The objective of this research is to conduct the theoretical studies needed to design a microfluidic reactor for synthesizing nanocrystals on an industrial scale, for point-of-use manufacture of nanocrystals, or to probe the processes occurring during their formation. Numerous individual microreactors, including their reagent introduction systems and flow channels, could be contained in a single silicon-on-insulator wafer, allowing parallelization, and unprecedented control and scalability in synthesis and manufacturing. The approach is to employ two immiscible liquids, with a channel geometry that induces spontaneous generation of droplets of one phase dispersed in the other. These droplets will then pass through the reactor with a tightly controlled residence time. Individual zones within the reactor will be heated to promote chemical reactions leading to the nucleation of semiconducting nanocrystals. The nuclei will then flow to other, cooler zones where no further nucleation could occur, but existing nuclei could grow to achieve desired particle characteristics. The first phase of work will be integrated modeling of the chip design, microfluidic phenomena, and nanocrystal formation and evolution. The second will model the stable two-phase flow, and optimize the microreactor flow channel configuration. The third will complete the thermochemical and kinetic description of nanocrystal synthesis, using the model cadmium selenide system, and create a "virtual" reactor.
The research addresses one of the most serious barriers to extending the benefits of the "nanorevolution" to the general public, namely our current inability to manufacture nanocrystals in quantities that are realistic for commercial applications. Without this crucial stepping-stone to manufacturing, the vast amount of fundamental research that has identified innumerable applications of nanocrystals would be wasted. The research will also offer research experiences to historically under-represented engineering undergraduates through the College of Engineering's SUPERB program.
