Irradiation induced elongation of Fe nanoparticles embedded in silica films

© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Irradiation with swift heavy ions causes the deformation of Ferric nanoparticles in direction of the ion beam. Fe nanoparticles with mean diameter of about 20 nm were prepared by gas flow sputtering and subsequently confined within silica films. Two silica films wherein two different densities of Fe nanoparticles are encapsulated were irradiated with 50 MeV Ag ions with fluences of few 1014 ions.cm−2 at 300 K and normal incidence. Transmission electron microscopy analysis shows that the spherical Fe nanoparticles are deformed into prolate nanorods aligned in direction of the incident ion beam. The depth distribution profiles of irradiated particles reveal the presence of a critical fluence above which the elongation kinetics becomes dependent on the nanoparticles density. Analysis indicates that for the lower density particles, a saturation length is reached under irradiation to fluence between 3–4 × 1014 ions.cm−2. However, for the higher density, collective growth into aligned nanowires is presumed to take place. Hysteresis curves of the saturation magnetization and coercivity indicate an increasing magnetic anisotropy, which can be correlated with the deformation of nanoparticles in the direction of the ion beam

Libyan Boy with Autosomal Recessive Trait (P22-phox Defect) of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a primary immune deficiency disorder of the phagocytes. In this disorder, phagocytic cells (polymorphonuclear leukocytes and monocytes) cannot produce active oxygen metabolites and, therefore, cannot destroy the ingested intracellular bacteria. Clinically, patients with CGD usually have recurrent bacterial and fungal infections causing abscess and granuloma formation in the skin, lymph nodes and visceral organs

In-situ growth of nonstoichiometric CrO0.87 and Co3O4 hybrid system for the enhanced electrocatalytic water splitting in alkaline media

The development of electrocatalysts for electrochemical water splitting has received considerable attention in response to the growing demand for renewable energy sources and environmental concerns. In this study, a simple hydrothermal growth approach was developed for the in-situ growth of non-stoichiometric CrO0.87 and Co3O4 hybrid materials. It is apparent that the morphology of the prepared material shows a heterogeneous aggregate of irregularly shaped nanoparticles. Both CrO0.87 and Co3O4 have cubic crystal structures. Its chemical composition was governed by the presence of Co, Cr, and O as its main constituents. For understanding the role CrO0.87 plays in the half-cell oxygen evolution reaction (OER) in alkaline conditions, CrO0.87 was optimized into Co3O4 nanostructures. The hybrid material with the highest concentration of CrO0.87 was found to be highly efficient at driving OER reactions at 255 mV and 20 mA cm−2. The optimized material demonstrated excellent durability for 45 h and a Tafel slope of 56 mV dec−1. Several factors may explain the outstanding performance of CrO0.87 and Co3O4 hybrid materials, including multiple metallic oxidation states, tailored surface properties, fast charge transport, and surface defects. An alternative method is proposed for the preparation of new generations of electrocatalysts for the conversion and storage of energy

Исследование структурных, оптических и электрических характеристик наночастиц ZnO, легированных FeO

Наночастицы ZnO, легированные FeO (NPS FeO-ZnO), были синтезированы химическим методом золь-гель-покрытия на стеклянных подложках с концентрациями 0, 3 и 5%. Исследованы структурные, оптические и электрические свойства синтезированных пленок ZnO, легированных FeO. Методами дифракции рентгеновских лучей установлены кристаллическая структура, особенности роста кристаллов и химического состава образцов. УФ-спектры синтезированных пленок обнаруживают синее смещение в оптической запрещенной зоне наночастиц ZnO, интегрированных с FeO. Зависимости электропроводности от температуры (Т) пленок выявили ее линейное повышение обратно пропорционально температуре (1/Т)

Anisotropic deformation of colloidal particles under 4 MeV Cu ions irradiation

Anisotropic deformation of colloidal particles was investigated under ion irradiation with 4 MeV Cu ions. In this study, 0.5 mu m-diameter colloidal silica particles, 0.5 mu m-diameter Au-silica core-shell particles, and 15 nm-diameter Au colloids embedding in a planar Si/SiO2 matrix were irradiated with 4 MeV Cu ions at room temperature and normal incidence. In colloidal silica particles, ion beam irradiation causes dramatic anisotropic deformation; silica expands perpendicular to the beam and contracts parallel, whereas Au cores elongate. Au colloids in a planar SiO2 matrix were anisotropically transformed from spherical colloids to elongated nanorods by irradiating them with 4 MeV Cu ions. The degree of anisotropy varied with ion flux. Upon irradiating the embedded Au colloids, dark-field light scattering experiments revealed a distinct color shift to yellow, which indicates a shift in surface plasmon resonance. A surface plasmon resonance measurement reveals the plasmon resonance bands are split along the arrays of Au colloids. Our measurements have revealed resonance shifts that extend into the near-infrared spectrum by as much as 50 nm.Funding Agencies|Ajman University Internal Research Grant, UAE [2021-IRG-HBS-14]</p

Plasmon-Enhanced Light Absorption in (p-i-n) Junction GaAs Nanowire Solar Cells : An FDTD Simulation Method Study

A finite-difference time-domain method is developed for studying the plasmon enhancement of light absorption from vertically aligned GaAs nanowire arrays decorated with Au nanoparticles. Vertically aligned GaAs nanowires with a length of 1 mu m, a diameter of 100 nm and a periodicity of 165-500 nm are functionalized with Au nanoparticles with a diameter between 30 and 60 nm decorated in the sidewall of the nanowires. The results show that the metal nanoparticles can improve the absorption efficiency through their plasmonic resonances, most significantly within the near-bandgap edge of GaAs. By optimizing the nanoparticle parameters, an absorption enhancement of almost 35% at 800 nm wavelength is achieved. The latter increases the chance of generating more electron-hole pairs, which leads to an increase in the overall efficiency of the solar cell. The proposed structure emerges as a promising material combination for high-efficiency solar cells

Ion-induced elongation of gold nanoparticles in silica by irradiation with Ag and Cu swift heavy ions: track radius and energy loss threshold

International audienceSystematic investigations of the energy loss threshold above which the irradiation-induced elongation of spherical Au nanoparticles occurs are reported. Silica films containing Au nanoparticles with average diameters of 15-80 nm embedded within a single plane were irradiated with 12-54 MeV Ag and 10-45 MeV Cu ions at 300 K and at normal incidence. We demonstrate that the efficiency of the ion-induced nanoparticle elongation increases linearly with the electronic energy transferred per ion track length unit from the energetic ions to the silica film. Ion beam shaping occurs above a threshold value of the specific electronic energy transfer. Three relevant regions are identified with respect to the original size of the Au nanoparticles. For 15 and 30 nm diameter particles, elongation occurs for electronic stopping power larger than 3.5 keV nm−1. For Au nanoparticles with 40-50 nm diameter an electronic stopping power above 5.5 keV nm−1 is required for elongation to be observed. Elongation of Au nanoparticles with 80 nm diameter is observed for electronic stopping between ∼7-8 keV nm−1. For all combinations of ions and energies, the ion track temperature profiles are calculated within the framework of the thermal spike model. The correlation between experimental results and simulated data indicates a thermal origin of the increase in the elongation rate with increasing the track diameter. (Some figures in this article are in colour only in the electronic version