Effective Gating in Single-Molecule Junctions through Fano Resonances
Claudia R. Prindle, Wanzhuo Shi, Liang Li, Jesper Dahl Jensen, Bo W. Laursen, Michael L. Steigerwald, Colin Nuckolls, Latha Venkataraman
Abstract
The successful incorporation of molecules as active circuit elements relies on the ability to tune their electronic properties through chemical design. A synthetic strategy that has been used to manipulate and gate circuit conductance involves attaching a pendant substituent along the molecular conduction pathway. However, such a chemical gate has not yet been shown to significantly modify conductance. Here, we report a novel series of triarylmethylium and triangulenium carbocations gated by different substituents coupled to the delocalized conducting orbitals on the molecular backbone through a Fano resonance. By changing the pendant substituents to modulate the position of the Fano resonance and its coupling to the conducting orbitals, we can regulate the junction conductance by a remarkable factor of 450. This work thus provides a new design principle to enable effective chemical gating of single-molecule devices toward effective molecular transistors.