Silver and gold nanotriangles were fabricated by nanosphere lithography (NSL) their localized surface plasmon resonance (LSPR) spectra measured UV−vis extinction spectroscopy. It is demonstrated that the short range (viz., 0−2 nm) distance dependence of electromagnetic fields surround these nanoparticles when resonantly excited can be systematically tuned changing size, structure, composition. This accomplished measuring shift in peak wavelength, λmax, LSPR caused adsorption hexadecanethiol...

Using electrodynamics calculations, we have discovered one dimensional array structures built from spherical silver nanoparticles that produce remarkably narrow ( approximately meV or less) plasmon resonance spectra upon irradiation with light is polarized perpendicular to the axis. The lines require a minimum particle radius of about 30 nm achieve. Variations wavelength, extinction efficiency and width size, structure, interparticle distance polarization direction are examined, conditions...

The elucidation of the long range distance dependence localized surface plasmon resonance (LSPR) surface-confined noble metal nanoparticles is aim this work. It was suspected that linear found in CH3(CH2)xSH self-assembled monolayer (SAM) formation thin shell limit a longer range, nonlinear dependence. To verify this, multilayer SAM shells based on interaction HOOC(CH2)10SH and Cu2+ were assembled onto monitored using UV−visible spectroscopy. Measurement LSPR extinction peak shift versus...

We report on the optical properties of single isolated silver nanodisks and pairs disks fabricated by electron beam lithography. By systematically varying disk size surface separation recording elastic scattering spectra in different polarization configurations, we found evidence for extremely strong interparticle interactions. The dipolar plasmon resonance parallel to dimer axis exhibited a red shift as interdimer was decreased; expected from previous work, an observed. particles separated...

A comparative analysis of the properties two optical biosensor platforms: (1) propagating surface plasmon resonance (SPR) sensor based on a planar, thin film gold and (2) localized (LSPR) confined Ag nanoparticles fabricated by nanosphere lithography (NSL) are presented. The binding Concanavalin (ConA) to mannose-functionalized self-assembled monolayers (SAMs) was chosen highlight similarities differences between responses real-time angle shift SPR wavelength LSPR biosensors. During...

This article provides a review of our recent Rayleigh scattering measurements on single metal nanoparticles. Two different systems will be discussed in detail: gold nanorods with lengths between 30 and 80 nm, widths 8 nm; hollow gold–silver nanocubes (termed nanoboxes or nanocages depending their exact morphology) edge 100 160 wall thicknesses the order 10 nm. The goal this work is to understand how linewidth localized surface plasmon resonance depends size, shape, environment Specifically,...

The effect of diffractive coupling on the collective plasmon line shape linear arrays Ag nanoparticles fabricated by electron beam lithography has been investigated using Rayleigh scattering spectroscopy. array spectra exhibit an intricate multi-peak structure, including a narrow mode that gains strength for interparticle distances are close to single particle resonance wavelength. A version discrete dipole approximation method provides excellent qualitative description observed behavior.

We have developed a probe of the electromagnetic mechanism surface-enhanced Raman scattering via Au nanodisk arrays generated by using on-wire lithography. In this approach, disk thickness and interparticle gap are precisely controlled from 5 nm to many micrometers. Confocal microscopy demonstrates that play crucial role in determining intensities. Theoretical calculations also demonstrate these results consistent with mechanism, including surprising result largest enhancement does not occur...

Localized surface plasmon resonance (LSPR) is a key optical property of metallic nanoparticles. The peak position the LSPR for noble-metal nanoparticles highly dependent upon refractive index surrounding media and has therefore been used chemical biological sensing. In this work, we explore influence resonant adsorbates on bare Ag (lambda(max,bare)). Specifically, study effect rhodamine 6G (R6G) adsorption nanoparticle because its importance in single-molecule surface-enhanced Raman...

The mechanism of sodium borohydride removal organothiols from gold nanoparticles (AuNPs) was studied using an experimental investigation and computational modeling. Organothiols other AuNP surface adsorbates such as thiophene, adenine, rhodamine, small anions (Br– I–), a polymer (PVP, poly(N-vinylpyrrolidone)) can all be rapidly completely removed the surfaces. A study showed that hydride derived has higher binding affinity to AuNPs than organothiols. Thus, it displace tested AuNPs. Sodium...

The interaction of light with silver nanoparticle arrays can in some cases produce mixed plasmonic/photonic bands that have extremely narrow (<1 meV) line shapes extinction and scattering. In this paper we extend computational electrodynamics results a recent communication [S. Zou, N. Janel, G. C. Schatz, J. Chem. Phys. 120, 10871 (2004)] where effect was first described to study how these are influenced by number structural factors, determine useful might be for sensing applications....

Atomic layer deposition (ALD) is used to deposit 1−600 monolayers of Al2O3 on Ag nanotriangles fabricated by nanosphere lithography (NSL). Each monolayer has a thickness 1.1 Å. It demonstrated that the localized surface plasmon resonance (LSPR) nanosensor can detect film growth with atomic spatial resolution normal nanoparticle surface. This approximately 10 times greater than in our previous long-range distance-dependence study using multilayer self-assembled shells. The use ALD enables...

We present a combination of theory and experiment designed to elucidate the properties gold nanoshells. Wet chemistry methods are used prepare nanoshells, transmission electron microscopy (TEM) analysis is characterize shell structure, demonstrating presence pinholes in shells. Both Mie discrete dipole approximation (a numerical method) electrodynamics structures, including both perfect pinhole defected The calculations show that 2−5 nm have only small effect on extinction spectra; however,...

The peak location of the localized surface plasmon resonance (LSPR) noble metal nanoparticles is highly dependent upon refractive index nanoparticles' surrounding environment. In this study, new phenomena are revealed by exploring influence interacting molecular resonances and nanoparticle resonances. LSPR shift line shape induced a resonant molecule vary with wavelength. most instances, oscillatory dependence on wavelength tracks real part index, as determined Kramers-Kronig transformation...

Programmable positioning of one-dimensional (1D) gold nanorods (AuNRs) was achieved by DNA directed self-assembly. AuNR dimer structures with various predetermined inter-rod angles and relative distances were constructed high efficiency. These discrete anisotropic metallic nanostructures exhibit unique plasmonic properties, as measured experimentally simulated the dipole approximation method.

Directed assembly of nanoscale building blocks such as single-walled carbon nanotubes (SWNTs) into desired architectures is a major hurdle for broad range basic research and technological applications (e.g., electronic devices sensors). Here we demonstrate parallel process that allows one to simultaneously position, shape, link SWNTs with sub-100-nm resolution. Our method based on the observation are strongly attracted COOH-terminated self-assembled monolayers (COOH-SAMs) lengths greater...

The dependence of quantum dot (QD) fluorescence emission on the proximity 30 nm gold nanoparticles (AuNPs) was studied with controlled interparticle distances ranging from 15 to 70 nm. This achieved by coassembling DNA-conjugated QDs and AuNPs in a 1:1 ratio at precise positions triangular-shaped DNA origami platform. A profound, long-range quenching photoluminescence intensity observed. combination static time-resolved measurements suggests that is due an increase nonradiative decay rate QD...

Using stoichiometrically controlled 1:1 functionalization of gold nanoparticles with fluorescent dye molecules in which the molecule is held away from particle surface by a rigid DNA spacer allows precise determination distance-dependent effect metal on fluorescence intensity. Two dyes were studied, Cy3 and Cy5, two sizes nanoparticles, 5 10 nm. The larger particle, more quenching photoluminescence (PL) intensity, due to increased overlap dye's emission spectrum Au plasmon resonance....

Au nanorods are optically tunable anisotropic nanoparticles with built-in catalytic activities. The state-of-the-art seed-mediated nanorod synthesis offers excellent control over the aspect ratios of cylindrical nanorods, which enables fine-tuning plasmon resonances a broad spectral range. However, facet atomic-level precision remains significantly more challenging. coexistence various types low-index and high-index facets on highly curved surfaces makes it extremely challenging to...

Abstract Recently, surface-enhanced Raman scattering nanoprobes have shown tremendous potential in oncological imaging owing to the high sensitivity and specificity of their fingerprint-like spectra. As current scanners rely on a slow, point-by-point spectrum acquisition, there is an unmet need for faster cover clinically relevant area real-time. Herein, we report rational design optimization fluorescence-Raman bimodal nanoparticles (FRNPs) that synergistically combine spectroscopy with...

Current methods for tuning the plasmonic properties of metallic nanoparticles typically rely on alternating morphology (i.e., size and/or shape) nanoparticles. The variation oftentimes impairs their performance in certain applications. In this study, we report an effective approach based control internal structure to engineer morphology-invariant with tunable properties. Specifically, these were prepared through selective growth Ag inner surfaces preformed Ag–Au alloyed nanocages as seeds...

In this work, a detailed and systematic study of the plasmonic properties novel film over nanowell surface is investigated. These nanostructures are fabricated using nanosphere lithography reactive ion etching structurally characterized by AFM SEM. The resulting structures show remarkably narrow plasmon bands in reflectance spectra (as little as 0.10 eV) greater sensitivity to external dielectric environment than has been seen other nanoparticle systems, an improvement figure merit (FOM =...