Silicon nanocrystals and silicon-polymer hybrids: Synthesis, surface engineering, and applications

Silicon nanocrystals (Si-NCs) are emerging as an attractive class of quantum dots owing to the natural abundance of silicon in the Earth's crust, their low toxicity compared to many Group II-VI and III-V based quantum dots, compatibility with the existing semiconductor industry infrastructure, and their unique optoelectronic properties. Despite these favorable qualities, Si-NCs have not received the same attention as Group II-VI and III-V quantum dots, because of their lower emission quantum yields, difficulties associated with synthesizing monodisperse particles, and oxidative instability. Recent advancements indicate the surface chemistry of Si-NCs plays a key role in determining many of their properties. This Review summarizes new reports related to engineering Si-NC surfaces, synthesis of Si-NC/polymer hybrids, and their applications in sensing, diodes, catalysis, and batteries. The grand old newcomer: Silicon may be the "grand old semiconductor", however, it is a relative newcomer to the field of quantum dots. Silicon nanocrystals (Si-NCs) are emerging as a promising, non-toxic, and greener alternative to Group II-VI and III-V quantum dots. This Review highlights how surface chemistry can be used to engineer properties of Si-NCs and adapt them towards modern applications, such as sensors, photovoltaics, and light-emitting diodes.