One Pot Green Synthesis of Si Quantum Dots and Catalytic Au Nanoparticle–Si Quantum Dot Nanocomposite

We report a simple, green, and room temperature synthetic route for the formation of Si quantum dots (Si QDs) and Au nanoparticle–Si quantum dot (Au NP-Si QD) nanocomposites. Glucose was used as a reductant for one-pot synthesis of water-dispersible blue emitting Si QDs. The use of simple biomolecules for the generation of functional hybrid materials is of great significance for both economic and environmental benefits. The as prepared Si QDs have an average size of 2.7 nm with emission maximum at 467 nm. These Si QDs showed a reversible thermoresponsive emission in the temperature range of 20–80 °C in water and excellent salt tolerance enabling the QDs to be extremely suitable for biomolecular functionalization and use as probes for biological fluorescence imaging. Further, the as prepared hydrophilic Si QDs have been exploited as a reduction reagent to reduce Au3+ ions to Au NPs. The Si QDs also functioned as an effective stabilizer by forming a thin layer over the Au NPs leading to the formation of Au NP-Si QD nanocomposite. This composite material was found to exhibit catalytic activity to reduce nitroarenes. Such multifunctional hybrid nanomaterials are potential candidates for photocatalysis, bioimaging, and sensing applications.