Search results for " Nanoparticle"
showing 10 items of 936 documents
Self-Assembly of Amphiphilic Nanocrystals
2009
Amphiphilic hybrid materials are formed from polymer-coated semiconductor nanoparticles that simulate a surfactant-like response (see picture). The strength and density of the surface coating are the key assembling forces driving a transition from single particles to cylindrical or vesicular superstructures.
Molecular-mediated assembly of silver nanoparticles with controlled interparticle spacing and chain length
2012
In the present work, we report on a one-pot method for the assembly of noble metal nanoparticles with tunable optical properties, assembly length and interparticle spacing. The synthetic colloidal route is based on the covalent binding among OH-terminated silver nanoparticles by means of dicarboxylic acids with a defined molecular length. As a result, the initially symmetric plasmon band of silver nanoparticles splits into two plasmonic modes when nanoparticles are assembled due to the strong near-field plasmon coupling. We noticed a very good correlation between the plasmon wavelength shift and the interparticle spacing that is represented by the universal scaling law of the surface plasmo…
Cobalt hexacyanoferrate–poly(methyl methacrylate) composite: Synthesis and characterization
2010
Abstract The preparation of cobalt hexacyanoferrate nanoparticles–poly(methyl methacrylate) (CoHCF–PMMA) composites are described together with their characterization and thermochromic properties. CoHCF nanoparticles – investigated by dynamic light scattering – were prepared by optimizing solvent composition and temperature to obtain nanoparticles with a reduced degree of aggregation. The nanoparticles were embedded in a PMMA matrix to obtain a transparent coloured composite which was studied by transmission electron microscopy. The nanoparticle chromic features, enhanced by their reduced sizes, were investigated by UV–vis and FT-IR spectroscopy.
Tuning the Ultrafast Response of Fano Resonances in Halide Perovskite Nanoparticles
2020
International audience; The full control of the fundamental photophysics of nanosystems at frequencies as high as few THz is key for tunable and ultrafast nanophotonic devices and metamaterials. Here we combine geometrical and ultrafast control of the optical properties of halide perovskite nanoparticles, which constitute a prominent platform for nanophotonics. The pulsed photoinjection of free carriers across the semiconducting gap leads to a subpicosecond modification of the far-field electromagnetic properties that is fully controlled by the geometry of the system. When the nanoparticle size is tuned so as to achieve the overlap between the narrowband excitons and the geometry-controlled…
Effect of precursor concentration on size evolution of iron oxide nanoparticles
2017
Thermal decomposition is a promising route for the synthesis of magnetic nanoparticles. The simplicity of the synthesis method is counterbalanced by the complex chemistry of the system such as precursor decomposition and surfactant–reducing agent interactions. Control over nanoparticle size is achieved by adjusting the reaction parameters, namely, the precursor concentration. The results, however, are conflicting as both an increase and a decrease in nanoparticle size, as a function of increasing concentration, have been reported. Here, we address the issue of size-controlled synthesis via the precursor concentration. We synthesized iron oxide nanoparticles with sizes from 6 nm to 24 nm wit…
Novel silver-based nanoclay as an antimicrobial in polylactic acid food packaging coatings.
2010
This paper presents a comprehensive performance study of polylactic acid (PLA) biocomposites, obtained by solvent casting, containing a novel silver-based antimicrobial layered silicate additive for use in active food packaging applications. The silver-based nanoclay showed strong antimicrobial activity against Gram-negative Salmonella spp. Despite the fact that no exfoliation of the silver-based nanoclay in PLA was observed, as suggested by transmission electron microscopy (TEM) and wide angle X-ray scattering (WAXS) experiments, the additive dispersed nicely throughout the PLA matrix to a nanoscale, yielding nanobiocomposites. The films were highly transparent with enhanced water barrier …
Functionalization of theranostic AGuIX® nanoparticles for PET/MRI/optical imaging
2019
International audience; A novel trifunctional imaging probe containing a chelator of radiometal for PET, a NIR heptamethine cyanine dye, and a bioconjugatable handle, has been grafted onto AGuIX® nanoparticles via a Michael addition reaction. The resulting functionalized nanoparticles have been fully characterized, radiolabelled with 64Cu, and evaluated in a mice TSA tumor model using multimodal (PET/MRI/optical) imaging.
Highly Sensitive plasmonic silver nanorods
2011
We compare the single-particle plasmonic sensitivity of silver and gold nanorods with similar resonance wavelengths by monitoring the plasmon resonance shift upon changing the environment from water to 12.5% sucrose solution. We find that silver nanoparticles have 1.2 to 2 times higher sensitivity than gold, in good agreement with simulations based on the boundary-elements-method (BEM). To exclude the effect of particle volume on sensitivity, we test gold rods with increasing particle width at a given resonance wavelength. Using the Drude-model of optical properties of metals together with the quasi-static approximation (QSA) for localized surface plasmons, we show that the dominant contrib…
Usage of moving nanoparticles for improved holographic recording
2013
Metal nanoparticles are used for different applications in holographic configurations. The metal nanoparticles are placed close to an object and encode it by a time varying random mask. A decoding mask is computed and used to obtain super-resolution digital hologram and eliminate the twin image and DC from a digital hologram. The method is also shown to be applicable for other optical methods.
System Design Rules for Intensifying the Electrochemical Reduction of CO 2 to CO on Ag Nanoparticles
2020
Electroreduction of CO2 (eCO2RR) is a potentially sustainable approach for carbon-based chemical production. Despite significant progress, performing eCO2RR economically at scale is challenging. Here we report meeting key technoeconomic benchmarks simultaneously through electrolyte engineering and process optimization. A systematic flow electrolysis study - performing eCO2RR to CO on Ag nanoparticles as a function of electrolyte composition (cations, anions), electrolyte concentration, electrolyte flow rate, cathode catalyst loading, and CO2 flow rate - resulted in partial current densities of 417 and 866 mA/cm2 with faradaic efficiencies of 100 and 98 % at cell potentials of −2.5 and −3.0 …