Growth optimization of single-phase novel colloidal perovskite CsBiI nanocrystals and CsBiI@SiO core-shell nanocomposites for bio-medical application.

Lead-free halide perovskites have gained attention in recent years as viable materials with more distinctive characteristics than conventional semiconductor materials. Lead-free CsBiI colloidal perovskite nanocrystal is chosen to eliminate its single-phase synthesis difficulty and implement the material in bioimaging applications. Nanostructured CsBiI perovskite composites were coated with a thin coating of SiO by an tetraethyl orthosilicate/(3-aminopropyl)trimethoxysilane injection growth method to enhance their stability in aqueous medium and biocompatibility. Single-phase novel CsBiI colloidal perovskite nanocrystal synthesis was successfully developed and optimized by adopting different synthetic conditions with varied experimental parameters. Characterization studies, including X-ray diffractometry and transmission electron microscopy, confirm the hexagonal structure of CsBiI crystals and their cubic morphology. A broad emission peak in the red region was captured for pure and composite perovskite under different excitation wavelengths and was observed using a UV-visible spectrophotometer. Bioimaging of CsBiI@SiO composites incorporated with L929 cells was conducted using an inverted fluorescence microscope under blue and green excitation. The results obtained from bioimaging studies indicated that the CsBiI@SiO nanocomposites entered the cell field and exhibited an emission under excitation. The non-toxic behavior of the synthesized CsBiI@SiO composites was demonstrated using MTT cytotoxicity assay in L929 fibroblast mouse cells, showing better cell compatibility.