Search results for "gold"
showing 10 items of 1320 documents
Enhancement of visible light photoelectrocatalytic activity of ZnO(core)/TiO2(shell) composite by N-doping and decorating with Au0 nanoparticles
2017
Abstract The composites consisting of ITO-supported ZnO nanorods covered with TiO2 shell were doped with nitrogen and decorated with gold nanoparticles in order to improve their photocatalytic activity under visible light. N-doped TiO2 (TiO2(N)) was prepared under mild conditions through a simple sol-gel synthesis in the presence of NH4Cl. Such procedure results in formation of a highly porous shell of TiO2(N) on the ZnO nanorods. The gold nanoparticles (AuNPs) of the size 7–25 nm were grafted onto the surface of TiO2 as well as TiO2(N) by a photodeposition method from aqueous solution of [AuCl(4-x)(OH)x]− precursor at pH 6.7. The composition and microstructure of the prepared samples were …
Plasmonic versus catalytic effect of gold nanoparticles on mesoporous TiO2 electrodes for water splitting
2014
a b s t r a c t Solar water splitting with metal oxide semiconductors constitutes a promising approach to the conversion of solar energy into chemical energy stored in the atomic bonds of hydrogen molecules. In the present study, we evaluate the effect of the presence of Au nanoparticles on the photoelectrochemical behaviour of mesoporous TiO2 to photo-oxidize water. We observe that the presence of Au nanoparticles leads to enhanced photocurrents for water oxidation and we explore the origin of this enhancement by optical and electrochemical characterization techniques. Our results indicate that although the Au nanoparticles are responsible for a localized surface plasmonic resonance effect…
Plasmon-enhanced photocurrent in quasi-solid-state dye-sensitized solar cells by the inclusion of gold/silica core–shell nanoparticles in a TiO2 phot…
2013
Direct evidence of the effects of the localized surface plasmon resonance (LSPR) of gold nanoparticles (Au NPs) in TiO2 photoanodes on the performance enhancement in quasi-solid-state dye-sensitized solar cells (DSCs) is reported by comparing gold/silica core–shell nanoparticles (Au@SiO2 NPs) and hollow silica nanoparticles with the same shell size of the core–shell nanoparticles. The Au nanoparticles were shelled by a thin SiO2 layer to produce the core–shell structure, and the SiO2 hollow spheres were made by dissolving the Au cores of the gold/silica core–shell nanoparticles. Therefore, the size and morphology of the SiO2 hollow spheres were the same as the Au@SiO2 NPs. The energy conver…
Energy dependence of the decay pathways of optically excited small gold clusters
2001
The pathway competition between neutral monomer and neutral dimer evaporation from optically excited odd-size gold cluster ions Au+ n, n=7–15, has been investigated as a function of cluster size and excitation energy. Gold cluster ions of these sizes are the only ones to show observable pathway competition while all other sizes exclusively evaporate either neutral monomers or neutral dimers. The investigation has been performed by photoexcitation of stored size-selected gold cluster ions with a single 10-ns laser pulse. Subsequent time-resolved observation of the delayed dissociation allows us to quantitatively determine the relative fragment yields of the respective decay channels as a fun…
A coumarin based gold(i)-alkynyl complex: a new class of supramolecular hydrogelators.
2014
A phosphine-gold(I)-alkynyl-coumarin complex, [Au{7-(prop-2-ine-1-yloxy)-1-benzopyran-2-one}(DAPTA)] (1), was synthesized and the formation of long luminescent fibers in solution was characterized via fluorescence microscopy and dynamic light scattering. The fibers presented strong blue and green luminescence, suggesting that the gold(I) in the complex increased intersystem crossing due to the heavy atom effect, resulting in a significant increase in triplet emission. The X-ray structure of the fibers indicates that both aurophilic, π–π interactions and hydrogen bonding contribute to their formation in aqueous solvents.
Measurement of photon?jet transverse momentum correlations in 5.02 TeV Pb + Pb and pp collisions with ATLAS
2019
Jets created in association with a photon can be used as a calibrated probe to study energy loss in the medium created in nuclear collisions. Measurements of the transverse momentum balance between isolated photons and inclusive jets are presented using integrated luminosities of 0.49 nb−1 of Pb + Pb collision data at TeV and 25 pb−1 of pp collision data at TeV recorded with the ATLAS detector at the LHC. Photons with transverse momentum GeV and are paired with all jets in the event that have GeV and pseudorapidity . The transverse momentum balance given by the jet-to-photon ratio, , is measured for pairs with azimuthal opening angle . Distributions of the per-photon jet yield as a function…
Scanning optical microscopy modeling in nanoplasmonics
2012
International audience; One of the main purposes of nanoplasmonics is the miniaturization of optical and electro-optical components that could be integrable in coplanar geometry. In this context, we propose a numerical model of a polarized scanning optical microscope able to faithfully reproduce both photon luminescence and temperature distribution images associated with complex plasmonic structures. The images are computed, pixel by pixel, through a complete self-consistent scheme based on the Green dyadic functions (GDF) formalism. The basic principle consists in the numerical implementation of a realistic three-dimensional light beam acting as a virtual light tip able to probe the volume…
Wavelength dependence of visual acuity in goldfish.
2003
Visual acuity was measured in a two-choice training experiment with food reward. Four goldfish were trained to select a homogeneously illuminated testfield when a high-contrast grating (transparency) was shown for comparison at the second testfield. Measurements were performed for white and monochromatic testfield illuminations in the light adapted state. Fourteen wavelengths between 404 nm and 683 nm were tested. For each wavelength (and white light) the testfield intensity was determined for which spatial resolution was highest. Between 446 nm and 683 nm maximal values of 2.0 cycles/deg (corresponding to a visual acuity of 15' of arc) were found. At 404 nm and in the ultraviolet resolutio…
Synthesis ofN=127isotones through (p,n) charge-exchange reactions induced by relativistic208Pb projectiles
2011
The production cross sections of four N=127 isotones ({sup 207}Hg, {sup 206}Au, {sup 205}Pt, and {sup 204}Ir) have been measured using (p,n) charge-exchange reactions, induced in collisions of a {sup 208}Pb primary beam at 1 A GeV with a Be target. These data allow one to investigate the use of a reaction mechanism to extend the limits of the chart of nuclides toward the important r-process nuclei in the region of the third peak of elemental abundance distribution.
Small field motion detection in goldfish is red-green color blind and mediated by the M-cone type
2007
Large field motion detection in goldfish, measured in the optomotor response, is based on the L-cone type, and is therefore color-blind (Schaerer & Neumeyer, 1996). In experiments using a two-choice training procedure, we investigated now whether the same holds for the detection of a small moving object (size: 8 mm diameter; velocity: 7 cm/s). In initial experiments, we found that goldfish did not discriminate between a moving and a stationary stimulus, obviously not taking attention to the cue “moving.” Therefore, random dot patterns were used in which the stimulus was visible only when moving. Using black and white random dot patterns with variable contrast between 0.2 and 1, we found…