Asymmetric Interfacet Adatom Migration as a Mode of Anisotropic Nanocrystal Growth

• DOI: 10.1021/jacs.2c07423
• Publication Date: 2022-10-13T12:42:56Z
• Authors: Paul Z. Chen; Arianna Skirzynska; Tiange Yuan; Oleksandr Voznyy; Frank X. Gu
• Keywords: Vicinal; Nanorod; Supersaturation; Surface diffusion

Crystals are known to grow nonclassically or via four classical modes (the layer-by-layer, dislocation-driven, dendritic, and normal modes, which generally involve minimal interfacet surface diffusion). The field of nanoscience considers this framework interpret how nanocrystals grow; yet, the growth many anisotropic remains enigmatic, suggesting that may be incomplete. Here, we study solution-phase pentatwinned Au nanorods without Br, Ag, surfactants. Lower supersaturation conditions favored growth, appeared at variance with modes. Temporal electron microscopy revealed kinetically limited adatom funneling, as adatoms diffused asymmetrically along vicinal facets (situated inbetween {100} side-facets {111} end-facets) our nanorods. These were perpetuated throughout synthesis and, especially lower supersaturation, facilitated {100}-to-vicinal-to-{111} diffusion. We derived a model from theory in view findings, showed experimental kinetics consistent growing two simultaneously: radial occurred layer-by-layer mode on side-facets, whereas asymmetric diffusion end-facets mediated longitudinal growth. Thus, shape anisotropy was not driven by modulating relative rates monomer deposition different facets, conventionally thought, but rather integration This work shows controlling thermodynamic parameter, can uncover distinct kinetic phenomena nanocrystals, such fundamental for occur facets.