The role of ad-atoms in the coalescence of alkanethiol-passivated gold nanoparticles

C. GUTIERREZ-WING; JIMENA A. OLMOS ASAR; R. ESPARZA; MARCELO M MARISCAL; MIGUEL JOSE YACAMAN

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2013 vol. 101 p. 301 - 301

span data-reactid=".0.1.0.4.1.0" class="foldable-text" id="yui_3_14_1_1_1444932331873_1548">In the present work we show how the role of ad-atoms and surface imperfections play a key role during the coalescence of thiol-passivated Au nanoparticles (NPs) below 4 nm in diameter. Using spherical aberration corrected scanning transmission electron microscopy (STEM) with ultra-high resolution and computer simulations we reveal the main structural and energetic changes throughout the diffusion/migration of surface atoms during coalescence of monolayer-protected NPs. The sintering process of nanoparticles with similar size (diameter) follows a neck-formation mechanism. However, in the case of thiol-protected Au NPs with different size (i.e. with dissimilar surface curvature) the Ostwald ripening mechanism has been detected with atomic resolution in situ STEM measurements for the first time