Optical Gating Electron Transport through Nonphotoresponisive Molecular Junctions

The manipulation of electron transport through single-molecule junctions via light illumination is a critical step towards molecular hybrid devices. However, most kinds of molecules are nonphotoresponsive without photo absorption upon a specific light illumination. Here, a strategy for high efficiently gating electron transport through a nonphotoresponsive molecular junction with a general light source is provided by introducing nanogap plasmons and molecular design. It is found the conductance of the triphenylamine-based molecules, a nonphotoresponsive molecule with buried anchoring groups, can be enhanced by two orders of magnitude under a general light illumination, which should be the greatest enhancement in the family of nonphotoresponsive molecules. It is further revealed that the giant conductance modulation originates from the coupling of the buried anchoring groups and plasmon-excited hot electrons. This work would contribute to the understanding of the interaction mechanisms between light and bridged molecules, assisting the development of the molecule-based hybrid optoelectronic devices.