Full-Color-Tunable and pH-Responsive Ultralong Afterglow Based on a Single Polymeric Phosphor with Triple-Mode Delayed Emission

Full-color-tunable ultralong afterglow is significant for high-level information encryption. Herein, we report such an afterglow from a polymer synthesized via one-step anionic hybrid copolymerization of maleimide and N,N-dimethylaminopropylacrylamide. The polymer film exhibits an optimal delayed emission wavelength varying from 428 to 629 nm with a duration of afterglow of up to 4 s under ambient conditions. Particularly, the afterglow is pH-responsive. Our study reveals that the unique afterglow originates from the concurrence of three distinct delayed emission modes, i.e., persistent room-temperature phosphorescence, thermally activated delayed fluorescence, and delayed fluorescence through Förster-resonance energy transfer. This present study provides a facile approach to developing high-performance afterglow materials for information encryption and decryption.