Facile, Large-Quantity Synthesis of Stable, Tunable-Color Silicon Nanoparticles and Their Application for Long-Term Cellular Imaging.

We herein introduce a facile, low-cost photochemical method capable of rapid (<40 min) and large-quantity (∼10 g) production of highly fluorescent (quantum yield: 25%) silicon nanoparticles (SiNPs) of tunable optical properties (peak emission wavelength in the range of 470-560 nm) under ambient air conditions, by introducing 1,8-naphthalimide as a reducing agent and surface ligands. The as-prepared SiNPs feature robust storage stability and photostability preserving strong and stable fluorescent during long-term (>3 h) high-power UV irradiation, in contrast to the rapid fluorescence quenching within 2 h of conventional organic dyes and II-VI quantum dots under the same conditions. The as-prepared SiNPs serving as photostable nanoprobes are workable for cellular imaging in long-term manners. Our findings provide a powerful method for mild-condition and low-cost, large-quantity production of highly fluorescent and photostable SiNPs for various promising applications.