Tomography Study and Growth Control of Spiky Gold Nanoparticles

https://doi.org/10.1002/sstr.202300502 

Abstract

A fundamental understanding of the morphological stability and microstructural characteristics of gold nanoparticles (Au NPs) is crucial for their diverse applications. In this study, spiky Au NPs are prepared by a seed-mediated approach using citrate-capped Au nanospheres as seeds. The morphological and microstructural characteristics of the spiky Au NPs are studied using 3D tomography transmission electron microscopy (TEM) analysis. Twin boundaries in all spikes of the Au NPs are identified by straight lines in the TEM images and specific crystallographic orientations. In addition, the analysis reveals that a careful approach is required when evaluating the morphological characteristics of spiky Au NPs using 2D images. A series of spiky Au NPs with sizes ranging from 62 to 323 nm is prepared by precisely controlling the amount of seed solution and first growth solution added during seed-mediated growth. To elucidate the morphological and microstructural characteristics of the spiky Au NPs, a mechanism for the formation and evolution of the spikes is proposed based on the TEM results.