Abstract
Self-assembly of inorganic nanoparticles (NPs) into ordered structures
(“superlattices”) has led to a wide range of nanomaterials with unique optical,
electronic, and catalytic properties. Various interactions have been employed to
direct the crystallization of NPs, including van der Waals forces, hydrogen
bonding, as well as electric and magnetic dipolar interactions. Among them,
Coulombic interactions have remained largely unexplored, owing to the rapid
charge ligand exchange between NPs bearing high densities of opposite
charges. In this talk, I will describe a new method to assemble such “superionic
NPs” under conditions that preserve their native surface charge density. Our
methodology was used to assemble oppositely charged NPs into high-quality
superlattices exhibiting Catalan shapes. The methodology can be applied to a
wide range of charged nanoparticles of various sizes, shapes, and compositions.
I will also discuss two ways to employ electrostatic interactions to assemble NPs
into transient assemblies, whose lifetimes depend on and can be controlled by
the availability of small-molecule ionic “fuels”.