Reversible and Continuous Color-Tunable Persistent Luminescence of Metal-Free Organic Materials by “Self” Interface Energy Transfer

Persistent luminescence from metal-free organic materials is attractive for their ultra-long excitons lifetimes. However, color-tunable persistent luminescence from single-component organic materials is fascinating but still challenging. By utilizing an efficient approach of “self” interface energy transfer (IET), the persistent luminescence color of an organic phosphors (CTXO) can be reversibly and continuously tuned by external physical stimuli. Its color circularly changes between green (lifetime = 0.24 s) and deep-yellow (lifetime = 0.10 s), when CTXO is repeatedly triggered with thermally annealing and mechanically grinding. “Self” IET from crystalline part (donor), which exhibits persistent room-temperature phosphorescence, to amorphous part (acceptor) inside its semi-crystal during these treatments is found to be the key excitons process for such novel color modulation. This also provides opportunity for designing stimuli-responsive smart materials with controlled persistent luminescence.