Achieving Charge‐Transfer‐Featured Organic Room‐Temperature Phosphorescence with Combined High Efficiency and Long Lifetime via V‐Shaped D–A Dyads

Abstract

Abstract The realization of long‐lived charge‐transfer‐based organic room‐temperature phosphorescence ( 3 CT‐RTP, τ Ph  = 210 ms) via the construction of U‐shaped donor–acceptor (D–A) dyads is impeded by suboptimal phosphorescence efficiency ( = 6%). Herein, we reveal that modifying the skeleton of D–A dyads from U‐shaped to V‐shaped configurations yields 3 CT‐RTP with both long τ Ph (150–220 ms) and high (13%–25%). This improvement stems from preserving a substantial degree of forbiddenness in the radiative transition process of the compound while simultaneously increasing its D–A dihedral angle, which can promote more efficient spin‐orbit coupling and thus more rapid intersystem crossing. Additionally, augmenting the framework rigidity of a V‐shaped D–A dyad can potentially reduce the non‐radiative transition rate constant of triplet excitons ( k nr,T ), thereby facilitating the attainment of long τ Ph and high .