Superlattice Engineering with Chemically Precise Molecular Building Blocks.

Abstract

Correlating nanoscale building blocks with mesoscale superlattices, mimicking metal alloys, a rational engineering strategy becomes critical to generate designed periodicity with emergent properties. For molecule-based superlattices, nevertheless, nonrigid molecular features and multistep self-assembly make the molecule-to-superlattice correlation less straightforward. In addition, single component systems possess intrinsically limited volume asymmetry of self-assembled spherical motifs (also known as "mesoatoms"), further hampering novel superlattices' emergence. In the current work, we demonstrate that properly designed molecular systems could generate a spectrum of unconventional superlattices. Four categories of giant molecules are presented. We systematically explore the lattice-forming principles in unary and binary systems, unveiling how molecular stoichiometry, topology, and size differences impact the mesoatoms and further toward their superlattices. The presence of novel superlattices helps to correlate with Frank-Kasper phases previously discovered in soft matter. We envision the present work offers new insights about how complex superlattices could be rationally fabricated by scalable-preparation and easy-to-process materials.