The Plasmon-Driven Surface-Catalyzed Reactions In Nanowire Dimer System On Metal Film

Plasmonics as a branch of nano-optics, and its research content involves novel properties of light in the range of nanometer scale, is an interdisciplinarity covering optical physics, optical engineering, materials science and nanotechnology. Plasmonics is a specific application by utilizing surface enhanced Raman scattering(SERS) to operate and control the photons in range of nanometer scale. This paper improves traditional plasmon driven surface catalysis(PDSC) particle system and studies plasma driven surface catalytic reaction of silver nanowire-gold film system. Furthermore, built up a Raman spectrometer independently which could carry on the micron scale measurement and could be very flexible to measure Raman spectra, for example, change the polarization of the incident light, intensity and so on.When the surface plasma of nano-structure is irradiated by light, and the energy of the incident light field can be gathered in a local area, making the electromagnetic field greatly enhanced in this area, it is the enhanced electromagnetic field effect that makes the PATP or 4NBT molecules which adsorption on the metal surface to convert to DMAB. Though the PATP or 4NBT molecules can be both converted to DMAB, the reaction mechanism of them are not the same. In conversion process(PATP or 4NBT to DMAB), PATP is belong to the oxidation reaction, and 4NBT is belong to the reduction reaction. Their catalytic reaction could be characterized by surface enhanced Raman spectra, whose intensity can be used to reflect the intensity of catalytic reaction to a certain extent. Cross section of Ag nanowire dimer adjacent part which is similar to dual particle dimer system(of a smoother surface than the particle system), has greater capacity to gather energy to local scale than the extremity of Ag nanowire, so the Raman spectra intensity of Ag nanowire dimer adjacent part(cross section similar to single particle system') is stronger than the extremity of Ag nanowire, at the same time, plasma driven surface catalyzed reactions is easy to happen to Ag nanowire dimer adjacent part.Due to the presence of a plasma waveguide effect of silver nanowire, so the silver nanowire-gold film system have weak intensity of surface enhanced Raman spectra than the particle system under the same condition. In the experiment, adjust the incident light intensity to suitable strength to make the polarization of the incident light vertical(relative to the direction of silver nanowire), this moment, plasma driven surface catalytic reaction occurs, and parallel incident does not occur. This feature probably will become a control means to decide surface catalytic reaction to occur or not.In addition, we also discuss the influence of different wavelength on surface catalytic reaction of the silver nanowire-gold film system. Because samples of the silver nanowire-gold film system is easier to prepare and observe, and silver nanowire-gold film system is of waveguide effect, so this simple nano-particles structures can provide reference for development of optical devices, such as the detection, sensing, optical radiation and so on.