In situ polymerization-prepared water-stable CsPbX3/PMMA composites for water-stimulated anti-counterfeiting and bioimaging

A modified method achieves in-situ synthesis of water-stable CsPbBr 3 /PMMA composites. • Pb O coordination bonds and Si-O-C covalent bonds enable a stable structure. • The composites remain fluorescently stable after 30 days of water immersion. • CsPbBr 3 /PMMA composites achieve dynamic anti-counterfeiting in water. • Excellent biocompatibility enables 24 h fluorescence imaging in osteosarcoma cells. Halide perovskite nanocrystals (HPNCs) exhibit exceptional optoelectronic properties but suffer from poor stability in polar environments and potential toxicity, limiting their practical applications in information anti-counterfeiting, data encryption, and biological fields. Combining HPNCs with poly(methyl methacrylate) (PMMA) can provide a strategy to construct CsPbBr 3 /PMMA composites that exhibit enhanced structural stability and tunable emission. This work reports an improved facile room-temperature ligand-assisted re-precipitation strategy for the in situ synthesis of CsPbBr 3 /PMMA composites with a silane-mediated protective shell, which significantly enhances the optical performance with a high PLQY of up to 86.0%, tunable emission wavelength ranging from 463 nm to 619 nm and photoluminescence average lifetimes spanning from 70.5 ns to 155.9 ns. PMMA bridges CsPbBr 3 and the silane agent by forming Pb O coordination bonds with Pb 2+ on the crystal surface and Si-O-C covalent bonds with the silane's Si O groups, thereby generating a dual-layer inert protective shell of PMMA and SiO 2 around the crystal that passivates surface defects and enhances structural stability of the composite. In addition, the CsPbBr 3 /PMMA composites exhibit excellent stability in water, ethanol, phosphate buffer saline (PBS), and Dulbecco's Modified Eagle's Medium (DMEM), particularly retaining over 90.0% of initial emission after 30 days in water, which enables a water-stimulated anti-counterfeiting application, displaying a “VICTORY” signal. Furthermore, the CsPbBr 3 /PMMA composites demonstrate high cell viability (>90.0% at 1000 μg/mL) and effective fluorescence imaging after 24 h in osteosarcoma cells. This work can be extended to other HPNCs, realizing stable optoelectronic devices for applications in advanced anti-counterfeiting and biological fields. A modified in-siu synthesis method produces CsPbBr 3 /PMMA composites that remain optically stable in water for over 30 days and are suitable for water-stimulated anti-counterfeiting and clear biological imaging. Download: Download high-res image (230KB) Download: Download full-size image