Gold nanoparticles of different shapes and sizes, including nanospheres, nanocubes, nanobranches, nanorods, nanobipyramids, were dispersed into water−glycerol mixtures varying volume ratios to investigate the response their surface plasmon peaks refractive index surrounding medium. The sensitivities figures merit found be dependent on both shape size Au nanoparticles. generally increase as become elongated apexes sharper. nanospheres exhibit smallest sensitivity 44 nm/RIU nanobranches...

Tailoring the longitudinal surface plasmon wavelengths (LSPWs), scattering, and absorption cross sections of gold nanorods has been demonstrated by combining anisotropic shortening transverse overgrowth judiciously choosing starting Au nanorods. Shortening yields with decreasing lengths but a fixed diameter, while produces increasing diameters nearly unchanged length. Two series LSPWs varying in same spectral range distinct extinction coefficients are thus obtained. The systematic changes...

Discrete three-dimensional (3D) plasmonic nanoarchitectures with well-defined spatial configuration and geometry have aroused increasing interest, as new optical properties may originate from plasmon resonance coupling within the nanoarchitectures. Although spherical building blocks been successfully employed in constructing 3D because their isotropic nature facilitates unoriented localization, it still remains challenging to assemble anisotropic into discrete rationally tailored Here we...

pH-Controlled assembly and disassembly of gold nanorods in both end-to-end side-by-side fashions are demonstrated using bifunctional molecules that contain a thiol group at one end different functional the other (see image). The processes reversible can be repeated for many cycles. Supporting information this article is available on WWW under http://www.wiley-vch.de/contents/jc_2296/2008/smll200800099_s.pdf or from author. Please note: publisher not responsible content functionality any...

Abstract The surface‐plasmon properties of Au bipyramids are investigated using the finite‐difference time‐domain method. It is found that both extinction cross sections and local electric‐field enhancements larger than those nanorods have longitudinal surface plasmon (LSP) wavelengths close to bipyramids. Following this result growth cationic surfactants variously sized headgroups as stabilizing agents carried out. cetyltributylammonium bromide (CTBAB) produces with tunable LSP in high...

Cores and effect: Water-dispersible core-shell structures heterostructures incorporating gold nanocrystals of different shapes (polyhedra, cubes, rods) a variety transition metal sulfide semiconductors (ZnS, CdS, NiS, Ag(2)S, CuS) are synthesized using cetyltrimethylammonium bromide-encapsulated thiobenzoates as starting materials.

We present a theoretical and experimental study involving the sensing characteristics of wavelength-interrogated plasmonic sensors based on surface plasmon polaritons (SPP) in planar gold films localized resonances (LSPR) single nanorods. The tunability both platforms allowed us to analyze their bulk as function resonance position. demonstrate that general figure merit (FOM), which is equivalent wavelength energy scales, can be employed mutually compare schemes. Most interestingly, this FOM...

Hybrid nanostructures of organic dyes and inorganic gold nanorods are constructed using the layer-by-layer assembly method via electrostatic interactions. Strong coupling is observed between molecular resonance plasmonic when their spectra overlap strongly. The strength tuned by choosing with longitudinal plasmon wavelengths varying from 570 to 870 nm. coupling-induced shift found be strongly dependent on dye concentration spacing nanorod. Moreover, can switched off laser illumination...

Strong plasmonic-molecular resonance coupling occurs between noble metal nanocrystals and organic adsorbates when the plasmonic is degenerate with molecular one. This interaction forms basis for many fundamental studies practical applications. We describe here first direct measurement of on single gold nanorods. The dark-field scattering technique employed. nanorods are embedded in hydrogel to facilitate uniform dye adsorption. adsorbed molecules exhibit both monomer H-aggregate absorption...

SERS substrates were fabricated through self-assembly of gold nanoparticles upon solution-drying in a periodic confining structure. The technique leads to uniform, parallel linear nanoparticle arrays with the precise arrangement defined dimensions particles and grooves, which provide high uniform enhancement over extended areas.

Circular dichroism (CD) studies on single nanostructures can yield novel insights into chiroptical physics that are not available from traditional ensemble-based measurements, yet they challenging because of their weak signals. By introducing an oblique excitation beam, we demonstrate the observation and spectroscopic analysis a prominent plasmonic response v-shaped gold nanorod dimer nanostructure. We show circular differential scattering obliquely excited yields characteristic bisignate...

Abstract Gold nanocubes are assembled into clusters of varying numbers and ordering on indium tin oxide substrates. The plasmon coupling in the is studied with both dark‐field imaging finite‐difference time‐domain calculations. Generally, as a cluster becomes larger more asymmetric, it exhibits scattering peaks towards longer wavelengths. vertically oriented dipole nanocube its image substrate generates two peaks. One fixed energy other red‐shifts increasing size. horizontally dipoles among...

The effects of various factors on the resonance coupling between elongated Au nanocrystals and organic dyes have been systematically investigated through preparation hybrid nanostructures electrostatically adsorbed dye molecules. A nanocrystal sample is chosen for each to match longitudinal plasmon wavelength with absorption peak as close possible so that strength can be maximized. found approximately increase molecular volume-normalized absorptivity increased. It mainly determined by energy...

We report experimental and theoretical demonstration regarding the hydrogen-bonding mechanism behind end-to-end assembly of gold nanorods modified with bifunctional linking molecules. Time-dependent studies were carried out for different molecules at both higher lower pH values respect to their respective pKa all found be in agreement a theory. The results indicate that hydrogen bonding between protonated unprotonated is responsible nanorod aqueous solution. Complementary information...

Abstract Mesostructured silica nanofibers synthesized in high yields with cetyltrimethylammonium bromide as the structure‐directing agent HBr solutions are used templates for assembly of Au and Ag nanoparticles formation thin shells along fiber axis. Presynthesized spherical adsorbed varying amounts onto through bifunctional linking molecules. Nonspherical sharp tips on a seed‐mediated growth approach. The number density nonspherical is controlled by amount seeded relative to supplied...

Emission enhancement from ZnO thin films coated with Al∕AlOx has been studied by photoluminescence spectroscopy. While Al exhibits a moderate on ZnO, the introduction of an ultrathin AlOx spacer can increase luminescence significantly. By examining dependence light emission Al∕AlOx∕ZnO thickness, we found, other than surface plasmon mediation, short-ranged nonradiative channel that plays crucial role in determining overall is also present. Based simple analytical model, it found process...

In recent years hydrogen peroxide has often been used as the oxidizing agent to tune resonance wavelength of gold nanorods (AuNRs) through anisotropic shortening in presence cetyltrimethylammonium bromide (CTAB). However, a complete picture reaction mechanism remains elusive. this work, we present systematic study on AuNR oxidation by revealing important role bromide. Hydrogen slowly oxidizes into elemental bromine. The latter two form tribromide, which exhibits characteristic 272 nm...

Surface-chemistry of individual, optically trapped plasmonic nanoparticles is modified and accelerated by overheating. Depending on the optical trapping power, gold nanorods can exhibit red shifts their plasmon resonance (i.e., increasing aspect ratio) under oxidative conditions. In contrast, in bulk exclusively blue (decreasing ratios) are observed. Supported calculations, we explain this finding local temperatures trap exceeding boiling point solvent that cannot be achieved bulk.

Biosynthesis of gold nanostructures has drawn increasing concerns because its green and sustainable synthetic process. However, biosynthesis nanoplates is still a challenge the expensive source difficulties controllable formation morphology size. Herein, one-pot proposed, in which cheap yeast was extracted as precursor. The morphologies sizes can be controlled via varying pH value biomedium. In acid condition, with side length from 1300 ± 200 to 300 100 nm height 18 15 were obtained by...

Abstract Multifunctional mesostructured silica microspheres are prepared using ultrasonic aerosol spray in conjunction with solvent evaporation‐induced assembly. Rare earth ion–phenanthroline complexes, magnetite particles, photoacid generators, and pH‐sensitive dyes chosen as luminescent, magnetic, photosensitive components. The incorporation of these functional components into can be readily realized by dispersing them the precursor solution process. Luminescent that emit at multiple...

Gold nanorods with longitudinal surface plasmon resonance wavelengths ranging from 544 to 840 nm have been coated silica at varying thicknesses. Silica-coated Au are vitreophilic, and mesostructured composite thin films thereafter prepared by dispersing silica-coated in the precursor solution. distributed relatively uniformly resultant their incorporation amounts can be readily varied. Mesostructured containing both fluorophores further fabricated. Each nanorod these treated as being...

We developed a facile approach toward hybrid AgNP–graphene–AgNP sandwiched structures using self-organized monolayered AgNPs from wet chemical synthesis for the optimized enhancement of Raman response monolayer graphene. demonstrate that scattering graphene can be enhanced 530 fold in structure. The is sensitively dependent on structure, incident angle, and excitation wavelength. A systematic simulation performed, which well explains mechanism. Our study indicates resulted plasmonic coupling...