Search results for "plasmon"
showing 10 items of 614 documents
A 3.3 V Output Voltage Optical Plasmonic Solar Energy Harvester
2021
In this paper, for the first time, the design of a solar energy-harvester (EH) based on plasmonic optical nanorectennas and without the step-up converter is presented. The novel optical harvester with a 49497∗14286 nanoarray of about 21,21 mm2 presents an output voltage value of 3.3 V and an output current of 10 mA.
An advance Towards the Synthesis of Ag Nanorod Arrays with Controlled Surface Roughness for SERS Substrates
2016
An innovative approach to produce silver nanorod (NRs) arrays with controlled morphological parameters and surface roughness is presented. The Ag NRs were obtained using a three-stage fabrication process based on the electron beam exposure of a metal-polymer nanocomposite resist on a transparent substrate and development, a post bake and then a series of non-electrochemical metallization steps. After each step the evolution of the Ag NRs was characterized by scanning electron microscopy (SEM) for morphology and optical transmittance (T) measurements for Localized Surface Plasmon Resonance (LSPR). The transmittance measurements were interpreted using models based on the Finite Element Method…
Au-PVA Nanocomposite Negative Resist for One-Step Three-Dimensional e-Beam Lithography
2009
Au nanoparticles are synthesized in situ upon the electron beam exposure of a poly(vinyl alcohol) (PVA) thin film containing Au(III). The e-beam-irradiated areas are insoluble in water (negative-tone resist), and Au-PVA nanocomposite patterns with a variable profile along the structure can be thus generated (3D lithography) in a single step. A local characterization of the generated patterns is performed by high-resolution transmission electron microscopy and UV-vis localized surface plasmon resonance microspectroscopy. This characterization confirms the presence of crystalline nanoparticles and aggregates.
Green synthesis and characterizations of silver and gold nanoparticles using leaf extract of Rosa rugosa
2010
Abstract Metal nanostructures have unusual physicochemical properties and biological activities compared to their bulk parent materials. Thus in recent years a number of physical, chemical and biological techniques were applied for the development of metal nanoparticles (NP). Here we have synthesized silver and gold nanoparticles (AgNPs and AuNPs) by using leaves extracts of Rosa rugosa . Surface plasmon resonance spectra for silver and gold are obtained at 451 and 578 nm with brown yellow and pink-red color, respectively. AgNPs and AuNPs vary in size according to different leaves extract and metal concentration used for the synthesis. Different instrumental techniques were applied to chara…
Metallic Nanostructures Based on DNA Nanoshapes
2016
Metallic nanostructures have inspired extensive research over several decades, particularly within the field of nanoelectronics and increasingly in plasmonics. Due to the limitations of conventional lithography methods, the development of bottom-up fabricated metallic nanostructures has become more and more in demand. The remarkable development of DNA-based nanostructures has provided many successful methods and realizations for these needs, such as chemical DNA metallization via seeding or ionization, as well as DNA-guided lithography and casting of metallic nanoparticles by DNA molds. These methods offer high resolution, versatility and throughput and could enable the fabrication of arbit…
Custom-shaped metal nanostructures based on DNA origami silhouettes.
2015
The DNA origami technique provides an intriguing possibility to develop customized nanostructures for various bionanotechnological purposes. One target is to create tailored bottom-up-based plasmonic devices and metamaterials based on DNA metallization or controlled attachment of nanoparticles to the DNA designs. In this article, we demonstrate an alternative approach: DNA origami nanoshapes can be utilized in creating accurate, uniform and entirely metallic (e.g. gold, silver and copper) nanostructures on silicon substrates. The technique is based on developing silhouettes of the origamis in the grown silicon dioxide layer, and subsequently using this layer as a mask for further patterning…
Single Out-of-Resonance Dielectric Nanoparticles as Molecular Sensors.
2021
Light scattering from single nanoparticles and nanostructures is a commonly used readout method for nanosensors. Increasing the spectral sensitivity of resonant nanosensors to changes in their local surrounding has been the focus of many studies. Switching from spectral to intensity monitoring allows one to investigate nonresonant or out-of-resonance dielectric nanoparticles. Here, we systematically compared such dielectric silica nanoparticles with plasmonic gold nanorods by deriving analytical expressions and by performing experiments. The experiments show a similar sensitivity for the detection of an adsorbate layer for both particle types, which is in good agreement with theory. The fla…
Plasmonic twinned silver nanoparticles with molecular precision
2016
Determining the structures of nanoparticles at atomic resolution is vital to understand their structure–property correlations. Large metal nanoparticles with core diameter beyond 2 nm have, to date, eluded characterization by single-crystal X-ray analysis. Here we report the chemical syntheses and structures of two giant thiolated Ag nanoparticles containing 136 and 374 Ag atoms (that is, up to 3 nm core diameter). As the largest thiolated metal nanoparticles crystallographically determined so far, these Ag nanoparticles enter the truly metallic regime with the emergence of surface plasmon resonance. As miniatures of fivefold twinned nanostructures, these structures demonstrate a subtle dis…
Surface waves in plasmonic anisotropie media
2012
We investigate the spatial dispersion of hybrid-polarized surface waves excited at the boundary of a semi-infinite layered metal-dielectric nanostructure. We put emphasis in the case that the thickness of a metal layer becomes of the order of the metal skin depth. We demonstrate that the use of the so-called effective medium approximation (EMA) is not justified, in general. For that purpose, we compare the results using the EMA model and numerical simulations based on the finite-element method. We include an analysis of the influence of metallic losses.
Plasmon-assisted spin transition in gold nanostar@spin crossover heterostructures
2021
Aquí presentamos el diseño de nanopartículas core@shell formadas por un núcleo de nanoestrella de Au metálico y una capa cruzada de espín basada en el polímero de coordinación [Fe(Htrz)2(trz)](BF4). Este procedimiento es general y se ha extendido a otras morfologías metálicas (nanovarillas, nanotriángulos). Gracias al efecto fototérmico derivado de las propiedades plasmónicas de la nanoestrella de Au, el 60 % de los centros de hierro experimentan una transición de espín térmico dentro de la histéresis térmica provocada por una irradiación de baja intensidad con un láser de 808 nm. En comparación con otras morfologías de Au, la gran ventaja de la forma de nanoestrella surge de los puntos cal…