Development of colloidal nanomaterials has impacted many areas of materials design. There are extensive R&D efforts toward using nanocrystal-based materials in light-emitting devices, electronic circuits, solar cells and other electronic and optoelectronic devices. However, we have very little understanding of dynamic processes that occur at the nanocrystal surface during synthesis and post-synthetic modifications. The field also lacks techniques for in situ monitoring of surface chemistry. We show how electrochemistry can be used to study the surface of colloidal nanocrystals under realistic reaction conditions. We have performed potentiometric titrations of CdSe quantum dots and nanoplatelets at different temperatures in polar and non-polar media, quantified the affinity of ligands to the nanocrystal surface, and studied reaction kinetics at nanocrystal surface. This study showed that potentiometry is a powerful technique to measure the active surface area of nanocrystals of different size and shape in solution, to probe the reaction dynamics, and to determine the affinity of the ligands to the surface. Moreover, potentiometry can provide real time feedback during SILAR synthesis of core-shell nanostructures.

Probing surface of colloidal nanocrystals with potentiometry

248th National Meeting (2014)

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