Precisely controlling full-color nanofilms for multi-level spatial-time-evolved via phosphorescence decay.

Sustainable rigid matrices and ultra-long lifetime organic room-temperature phosphorescent (ORTP) materials with precisely controlling phosphorescent properties establishes an innovative paradigm for achieving ideal variable afterglow, facilitating multi-level spatial-time-evolved in information encryption. Herein, we have constructed a full-color nanofilm with multi-level spatial-time evolution from a donor of rigid-structure enhanced ORTP material and a molecular acceptor bridged by cellulose nanocrystal (CNC). CNC induced the polymerization of melamine, isophthalic acid and its isomers, creating a denser hydrogen bond environment, which effectively enhanced spin-orbit coupling, inhibited non-radiative transitions, and extended the phosphorescence lifetime to 2.03 s, while increasing the absolute quantum yield to 29.54%. Remarkably, this phosphorescent property, such as intensity, lifetime and color, could be finely controlled by modifying the rhodamine B acceptor dopant in the förster-resonance energy transfer system. Utilizing precisely controlling the ORTP characteristics and the response performance to ofloxacin, a multi-level information encryption including attacker misdirection, multi-layer encryption matrices, and spatial-time-evolved cryptographic systems is successfully developed. This work provides a new direction for enhancing phosphorescence lifetime and precisely controlling phosphorescent properties, stimulating innovations the applications of ORTP materials in high-level anti-counterfeiting and secure information encryption.