Abstract

The transformation of para-aminothiophenol (PATP) to dimercaptoazobenzene (DMAB) is widely believed to be due to the emission of hot electrons from the plasmonic nanostructures,¹ which are generated during the decay of the surface plasmons (LSPPs). Our aim here is to separate the catalytic activity of plasmonic nanostructures from their SERS activity by using a 5 nm thick silicon dioxide (SiO₂) layer. This layer blocks hot electrons from reaching the PATP molecules but lets the electromagnetic field penetrate, allowing us to measure the SERS of the monomer without triggering a chemical reaction. The SERS measurement was performed at 633 nm on two-dimensional gold nanoparticle (2D AuNP) arrays covered with/without thin SiO₂.

© 2017 Japan Society of Applied Physics, Optical Society of America