Green Synthesis of Silicon Quantum Dots Using Ocimum basilicum var. Purpurascens as an Organic Reductor Agent

In the present work, the synthesis and characterization of silicon quantum dots (SiQDs) were carried out using a novel approach involving fresh leaf extract of Ocimum basilicum var. purpurascens (OBP) as an organic silicon-reducing agent and 3-Aminopropyltriethoxysilane (APTES) as a precursor. This method offers a promising and sustainable alternative for SiQDs production. The synthesized SiQDs demonstrated water dispersibility, making them suitable for various biotechnological applications. Additionally, an increase in the hydrodynamic diameter of the SiQDs from 1.7 to 2 nm was observed, which can have significant implications in terms of stability and functionality. A notable feature of synthesized SiQDs is their ability to absorb UV radiation. This property can be exploited in photovoltaic applications, such as silicon-based solar cells, where efficient conversion of UV radiation into electrical energy is crucial. Furthermore, a decreasing emission centered at 457 nm (2.71 eV) with chromaticity coordinates from the International Commission on Illumination 1931 (CIE1931) located in the blue region was observed. This indicates that SiQDs have a wide potential for use in high-efficiency light-emitting devices with vibrant colors. To determine the energy gap (Eg) size of the SiQDs, the Tauc method based on experimental absorbance was employed. The results revealed a decrease in Eg from 2.99 eV to 2.97 eV, which is significant in terms of tailoring the optical properties of SiQDs for specific applications.