期刊
ACS NANO
卷 6, 期 10, 页码 8599-8610出版社
AMER CHEMICAL SOC
DOI: 10.1021/nn303371y
关键词
In situ fluid; STEM; nanoparticle growth; silver nanoparticles; in situ electron microscopy; classical nucleation theory
类别
资金
- DOE [DE-FG02-03ER46057]
- Presidential Early Career Award for Scientists and Engineers
- UC Lab Fee Program
- UC Academic Senate
- NIH [5RC1GM091755]
- Department of Energy's Office of Biological and Environmental Research
- U.S. Department of Energy [DE-AC05-76RL01830]
Although nanocrystal morphology is controllable using conventional colloidal synthesis, multiple characterization techniques are typically needed to determine key properties like the nucleation rate, induction time, growth rate, and the resulting morphology. Recently, researchers have demonstrated growth of nanocrystals by in situ electron beam reduction, offering direct observations of single nanocrystals and eliminating the need for multiple characterization techniques; however, they found nanocrystal morphologies consistent with two different growth mechanisms for the same electron beam parameters. Here we show that the electron beam current plays a role analogous to the concentration of reducing agent in conventional synthesis, by controlling the growth mechanism and final morphology of silver nanocrystals grown via in situ electron beam reduction. We demonstrate that low beam currents encourage reaction limited growth that yield nanocrystals with faceted structures, while higher beam currents encourage diffusion limited growth that yield spherical nanocrystals. By isolating these two growth regimes, we demonstrate a new level of control over nanocrystal morphology, regulated by the fundamental growth mechanism. We find that the induction threshold dose for nucleation is independent of the beam current, pixel dwell time, and magnification being used. Our results indicate that in situ electron microscopy data can be interpreted by classical models and that systematic dose experiments should be performed for all future in situ liquid studies to confirm the exact mechanisms underlying observations of nucleation and growth.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据