Organic Near-Infrared Afterglow Materials with Ultralong Lifetimes and Aggregation-Induced Emission Features Through Relay Phosphor Strategy.

Organic materials with afterglow properties have gained significant interest owing to their long lifetimes and potential applications. However, most of these organic materials emit light in the visible region, posing a significant challenge for developing near-infrared afterglow (NIR-AG). In this study, NIR-AG materials with ultralong lifetimes and aggregation-induced emission (AIE) features are fabricated using a relay phosphor strategy. Red relay phosphors are easily fabricated by incorporating pyrene derivatives into an electron-rich matrix. The triplet excited energy of the relay phosphor is manipulated and effectively transferred to the excited singlet state of the AIE molecule via phosphorescence resonance energy transfer. Following the radiative decay of the excitons, an exceptional NIR-AG is ultimately generated with an ultralong lifetime of 269 ms at an emission maximum of 822 nm. The NIR-AG materials with ultralong lifetimes and AIE characteristics are reported for the first time, demonstrating one of the best performances among the organic afterglow materials. Notably, the NIR-AG materials can be processed into diverse aggregated forms for advanced anticounterfeiting, fingerprint identification, information encryption, and tissue penetration imaging using red and NIR dual-delay channels with good performances. These promising findings are encouraging for the development of organic NIR-AG materials with exceptional performance.