enhancing Conductance in Single-Molecule Junctions through Nitrogen Bridge-Mediated p-π Conjugation

Abstract

Developing novel strategies to modulate charge transport properties remains a central objective in molecular electronics. Here, we demonstrate that nitrogen bridge-mediated p-π conjugated molecule N-FBTZ-SMe exhibits higher conductance than its nitrogen-free π-conjugated analogue FBTZ-SMe. Transition voltage spectroscopy and density functional theory calculations reveal that, through p-π conjugation, the nitrogen bridge preserves HOMO delocalization while elevating the HOMO energy level, thereby improving alignment between the dominant transport channel and the Fermi level of the electrodes and enhancing molecular conductance. The generality of this nitrogen bridge-mediated p-π conjugation effect is validated in extended systems. These findings establish a new strategy for tuning charge transport at the single-molecule level, expand the repertoire of high-conductance molecular wires for advanced molecular electronics.