Controlling Optically Driven Atomic Migration Using Crystal-Facet Control in Plasmonic Nanocavities

Abstract

Plasmonic nanoconstructs are widely exploited to confine light for applications ranging from quantum emitters to medical imaging and biosensing. However, accessing extreme near-field confinement using the surfaces of metallic nanoparticles often induces permanent structural changes from light, even at low intensities. Here, we report a robust and simple technique to exploit crystal facets and their atomic boundaries to prevent the hopping of atoms along and between facet planes. Avoiding X-ray or electron microscopy techniques that perturb these atomic restructurings, we use elastic and inelastic light scattering to resolve the influence of crystal habit. A clear increase in stability is found for {100} facets with steep inter-facet angles, compared to multiple atomic steps and shallow facet curvature on spherical nanoparticles. Avoiding atomic hopping allows Raman scattering on molecules with low Raman cross-section while circumventing effects of charging and adatom binding, even over long measurement times. These nanoconstructs allow the optical probing of dynamic reconstruction in nanoscale surface science, photocatalysis, and molecular electronics.

Hybrid photonic-plasmonic cavities based on the nanoparticle-on-a-mirror configuration

“…17(c) and 17(d), we show the results for the LDOS, Q factor, and V corresponding to the bare nanocube and nanoellipse, respectively. Metal nanocubes, which like nanospheres can be easily built by chemical procedures, are also able to play the role of the plasmonic particle in NPoM configurations [37,50]. Remarkably, the results in terms of Q and V are similar to the case of the nanosphere previously presented in Fig.…”

Tracking interfacial single-molecule pH and binding dynamics via vibrational spectroscopy

“…Similar signals are achieved using a nanocube-on-mirror (NCoM) (80 nm) geometry (Fig. 1B, green) (40).…”

“…1A and fig. S1) (40). Even with the enhancement provided by this nanocavity, the low SERS cross section of MPA limits the speed of observations to tens of seconds (Fig.…”

Spectrally Resolved Surface-Enhanced Raman Scattering Imaging Reveals Plasmon-Mediated Chemical Transformations

“…Current theories regarding the SIFs at a single-nanoparticle level implicate the surface roughness of the single nanoparticle formed by protrusions and adatoms. 37 , 40 , 52 These atomic dislocations have been called “picocavities”, 53 which support highly confined intense electromagnetic fields in very small volumes. 54 It has been suggested that these intense fields can generate strong plasmonic enhancement effects that alter the symmetry of adsorbed molecules, altering the observed spectrum.…”