Adv. Funct. Mater.

This work explored how molecular spin-conversion dynamics influence exciton accumulation and efficiency roll-off in TADF-based OLEDs. By employing an internal heavy-atom effect, the study enhanced spin-orbit coupling and achieved an exceptionally rapid reverse intersystem crossing process. Rather than relying on conventional donor–acceptor design alone, this strategy provides a molecular-level framework for understanding and controlling exciton dynamics in TADF emitters.