Eu‐Doped Polyurethane with Efficient Multicolor Fluorescence, Self‐Healing, Stimuli‐Responsiveness and Its Diverse Applications

Abstract Multicolor lanthanide‐doped polymers have found versatile applications in data encryption, sensing, and smart display. However, multiple components, sophisticated design, and complex preparation procedures are often required. In contrast, their intrinsic and multicolor fluorescence emission is been effectively used. Herein, Eu‐doped polyurethane (ETP@PU), integrating tunable multicolor emission, self‐healing, and multi‐responsiveness, is prepared through a facile route via step‐growth polymerization of PU using commercial Eu‐ligand (Eu(TTA)₃Phen, ETP) as a fluorophore. FTIR and XPS analysis demonstrate the successful coordination of Eu³⁺ with carbamate groups of PU, which not only enhances the mechanical properties of PU but also bestows unique luminescent properties. With increasing ETP content, the intrinsic fluorescence of PU declines, while that of Eu displays a discernible enhancement, resulting in the tunable multicolor emission. The highest quantum yield of Eu‐related emission reaches 71.3% due to the robust coordination and efficient energy transfer between Eu³⁺ and PU. Moreover, the ETP@PU exhibits excellent self‐healing capacity and multi‐responsiveness, and their potential applications are also investigated in the field of light‐emitting diodes, data encryption, and self‐healing process monitoring. This work provides a facile and efficient strategy to develop multicolor lanthanide‐doped polymers promising for various applications.