Functional Upcycling Discarded Poly(Ethylene Terephthalate) Bottles for Ultralong Organic Phosphorescence Polymer Elements

Abstract Thermomechanical processing serves as an energy‐ and carbon‐efficient platform for large‐scale alleviation of the growing discarded poly(ethylene terephthalate) (PET) stream. However, achieving high‐value recycled PET products, especially for functional elements, remains a significant challenge. Here, functional ultralong organic phosphorescence (UOP) polymer is achieved by incorporating polycyclic aromatic hydrocarbons (PAHs) into recycled PET (R‐PET) during the recycling process, which enables customized luminescent polymer elements with optical, thermal, and mechanical properties comparable to those of virgin PET's counterparts. The COR@R‐PET (0.05 wt%) system demonstrates an impressive afterglow lifetime of 5.01 s and an 18.3% afterglow quantum yield under ambient conditions. Experimental and simulation analyses indicate that COR possesses abundant triplet excitons for efficient luminescence, while R‐PET's oxygen‐barrier effect preserves these excitons. Leveraging scalable hot‐press, melt‐spun, and melt‐blown techniques, flexible UOP films and fibers are fabricated with thermal responsiveness, visible‐light excitability, robust mechanics, and high transparency. These properties enable applications spanning multiple information encryption, anti‐counterfeiting, energy‐efficient displays, wearable display devices, and luminous textiles. This study provides valuable insights into a feasible solution for the scalable upcycling of PET waste into functional luminescence materials, and broadens the potential application scope of responsive UOP elements.