Efficient synthesis of high-purity carbon dots via self-polymerization driven bottom-up growth for high-selectivity sensing and high-efficiency separation

Carbon dots (CDs) have attracted extensive interest due to their exceptional optical properties and facile synthesis processes. However, achieving high-efficiency synthesis of high-purity CDs with high yield remains an unresolved critical issue. Herein, we report a facile and versatile self-polymerization-driven bottom-up growth strategy for efficient fabrication of high-purity CDs. As a proof-of-concept demonstration, dopamine and its four analogues were used as the self-polymerizable precursors for self-driven synthesis of fluorescent CDs with high-purity. By employing a mixed-solvent system and rationally regulating periodate oxidation process, the highly controllable self-polymerization processes and efficient solvothermal-assisted production of polydopamine and polyphenols derived CDs were readily achieved. Further integrating high molecular weight membrane dialysis, we successfully obtained the highly purified polydopamine-derived CDs with high yield of 21.1% and quantum yield of 3.6%, confirmed by nuclear magnetic resonance, capillary electrophoresis and other types of high-resolution characterization techniques. The formation and luminescence mechanisms of the self-polymerized CDs were also elucidated through comparative analysis of their morphological features and elemental compositions. We also demonstrated the broad universality of this self-polymerization driven bottom-up strategy by utilizing by employing four other phenolic compounds, including L-dopa, gallic acid, catechol, and pyrogallol, as readily accessible precursors for high-yield synthesizing highly purified fluorescent CDs. Moreover, the enormous application potential of the high-purity CDs for high-selectivity sensing and high-efficiency electrochromatographic separation was thoroughly demonstrated.