Dynamic Long‐Afterglow Materials with Ultralong Lifetime for Advanced Message Encryption

Abstract Ultralong afterglow materials has special optical properties and a broad application prospect in the field of information encryption. A single afterglow color largely limits the application of afterglow materials in the direction of advanced encryption, and materials with dynamic afterglow are more popular. However, most of the dynamic afterglow materials are doped with multiple chromophores, and these materials with a single chromophore are rarely reported and have low lifetimes. Herein, a series of dynamic afterglow materials with time‐dependent phosphorescence is obtained by a simple one‐step strategy, and the longest lifetime reached 1.39 s, the maximum PLQY reached 85.9%, and the naked‐eye duration reached 20 s, which is the best level reported so far. The dynamic afterglow phenomenon is attributed to the multiple phosphorescence emission centers of the guest molecule with different decay rates, which results in a dynamic shift of the phosphorescence color. It is demonstrated through a series of characterizations that the covalent bonding interaction between the guest molecule and the host boric acid largely inhibits the nonradiative leaps of the guest molecule and provides it with a rigid matrix environment. Crucially, the dynamic afterglow material has been successfully applied in the field of displays and advanced information encryption.