It remains a great challenge to develop polymer‐based materials with efficient and color‐tunable organic afterglow. Two indolocarbazole derivatives IaCzA and IbCzA have been synthesized and doped into poly(vinyl alcohol) (PVA) matrices. It is found that the resulting films can produce unique dual‐mode afterglow, which is composed of persistent thermally activated delayed fluorescence and ultralong organic phosphorescence. Besides, the IbCzA‐doped PVA film exhibits intense blue afterglow with Φafterglow and τafterglow up to 19.8 % and 1.81 s, respectively, representing state‐of‐the‐art dual‐mode organic afterglow performance. Moreover, our reported film has high flexibility, excellent transparency, and large‐area producibility; and the afterglow color of the film can be linearly tuned by temperature. Inspired by these distinctive properties, the PVA doped with IbCzA was employed as temperature‐sensitive security ink for anti‐counterfeiting and information encryption.

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In this work, an efficient polymer-based organic afterglow system, which shows reversible photochromism, switchable ultralong organic phosphorescence (UOP), and prominent water and chemical resistance simultaneously, has been developed for the first time. By doping phenoxazine (PXZ) and 10-ethyl-10H-phenoxazine (PXZEt) into epoxy polymers, the

Color-tunable dual-mode organic afterglow excited by ultraviolet (UV) and white light was achieved from classical aggregation-caused quenching compounds for the first time. Specifically, two luminescent systems, which could produce significant organic afterglow composed of persistent thermally activated delayed fluorescence and ultralong organic phosphorescence under ambient conditions, were constructed by doping fluorescein sodium and calcein sodium into aluminum sulfate. Their lifetimes surpassed 600 ms, and the dopant concentrations were as low as 5 × 10 À 6 wt %. Moreover, the persistent luminescence colors of the materials could be tuned from blue to green and then to yellow by simply varying the concentrations of guest compounds or the temperature in the range of 260-340 K. Inspired by these exciting results, the afterglow materials were used for UV-and white-light-manipulated anti-counterfeiting and preparation of elastomers with different colors of persistent luminescence.

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