2022 Annual Meeting
Multi-Stage Flow Chemistry for Accelerated Quantum Dot Synthesis
Quantum dots (QDs) are a high-performing class of advanced functional materials, exhibiting tunable optical and optoelectronic properties enabled through precise control of their size, morphology, and composition. The size and morphology of QDs, and thereby their optical properties, are governed by their reaction conditions and starting capping ligands. Over the last decade, QDs have been successfully synthesized through hot-injection and heat-up syntheses techniques in batch reactors, resulting in near-unity photoluminescence quantum yields and enhanced photostability. In order to broaden the integration of QDs to a wide set of applications in healthcare, energy and chemical industries, the search for safer, simpler, faster, and more efficient routes for QD syntheses has become a priority in both academia and industry. However, the use of manual flask-based batch synthesis as an experimental exploration platform for exponentially growing synthesis space of QDs is limited by a slow heating and cooling rate, delayed startup and shutdown times, a large reaction time scale, copious resource consumption, and lack or difficulty of in-situ characterization techniques. The search through the synthesis universe of emerging environmentally-friendly QDs can be drastically accelerated using continuous flow chemistry, by performing QD synthesis in flow reactors. Despite decreasing time and chemical consumption by an order of magnitude, there exists a significant gap between the highest reported quality of batch and continuous flow QDs. Consequently, we propose a method for multi-stage QD synthesis, utilizing modular continuous flow microreactors. The modular fluidic platform is designed around a tube-based microreactor library that facilitates the reconfiguration of different stages of QD syntheses. Thus, we are able to expand the available design space of current flow chemistry strategies by the exploration of multiple time-and temperature-to-distance configurations, achieved by precisely tuning the heating profile along each flow reactor module. Further implementation of this modular flow chemistry strategy can greatly accelerate the discovery, development, and manufacturing of QDs relevant to energy, sustainability, and healthcare.