High-efficiency blue thermally activated delayed fluorescence from donor–acceptor–donor systems via the through-space conjugation effect

) and increases FMO overlaps for radiation facilitation, resulting in the 4-6 fold increased rate constants of reverse intersystem crossing (RISC) and singlet radiation. The maximum external quantum efficiency beyond 20% and the state-of-the-art efficiency stability from sky-blue TADF OLEDs demonstrate the effectiveness of the "conjugation modulation" strategy for developing high-performance optoelectronic D-A systems.