Supramolecular Modulation of Photoinduced Charge Transfer: Tuning Between Tunneling and Incoherent Hopping

Abstract

ABSTRACT Photoinduced charge transfer (CT) underpins photosynthesis and solar energy conversion technologies. However, achieving comprehensive control over CT in traditional covalent donor−bridge−acceptor (D−B−A) systems remains challenging, hindered by tedious organic synthesis and limited tunability. In this investigation, we harness molecular recognition to regulate photoinduced CT—including charge separation and recombination—leveraging its facile preparation and dynamic reversibility. By integrating guest molecules with a wide range of frontier orbital energies into a rigid cyclophane host ( DAPPTTzBox 4+ ), which features directional photoinduced intramolecular CT through cofacially stacked chromophores, we achieve comprehensive modulation of CT within well‐defined supramolecular complexes. This modulation spans mechanisms from tunneling to incoherent hopping. Notably, molecular recognition accelerates charge separation in DAPPTTzBox 4+ by 5.9‐ to 230‐fold, shifting from single‐step superexchange to multistep incoherent charge shift, while charge recombination rates are decreased (from 1.3‑ to 2.8‑fold) in superexchange systems. Additionally, guest‐induced charge trapping was also successfully demonstrated. This research exemplifies a fresh strategy for manipulating CT dynamics via noncovalent interactions, opening new avenues for the design of advanced artificial light‐harvesting materials.