Real-time detection of redox events in molecular junctions.

Redox molecular junctions are promising systems for nanoelectronics applications, and yet they are still only marginally understood. The study of these systems has so far been conducted in solution, utilizing "electrolyte gating" to control their redox states and, as a result, their steady-state transistor-like conductance behavior. Here we explore redox junctions under vacuum at 77 K, and report real time detection of redox events in junctions of the type Au-6-thiohexanethiolferrocene-Au. Redox events are revealed as a two-level fluctuating signal in current-time traces with potential-dependent amplitude and frequency. Using a theoretical model for signals with a telegraph-like noise, the current-time traces are analyzed to extract the various molecular parameters which define the dynamics of the system. The presented method, which can be applied to other types of redox molecules, offers a new approach to study the unexplored territory of molecular dynamics in molecular junctions.