Functional Redox‐Active Molecular Tunnel Junctions

Redox‐active molecular junctions have attracted considerable attention because redox‐active molecules provide accessible energy levels enabling electronic function at the molecular length scales, such as, rectification, conductance switching, or molecular transistors. Unlike charge transfer in wet electrochemical environments, it is still challenging to understand how redox‐processes proceed in solid‐state molecular junctions which lack counterions and solvent molecules to stabilize the charge on the molecules. In this minireview, we first introduce molecular junctions based on redox‐active molecules and discuss their properties from both a chemistry and nanoelectronics point of view, and then discuss briefly the mechanisms of charge transport in solid‐state redox‐junctions followed by examples where redox‐molecules generate new electronic function. We conclude with challenges that need to be addressed and interesting future directions from a chemical engineering and molecular design perspectives. In recent years, redox‐active molecules have contributed significantly to the development of functional molecular junctions including molecular diodes, molecular memory and molecular transistors. This minireview gives an overview of recent progresses in functional redox‐active molecular junctions and introduces the underlying operating mechanisms of the different types of functional molecular junctions.