Synthesis, properties and applications of one- and two- dimensional gold nanostructures

The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and dimensionality. Especially, anisotropic gold nanocrystals, such as nanowires, nanobelts, nanoplates and nanosheets, have attracted much attention due to their striking properties and promising applications in electronics, catalysis, photonics, sensing and biomedicine. In this review, we will summarize the recent developments of one- dimensional （1D） and two-dimensional （2D） gold nanostructures. Various kinds of synthetic methods for preparation of these 1D and 2D gold nanocrystals will be described. Moreover, we will also briefly introduce the properties and potential applications of these 1D and 2D gold nanocrystals.

Effects of the physicochemical properties of gold nanostructures on cellular internalization

Unique physicochemical properties of Au nanomaterials make them potential star materials in biomedicalapplications. However, we still know a little about the basic problem of what really mattersin fabrication of Au nanomaterials which can get into biological systems, especially cells, with highefficiency. An understanding of how the physicochemical properties of Au nanomaterials affecttheir cell internalization is of significant interest. Studies devoted to clarify the functions of variousproperties of Au nanostructures such as size, shape and kinds of surface characteristics in cell internalizationare under way. These fundamental investigations will give us a foundation for constructingAu nanomaterial-based biomedical devices in the future. In this review, we present the current advancesand rationales in study of the relationship between the physicochemical properties of Aunanomaterials and cell uptake. We also provide a perspective on the Au nanomaterial-cell interactionresearch.

Electrochemical construction of porous gold nanostructures on DVD substrate and its application as nonenzymatic hydrogen peroxide sensor

A simple acid-etching method was used to leach out silver from a bimetallic gold-silver based Digital Video Disc(DVD), which was further treated via a cyclic voltammetric scanning in 1 mmol/L HAu Cl4 solution to create a porous gold nanostructure. The as-fabricated electrode was characterized by field-emission scanning electron microscopy, energy-dispersed X-ray spectroscopy and X-ray diffraction. The high electro-catalytic activity of the resulting electrode toward the reduction of hydrogen peroxide(H2O2) presented excellent linear relationship in the range of 8.0×10?5 to 1.26×10?2 mol/L with the detection limit of 2.0×10-5 mol/L(S/N=3). The as-developed non-enzyme-sensor showed good reproducibility, stability, and selectivity.

Probing of Ultrafast Plasmon Dynamics on Gold Bowtie Nanostructure Using Photoemission Electron Microscopy

We report the direct imaging of plasmon on the tips pulses and probing of ultrafast plasmon dynamics by of nano-prisms in a bowtie structure excited by 7 fs laser combining the pump-probe technology with three-photon photoemission electron microscopy. Different photoemission patterns induced by the plasmon effect are observed when the bowties are excited by s- and p-polarized femtosecond laser pulses. A series of images of the evolution of local surface plasmon modes on different tips of the bowtie are obtained by the time-resolved three-photon photoemission electron microscopy, and the result discloses that plasmon excitation is dominated by the interfer- ence of the pump and probe pulses within the first 13 fs of the delay time, and thereafter the individual plasmon starts to oscillate on its own characteristic resonant frequencies.

Importance of Au nanostructures in CO2 electrochemical reduction reaction

Electrochemical conversion of CO2 into fuels is a promising means to solve greenhouse effect and recycle chemical energy. However, the CO2 reduction reaction(CO2 RR) is limited by the high overpotential, slow kinetics and the accompanied side reaction of hydrogen evolution reaction. Au nanocatalysts exhibit high activity and selectivity toward the reduction of CO2 into CO. Here, we explore the Faradaic efficiency(FE)of CO2 RR catalyzed by 50 nm gold colloid and trisoctahedron. It is found that the maximum FE for CO formation on Au trisoctahedron reaches 88.80% at -0.6 V, which is 1.5 times as high as that on Au colloids(59.04% at -0.7 V). The particle-size effect of Au trisoctahedron has also been investigated, showing that the FE for CO decreases almost linearly to 62.13% when the particle diameter increases to 100 nm. The Xray diffraction characterizations together with the computational hydrogen electrode(CHE) analyses reveal that the(2 2 1) facets on Au trisoctahedron are more feasible than the(1 1 1) facets on Au colloids in stabilizing the critical intermediate COOH*, which are responsible for the higher FE and lower overpotential observed on Au trisoctahedron.

Synthesis and Optical Properties of Cubic Gold Nanoframes

This paper describes a facile method of preparing cubic Au nanoframes with open structures via the galvanic replacement reaction between Ag nanocubes and AuCl_(2)^(-).A mechanistic study of the reaction revealed that the formation of Au nanoframes relies on the diffusion of both Au and Ag atoms.The effect of the edge length and ridge thickness of the nanoframes on the localized surface plasmon resonance peak was explored by a combination of discrete dipole approximation calculations and single nanoparticle spectroscopy.With their hollow and open structures,the Au nanoframes represent a novel class of substrates for applications including surface plasmonics and surface-enhanced Raman scattering.

Gold nanostructure based LSPR biosensors

The localized surface plasmon resonance (LSPR) of noble metal nanoparticles have been described in numerous articles. Changes in the peak intensity and wavelength of

Plasmon hybridization engineering in self-organized anisotropic metasurfaces

The engineering of self-organized plasmonic metasurfaces is demonstrated using a maskless technique with defocused ion-beam sputtering and kinetically controlled deposition. The proposed reliable, cost-effective, and controllable approach enables large-area （order of square centimeter） sub-wavelength periodic patterning with close-packed gold nanostrips. A multi-level variant of the method leads to high-resolution manufacturing of vertically stacked nanostrip dimer arrays, without resorting to lithographic approaches. The design of these self-organized metasurfaces is optimized by employing plasmon hybridization methods. In particular, preliminary results on the so-called gap-plasmon configuration of the nanostrip dimers, implementing magnetic dipole resonance in the near-infrared range, are reported. This resonance offers a superior sensitivity and field enhancement, compared with the more conventional electric dipole resonance. The translational invariance of the nanostrip configuration leads to a high filling factor of the hot spots. These advanced features make the large-area metasurface based on gap-plasmon nanostrip dimers very attractive for surface-enhanced linear and nonlinear spectroscopy （e.g., surface-enhanced Raman scattering） and plasmon-enhanced photon harvesting in solar and photovoltaic cells.