Terefe Habteyes1 Bijesh Kafle1 Tefera Tesema1 Meron Tadesse1 Marisa Poveda1

1, University of New Mexico, Albuquerque, New Mexico, United States

Recent advances show that localized surface plasmon resonances can be utilized to drive important photochemical reactions at low incident photon flux at room temperature. Central to this application is a localized surface plasmon near-field that drives the surface photochemical reactions and enables us to detect the reactant and product species in situ with high sensitivity using for example surface enhanced Raman spectroscopy. The presentation will start with a brief discussion of plasmon near-field localization based on experimental results recently obtained in our lab using super-resolution near-field scanning optical microscopy. Plasmon-driven photochemical reactions will be discussed based on our recent exciting experimental observations, where the remarkable effect of surface ligands is demonstrated. We show that the same plasmonic optical nanoantennas can lead to different reaction pathways depending on the surface ligands. We propose that the surface ligands are influencing the reaction pathways through their interaction with the charge carriers (electrons and holes), thereby changing the concentration of reactive intermediates. The results provide important insight into the mechanism of plasmon-driven surface photochemistry, and at the same time, indicate the hidden chemistry on metal surfaces, where looking at molecules based on their fluorescence is no longer a possibility.