Synthesis of multicolor luminescent adjustable carbon dots and their application in anti-counterfeiting

A novel approach for fabricating color-adjustable carbon dots (CDs) is proposed via hydrothermal treatment of p-aminobenzenesulfonic acid and o-, m-, or p-phenylenediamines, respectively. The as-synthesized CDs can emit blue, green, and orange fluorescence and are named b-CDs, g-CDs, and o-CDs, respectively. All of them have strict excitation independence and excellent photostability. Variations of photoluminescence emitting them are attributed to the difference in their particle size, the degree of oxidation, and the content of N-related states on their surface. Furthermore, these multicolor CDs have been used as fluorescents inks, which perform well in anti-counterfeiting and information security.