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From Gold Nanoseeds to Nanorods: The Microscopic Origin of the Anisotropic Growth
Author(s) -
Meena Santosh Kumar,
Sulpizi Marialore
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201604594
Subject(s) - nanorod , pulmonary surfactant , chemical physics , anisotropy , nanotechnology , passivation , materials science , nanometre , chemical engineering , nanoparticle , layer (electronics) , metal , nanostructure , chemistry , physics , optics , metallurgy , composite material , engineering
Directly manipulating and controlling the size and shape of metal nanoparticles is a key step for their tailored applications. In this work, molecular dynamics simulations were applied to understand the microscopic origin of the asymmetric growth mechanism in gold nanorods. Different factors influencing the growth were selectively included in the models to unravel the role of the surfactants and ions. In the early stage of the growth, when the seed is only a few nanometers large, a dramatic symmetry breaking occurs as the surfactant layer preferentially covers the (100) and (110) facets, leaving the (111) facets unprotected. This anisotropic surfactant layer in turn promotes anisotropic growth with the less protected tips growing faster. When silver salt is added to the growth solution, the asymmetry of the facets is preserved, but the Br − concentration at the interface increases, resulting in increased surface passivation.