Aqueous-stable CsPbBr₃ QDs as a fluorescence sensor for rapid and sensitive tetracycline detection

The development of a facile, rapid, and sensitive strategy for antibiotic residue monitoring is of great significance for food safety. Perovskite quantum dots (PQDs) have emerged as a promising fluorescent material, garnering considerable interest for their exceptional optical properties, featuring high photoluminescence quantum yield, spectral tunability, and narrow-band emission. However, their poor stability in aqueous environments limits their practical application in sensing. In this work, we developed an aqueous synthesis strategy for CsPbBr₃ QDs using oleylamine and 5-bromovaleric acid (OAm/BVA) as synergistic ligands, yielding uniform morphology and excellent luminescent properties. The water-stable CsPbBr₃ QDs were further employed as a sensitive fluorescent sensor for tetracycline (TC) detection. Based on experimental and density functional theory (DFT) calculations, we elucidated the detection mechanism, demonstrating that fluorescence quenching is predominantly governed by a photoinduced electron transfer (PET) process. The developed sensor exhibits a wide linear range (1∼64 μM), a low detection limit (40.5 nM), high selectivity, and a rapid response. Furthermore, the capability to reliably detect TC in tap water with satisfactory recovery rates (99.74∼102.66%) and low relative standard deviations (1.2%∼3.4%) demonstrates the promising application of TC detection in real water samples.