(Invited) Exotic Electronic Excitation to Manipulate Electrochemical Potential of Electrons and Holes at Liquid/Solid Interfaces

Abstract

Spectroelectrochemistry is powerful tool to investigate electronic sates and geometrical structures of electrified interfaces in-situ under the conditions where photonic and electronic energy conversion functionalities emerge. One can use plasmon-powered processes to expand the ability of the spectroscopy regarding sensitivities in space, time, and energy resolutions. As their characteristics on localization of surface plasmons into molecule scale, huge intensity gradient of electromagnetic field would break the limit of light-matter interactions via the modification of the selection rule of the electronic excitation process. I have discussed about the possibility for the surface-enhanced-Raman scattering (SERS) as the probe to monitor the exotic electronic excitation processes[1-7]. Based on the observation of a small number of molecules at the plasmonic metal nanostructures by SERS, possibilities leading to the future innovative photo-functionalities were demonstrated by showing improved properties at optical manipulation of electrons and molecules, and ions. In this presentation, we will show that the localized surface plasmons of the Au nanodimer structures prepared on defect-free graphene provide highly-confined electromagnetic field to generate holes and electrons of the electrochemical potentials beyond the limit of far field light illumination [8]. Novel non-zero wavevector excitation results in the generation of highly reductive and oxidative powers for electrochemical reactions. The present findings point to a novel approach to breaking the limit of opto-electronic interactions and photochemical reactions using various materials.