Preparation and application of carbon dot composite materials with long-lasting phosphorescence emission under extreme acidic and alkaline conditions

Carbon dots (CDs), as a novel luminescent material, have demonstrated broad application prospects in fields such as bioimaging, sensing, and information encryption. However, their room temperature phosphorescence (RTP) performance is susceptible to environmental factors (e.g., oxygen, moisture, and pH), with stability and luminescence efficiency under extreme pH conditions remaining significant challenges. In this study, a cross-linked hydrogen bond network was constructed through a one-step hydrothermal method using 3-aminophenylboronic acid and biuret as raw materials. The resulting MB-II composite material exhibits an ultra-long phosphorescence lifetime (1.48 s) and exceptional stability in aqueous solutions across a broad pH range (pH = 1–14) and organic solvents. This breakthrough surpasses the environmental adaptability limitations of current materials. The design integrates surface state engineering regulated by pH and optimized CD-matrix interactions, providing new perspectives for information encryption and biosensing under extreme conditions.