Search results for "nanoparticle"

Matching emission centers of electrons and photons in current-carrying silver nanoparticle films

2019

Current flow through a nanoparticle film (two-dimensional ensemble of small tunnel-coupled metal particles on a dielectric substrate) is accompanied by electron and photon emission. It has a localized character (originates from emission centers). With an increase in applied voltage, the number of emission centers increases, and with further increase, some of them may burn out. In dark conditions, photon emission centers are visible with a bare eye. To visualize electron emission centers, emission electron microscopy is used. The conducted measurements allow comparison of the number and relative positions of electron and photon emission centers. It is shown that electrons and photons are emi…

Broadband light trapping in thin film solar cells with self-organized plasmonic nano-colloids

2015

The intense light scattered from metal nanoparticles sustaining surface plasmons makes them attractive for light trapping in photovoltaic applications. However, a strong resonant response from nanoparticle ensembles can only be obtained if the particles have monodisperse physical properties. Presently, the chemical synthesis of colloidal nanoparticles is the method that produces the highest monodispersion in geometry and material quality, with the added benefits of being low-temperature, low-cost, easily scalable and of allowing control of the surface coverage of the deposited particles. In this paper, novel plasmonic back-reflector structures were developed using spherical gold colloids wi…

Modification of a photoanode by means of localized surface plasmon resonance from Au nanoparticles decorated on ZnO nanorods for photoelectrochemical…

2019

Graphene in strong laser field: experiment and theory

2015

The interaction of graphene nanoparticles and strong 64 fs pulses is examined. We demonstrate high-order harmonic generation in the plasma contained in crumpled sheets of graphene. The morphological studies of the debris of ablated graphene, application of single-color and two-color pumps of graphene-containing plasma, and theoretical consideration of the high-order harmonic generation in this medium are presented.

In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets

2012

Import JabRef; International audience; Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.

Direct hot-carrier transfer in plasmonic catalysis

2019

Plasmonic metal nanoparticles can concentrate optical energy and enhance chemical reactions on their surfaces. Plasmons can interact with adsorbate orbitals and decay by directly exciting a carrier from the metal to the adsorbate in a process termed the direct-transfer process. Although this process could be useful for enhancing the efficiency of a chemical reaction, it remains poorly understood. Here, we report a preliminary investigation employing time-dependent density-functional theory (TDDFT) calculations to capture this process at a model metal-adsorbate interface formed by a silver nanoparticle (Ag147) and a carbon monoxide molecule (CO). Direct hot-electron transfer is observed to o…

Charge Transfer Plasmons in Dimeric Electron Clusters

2020

The tunability of the optical response of dimers of metal clusters and nanoparticles makes them ideal for many applications from sensing and imaging to inducing chemical reactions. We have studied charge transfer plasmons in separate and linked dimers of closed-shell electron clusters of 8 and 138 electrons using time-dependent density functional theory. The simple model clusters enable the systematic study of the charge transfer phenomenon from the electronic perspective. To identify the charge transfer plasmons, we have developed an index, the Charge Transfer Ratio, for quantifying the charge transfer nature of the excitations. In addition, we analyze the induced transition density and th…

Development of a three-dimensional cell culture system based on microfluidics for nuclear magnetic resonance and optical monitoring

2014

A new microfluidic cell culture device compatible with real-time nuclear magnetic resonance (NMR) is presented here. The intended application is the long-term monitoring of 3D cell cultures by several techniques. The system has been designed to fit inside commercially available NMR equipment to obtain maximum readout resolution when working with small samples. Moreover, the microfluidic device integrates a fibre-optic-based sensor to monitor parameters such as oxygen, pH, or temperature during NMR monitoring, and it also allows the use of optical microscopy techniques such as confocal fluorescence microscopy. This manuscript reports the initial trials culturing neurospheres inside the micro…

Colloidal nanoparticle sorting and ordering on anodic alumina patterned surfaces using templated capillary force assembly

2017

Abstract A new, robust technique of size-selective nanoparticle ordering on porous anodized aluminum oxide (PAAO) templates is presented. Simultaneous particle sorting and array formation is achieved for the first time using a polydisperse suspension of irregularly shaped diamond nanocrystals. The array parameters can be tuned through a balance of evaporation driven particle flux, capillary, electrostatic, and adhesion forces, which are influenced by the asperities of the surface during the capillary and convective assembly dip-coating process. The resulting structures are dense (lower limit approximately 50 nm center separation), isolated (non-touching) nanoparticle arrays with a size dist…

Direct formation of Sub-Micron and Nanoparticles of a bioinspired coordination polymer based on Copper with Adenine

2017

We report on the use of different reaction conditions, e.g., temperature, time, and/or concentration of reactants, to gain control over the particle formation of a bioinspired coordination polymer based on copper(II) and adenine, allowing homogeneous particle production from microto submicro-, and up to nano-size. Additionally, studies on this reaction carried out in the presence of different surfactants gives rise to the control of the particle size due to the modulation of the electrostatic interactions. Stability of the water suspensions obtained within the time and pH has been evaluated. We have also studied that there is no significant effect of the size reduction in the magnetic prope…