Near‐Infrared Afterglow in Aqueous Solution via Carbon Dots Cascade Phosphorescence Resonance Energy Transfer Engineering

Abstract Near‐infrared (NIR) long‐lived afterglow materials are precious and valuable in high signal‐to‐noise ratio bioimaging due to their remarkable penetration depth and extended lifetime. However, the development of NIR afterglow materials with wavelengths over 700 nm in aqueous solution remains challenging, particularly with a lifetime of over 100 ms. Here, efficient NIR afterglow with a peak wavelength exceeding 780 nm in aqueous solution is demonstrated through carbon dots cascade phosphorescence resonance energy transfer (CDs‐c‐PRET) engineering. This approach incorporates phosphorescent CDs, energy intermediates, and NIR emitters, resulting in a series of nanocomposites exhibiting bright red to NIR afterglow with peaks of 670, 690, 730, 770 nm, in addition to 780 nm. The continuous NIR afterglow time exceeds 1s, and the corresponding afterglow quantum yield achieves 0.24%. In vivo, afterglow imaging is demonstrated with the NIR afterglow nanocomposite as an afterglow imaging agent. Furthermore, the demonstration in flexible and wearable delay lighting highlights the versatility of these materials.