Enabling robust and hour-level organic long persistent luminescence from carbon dots by covalent fixation

The first carbon dot (CD)-based organic long persistent luminescence (OLPL) system exhibiting more than 1 h of duration was developed. In contrast to the established OLPL systems, herein, the reported CDs-based system (named m-CDs@CA) can be facilely and effectively fabricated using a household microwave oven, and more impressively, its LPL can be observed under ambient conditions and even in aqueous media. XRD and TEM characterizations, afterglow decay, time-resolved spectroscopy, and ESR analysis were performed, showing the successful composition of CDs and CA, the formation of exciplexes and long-lived charged-separated states. Further studies suggest that the production of covalent bonds between CA and CDs plays pivotal roles in activating LPL and preventing its quenching from oxygen and water. To the best of our knowledge, this is a very rare example of an OLPL system that exhibits hour-level afterglow under ambient conditions. Finally, applications of m-CDs@CA in glow-in-the-dark paints for emergency signs and multicolored luminous pearls were preliminarily demonstrated. This work may provide new insights for the development of rare-earth-free and robust OLPL materials.

Automated summary

The first organic long persistent luminescence (OLPL) system based on carbon dots (CDs) with a duration of over 1 hour has been developed. The CDs-based system, named m-CDs@CA, can be easily fabricated using a household microwave oven and exhibits long persistent luminescence under ambient conditions and even in aqueous media. The successful composition of CDs and CA, the formation of exciplexes and long-lived charged-separated states were confirmed by various characterizations. Covalent bond formation between CA and CDs was found to play a key role in activating long persistent luminescence and preventing its quenching from oxygen and water. This work provides new insights for the development of rare-earth-free and robust OLPL materials.