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Droplet-Based Microfluidic Synthesis of Anisotropic Metal Nanocrystals

Authors

  • Suhanya Duraiswamy,

    1. Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4, E5-02-28, 117576 (Singapore)
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  • Saif A. Khan

    Corresponding author
    1. Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4, E5-02-28, 117576 (Singapore)
    2. Singapore–MIT Alliance 4 Engineering Drive 3, E4-04-10, 117576 (Singapore)
    • Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4, E5-02-28, 117576 (Singapore).
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Abstract

A droplet-based microfluidic method for the preparation of anisotropic gold nanocrystal dispersions is presented. Gold nanoparticle seeds and growth reagents are dispensed into monodisperse picoliter droplets within a microchannel. Confinement within small droplets prevents contact between the growing nanocrystals and the microchannel walls. The critical factors in translating macroscale flask-based methods to a flow-based microfluidic method are highlighted and approaches are demonstrated to flexibly fine tune nanoparticle shapes into three broad classes: spheres/spheroids, rods, and extended sharp-edged structures, thus varying the optical resonances in the visible–near-infrared (NIR) spectral range.

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