Mapping Molecular Adsorption Configurations with <5 nm Spatial Resolution through Ambient Tip-Enhanced Raman Imaging.

We interrogate -mercaptobenzoic acid (MBA) molecules chemisorbed onto plasmonic silver nanocubes through tip-enhanced Raman (TER) spectral nanoimaging. Through a detailed examination of the spectra, aided by correlation analysis and density functional theory calculations, we find that MBA chemisorbs onto the plasmonic particles with at least two distinct configurations: S- and CO-bound. High spatial resolution TER mapping allows us to distinguish between the distinct adsorption geometries with a pixel-limited (<5 nm) spatial resolution under ambient laboratory conditions.

Effects of Size and Structural Defects on the Vibrational Properties of Lanthanum Hexaboride Nanocrystals.

Lanthanum hexaboride (LaB) is notable for its thermionic emission and mechanical strength and is being explored for its potential applications in IR-absorbing photovoltaic cells and thermally insulating window coatings. Previous studies have not investigated how the properties of LaB change on the nanoscale. Despite interest in the tunable plasmonic properties of nanocrystalline LaB, studies have been limited due to challenges in the synthesis of phase-pure, size-controlled, high-purity nanocrystals without high temperatures or pressures.