Probing Solvent Dynamics at the Single-Molecule Limit

Description

Roberto Listo and thirteen colleagues use a single molecule wired between electrodes as an exquisitely sensitive probe of the electric double layer. That layer is the charged skin that forms wherever an electrode meets a liquid. That layer's structure has been studied for a century and a half, while its moment-to-moment dynamics remain murky.

Under a square-wave voltage, the current through single-molecule junctions answered in three distinct dialects depending on the solvent. Strongly polar solvents produced large nonlinear surges, middling solvents behaved like tidy capacitors, and nonpolar solvents showed no measurable transient at all within the tested frequencies. Fitting the responses to a molecular-scale circuit extracted how each solvent shapes the innermost layer's behavior and where the nonlinearity comes from. The authors say single-molecule devices can now interrogate interfacial dynamics that bulk measurements average away, with relevance to molecular memory and sensing devices.

Catalog record

Source: https://europepmc.org/article/MED/PMC13651600