Ultralong and Thermally Enhanced Persistent Luminescence in Printable Recycled Polymers for Advanced Thermal Imaging

Achieving long persistent luminescence (LPL) in fully organic materials with both hour-level duration and high thermal stability remains a fundamental challenge attributable to rapid exciton quenching and poor resistance to thermal disturbances. Herein, a trap engineering strategy is reported based on rigidified triphenylamine derivatives and boronic ester functionalization embedded in recycled poly(ethylene terephthalate) (PET), enabling the first fully organic polymer-based LPL system that exhibits simultaneously ultralong LPL and exceptional thermal robustness. Molecular conformation locking and optimized donor-acceptor charge transfer lead to deep trap states (≈1.03 eV), resulting in ambient LPL lifetimes exceeding 12 h. Remarkably, the luminescence is thermally enhanced by over 56 times at 500 K, rivaling high-performance inorganic phosphors. In addition, 980 nm near-infrared photo excitation further amplifies the emission, showcasing strong photo-stimulated luminescence capability. Taking advantage of PET's processability, 3D-printed luminescent structures are fabricated that retain LPL functionality and enable spatially resolved thermal sensing and real-time damage detection. This work not only introduces a sustainable and scalable platform for advanced thermal imaging and optoelectronics, but also sets a new benchmark in the design of heat-resistant organic LPL materials, bridging the gap between high-performance functionality and environmental compatibility.