Modulating Tri‐Mode Emission for Single‐Component White Organic Afterglow

Achieving single-component white organic afterglow remains a great challenge owing to the difficulties in simultaneously supporting long-lived emissions from varied excited states of a molecule for complementary afterglow. Here, an extraordinary tri-mode emission from the radiative decays of singlet (S1 ), triplet (T1 ), and stabilized triplet (T1* ) excited states was proposed to afford white afterglow through modulating the singlet-triplet splitting energy (ΔEST ) and exciton trapping depth (ETD ). Low-lying T1 * for yellow afterglow was constructed by H-aggregation engineering with large ETD and trace isomer doping, while high-lying T1 and S1 for blue afterglow with thermally activated emission feature were realized by reducing ΔEST through donor-acceptor molecular design. Therefore, the single-component white afterglow with high efficiency of 14.1 % and a lifetime of 0.61 s was achieved by rationally regulating the afterglow intensity ratios of complementary emissions from S1 , T1 , and T1 *.