Biocompatible Silica‐Coated Europium‐Doped CsPbBr 3 Nanoparticles with Luminescence in Water for Zebrafish Bioimaging

Abstract Cesium lead halide (CsPbX 3 , X = Br, Cl, and I) nanocrystals (NCs) are widely concerned and applied in many fields due to the excellent photoelectric performance. However, the toxicity of Pb and the loss of luminescence in water limit its application in vivo. A stable perovskite nanomaterial with good bioimaging properties is developed by incorporating europium (Eu) in CsPbX 3 NCs followed with the surface coating of silica (SiO 2 ) shell (CsPbX 3 :Eu@SiO 2 ). Through the surface coating of SiO 2 , the luminescence stability of CsPbBr 3 in water is improved and the leakage of Pb 2+ is significantly reduced. In particular, Eu doping inhibits the photoluminescence quantum yield reduction of CsPbBr 3 caused by SiO 2 coating, and further reduces the release of Pb 2+ . CsPbBr 3 :Eu@SiO 2 nanoparticles (NPs) show efficient luminescence in water and good biocompatibility to achieve cell imaging. More importantly, CsPb(ClBr) 3 :Eu@SiO 2 NPs are obtained by adjusting the halogen components, and green light and blue light are realized in zebrafish imaging, showing good imaging effect and biosafety. The work provides a strategy for advanced perovskite nanomaterials toward biological practical application.