Synthesis of Silver Sulfide Quantum Dots Via the Liquid-Liquid Interface Reaction in a Rotating Packed Bed Reactor

We developed the high-gravity coupled liquid-liquid interface reaction technique on the basis of the rotating packed bed (RPB) reactor for the continuous and ultrafast synthesis of silver sulfide (Ag2S) quantum dots (QDs) with near-infrared (NIR) luminescence. The formation of Ag2S QDs occurs at the interface of microdroplets, and the average size of Ag2S QDs was 4.5 nm with a narrow size distribution. Ag2S QDs can disperse well in various organic solvents and exhibit NIR luminescence with a peak wavelength at 1270 nm under 980-nm laser excitation. The mechanism of the process intensification was revealed by both the computational fluid dynamics simulation and fluorescence imaging, and the mechanism is attributed to the small and uniform droplet formation in the RPB reactor. This study provides a novel approach for the continuous and ultrafast synthesis of NIR Ag2S QDs for potential scale-up.