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

Abstract 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 (S 1 ), triplet (T 1 ), and stabilized triplet (T 1 * ) excited states was proposed to afford white afterglow through modulating the singlet–triplet splitting energy (ΔE ST ) and exciton trapping depth (E TD ). Low‐lying T 1 * for yellow afterglow was constructed by H‐aggregation engineering with large E TD and trace isomer doping, while high‐lying T 1 and S 1 for blue afterglow with thermally activated emission feature were realized by reducing ΔE ST 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 S 1 , T 1 , and T 1 *.