Manipulating 3-D Nanoparticle Assembly to Tune Optical Properties of Lamellar Nanocomposite Thin Films

Well-defined metal nanoparticles (NPs) assemblies exhibiting unique collective optical properties are promising candidates for metamaterials. Tailoring the coupling between the collective electron oscillations confined within individual NPs opens up a new way for comprehensive manipulation of light at nanoscale. The current challenge is how to rapidly fabricate large-scale hierarchical NP assemblies while maintaining precise control of inter-particle coupling in three-dimension (3-D). Here, we report a method to rapidly fabricate 3-D NP assemblies in lamellar supramolecular thin films by solvent vapor annealing and fast solvent removal, which efficiently decrease the lamellar periodicity and hence promotes strong coupling of the induced particle plasmon resonance. We found that films compromising 3-D array of 12 nm Au NPs exhibit pronounced optical anisotropy due to the presence of strong plasmonic coupling, which is in clear contrast to the films with 3 nm Au NPs featuring trivial plasmon coupling. This work presented an approach for scalable nanomanufacturing of optical metamaterials that fully exploiting 3-D coupling phenomena.