Constructionof Carbon Dot-Based Color-Tunable CircularlyPolarized Long Afterglow via in Situ Phosphorescence Resonance EnergyTransfer

Carbon dots (CDs) with circularly polarized long afterglow (CPLA) properties have received increasing attention as a cutting-edge research field. However, because the CDs with both long afterglow and chirality are difficult to prepare and the afterglow color of most phosphorescent CDs is mainly concentrated in short wavelengths, it is still a formidable challenge to explore a facile route to achieve intrinsic CD-based color-tunable CPLA materials on a large scale. Herein, we developed a facile gram-scale synthesis method to prepare intrinsic CD-based color-tunable CPLA materials via a simple hydrothermal mixture of boric acid, arginine, and various fluorescent dyes. The tunable afterglow color is successfully achieved by engineering in situ phosphorescence resonance energy transfer (PRET) between the CDs formed by carbonization of arginine with some of the dyes and those uncarbonized dyes. Finally, the applications of CD composites in multimode advanced anti-counterfeiting and information encryption were explored.