We will demonstrate that aggregative growth of colloidal semiconductor nanocrystals provides a powerful strategy for tuning nanoparticle shapes. Unlike conventional growth techniques that rely on the reaction of atomic precursors, the present approach employs the coalescence of small-size nanoparticles into larger colloidal structures. The absence of atomic species during aggregative growth prevents shape evolution by monomer precipitation, allowing nanoparticles to transform into a "lowest energy" morphology. With this approach, controlling the shape of nanocrystals is achieved through the use of different reaction environments, which uniquely affect the final particle geometry. This concept is conclusively demonstrated by performing a shape-selective growth of CdX (X = S, Se) cubes, spheres, nanorods, nanorings, and donut-like structures. The aggregative growth mechanism is explained using a thermodynamic model of interacting viscous colloids. We expect that the present growth strategy will provide a viable platform for the shape-selective synthesis of many other types of inorganic colloids, stimulating the discovery of novel optoelectronic properties.

Shape control of colloidal semiconductor nanocrystals through thermodynamically: Driven aggregative growth

ACS Spring 2022

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