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Here, we provide a simulation based on finite-difference time-domain (FDTD) way of the properties of surface plasmons on Ag nanoring and study their electric field distribution in order to identify different multiple surface plasmon resonances. We can obtain the symmetric field distribution that parallels to the orientation of direction of incident light. We find their propagation can be controlled. And we discuss some of the parameters that influence the optical response of the Ag nanoring. Adjustment of nanoring radius (inner radius and outer radius) and height can change the absorption intensity and the resonance peaks. The simulation of the field distribution also displays that the location of the field enhancement is specified by the different resonance patterns. Dipole, quadrupole, and octupole plasmon resonance modes can be found in the Ag nanoring at resonance wavelength. This is an important step toward a thorough understanding of plasmon resonance in Ag nanorings. [ABSTRACT FROM AUTHOR]

We reported a simple hydrothermal method to fabricate Au nanoparticles-decorated ZnO nanorods (ZnO-NRs) using aligned ZnO-NRs arrays as a template. Via changing the concentration of HAuCl aqueous solution, the size and density of Au nanoparticles (NPs) on the surface of ZnO-NRs could be readily tuned. The photoluminescence of Au-NPs decorated ZnO-NRs were investigated, in order to optimize the configuration of the Au-NPs decorated ZnO-NRs system realizing the maximum band emission. Due to a synergistic effect of the adjacent Au NPs and ZnO-NRs and efficiently coupled localized surface plasmon resonance (SPR) excitation, an optimized sample employing Au NPs with 15-nm size showed best catalytic efficiency. We have proposed a mechanism that is the electron transfer from surface-plasmon-stimulated \Au NPs to the conduction band of ZnO-NRs. These results demonstrate that Au NPs can significantly enhance the charge separation by extracting electrons from the photoexcited ZnO and consequently improve the photocatalytic activity of the composites. [ABSTRACT FROM AUTHOR]