Benzothiadiazole-based D–A–D structured red TADF emitter results in high-performance OLEDs with a maximum EQE of 8.8% and CIE (0.61, 0.39).

Thermally activated delayed fluorescence (TADF) materials have provided new strategies for time‐resolved luminescence imaging (TRLI); however, the development of hydrophilic TADF luminophores for specific imaging in cells remains a substantial challenge. In this study, a mitochondria‐induced aggregation strategy for TRLI is proposed with the design and utilization of the hydrophilic TADF luminophore ((10‐(1,3‐dioxo‐2‐phenyl‐2,3‐dihydro‐1H‐benzo[de]isoquinolin‐6‐yl)‐9,9‐dimethyl‐9,10‐dihydroacridin‐2‐yl)methyl)triphenylphosphonium bromide (NID‐TPP) . Using a nonconjugated linker to introduce a triphenylphosphonium (TPP + ) group into the 6‐(9,9‐dimethylacridin‐10(9 H )‐yl)‐2‐phenyl‐1H‐benzo[ de ]isoquinoline‐1,3(2 H )‐dione (NID) TADF luminophore preserves the TADF emission of NID‐TPP . NID‐TPP shows clear aggregation‐induced delayed fluorescence enhancement behavior, which provides a practical strategy for long‐lived delayed fluorescence emission in an oxygen‐containing environment. Finally, the designed mitochondrion‐targeting TPP + group in NID‐TPP induces the adequate accumulation of NID‐TPP and results in the first reported TADF‐based time‐resolved luminescence imaging and two‐photon imaging of mitochondria in living cells.

The device with bis-PXZ-PCN reveals a maximum external quantum efficiency of 9.8% and a slow efficiency roll-off of 15%.

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