Localized surface plasmon controlled chemistry at and beyond the nanoscale

Abstract

Gaining valuable insight into chemistry-related fields, such as molecular and catalytic systems, surface science, and biochemistry, requires probing physical and chemical processes at the sub-nanoscale level. Recent progress and advancements in nano-optics and nano-photonics, particularly in scanning near-field optical microscopy, have enabled the coupling of light with nano-objects using surface plasmons with sub-nanoscale precision, providing access to photophysical and photochemical processes. Herein, this review highlights the basic concepts of surface plasmons and recent experimental findings of tip-assisted plasmon-induced research works and offers a glimpse into future perspectives.

Nanoscale Chemical Probing of Metal-Supported Ultrathin Ferrous Oxide via Tip-Enhanced Raman Spectroscopy and Scanning Tunneling Microscopy

“…While X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) are able to trace chemical reactions, − lack of spatial resolution hinders them from investigating site-specific structure–property relationships. In contrast, tip-enhanced Raman spectroscopy (TERS) enables chemical interrogation at the nano- and even atomic scale by coupling the spatial resolution of STM and the chemical sensitivity of Raman spectroscopy. − TERS has proven its exceptional capacity in exploring the highly localized interfacial properties and interactions of both molecular − and thin-film materials, − which is of significant importance in probing the chemical activities of catalysts . In addition, TERS is sensitive to vertical interfacial interactions at the nanoscale, − which contributes significantly to the understanding of the substrate effect of supported materials.…”

Charge Recognition in Ru(bpy)32+ on a Metal Surface via Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy

“…Tip-enhanced Raman spectroscopy (TERS), a tandem technique of STM with optical spectroscopy, offers a way to enable topographic imaging of single molecules and chemical identification through Raman spectroscopy, simultaneously. 8−18 By confining light at a plasmonically active metallic tip apex (made of Ag or Au) and taking advantage of plasmonenhanced Raman scattering, 19 TERS can investigate nanoscale chemistry ranging from biomolecules, 20−25 two-dimensional materials, 26−30 and catalytic systems 31−36 to molecular selfassembly 37−44 and so forth. Recent high-resolution TERS studies also allow chemical bonds to be resolved and mapped inside a single molecule.…”

Visualizing nanoscale heterogeneity in perylene thin films via tip-enhanced photoluminescence with unsupervised machine learning

“…Sequential or even simultaneously recorded topographic maps may also be readily used to inspect correlations between structure and optical properties on the nanoscale. Even though TERS and TEPL have been amply used to characterize molecular and materials systems, 13–18 these techniques have not been thoroughly explored within nanometer-scale organic semiconductor research, specifically in exciton-supporting molecular thin films. This is the topic of this work.…”