Electrochemical control of ultra-small gap distance at metal nanodimer creating highly localized plasmonic field

摘要

The optical property of plasmon-active metal nano dimer structure strongly depends on its shape and gap distance. Thus, the precise control of metal nano structure has been receiving much attention in various field. In the present study, we have tried to control the plasmonic property by combining electrochemical method with in-situ dark-field microscopy. Controlled metal dissolution in the size range below a few nm leads to the successful switching from the charge transfer plasmon (CTP) to the bonding dipolar plasmon (BDP) mode. The highly localized plasmonic field generated during the switching could be applied for various applications including molecular optical trapping in solution at room temperature.