Novel visible-light-excited afterglow rose-bengal-derived carbon dots and their applications

Compared to ultraviolet light, visible light is much more accessible and less damaging. However, afterglow materials that are excited by visible light remain a challenging issue. In this study, visible-light-excited phos-phorescence combined with thermally activated delayed fluorescence were achieved by embedding Rose bengal (R) CDs (R-CDs) with a high quantum yield in a boric acid (BA) matrix. The R-CDs were prepared by thermally cleaving Rose bengal in an aqueous solution. At room temperature, the R-CDs@BA composite exhibited a dual -emission afterglow spectrum with an afterglow lifetime of 583 ms at an emission wavelength of 450 nm. The afterglow time was visible to the naked eye for up to 5 s, and the photoluminescence quantum yield reached 18.09%. The quantum yield of phosphorescence is 0.6%. Consequently, the R-CDs@BA composite materials were successfully employed in anti-counterfeiting, graphic security and white led emitting diodes. In summary, R-CDs@BA hold great promises for the application in different fields. New afterglow materials and applications that are stimulated by visible light may be made possible as a result of these discoveries.