  We report the growth of an unstable shell-like gold structure around
dihexagonal pyramidal CdSe nanocrystals in organic solution and the structural
transformation to spherical domains by two means: i) electron beam irradiation
(in situ) and (ii) addition of a strong reducing agent during synthesis. By
varying the conditions of gold deposition, such as ligands present or the
geometry of the CdSe nanocrystals, we were able to tune the gold domain size
between 1.4 nm to 3.9 nm and gain important information on the role of surface
chemistry in hetero nanoparticle synthesis and seed reactivity, both of which
are crucial points regarding the chemical design of new materials for
photocatalysis and optoelectronic applications.
