Silver sulfide quantum dots stabilized with l-Cysteine - Optimization of synthesis in aqueous phase and optical characterization

In this study, we investigate the properties of silver sulfide (Ag₂S) quantum dots (QDs) coated with l-cysteine (L-Cys). We elucidate the formation mechanism of Ag₂S/L-Cys QDs from AgNO₃, Na₂S, and L-Cys through FT-IR, TEM and luminescent analyses. The influence of reaction parameters on the spectroscopic properties, including absorption spectra, emission spectra, fluorescence lifetime, and quantum yield, is thoroughly examined. We propose an optimal fabrication processing by analyzing the properties of QDs throughout the reaction process. Additionally, we demonstrate that 4–6 nm Ag₂S QDs can be effectively imaged using high resolution transmission electron microscopy (HR-TEM) which is particularly beneficial for developing layers incorporating these nanoparticles. Our findings are systematically compared with previous literature, providing a comprehensive understanding of the properties and potential applications of L-Cys coated Ag₂S QDs.