Synergistic lifetime extension strategy based on Förster resonance energy transfer and TADF for carbon-dot-based room temperature afterglow

Carbon dot (CD)-based room temperature afterglow (RTA) materials have attracted extensive attention due to their great application prospects in many fields. However, the afterglow lifetimes of most CD-based RTA materials with long-wavelength emission are short. Herein, a strategy has been proposed to effectively extend the lifetime of CD-based RTA materials with long-wavelength emission. It is based on the synergy of Förster resonance energy transfer (FRET) and thermally activated delayed fluorescence (TADF). A molecule with TADF, PDINSA (2-naphthalenesulfonic-acid-substituted perylene diimide), was designed as a FRET acceptor, which was complexed with an RTA donor CDs@BA (BA: boric acid). As anticipated, a complex with an emission center at 595 nm and an afterglow lifetime of 549.69 ms was successfully constructed. This strategy can produce a synergistic effect of "1 + 1 > 2," enabling the composite to obtain an enhanced lifetime of 1.76 times that of CDs@BA.