Microfluidic Synthesis of Semiconducting Colloidal Quantum Dots and Their Applications

The large-scale synthesis of high-quality quantum dots (QDs) for commercial applications, such as lighting, displays, and biomedical devices, is an urgent necessity. Batch reactor systems present a number of problems, such as improper mixing, heating, and reagent addition. Hence, controlling the growth and size of nanocrystals is difficult in this type of system. A number of microfluidic techniques have been developed to enable semiconductor colloidal QD synthesis. The reaction parameters of these techniques are controlled precisely during synthesis. Over the last 16 years, many advancements have been introduced to achieve products similar to those obtained from batch systems. Multiphase flow reactors reduce reactor fouling by using immiscible carrier liquids, which decrease the contact between reagents and the channel wall. Online monitoring of the nanocrystal growth through absorbance and fluorescence spectrometry provides detailed information on the reaction parameters. Chip-based reactors with subchannels decrease backflow and control the addition of reagents. In this review, we discuss all aspects and developments in microfluidic systems for the production and applications of QDs.