Plasmon-Induced\nSimultaneous Electrochemical and Fluorescence\nSwitches Probed by Combined SECM and Fluorescence Microscopy

An unprecedented dual simultaneous\nswitch of fluorescence\nintensity\nand electrochemical current induced by plasmon activation is demonstrated\nusing a combination of electrochemical (SECM) and fluorescence microscopies\nwith a fluorescent redox-active probe (tetrazine derivative) in solution.\nThe mechanism of this dual switch is assigned to an asymmetric charge\ninjection involving holes rather than electrons, despite the oxidant\ncharacter of the redox probe. Thermal effects due to plasmon activation\nhave been measured by using quantitative phase imaging and revealed\nnegligible solution temperature increases, corroborating the main\nrole of charge injection. This demonstrates for the first time that\nelectrofluorochromism, which involves a redox switch monitoring the\nluminescence properties, can be optically triggered.