Seed mediated growth of gold nanorods: towards nanorod matryoshkas

After a brief review of anisotropy on the nanoscale, experiments in which nanorod core–shell–shell particles are grown are presented. These “nanomatryoshkas” consist of a gold nanorod core, a silica shell, and a final gold shell. Calculation of the near-field properties of these structures using the discrete dipole approximation uncovers the change in location of local electric fields upon gold outer shell growth. Electrochemical experiments of the weak reducing agents used to grow the gold nanorod cores suggest a correlation between the strength of the reducing agent and its ability to promote longer nanorod growth. The final nanostructures do not exhibit a smooth outer shell, unlike their spherical counterparts.