Long-lived room-temperature phosphorescent carbon dot-based composites for anti-counterfeiting and information encryption

Here, we report a simple solvent-free strategy for preparing blue-green room-temperature phosphorescent carbon dot-based composites by heat treating terephthalic acid (TPA) and boric acid (BA) at 250 °C. The designed composites (CDs@B₂O₃) exhibit an ultralong lifetime of 1.768 s, lasting over 25 s to the naked eye, concurrently with a photoluminescence quantum yield (PLQY) of 33.2%. Furthermore, the CDs@B₂O₃ composites have been applied to anti-counterfeiting, information encryption, and delayed lighting. This work provides a novel strategy for designing metal-free room-temperature phosphorescent carbon dots with sustained luminescence, revealing promising potential for advanced applications.