Microfluidic-Based Nanocrystal Synthesis—Towards Ultra-Fast Parametric Space Mapping

Recent years have seen considerable progress in the development of microfluidic systems for use in the chemical and biological sciences. At a primary level, interest in such systems has been stimulated by the fact that physical processes can be more easily controlled and harnessed when instrumental dimensions are reduced to the micron scale. For example, it is well recognized that when compared to macroscale instruments, microfluidic systems engender a number of distinct advantages with respect to speed, analytical throughput, reagent usage, process control and operational/configurational flexibility. Put simply, microfluidic systems define new operational paradigms and provide predictions about how molecular synthesis and analysis might be revolutionized.
 
Nanomaterials exhibit optical and electronic properties that depend on their size and shape, and are seen as tailored precursors for functional materials. These critical dependencies indicate that ‘bottom-up’ approaches for nanomaterial synthesis must provide for fine control of the physical dimensions of the final product. Synthetic routes have attracted significant interest owing to their versatility and ease of use, but for most applications deviations about the mean particle diameter must be <1%. This is beyond the tolerance of standard macroscale syntheses, and it is almost always necessary to post-treat to extract the desired particle size. Conversely, microfluidic systems provide an ideal medium for nanoparticle production. Since both mass and thermal transfer are rapid, temperatures may be defined with precision and reagents rapidly mixed to ensure homogeneous reaction environments. I will describe how we have utilized microfluidic reactors for highly efficient nanomaterial synthesis. This discussion will include autonomous ‘black-box’ systems for the controlled synthesis of nanoparticles, such as CdSe, ZnS, ZnSe and CdSeTe. I will also discuss how droplets can be used for the synthesis of high-quality Cesium Lead Halide Perovskite nanocrystals on short timescales.
 
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Bio: Andrew deMello is currently Professor of Biochemical Engineering in the Department of Chemistry & Applied Biosciences at ETH Zürich. Prior to this, he was Professor of Chemical Nanosciences and Head of the Nanostructured Materials and Devices Section in the Chemistry Department at Imperial College London. He obtained a first-class degree in Chemistry and Ph.D. in Molecular Photophysics from Imperial College London and subsequently held a Postdoctoral Fellowship in the Department of Chemistry at the University of California, Berkeley, working with Professor Richard Mathies. His current research interests cover a broad range of activities in the general area of microfluidics and nanoscale science.