Abstract
For the novel interpretation of Raman spectrum from molecule at metal surface, the plasmon driven surface catalysis (PDSC) reactions have become an interesting topic in the research field of surface enhanced Raman scattering (SERS). In this work, the selective PDSC reactions of p,p’-dimercaptoazobenzene (DMAB) produced from para-aminothiophenol (PATP) or 4-nitrobenzenethiol (4NBT) were demonstrated in the Ag nanowires dimer-Au film systems. The different SERS spectra collected at individual part and adjacent part of the same nanowire-film system pointed out the importance of the electromagnetic field redistribution induced by image charge on film in this selective surface catalysis, which was confirmed by the simulated electromagnetic simulated electro- magnetic field distributions. Our result indicated this electromagnetic field redistribution induced selective surface catalysis was largely affected by the polarization and wavelength of incident light but slightly by the difference in diameters between two nanowires. Our work provides a further understanding of PDSC reaction in metal nanostructure and could be a deep support for the researches on surface catalysis and surface analysis.
Highlights
Through surface enhanced Raman scattering (SERS) of 4NBT or PATP monolayer adsorbed on Au film, the electromagnetic field redistribution is demonstrated in two adjacent nanowires located on film to exclude the difference in size and shape between nanoparticles
In the perpendicular excited situations, the oscillation of surface plasmon polaritons (SPPs) are vertical to the axis of nanowires and a strong plasmon coupling occurred between two adjacent nanowires that it could be treated as two adjacent nanoparticles
With the help of induced image charge on Au films, the effective electric dipoles were located at the nanowire-film gaps at the adjacent part but not the individual part, which was similar to our previous work in the nanoparticle dimer system[25,26,30,31]
Summary
The electromagnetic field redistribution caused by the coupling of surface charge on nanoparticle and image charge on film in the systems has been reported that the confined light energy could be modulated at different sub-wavelength areas through manipulating wavelength of incident light[29,30,31]. In this metal nanowire-film system, the SERS spectra from nanowire dimer-film gaps exhibited the obvious Raman feature of DMAB while that from individual nanowire-film gaps presented the behavior of PATP or 4NBT These experimental results demonstrated strictly the interesting theoretical predication of electromagnetic field redistribution and indicated its great influence on the PDSC reactions. Our studying expanded the understanding of PDSC reactions and had great significance in field of SERS and surface analysis
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
