DNA‐Encoded Gold‐Gold Wettability for Programmable Plasmonic Engineering

Abstract

AbstractControlling the deposition and diffusion of adsorbed atoms (adatoms) on the surface of a solid material is vital for engineering the shape and function of nanocrystals. Here, we report the use of single‐stranded DNA (oligo‐adenine, oligo‐A) to encode the wettability of gold seeds by homogeneous gold adatoms to synthesize highly tunable plasmonic nanostructures. We find that the oligo‐A attachment transforms the nanocrystal growth mode from the classical Frank‐van der Merwe to the Volmer‐Weber island growth. Finely tuning the oligo‐A density can continuously change the gold‐gold contact angle (θ) from 35.1±3.6° to 125.3±8.0°. We further demonstrate the versatility of this strategy for engineering nanoparticles with different curvature and dimensions. With this unconventional growth mode, we synthesize a sub‐nanometer plasmonic cavity with a geometrical singularity when θ>90°. Superfocusing of light in this nanocavity produces a near‐infrared intraparticle plasmonic coupling, which paves the way to surface engineering of single‐particle plasmonic devices.