Facile synthesis of carbonized polymer dots and their applications in security inks, sensing, light emitting diodes, and UV shielding films

Carbonized polymer dots (CPDs) have received much attention in recent years owing to their cost-effective synthesis, high resistance to photobleaching, environmental friendliness, and excellent biocompatibility. However, the aggregation-induced fluorescence quenching is a great obstacle to its applications. In this work, the highly fluorescent CPDs are prepared by a facile hydrothermal method assisted by polyethylene glycol (PEG) as the surface passivation agent, where phthalic acid and ethylenediamine are used as carbon and nitrogen source, respectively. Meanwhile, five types of PEG species are applied to prepare five CPDs to investigate PEG on optical properties of the resultant CPDs, among which the best quantum yield reaches 57.0%. The promising applications of CPDs as fluorescent inks, sensors, light emitting diodes, and UV shielding films have been demonstrated. Overall, our contribution here develops a facile and accessible route for the synthesis of CPDs and further demonstrates its versatile applications.