Proton transfer regulated photocured robust room-temperature phosphorescence from naphthalimide

Photocured room-temperature phosphorescence (RTP) materials have considerable potential applications but are rarely reported. Here, we reported photocured RTP materials from naphthalimide, which simultaneously acts as RTP chromophore and photo-initiator. Specifically, naphthalimide generates radicals to polymerize acrylic acid and acrylamide upon UV irradiation. The resulting naphthalimide is tightly restricted in in-situ formed crosslinked matrix to achieve robust RTP (τ_p = 389.58 ms, φ_p = 17.83%, water and organic solvents resistance). Significantly, carboxyl can bind onto lone-pair electrons of tertiary amine in naphthalimide through proton transfer hydrogen-bonds (PTHBs), inhibiting nonradiative decay of S₁ induced by photoinduced electron transfer (PET); increasing spin-orbit coupling (SOC) to promote intersystem crossing (ISC); cooperating with intermolecular hydrogen-bonds afford rigid microenvironment to stabilize triplet excitons. Moreover, afterglow colors are continuously tuned after loading different mass RhB via energy transfer. The as prepared materials are used as RTP inks for fabricating 3D printing and photopatterning for anti-counterfeiting and information encryption applications.