Multi-armed star-shaped PEG₁₀₀₀-encapsulated Mn²⁺:CsPbCl₃ perovskite quantum dots for sensitive detection of crystal...

Mn²⁺-doped CsPbCl₃ quantum dots (Mn²⁺:CsPbCl₃ QDs) exhibit high photoluminescence quantum yields (PLQYs) and extended carrier diffusion lengths, but their use in aqueous environmental monitoring is hindered by poor water stability and fluorescence quenching. To address this challenge, a surface engineering strategy was employed in which the surfaces of Mn²⁺:CsPbCl₃ QDs were coated with star-shaped polyethylene glycol-1000 (PEG₁₀₀₀) ligands, it has significantly improved stability in aqueous solutions while maintaining optical performance. Taking into account the steric hindrance and surface passivation effects of multi-arm star-shaped PEG₁₀₀₀, the three-arm and four-arm star-shaped PEG₁₀₀₀ encapsulated Mn²⁺:CsPbCl₃ QDs exhibit good stability under weakly acidic conditions. Crystal Violet (CV) is an effective fluorescence quencher. Using the advantages of enhanced water stability of QDs and the fluorescence inner filter effect (IFE) between CV and QDs, a fluorescence detection platform was constructed. This platform enables quantitative detection of CV in aqueous solutions, achieving a detection limit of 1.136 µmol/L and a linear dynamic range of 0-23.78 µmol/L. This method presents a promising strategy for monitoring environmental pollutants and demonstrates distinct advantages in challenging aqueous matrices through the utilization of perovskite nanomaterials.