Evolution Of Surface Plasmon Resonance Research Articles

Synthesis of surface plasmon resonance (SPR) triggered Ag/TiO2 photocatalyst for degradation of endocrine disturbing compounds

Surface deposition of silver nanoparticles (Ag NPs) onto the 100% anatase titania (Ag/TiO2) for evolution of surface plasmon resonance (SPR) was achieved sustainably with the assistance of solar energy. The preparation resulted in Ag/TiO2 photocatalyst with varied Ag depositions (0.5wt%, 1.0wt%, 3.0wt% and 5.0wt%). All obtained photocatalysts were characterized for the evolution of SPR via crystalline phase analysis, morphology, lattice fringes, surface area and pore size characteristics, chemical composition with chemical and electronic state, Raman scattering, optical and photoluminescence properties. The deposition of synthesized Ag NPs exhibited high uniformity and homogeneity and laid pathway for effective utilization of the visible region of electromagnetic spectrum through SPR. The depositions also lead for suppressing recombination rates of electron–hole. The photocatalytic evaluation was carried out by adopting two different class of endocrine disturbing compound (EDC) i.e., amoxicillin (pharmaceutical) and 2,4-dichlorophenol (pesticide) excited with artificial visible light source. Ag/TiO2 with Ag>0.5wt% exhibited significant degradation efficiency for both amoxicillin and 2,4-dichlorophenol. Thus synthesized Ag/TiO2 revealed the implication of plasmonics on TiO2 for the enhanced visible light photocatalytic activity.

Evolution of surface plasmon resonance with slab thickness in hybrid nano-structures of Au/InGaAs slab waveguide

We report on the evolution of the surface plasmon (SP) and waveguide mode (WM) as the core thickness is varied in InGaAs slab waveguides covered by metallic sub-wavelength slit arrays. By comparing transmission spectrum in the near-infrared region with numerical simulations, transmission dips were assigned to resonant excitations of either SPs or WMs. As the core thickness was smaller than the SP penetration depth, the resonance energy exhibits a blue shift, which scales with the field intrusion into the substrate region. For the core thickness of 400 nm supporting both the WM and SP, effective refractive index of the SP is almost constant due to the field decay within the InGaAs region, which is different to the case of the WM.

Kinetic effects of halide ions on the morphological evolution of silver nanoplates

Time-resolved extinction spectroscopy is employed to study the reaction kinetics in the shape-conversion reaction involving halide ions (including Cl(-), Br(-) and I(-)) etching (sculpturing) silver nanoplates. A series of time-resolved extinction spectra are obtained during the in situ etching process and the evolution of surface plasmon resonance (SPR) of the silver nanoparticles is analyzed. Spectral analysis indicates that the conversion of nanoprisms starts simultaneously with the emergence of nanodisks when the halide ions are added. The etching rate of different halide ions is evaluated through the in-plane dipole resonance peak intensity of silver nanoplates vs. the reaction time (dI/dt). The relationship between the etching rate and the halide ion concentration shows that the halide ion etching reaction can be considered as a pseudo-first-order reaction. The effect of different halide ions on the shape-conversion of silver nanoplates is compared in detail. The activation energy of the etching reaction is calculated, which indicates that the etching ability of different halide ions is on the order of Cl(-) < I(-) < Br(-).

Three-Dimensional Analysis of Scattering Field Interactions and Surface Plasmon Resonance in Coupled Silver Nanospheres

Scattering field interactions and surface plasmon resonance (SPR) in coupled silver nanospheres are simulated by using the finite-element method, which includes the influences of near-field enhancements of electric field by the particle sizes, separation distances, propagation directions, as well as the polarizations of the incident wave. The proposed structures exhibit a red- and blue-shifted that can be tuned by varying the particle sizes and the separation distances, respectively. Implications for surface-enhance Raman scattering and nano-optics are discussed in three-dimensional models. The evolution of SPR and nano-photonic device with the structural variations can be designed in a controlled manner.

Substrate dependent surface plasmon resonance evolution of Ag nanoparticles treated inatmospheres

The evolution of surface plasmon resonance (SPR) with alternate air andH2 treatment was investigated for silver nanoparticles on differentSiO2-based substrates (soda-lime glass, quartz glass and mesoporousSiO2). It has been shown that evolution behaviours on the three substratesare very different. For silver nanoparticles on the mesoporousSiO2 substrate,alternate air and H2 heat treatment led to the alternate disappearance and appearance of the SPR, showing thereversibility of optical changes. For a soda-lime glass substrate, the SPR absorption alsodisappeared after the first run heat treatment in air and re-appeared after subsequentH2 heat treatment, but the second run heat treatment in air could not induce there-disappearance of the SPR. After alternate heating of the sample in air andH2 for four or more cycles, the SPR stayed almost unchanged. For a quartz glasssubstrate, however, the SPR absorption became negligible after alternate air andH2 heattreatment. Such effects of the substrate on the SPR are explained in terms of the subtle difference of thethree SiO2-based substrates in micro-structure or chemical composition, and theredox of silver in the treatment atmospheres. This study could beimportant for the design and architectonics of new optical devices based onSiO2 materials and could also promote the understanding of the interaction of silvernanoparticles with the environment.