Enhanced Aggregation-Induced Phosphorescence of Carbon Dots for Information Encryption Applications

Aggregation-induced phosphorescence (AIP) has attracted much attention for its unique luminescent characteristics. Nevertheless, this fascinating phenomenon is rarely reported in the field of carbon dots (CDs). Herein, a simple method to prepare CDs simultaneously with dispersion-state fluorescence, aggregation-state fluorescence, and phosphorescence is presented by a one-step solvothermal process. The resultant AIP CDs (A-CDs) display a long afterglow lifetime of 0.51 s in the aggregation state, lasting about 5 s to the naked eye. The phosphorescence emission of A-CDs resulted from the rigid, protective structure due to the aggregation state. In addition, inorganic silica has been employed as a doping matrix to effectively improve phosphorescent properties (1.11 s). Benefitting from the unique luminescence feature and excellent water dispersibility, the A-CDs can be dispersed directly in water, and the phosphorescent emission could be controlled by regulating the concentration, thus enabling information encryption.