Versatile Thermally\nActivated Delayed Fluorescence\nMaterial Enabling High Efficiencies in both Photodynamic Therapy and\nDeep-Red/NIR Electroluminescence

Thermally activated delayed fluorescence (TADF) materials\nhave\nreceived increasing attention from organic electronics to other related\nfields, such as bioapplications and photocatalysts. However, it remains\na challenging task for TADF emitters to showcase the versatility concurrent\nwith high performance in multiple applications. Herein, we first present\nsuch a proof-of-concept TADF material, namely, QCN-SAC, through strategically\nmanipulating exciton dynamics. On the one hand, QCN-SAC displays obvious\naggregate-induced deep-red/near-infrared emission with a high radiative\nrate beyond 10<sup>7</sup> s<sup>–1</sup>, thereby demonstrating\nnearly 100% exciton utilization under oxygen-free conditions. In a\nQCN-SAC-based nondoped organic light-emitting diode (OLED), a superb\nexternal quantum efficiency of 16.4% can be reached with a peak at\n708 nm. On the other hand, QCN-SAC also exhibits a high intersystem\ncrossing rate over 10<sup>8</sup> s<sup>–1</sup> without leveraging\nthe heavy-atom effect, which makes QCN-SAC-based nanoparticles perform\nwell in boosting reactive oxygen species generation for imaging-guided\nphotodynamic therapy (PDT). This work presents a fundamental principle\nfor designing high-performance all-in-one TADF molecules for OLED\nand PDT applications. This discovery holds promise for advancing the\ndevelopment of versatile TADF materials with a range of uses in the\nnear future.