Three-component color-tunable room temperature afterglow doped materials through Forster-resonance energy transfer

There have been some reports on room-temperature afterglow doped materials originating from phosphorescence emission, but there are still few reports on afterglow doped materials based on delayed fluorescence. Additionally, although fluorescent molecules constructed through olefinic bonds have been widely used in solid-state luminescent materials, their application in afterglow materials is clearly overlooked. Herein, a series of room temperature afterglow materials are constructed using phenyl(pyridin-2-yl)methanone as the host, triphenylamine-based 4H-chromen-4-one as the guest, and D-pi-A 1,4-dihydropyridine derivative as the third component. The two-component doped material shows green phosphorescence with a delayed lifetime of 351 ms under conditions of rigid environment and assistance in energy transfer caused by the host molecule. Three-component doped materials display color-tunable delayed fluorescence adjusted by the concentration of the third component. The afterglow phenomena are confirmed to come from the Forster-resonance energy transfer from the guest to the third component. This work provides a facile and versatile strategy for the development of room-temperature afterglow doped materials based on fluorescent molecules containing olefinic bonds.