Kinetic Control of Morphological Evolution in Tellurium Nanocrystals via Sequential Surfactant Addition

High Resolution Image Download MS PowerPoint Slide Colloidal tellurium nanocrystals (NCs) typically crystallize as chiral bipyramids when grown in the presence of chiral penicillamine molecules, or as high aspect-ratio (AR) nanowires when grown with sodium dodecyl sulfate (SDS), representing two distinct morphological extremes. Here, we demonstrate a method for the kinetic control of tellurium NC morphologies by transitioning between the growth regimes of chiral-shaped bipyramids and achiral-shaped nanowires. By introducing SDS at varying time intervals into a penicillamine-mediated synthesis, we redirect the growth from a three-dimensional habit to an axial mode, resulting in elongated chiral nanorods that retain the characteristic chiral geometry while achieving high ARs. Circular dichroism peak magnitude is a direct function of this temporal window, with stronger chiroptical signals observed for longer SDS addition delays. X-ray photoelectron spectroscopy analysis indicates that the final NC surface coverage is dominated by SDS, with negligible penicillamine concentration, suggesting that the penicillamine’s influence is limited to early growth stages. Hence, penicillamine imprints NC handedness during nucleation, after which the added SDS densely packs on low-curvature prismatic facets to block lateral monomer addition, while high-curvature pyramidal facets remain accessible for axial growth. This sequentially added cosurfactant strategy provides a versatile framework for synthesizing nanostructures with unique morphologies.