High-efficiency NP-carbon dots above 60% with both delayed fluorescence and room-temperature phosphorescence.

This report introduces a groundbreaking technique for synthesizing carbon dots (CDs) that display both delayed fluorescence and room-temperature phosphorescence. This achievement is made possible through a straightforward solvent-thermal reaction, followed by thermal treatment. The CDs are simultaneously provided with blue fluorescence and cyan afterglow, with an afterglow quantum yield (QY) of up to 60.47%, which is an expected figure for non-metallic CDs afterglow materials. Moreover, these CDs show an average afterglow lifetime of 1.11 s with a visually recognizable period of 16 s. We subsequently demonstrate the pragmatic application of CDs in cutting-edge fields such as anti-counterfeiting security and optical information storage.