Structural reconstruction synthesis of highly luminous water-stable CsPbBr3@CsPb2Br5@DSPE core-shell perovskite nanocrystals for bioimaging, pattering, and LEDs

Lead halide perovskite (LHP) nanocrystals (NCs) suffer from poor stability against environmental factors (heat, moisture, oxygen, etc.), which seriously hinders their practical application. Constructing a core-shell structure could be an effective approach to improve the stability and optical properties of the LHP NCs. Herein, a novel strategy of water-triggered phase transformation and phospholipid (DSPE) micelle encapsulation is proposed, generating highly luminescent water-dispersed CsPbBr₃@CsPb₂Br₅@DSPE core-shell-shell nanocrystals. The epitaxial growth of the CsPb₂Br₅ shell is induced by the in-situ reconstruction of the CsPbBr₃ surface by water erosion, and the lattice mismatch with the CsPbBr₃ core is small (3.8%). The further amphipathic phospholipid encapsulation guarantees their excellent water dispersity and stability. Revealed by the femtosecond transient absorption spectroscopy, the dense CsPb₂Br₅@DSPE shell effectively passivates the surface of the CsPbBr₃ core, thus improving its stability and luminescence performance. The resulting CsPbBr₃@CsPb₂Br₅@DSPE nanoparticles exhibit excellent performance as fluorescent probes for bioimaging, aqueous inks for high-resolution pattering, and light conversion layers for LEDs, demonstrating their promising potential in multiple applications.