An advanced centrifugal microsystem toward high-throughput multiplex colloidal nanocrystal synthesis

An advanced centrifugal microsystem is developed which has capability of automatic and programmed chemical reagent loading and reactions to screen the colloidal nanocrystal synthesis in a high-throughput manner. As a proof of concept, triplicate synthetic reactions for water-soluble multi-color CdS nanocrystals are executed under ten different conditions on a chip. The proposed disk-shaped microdevice contains a top layer for distributing the reagents through zig-zag continuous channels and a bottom layer for 30 functional units, each of which is composed of a reaction chamber and three reservoirs connected with a control, a precursor, and a basic solution, respectively. All the reservoirs are linked to the main channel via different microfluidic channel dimension, and the main channel is directed to the reaction chamber. Through rotational speed control, the three solutions are sequentially loaded to the reaction chamber with precise volume, and the multiplex CdS nanocrystals synthesis is processed. By tuning the concentration of sulfur in a control solution, multi-color CdS nanocrystals are produced from green to red depending on the molar ratios of Cd²⁺ to S^2-.