High-Efficiency Multistimuli Responsive Carbon Dots with Near-100% Photoluminescence Quantum Yield for Anticounterfeiting Technologies

Abstract With the rising demand for information security and anticounterfeiting, developing intelligent luminescent materials responsive to external stimuli is crucial for enhancing encryption and anticounterfeiting technologies. Herein, a facile one-pot solvothermal strategy was developed to prepare multistimuli responsive carbon dots (CDs), which exhibit solvent-responsive, concentration-responsive, and pH-responsive properties, along with a photoluminescence quantum yield (PLQY) approaching 100% in aqueous dispersion. Systematic investigations reveal that the high PLQY of the CDs originates from the cross-arranged nonextended conjugation of perylene-based backbones in the CDs core, which prevent further π–π stacking. In addition, surface functional groups regulate solvent-dependent luminescence behavior through polar interactions and hydrogen bonding. As the concentration increased, enhanced intermolecular interactions induce the emission from monomer-dominated to aggregate-dominated states. Furthermore, under different pH conditions, reversible protonation and deprotonation of surface functional groups enable dynamic modulation of the electronic structure, thereby regulating the fluorescence emission. By combining with polymers, multicolor high-brightness polymer powders with PLQY approaching 100% were successfully prepared. These composite materials demonstrate excellent performance in handicraft decoration and anticounterfeiting systems. This work not only provides a theoretical basis for the design of highly efficient luminescent CDs but also expands their potential in intelligent materials and photonic applications.