Versatile Thermally Activated Delayed Fluorescence Material Enabling High Efficiencies in both Photodynamic Therapy...

Thermally activated delayed fluorescence (TADF) materials have received increasing attention from organic electronics to other related fields, such as bioapplications and photocatalysts. However, it remains a challenging task for TADF emitters to showcase the versatility concurrent with high performance in multiple applications. Herein, we first present such a proof-of-concept TADF material, namely, QCN-SAC, through strategically manipulating exciton dynamics. On the one hand, QCN-SAC displays obvious aggregate-induced deep-red/near-infrared emission with a high radiative rate beyond 10⁷ s^-1, thereby demonstrating nearly 100% exciton utilization under oxygen-free conditions. In a QCN-SAC-based nondoped organic light-emitting diode (OLED), a superb external quantum efficiency of 16.4% can be reached with a peak at 708 nm. On the other hand, QCN-SAC also exhibits a high intersystem crossing rate over 10⁸ s^-1 without leveraging the heavy-atom effect, which makes QCN-SAC-based nanoparticles perform well in boosting reactive oxygen species generation for imaging-guided photodynamic therapy (PDT). This work presents a fundamental principle for designing high-performance all-in-one TADF molecules for OLED and PDT applications. This discovery holds promise for advancing the development of versatile TADF materials with a range of uses in the near future.