Photoinduced Charge-Transfer Enables Dynamic Photochromism and Fluorochromism in Polymer Matrix

Photo-stimuli-responsive luminescent materials are limited in application due to poor stability of their excited states. In donor-acceptor organic systems, photoinduced charge transfer and triplet-state dynamics are strongly governed by molecular interactions and environmental confinement, but their mechanistic regulation remains incompletely understood. Herein, we report a facile strategy to construct dynamic luminescent thin films by incorporating an electron acceptor and tertiary amine donors into a poly(methyl methacrylate) (PMMA) matrix. Photoinduced charge-transfer complexes (PCTCs) are generated in situ. The resulting modulation of charge-transfer and localized triplet states leads to prolonged excited-state lifetimes and distinct emission behaviors, exhibiting color-tunable emission spanning from blue fluorescence to green, yellow, and red, along with a visible orange-yellow afterglow persisting for 2 s. This work elucidates a matrix-assisted mechanism for regulating excited-state dynamics and provides general design principles for stable, high-contrast photoresponsive luminescent materials applicable to anti-counterfeiting and optical patterning.