Organic–inorganic hybrid silica systems: synthesis strategies and optical applications

The integration of organic components into inorganic silica systems through sol–gel synthesis has significantly expanded the potential applications of these materials by enhancing features such as transparency, crack resistance, flexibility, and the introduction of new functional groups. Understanding the influence of organic groups on the sol–gel process and exploring various approaches to crafting organic-inorganic hybrid (OIH) silica systems are essential endeavors. This review aims to provide a comprehensive guide, particularly targeted towards researchers new to OIH synthesis. It delineates the key parameters of the sol–gel process, presents five distinct synthesis strategies, and provides exemplary applications. Beyond traditional methods like co-condensation with organoalkoxysilanes and bridged-organoalkoxysilanes, alternative strategies are elucidated, including biopolymer functionalization, photopolymerization enabling 3D printing, and utilization of polyhedral oligomeric silsesquioxanes (POSS). Furthermore, recent literature exploration has uncovered promising optical applications for OIH materials. These materials serve as excellent hosts for luminophores due to their inherent transparency and the synergistic interactions between the organic functional groups and luminophores, which can enhance properties such as quantum yield, particularly with lanthanides, and even improve the photochromic performance of polyoxometalates. Consequently, OIH materials find extensive utilization in optical technologies, encompassing luminescent solar concentrators, light-emitting diodes, photochromism, random lasers, optical sensing, and various optical components, as we aim to demonstrate comprehensively herein.