Free-Standing Polymer–Nanoparticle Superlattice Sheets Self-Assembled at the Air–Liquid Interface

We report on a generic approach to use polymers as ligands to fabricate the free-standing, monolayered nanoparticle superlattice sheets based on drying-mediated, entropy-driven self-assembly at the air–liquid interface. Such superlattice nanosheets are the thinnest possible two-dimensional crystals whose structural features and functional properties can be adjusted by tailoring the sizes of their nanoparticle constituents. The monolayered superlattice nanosheets are highly stable under various conditions, transferable to any arbitrary substrates, and can be manufactured with focused ion beams. This demonstrates the potential to integrate the superlattice nanosheets into miniaturized optical and electronic devices.