[5a-A410-1~8] 4.1 Plasmonics

▲ [5a-A410-5] Blocking Hot Electron Emission by SiO₂ Coating Plasmonic Nanostructures

〇Nobuyuki Takeyasu¹, Kenzo Yamaguchi^2,3, Ryusuke Kagawa¹, Takashi Kaneta¹, Felix Benz³, Masamitsu Fujii⁴, Jeremy Baumberg³ (1.Okayama Univ., 2.Kagawa Univ., 3.Univ. Cambridge, 4.Toba Nat. Col. Maritime Tech.)

Keywords:gold nanostructure, surface-enhanced Raman scattering, chemical transformation

Noble metallic nanostructures provide a platform for high-sensitivity spectroscopic sensing with significantly enhanced electromagnetic fields due to surface plasmon polaritons. However, target molecules can be transformed into other molecules under irradiation with an excitation laser during the surface-enhanced measurement, which thus disturbs detection of unknown samples. In this paper, we perform Raman measurements of para-aminothiophenol on gold nano-surfaces with and without deposition of SiO₂ thin films at the surface. The Raman signals are enhanced on both substrates, but the deposition of the glass thin film clearly prevents the chemical transformation. This indicates that hot electrons are effective for chemical transformation, and that thin glass films are sufficient to prevent this while still benefiting from surface plasmons.