nl5b00140_si_001.pdf (2.64 MB)
Unravelling Kinetic and Thermodynamic Effects on the Growth of Gold Nanoplates by Liquid Transmission Electron Microscopy
journal contribution
posted on 2015-04-08, 00:00 authored by Damien Alloyeau, Walid Dachraoui, Yasir Javed, Hannen Belkahla, Guillaume Wang, Hélène Lecoq, Souad Ammar, Ovidiu Ersen, Andreas Wisnet, Florence Gazeau, Christian RicolleauThe
growth of colloidal nanoparticles is simultaneously driven by kinetic
and thermodynamic effects that are difficult to distinguish. We have
exploited in situ scanning transmission electron microscopy in liquid
to study the growth of Au nanoplates by radiolysis and unravel the
mechanisms influencing their formation and shape. The electron dose
provides a straightforward control of the growth rate that allows
quantifying the kinetic effects on the planar nanoparticles formation.
Indeed, we demonstrate that the surface-reaction rate per unit area
has the same dose-rate dependent behavior than the concentration of
reducing agents in the liquid cell. Interestingly, we also determine
a critical supply rate of gold monomers for nanoparticle faceting,
corresponding to three layers per second, above which the formation
of nanoplates is not possible because the growth is then dominated
by kinetic effects. At lower electron dose, the growth is driven by
thermodynamic and the formation and shape of nanoplates are directly
related to the twin-planes formed during the growth.