Supramolecular Diodes with Donor–Acceptor Interactions

Abstract

Inspired by the initial proposal of σ-bridged donor–acceptor (D-σ-A) single-molecule diodes in 1974, extensive studies over the past 50 years have explored various designs for π-conjugated D-π–A single-molecule diodes due to their feasible chemical synthesis and effective charge transfer. However, the rectification ratio of π-conjugated single-molecule diodes has been long-term limited by the challenge of asymmetric electronic coupling to induce the rectification effect. Here, we present a supramolecular diode constructed through an intramolecular π–π interaction-driven assembly strategy. The asymmetric transmission in this system is tunable via subangström mechanical control, resulting in a rectification ratio of up to 16. Electron transport studies reveal that this through-space D-π–π–A system constructed by the π–π stacking between pyrene (Py) and naphthalenediimide (NDI) is crucial for achieving asymmetric currents under different bias polarization. Theoretical calculations suggest that the intermolecular destructive quantum interference not only enables a sharp variation in electron transmission but also facilitates asymmetric electronic energy shifts through mechanical stretching, significantly improving the rectification ratio. Our work provides a general approach to fabricating and modulating asymmetric molecular architectures through noncovalent supramolecular interactions, showcasing the potential of high-performance single-molecule rectifiers.