Multiscale Engineering of Plasmonic Nanocubes for Tunable Light–Matter Interactions

Precise control of light–matter interactions at the nanoscale is essential for advancing quantum, photonic, and energy conversion technologies. Here, we present a multiscale approach to engineering gold nanocube (AuNC) architectures as versatile building blocks for tunable nanophotonic materials. A centrifugal depletion–induced flocculation process enables exceptional purification efficiency, yielding ultrahigh recoveries of uniform nanocubes within minutes. When nanoparticle imprinting is applied using these nanocubes as building blocks, the resulting structures exhibit well-ordered AuNC lattices. Within this platform, we exploit two distinct length scales: locally, tight plasmon coupling within the interparticle gaps generates intensely confined near fields; globally, the periodic array couples this localized resonance to lattice diffraction, producing narrow, high-quality surface lattice resonances. Together, these two complementary studies expand the design space of plasmonic nanocube systems for quantitative spectroscopy, ultrasensitive sensing, and integrated nanophotonics.