Intermolecular charge-transfer aggregates enable high-efficiency near-infrared emissions by nonadiabatic coupling suppression

Pursuing purely organic materials with high-efficiency near-infrared (NIR) emissions is fundamentally limited by the large non-radiative decay rates (knr) governed by the energy gap law. To date, reported endeavors to decelerate knr are mainly focused on reducing the electron-vibration coupling with the electronic nonadiabatic coupling assumed as a constant. Here, we demonstrated a feasible and innovative strategy by employing intermolecular charge-transfer (CT) aggregates (CTA) to realize high-efficiency NIR emissions via nonadiabatic coupling suppression. The formation of CTA engenders intermolecular CT in the excited states; thereby, not only reducing the electronic nonadiabatic coupling and contributing to small knr for high-efficiency NIR photoluminescence, but also stabilizing excited-state energies and achieving thermally activated delayed fluorescence for high-efficiency NIR electroluminescence. This work provides new insights into aggregates and opens a new avenue for organic materials to overcome the energy gap law and achieve high-efficiency NIR emissions.