the weakly coupled D‐σ‐A intramolecular charge‐transfer state, a transition from the
localized excited triplet state (3LE) and charge‐transfer triplet state (3CT) to the charge‐
transfer singlet state (1CT) occurred with a small activation energy and high
photoluminescence quantum efficiency. Two thermally activated delayed fluorescence
(TADF) components were identified, one of which has a very short lifetime of 200–400 ns …