Endowing Photodeformation Film With Near‐Infrared Afterglow

ABSTRACT The near‐infrared (NIR) afterglow visualization in photodeformation materials offers real‐time, light‐off tracking of dynamic photoresponsive processes in deep tissues and optomechanical systems. However, it remains a fundamental challenge to simultaneously achieve photodeformation and NIR afterglow, due to the competing requirements of molecular design: molecular flexibility for photodeformation versus structural rigidity for afterglow emission, in addition to the intrinsic difficulty in realizing NIR afterglow. To resolve this dichotomy, we developed a rigidity–flexibility compartmentalized molecular structure. A rigid conjugated framework with strong charge transfer (CT) character is responsible for the persistent NIR afterglow via radiative recombination of charge‐separated states (CSS), while flexible tautomerism units featuring an excited‐state intramolecular proton transfer (ESIPT) process enable photodeformation. Once these dyes are doped into polyethylene terephthalate (PET) films, the visible‐light‐driven photocontraction (with a contraction rate up to 48%) and persistent NIR afterglow can be realized. Furthermore, it has been successfully utilized for in vivo precision control in bioimaging with high signal‐to‐background ratio (SBR), and applied in the dynamic modulation of vascular stents with afterglow visualization.