24‐Hour‐Long Afterglow from Single Polymer Chains Through Engineering‐Compatible One‐Pot Polycondensation Approach

Abstract We report the unprecedented observation of 24‐h‐long afterglow (HLA) emission from single polymer chains. The polymer chains were synthesized through a straightforward engineering‐compatible one‐pot polycondensation reaction. These polymers exhibit afterglow emissions exceeding 24 h under ambient conditions through charge separation and recombination mechanisms. Remarkably, these HLA polymers can be activated by sunlight and sustain a green afterglow for over 6 h at room temperature in air, rendering them suitable for practical engineering applications. Notably, the HLA is temperature‐dependent, with lower temperatures substantially prolonging emission duration. At − 18 °C, afterglow persists for up to 10 days after ceasing photoexcitation, establishing these polymers as the longest‐lasting afterglow polymeric materials reported to date. Moreover, the excellent processability of the 24‐HLA polymers allows their facile fabrication into diverse forms including films and fibers using conventional polymer processing techniques, positioning them as promising candidates for flexible displays and wearable electronics.