A Universal Strategy for Tuning Afterglow Color In Situ Via Radiative Energy Transfer

Colorful afterglow materials have promising applications in optoelectronic displays. To effectively fine‐tune the afterglow color, an assembly structure that includes UV lamp, persistent room temperature phosphorescence (pRTP) layer, and fluorescent layer (from the bottom to the top) with superimposition of pRTP and fluorescence, is designed. The fluorescence component is emitted from a PMMA film doped with asymmetric 4‐(7‐methoxy‐5,6‐dinitrobenzo[c][1,2,5,]thiadiazol‐4‐yl)‐N,N‐diphenylaniline (TPA‐TD), which has a broad absorption that covers the entire visible region, facilitating effective radiative energy transfer between various pRTP materials and TPA‐TD. Due to its aggregation‐induced‐emission nature, the fluorescence intensity of TPA‐TD enhances with increased doping concentration in PMMA films. Meanwhile, the transmission of TPA‐TD film reduces as the doping concentration increases, which results in a reduction of pRTP intensity through the TPA‐TD film. Therefore, the afterglow color can be fine‐tuned in situ by regulating the ratio of pRTP and fluorescence.