetic fields is nowadays mainly applied in environmental and biomedical research, e.g. in order to transport functionalised magnetic particles for drug delivery, sensing, thermal cancer therapy, or for the extraction of pollutants in waste water cleaning. Application examples of field assisted nanoparticle assembly or fluid control in coating and printing, e.g. for the structural colour generation in photonics, are recently emerging. In this paper, we address the topic of field assisted patterning by the design of a versatile magnetic pattering and structuring platform for field assisted nanoparticle assembly and locally tailored pattern formation in printing and thin film coating. 2D finite element modelling for tailored magnetic field patterning, as well as experimental inkjet printing and coating results for Fe2O3 iron oxide nanoparticles on glass are presented and discussed. The developed print patterning technique is of interest for decorative and functional printing and coating, e.g. for further developments in the application field of smart security tags.
关键词： superparamagnetic nanoparticles,coating,patterning system design,inkjet printing,nanoparticle inks,field assisted patterning
更新于2025-09-09 09:28:46