Silicon nanocrystals and their composites：syntheses, fluorescence mechanisms and biological applications

Due to the excellent fluorescence intensity, low toxicity, good biocompatibility and stability, silicon nanocrystals (Si NCs) and Si NCs-based composites have attracted extensive attention, which have been widely applied in analytical detection, biomarkers, photocatalysts, photodiodes, and solar cells. In this article, we summarize the recent advances in the synthesis of Si NCs and their composites and also discuss their fluorescence property and mechanism in detail. We also introduce their biological applications. Finally, the outlooks and future challenges of the promising research field are briefly discussed. This review is hoped to make a contribution to the subsequent synthesis and biological applications of Si NCs and their composites.