Growth Kinetics of Individual Au Spiky NanoparticlesUsing Liquid-Cell Transmission Electron Microscopy

A precise control over size and morphology of the Au spiky nanoparticle (SNP) is essential to obtain narrow and tunable surface plasmon resonance (SPR). However, these challenges require a fundamental understanding of the particle growth mechanism and kinetics, as well as its morphological transition, which can only be achieved by real time observation at nanometer resolution. Here, we report in situ liquid cell transmission electron microscopy studies of single and multiple Au SNP growth at various conditions of such parameters as size and dose rate of electron beam, and HAuCl4 solution concentration. The particle evolves via a mixture of reaction and Au formation-limited growth, followed by Au formation-limited growth ‒ a transition from facetted to roughened surfaces, confirmed by the analysis with different beam sizes and the UV-vis spectra that feature a unique trend of short and long wavelength plasmon band shift. Quantitative analyses combined with a theoretical model determine the transition time ...