Day‐Long Organic Persistent Luminescence in Flexible Polymeric Materials

Abstract The progress in organic afterglow materials has drawn significant attention due to their extensive applications in fields such as optoelectronics, anti‐counterfeiting, and bioimaging. Nonetheless, a general limitation of organic afterglow materials is their short emission lifetimes, typically spanning from milliseconds to seconds, which creates a substantial challenge in developing day‐long organic afterglow (DOA). In this study, a DOA system is demonstrated through the incorporation of electron donor/acceptor exciplexes. Polyethylene naphthalate is used for both the electron acceptor and charge storage units, coupling with a spirobifluorene‐carbazole derivative as the electron donor, providing effective charge separations under UV‐light and sunlight excitation. The resulting DOA polymers demonstrate an exceptional bluish‐green afterglow that endures for over 28 h under ambient conditions, setting a new record for the longest afterglow duration in polymeric materials. Moreover, the DOA‐doped polymers, as both films and fibers, exhibit outstanding flexibility and transparency, making them highly suitable for flexible technologies and wearable devices.