Silicon-Based Nanocomposites as Photoluminescent Materials: A Perspective and Advantages of the Radiation-Assisted Synthetic Approach

Silicon (Si), an indirect band gap semiconductor, was frequently overlooked as a photoluminescent material. However, with the discovery of photoluminescence from porous Si in the 1990s, the scientific community realized the relevance of quantum confinement in the observed phenomena. Consequently, interest in the fabrication of Si-based nanomaterials or nanocomposites has grown exponentially over the past two decades. This interest was further fueled by the advantageous properties of Si, such as, economical, low toxicity, and wide abundance in nature. Due to these alluring characteristics, Si-based nanomaterials have been and continue to be intensively studied for numerous applications, including catalysis, optoelectronics, energy, and biology. Of course, various strategies have been devised to synthesize Si-based nanomaterials with controlled morphologies, tunable photoluminescence, and enhanced quantum yields. However, considering the imminent applications of nanomaterials based on Si, it is pertinent to design or further improve existing synthetic protocols by incorporating various features, such as, being eco-friendly, cost-effective, and time-efficient. The ionizing radiation-assisted approach described in this perspective could play a key role, as it inherits these advantages. Some of the exemplary works in this chapter have been summarized to highlight recent developments in the synthesis of Si-based nanomaterials by the most prominent methods as well as their pros and cons. Following this, findings regarding the use of ionizing radiation in the synthesis of Si-based nanomaterials will be presented. In addition, their formation mechanism, the effect of various biocompatible ligands on photoluminescence properties, and possible applications in forensics and biomedicine will also be discussed. Finally, some of the major challenges that must be addressed in view of the imminent commercial use of Si-based nanomaterials are highlighted.