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 (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 (Δ E 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 was realized by reducing Δ E ST through donor-acceptor molecular design. Therefore, the single-component white afterglow with high efficiency of 14.1% and 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 * .