Proceedings Article | 18 March 2023
KEYWORDS: Fluorescence, Nanocrystals, Perovskite, Silica, Quantum efficiency, Emission spectrum, Nanoparticles, Fluorescence intensity
Inorganic perovskite nanocrystals (IPNCs) have drawn much attention due to their unique photophysical properties such as high fluorescent quantum yield, narrow- and size-tunable emissions, excellent photostability, and large multiphoton absorption cross-section. IPNCs have been utilized as contrast agents for biomedical imaging, as well as other applications such as photovoltaics, light-emitting diodes, and photodetectors. IPNCs can be synthesized by a variety of different techniques, e.g., hot injection, ligand-assisted reprecipitation, and anion exchange methods, amongst others. These methods produce size controlled IPNCs but require multiple synthesis steps which can affect the reproducibility, i.e., variation in photophysical properties across batches. Here, we present a simple water-assisted one-pot strategy for the synthesis of highly bright IPNCs. This approach involves dissolving precursor salts in nonpolar solvents like toluene and hexane. Recrystallization is induced by the addition of minuscule quantities of water, due to phase separation between solvent and water, which leads to the formation of IPNCs. The fluorescence emission of these IPNCs was tuned by changing the halide ions, e.g., bromide for green-yellow fluorescence and iodide for red fluorescence. The size and shape, which affects the quantum yield, can be easily tuned by changing the reactant concentration and volume of water. These IPNCs were further modified to improve their water stability, by coating them with hydrophobic polymers, like silica, which facilitated their use as contrast agents for labeling cancer cells.
