Revealing Distinct σ–σ Stacked Supramolecular Configurations Through Electrode Interface Engineering

Supramolecular charge transport is commonly regulated through molecular design, while the role of the electrode interface remains far less explored, particularly in weakly coupled systems dominated by noncovalent interactions (NCI). Here, we demonstrate that engineering the electronic structure of the electrode interface enables selective access to distinct σ–σ stacked supramolecular configurations that are otherwise obscured in conventional single‐molecule measurements. Using scanning tunneling microscope break‐junction experiments, we investigate σ–σ stacked cyclohexane‐based supramolecular junctions formed between asymmetric Au and Au–Ge alloy electrodes. Whereas a single high‐conductance state is observed with pure gold electrodes, introducing an Au–Ge alloy electrode reproducibly resolves this feature into two distinct conductance states. Analysis of conductance plateaus, supported by density functional theory combined with nonequilibrium Green’s function calculations, assigns these states to ortho ‐ and para ‐stacked configurations, with the latter becoming energetically accessible only in the presence of the alloy electrode. Current–voltage analysis disentangles alloy‐induced changes in electrode‐orbital coupling and energy‐level alignment, revealing the origin of the configuration selectivity. These results establish electrode interface engineering as an effective strategy to resolve distinct transport states in a specific weakly coupled σ–σ stacked dimer configurations, highlighting the active role of the electrode interface in single‐molecule junctions governed by weak NCI.