A5057418785- Gold and Silver Nanoparticles Synthesis and Applications
- Quantum Dots Synthesis And Properties
- Spectroscopy and Quantum Chemical Studies
- Plasmonic and Surface Plasmon Research
- Nanocluster Synthesis and Applications
- Metamaterials and Metasurfaces Applications
- Advanced Chemical Physics Studies
- Characterization and Applications of Magnetic Nanoparticles
- Magnetic properties of thin films
- Molecular spectroscopy and chirality
- Nanomaterials and Printing Technologies
- Advanced biosensing and bioanalysis techniques
- Iron oxide chemistry and applications
- Magnetic Properties and Synthesis of Ferrites
- Synthesis and Properties of Aromatic Compounds
- Supramolecular Self-Assembly in Materials
- Molecular Junctions and Nanostructures
- Surface Chemistry and Catalysis
- ZnO doping and properties
- Photochemistry and Electron Transfer Studies
- Theoretical and Computational Physics
- Multiferroics and related materials
- Fluid Dynamics and Thin Films
- Photoreceptor and optogenetics research
- Advanced Sensor and Energy Harvesting Materials
Tel Aviv University
2016-2025
Nagoya University
2023
Bar-Ilan University
2001
University of California, Los Angeles
1997-1999
University of Liège
1999
Lawrence Berkeley National Laboratory
1997
Coated magnetite nanoparticles with a 6−8 nm average diameter were prepared. The surfactants used to stabilize the and disperse them in organic solvents oleic acid (OA), lauric , dodecyl phosphonate, hexadecyl dihexadecyl phosphate. Transmission electron microscopy analyses of aggregation coated particles suggest that carboxylate provide better isolation dispersibility as compared phosphonate surfactants. However, Fourier transform infrared spectra phosphate these cover surface islands high...
Uniform 2D arrays of organically passivated magnetite (Fe3O4) and cobalt ferrite (CoFe2O4) have been prepared by the Langmuir–Blodgett technique. Preliminary studies magnetization curves show small changes in shape depending on number deposited layers. Control over formation colloidal solutions arrays, combined with possibility to tune physical properties these may lead new information storage media as well novel magnetoresistive materials.
Chiral molecules are shown to induce circular dichroism (CD) at surface plasmon resonances of gold nanostructures when in proximity the metal without direct bonding metal. By changing molecule-Au separation, we were able learn about mechanism plasmonic CD induction for such nanostructures. It was found that even two monolayers chiral can observable CD, while presence their own signal is unmeasurable. Hence, arrays could offer a route enhanced sensitivity chirality detection.
Circular dichroism (CD) induced at exciton transitions by chiral ligands attached to single component and core/shell colloidal quantum dots (QDs) was used study the interactions between QDs their capping ligands. Analysis of CD line shapes CdSe CdS capped with l-cysteine reveals that all features in complex spectra can be assigned different excitonic transitions. It is shown each transition accompanied a derivative shape response, indicating ligand split level into two new sublevels,...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTArchitectonic Quantum Dot SolidsGil Markovich, C. Patrick Collier, Sven E. Henrichs, Françoise Remacle, Raphael D. Levine, and James R. HeathView Author Information Department of Chemistry Biochemistry, University California, Los Angeles, California 90095-1569, Departement de Chimie, B6, Université Liege, B 4000 Belgium Cite this: Acc. Chem. Res. 1999, 32, 5, 415–423Publication Date (Web):January 8, 1999Publication History Received4 May...
We present the photoelectron-spectra of Cl−, Br−, and I−, solvated in water clusters-(H2O)n, where n is 1–7, 1–16, 1–60, respectively, taken with 7.1 eV photon energy. The vertical binding energies anions are used to extract solvent electrostatic stabilization anion. photoelectron spectra I− indicate formation first solvation layer a coordination number six. Ab initio calculations support shell closure at n=6. This conclusion not born-out by current molecular dynamics calculations. These...
Silver nanocrystals grown on a poly(dG)-poly(dC) double stranded DNA scaffold displayed circular dichroism at their surface plasmon excitation band. This chiral signature was not observed in control experiment where silver of similar size were produced without the template and adsorbed to DNA. It is concluded that templated Ag had preferred structural handedness.
Colloidal Ag nanoparticles coated with L-glutathione attached to bimane chromophores were studied by absorption, circular dichroism (CD), and fluorescence spectroscopies. The absorption CD spectra resonantly enhanced surface plasmons. wavelength particle-size dependence of the enhancement indicated that an electromagnetic "antenna" effect is in action. Supporting information for this article available on WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z800231_s.pdf or from author....
Silver nanoparticles were prepared in aqueous solutions of chiral supramolecular structures made molecular building blocks. While these molecules display negligible circular dichroism (CD) as isolated molecules, their stacking produced a significant CD response at room temperature, which could be eliminated by heating to 80 °C due disordering the stacks. The stack-plasmon coupling has induced surface plasmon resonance absorption band silver nanoparticles. Switching between two plasmonic...
Equal and opposite: A chiral surfactant molecule was used to induce high enantioselectivity in the transformation from achiral phase of mercury sulfide, probably through binding thiolate groups Hg ions forming crystal. The generation truly inorganic nanocrystals tailored size shape should be useful for many applications, such as enantioselective catalysis sensing. Detailed facts importance specialist readers are published "Supporting Information". Such documents peer-reviewed, but not...
The synthesis of chiral penicillamine-capped CdS and CdSe quantum dots (QDs) was adjusted to control the size nanoparticles. This, together with separation, allowed for simultaneous tuning absorption, circular dichroism (CD), fluorescence on a wide wavelength range. Band edge transitions were accompanied by peaks which red-shifted increase in particle size. clear correlation between absorption CD bands as well semiconductor QDs used derive an experimental scaling law optical activity....
The preparation of conductive and transparent gold/silver nanowire mesh films is reported. nanowires formed after the reduction metal ions was triggered a thin growth solution film spread on substrate. Metal progressed within template highly concentrated surfactant liquid crystalline mesostructure substrate during drying to form ordered bundles ultrathin nanowires. exhibited metallic conductivity over large areas, high transparency, flexibility.
The photosystem I (PS I) protein is one of nature's most efficient light harvesting complexes and exhibits outstanding optoelectronic properties. Here we demonstrate how metal nanoparticles which act as artificial antennas can enhance the absorption protein. This hybrid system shows an increase in circular dichroism over entire band rather than at specific plasmon resonance wavelength spherical (NPs). explained by broad-resonant nonresonant field enhancements caused NP aggregates, high...
This Perspective concerns the latest developments in field of chiral nanocrystals (NCs) and metastructures, focusing primarily on plasmonic nanostructures. Such nanomaterials exhibit unusually strong near-field electromagnetic responses that enable efficient biosensing light manipulation. Herein we share our thoughts trends mark what call a paradigm shift for vast dynamic chiroptical materials. The topics to be considered include polarization-sensitive photocatalysis with NCs, bioconjugates,...
Nanoparticles deposited at the air-water interface are observed to form circular domains low density and stripes higher density. We interpret these patterns as equilibrium phenomena produced by a competition between an attraction longer-ranged repulsion. Computer simulations of generic pair potential with attractive repulsive parts this kind, reproduce both stripe patterns. Such have use in nanoelectronic applications.
Uniform, organically functionalized, 8.5-nm-diameter nanocrystals of ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ were synthesized and assembled into close-packed monolayer as well multilayer arrays using the Langmuir-Blodgett technique. The ac dc magnetic susceptibility measurements on in comparison with isolated particles indicate strong dipolar interactions a spin-glass-like slowing down relaxation times. Differences characteristics between to observed, such larger remanent magnetization higher...
We have measured the photoelectron spectra of clusters I- solvated in water up to fifteen molecules. The vertical binding energy electron increases with cluster size and levels off containing more than six These results strongly indicate that first solvation layer around ion consists This picture is quantitatively consistent spectroscopy result bulk water.
Low frequency impedance spectroscopy was applied on a Langmuir monolayer of alkylthiol passivated 35 \AA{} diameter silver quantum dots, as function interparticle separation distance. As spacing decreases below 30% particle diameter, reduction in charge tunneling time is observed. On further compression, the complex films undergoes transition from parallel $\mathrm{RC}$ equivalent circuit to an inductive circuit. Optical reflectance changes are consistent with deduced metal-insulator transition.
Tunneling junctions of stacked monolayers uniform, organically functionalized ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ nanocrystals 5.5 nm average diameter were prepared. Current-voltage characteristics the studied as function temperature and magnetic field. An abrupt increase in resistance was observed on cooling below 96 K. This is attributed to Verwey metal-insulator transition nanocrystals. Above K, $I\ensuremath{-}V$ curves reflect density states narrow conduction band. conductance peak...
Chiroptical effects are routinely observed in three dimensional objects lacking mirror symmetry or quasi-two-dimensional thin films in-plane symmetry. Here we show that symmetric plasmonic planar arrays of circular nanoholes produced strong chiroptical responses at visible wavelengths on tilting them with respect to the incident light beam due collective asymmetric nature their surface plasmon excitations. This extrinsic effect can be stronger than local response intrinsically chiral and may...
The optical activity of fabricated metallic nanostructures is investigated by complete polarimetry. While lattices decorated with nanoscale gammadia etched in thin films have been described as two dimensional, planar nanostructures, they are better quasi-planar structures some three dimensional character. We find that the these arises not only from dissymmetric backing a substrate but, more importantly, selective rounding nanostructure edges. A true chiroptical response far-field allowed...
Abstract Can chiral light induce shapes in nanocrystals a diluted solution? So far, it has been unclear whether could be and, if such, under which conditions may occur. By using realistic models of plasmonic nanocrystals, this work shows that the imprinting 3D chirality on solution by circularly polarized (CPL) is possible. Such 3D‐chiral patterns originate from electromagnetic retardation effect. This investigates formation spatial distributions near fields and hot electrons produced CPL...