Coreshell nanostructure is a popular structural scheme for
enhancing the chemical and colloidal stability of nanoparticles
(NPs) and for preventing the dissociation of their surface ligands.1 In
particular, silica has advantages as a shell material for its chemical
inertness, optical transparency, porous structure, and size-selective
permeability.2
The St€ober method has attracted much interest forthe
scalable fabrication of silica shells on NPs via the facile hydrolysis of
tetraethyl orthosilicate (TEOS).3 While the direct analysis of the
resulting nanoscale silica shells is difficult, it is generally believed that
the complete hydrolysis of TEOS and the subsequent condensation
of silicic acid give a network of tetrahedral SiO4 units with shared
vertices. As such, the silica shells are expected to be uniform and
robust, though their uniformity has rarely been explored