Ultralong Room‐Temperature Phosphorescent Coatings Enabled by Coronene Aggregates in Specialty Epoxy Resin: Wide‐Range Excitation From Violet to Green Light

ABSTRACT For practical applications, it is essential for room‐temperature phosphorescence (RTP) materials to possess both visible‐light excitability and prolonged afterglow characteristics. Herein, we report a strategy in which coronene (Cor)‐based aggregate luminophores, prepared via UV irradiation, are doped into a specialty epoxy resin (SER) precursor. Coating films are fabricated through a simple painting process that avoids hot‐pressing, thereby enabling straightforward application in practical coatings. The UV‐induced aggregates significantly broaden the visible‐light excitation range: in addition to violet, blue, and white light, the RTP material can be excited by green light at 520 nm, displaying a phosphorescence lifetime ( τ _Phos ) of 70 ms and an afterglow duration ( t _ag ) of 12 s, outperforming previously reported green‐light‐excitable RTP systems. Under violet, blue, or white light excitation, Cor and its aggregates achieve a maximum τ _Phos of 6.20 s and a remarkable t _ag of up to 90 s, far exceeding the 40 s record of Cor‐doped thermoplastic polymers. Furthermore, leveraging phosphorescence resonance energy transfer enables a red afterglow of 60 s under white‐light excitation. Owing to the high glass transition temperature of the SER matrix, the material retains afterglow emission even at 135°C. These combined characteristics significantly expand the application scope of RTP materials.