Directed Self-Assembly of Micron-Sized Gold Nanoplatelets into Oriented Flexible Stacks with Tunable Interplate...

A growing demand for control over the interparticle spacing and the orientation of anisotropic metallic particles into self-assembled structures is fuelled by their use in potential applications such as in plasmonics, catalysis, sensing, and optoelectronics. Here, we present an improved high yield synthesis method to fabricate micron- and submicron-sized gold nanoplatelets with a thickness less than 20 nm using silver nanoplatelets as seeds. By tuning the depth of the secondary minimum in the DLVO interaction potential between these particles, we are able to assemble the platelets into dynamic and flexible stacks containing thousands of platelets arranged face-to-face with well-defined spacing. Moreover, we demonstrate that the length of the stacks, and the interplate distance can be controlled between tens and hundreds of nm with the ionic strength. We use a high frequency external electric field to control the orientation of the stacks and direct the stacks into highly organized 2D and 3D assemblies that strongly polarize light.