Nanoconfinement Enabled High‐Efficiency and Long‐Lifetime Multicolor Afterglow Hydrogels for Advanced Spatiotemporal Encryption and Pathogen Eradication

ABSTRACT Multicolor organic afterglow hydrogels that simultaneously possess efficient exciton harvesting, ultralong lifetimes and large deformations are still rare. Here, a nano‐restriction engineered strategy that embeds a rigid and chromatically diverse hydrogen bond supramolecular framework into hydrogel networks is presented. The confined microenvironment of the supramolecular framework suppresses non‐radiative quenching to prolong triplet lifetimes and acts as stress‐dissipating nodes to reinforce the polymer matrix. The synthesized hydrogels exhibit tunable afterglow emissions from deep blue to orange–red, lifetimes up to 2535 ms, and quantum yields above 29.4%, while retaining a compressive strength of 7.7 MPa and fracture strain near 1400%, with excellent stability under repeated cycling. Programmable color and decay dynamics of afterglow hydrogels enable spatiotemporally resolved encryption. Moreover, the long‐lived triplet excitons efficiently sensitize singlet oxygen, delivering >99.9% antibacterial efficacy to accelerate infected wound healing. This approach provides a general route to develop multifunctional afterglow soft materials that couple high exciton utilization and ultralong lifetime with mechanical robustness.