Search results for "nanostructure"
showing 10 items of 792 documents
Engineering of nanostructured carbon materials with electron or ion beams.
2007
Irradiating solids with energetic particles is usually thought to introduce disorder, normally an undesirable phenomenon. But recent experiments on electron or ion irradiation of various nanostructures demonstrate that it can have beneficial effects and that electron or ion beams may be used to tailor the structure and properties of nanosystems with high precision. Moreover, in many cases irradiation can lead to self-organization or self-assembly in nanostructures. In this review we survey recent advances in the rapidly evolving area of irradiation effects in nanostructured materials, with particular emphasis on carbon systems because of their technological importance and the unique ability…
Advanced Functional Structures Based on Interpolyelectrolyte Complexes
2013
This review considers interpolyelectrolyte complexes, with a particular emphasis on advanced macromolecular co-assemblies based on polyionic species with nonlinear topology and on polymer–inorganic hybrids formed by interpolyelectrolyte complexes containing metal ions and/or metal nanoparticles.
Formation of ZnO nanowires by anodization under hydrodynamic conditions for photoelectrochemical water splitting
2020
[EN] The present work studies the influence of hydrodynamic conditions (from 0 to 5000 rpm) during Zn anodization process on the morphology, structure and photoelectrocatalytic behavior of ZnO nanostructures. For this purpose, analysis with Confocal Laser-Raman Spectroscopy, Field Emission Scanning Electron Microscope (FE-SEM) and photoelectrochemical water splitting tests were performed. This investigation reveals that hydrodynamic conditions during anodization promoted the formation of ordered ZnO nanowires along the surface that greatly enhance its stability and increases the photocurrent density response for water splitting in a 159% at the 5000 rpm electrode rotation speed.
Growth of low-density vertical quantum dot molecules with control in energy emission
2010
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License.-- This article is part of the series 8th International Workshop on Epitaxial Semiconductors on Patterned Substrates and Novel Index Surfaces.
Bimetallic PdAg nanoparticle arrays from monolayer films of diblock copolymer micelles
2015
MICROSCOPIE+ATARI+EEH:GMA:TBG:NSP:MAO; International audience; The self-assembly technique provides a highly efficient route to generate well-ordered structures on a nanometer scale. In this paper, well-ordered arrays of PdAg alloy nanoparticles on flat substrates with narrow distributions of particle size (6-7 nm) and interparticle spacing (about 60 nm) were synthesized by the block copolymer micelle approach. A home-made PS-b-P4VP diblock copolymer was prepared to obtain a micellar structure in toluene. Pd and Ag salts were then successfully loaded in the micellar core of the PS-b-P4VP copolymer. A self-assembled monolayer of the loaded micelles was obtained by dipping the flat substrate …
Current rectification by nanoparticle blocking in single cylindrical nanopores.
2014
Blocking of a charged pore by an oppositely charged nanoparticle can support rectifying properties in a cylindrical nanopore, as opposed to the usual case of a fixed asymmetry in the pore geometry and charge distribution. We present here experimental data and model calculations to confirm this fundamental effect. The nanostructure imaging and the effects of nanoparticle concentration, pore radius, and salt concentration on the electrical conductance–voltage (G–V) curves are discussed. Logic responses based on chemical and electrical inputs/outputs could also be implemented with a single pore acting as an effective nanofluidic diode. To better show the generality of the results, different ch…
Controlled hydrodynamic conditions on the formation of iron oxide nanostructures synthesized by electrochemical anodization: Effect of the electrode …
2017
[EN] Iron oxide nanostructures are of particular interest because they can be used as photocatalysts in water splitting due to their advantageous properties. Electrochemical anodization is one of the best techniques to synthesize nanostructures directly on the metal substrate (direct back contact). In the present study, a novel methodology consisting of the anodization of iron under hydrodynamic conditions is carried out in order to obtain mainly hematite (alpha-Fe2O3) nanostructures to be used as photocatalysts for photoelectrochemical water splitting applications. Different rotation speeds were studied with the aim of evaluating the obtained nanostructures and determining the most attract…
Iron oxide nanostructures for photoelectrochemical applications: Effect of applied potential during Fe anodization
2019
[EN] In photoelectrochemistry, a suitable photoanode leading to high efficiencies in photocatalytic processes is a research challenge. Iron oxide nanostructures are promising materials to be used as photoanodes. In this work, different potentials during iron anodization were applied to study the properties of the synthesized nanostructures. Results revealed that nanostructures anodized at 50V presented well-defined nanotubular structures with open-tube tops, and they achieved values of photocurrent density of 0.11 mA cm(-2) at 0 rpm and 0.14 mA cm(-2) at 1000 rpm (measured at 0.50 V-Ag/Agcl), corresponding to the oxygen evolution reaction from water, i.e. 2H(2)O+4h(+)-> 4H(+)+O-2, demonstra…
Electrochemical deposition of Ag2Se nanostructures
2017
Abstract AgSe based nanostructures (nanowires or nanotubes) were obtained by electrodeposition. A systematic investigation was carried out, varying concentration of the precursors, pH of the electrolytic solution, ligands, and deposition mode, to study the effect of all these parameters on the growth of nanostructures. Nanostructure morphology depends also on the type of metal that was used as support, due to the secondary reaction of hydrogen evolution. On Ni support, the H2 evolution reaction led to formation of only nanotubes, while on copper substrate also nanowires were obtained. Composition of nanostructures depends strongly on solution pH. X-ray diffraction and Raman spectroscopy sho…
Electrochemically Controlled Ion Dynamics in Porphyrin Nanostructures
2020
peer-reviewed The full text of this article will not be available in ULIR until the embargo expires on the 22/07/2021 The dynamics of ion intercalation into solid matrices influences the performance of key components in most energy storage devices (Li-ion batteries, supercapacitors, fuel cells, etc.). Electrochemical methods provide key information on the thermodynamics and kinetics of these ion-transfer processes but are restricted to matrices supported on electronically conductive substrates. In this article, the electrified liquid|liquid interface is introduced as an ideal platform to probe the thermodynamics and kinetics of reversible ion intercalation with nonelectronically active matr…