Search results for "nanoparticle"

Hybrid paper–TiO2 coupled with a Cu2O heterojunction: an efficient photocatalyst under sun-light irradiation

2016

Hybrid paper-TiO2, paper-Cu2O-TiO2 and paper-TiO2-Cu2O photocatalysts were prepared via a non-hydrolytic sol-gel process followed by mild hydrothermal treatment to generate the TiO2 layer, and a reduction process to form the Cu2O nanoparticles. The hybrid photocatalysts have been characterized by Raman, TGA, FE-SEM, UV-Vis and XPS. The immobilized TiO2 was found to form a homogeneous thin layer composed of nanoparticles with a size smaller than 10 nm. The Cu2O nanoparticles with sizes of 30-100 nm were generated either on the top of the TiO2 layer or by reduction of Cu2+ ions. All the prepared hybrid catalysts showed efficient photocatalytic properties for the degradation of toluidine when …

Self-assembled metal-oxide nanoparticles on GaAs: infrared absorption enabled by localized surface plasmons

2021

Abstract Metal-oxides hold promise as superior plasmonic materials in the mid-infrared compared to metals, although their integration over established material technologies still remains challenging. We demonstrate localized surface plasmons in self-assembled, hemispherical CdZnO metal-oxide nanoparticles on GaAs, as a route to enhance the absorption in mid-infrared photodetectors. In this system, two localized surface plasmon modes are identified at 5.3 and 2.7 μm, which yield an enhancement of the light intensity in the underlying GaAs. In the case of the long-wavelength mode the enhancement is as large as 100 near the interface, and persists at depths down to 50 nm. We show numerically t…

Ferulic Acid-Loaded Lipid Nanostructures as Drug Delivery Systems for Alzheimers Disease: Preparation, Characterization and Cytotoxicity Studies

2009

Off-Resonant Optical Excitation of Gold Nanorods: Nanoscale Imprint of Polarization Surface Charge Distribution

2011

International audience; We report on the nanoscale optical characterization of gold nanorods irradiated out of their plasmonic resonance. Our approach is based on the reticulation of a photopolymerizable formulation locally triggered by enhanced electromagnetic fields. The tiny local field enhancement stems from the surface polarization charges associated with the electric field discontinuity at the metal/dielectric interface. This allows us to get a nanoscale signature of the spatial distribution of the surface charge density in metallic nanoparticles irradiated off-resonance.

Effect of doping and crystallite size on the electrochemical performance of Li4Ti5O12

2016

Abstract Defect spinel phase lithium titanate (Li 4 Ti 5 O 12 ) has been suggested as a promising negative electrode material for next generation lithium ion batteries. Flame spray pyrolysis has been shown to be a viable fast, one-step process for synthesis of nanoparticulate Li 4 Ti 5 O 12 . However, due to the rapid quenching that is integral to the process the crystallite size remain very small and non-uniform. To overcome this shortcoming a vertical flow tube furnace was used to increase the high-temperature residence time. This resulted in an increase in the crystallite size and crystallinity of the product. As a result of this increase the electrochemical performance of the Li 4 Ti 5 …

Au102(p-MBA)44 nanocluster, a superatom suitable for bio-applications

2016

Inorganic nanoparticles, including metals, semiconductors and metal oxides, comprise a common set of structures exhibiting an inorganic core ‘passivated’ by an organic shell. Ligated inorganic nanoparticles currently provoke widespread fundamental interest in their structural, optical and magnetic properties, which differ fundamentally from bulk counterparts. These nanomaterials are already finding applications in biology, medicine, solar energy, and display panels. 1-6 Conjugating inorganic nanoparticles with organic (biological) material for applications in nanobiology and nanomedicine creates significant challenges for controlling the effects on the environment, particularly regarding to…

Direct optical measurement of light coupling into planar waveguide by plasmonic nanoparticles

2012

Coupling of light into a thin layer of high refractive index material by plasmonic nanoparticles has been widely studied for application in photovoltaic devices, such as thin-film solar cells. In numerous studies this coupling has been investigated through measurement of e.g. quantum efficiency or photocurrent enhancement. Here we present a direct optical measurement of light coupling into a waveguide by plasmonic nanoparticles. We investigate the coupling efficiency into the guided modes within the waveguide by illuminating the surface of a sample, consisting of a glass slide coated with a high refractive index planar waveguide and plasmonic nanoparticles, while directly measuring the inte…

A DNA-nanoparticle actuator enabling optical monitoring of nanoscale movements induced by an electric field.

2018

Merging biological and non-biological matter to fabricate nanoscale assemblies with controllable motion and function is of great interest due to its potential application, for example, in diagnostics and biosensing. Here, we have constructed a DNA-based bionanoactuator that interfaces with biological and non-biological matter via an electric field in a reversibly controllable fashion. The read-out of the actuator is based on motion-induced changes in the plasmon resonance of a gold nanoparticle immobilized to a gold surface by single stranded DNA. The motion of the gold nanoparticle and thus the conformational changes of the DNA under varying electric field were analyzed by dark field spect…

Atomic force microscopy and Raman investigation on the sintering process of amorphous SiO2 nanoparticles

2010

We report an experimental investigation on the sintering process induced in fumed silica powders by isochronal thermal treatments at T=1270 K. Three types of fumed silica are considered, consisting of amorphous SiO2 (a-SiO2) particles with mean diameters 7, 14, and 40 nm. The study is performed by atomic force microscopy (AFM), to follow the morphological changes, and by Raman scattering, to obtain information on the concomitant structural modifications. The former method indicates that the sintering process proceeds by aggregation of single particles into larger grains, whose sizes increase with the thermal treatment duration. Furthermore, for each fumed silica type considered, the quantit…

Functionalization of mesoporous silica nanoparticles through one-pot co-condensation in w/o emulsion

2022

In this work, three different functionalized mesoporous silica nanoparticles (MSNs) were synthesized through the co-condensation synthesis in oil/water emulsion. Hexadecyltrimethoxysilane, triethoxy-3-(2-imidazolin-1-yl)propylsilane and (3-mercaptopropyl)triethoxysilane were used as organo-substituted silica precursors with variable molar ratio with respect to tetraethylorthosilicate (TEOS, 1:4, 1:9, 1:19). The occurred functionalization was investigated by Infrared Spectroscopy and FT-Raman and 29Si {1H} CP-MAS-NMR spectroscopy. Results show that the three materials were successfully functionalized. The influence of the different pendant groups and their concentration on the mesostructured…